3QLCLM POWER CHUCKS - FORKARDT Inc....Table of contents 3QLCLM Edition: 04/2014 6 2.0 Safety instructions 2.1 General information Power chucks may result in risks if their use and

3QLCLM

POWER CHUCKS

GERMAN O P E R A T I N G M A N U A L

Table of contents

3QLCLM

Edition: 04/2014

2

Table of contents

1.0 General information about the documentation ................................................................................................. 4

1.1 General information ................................................................................................................................. 4

1.2 Explanation of symbols ............................................................................................................................. 5

1.3 Copyright ................................................................................................................................................... 5

2.0 Safety instructions ............................................................................................................................................ 6

2.1 General ..................................................................................................................................................... 6

2.2 Intended use ............................................................................................................................................. 7

2.3 Operating instructions ............................................................................................................................... 8

2.4 Maintenance and repair ............................................................................................................................. 8

2.5 Safety conditions for power chucks ........................................................................................................... 9

2.6 Notes ......................................................................................................................................................... 9

3.0 Transport and storage .................................................................................................................................... 10

3.1 Packaging, disassembly level ................................................................................................................. 10

3.2 Transport, handling and storage ............................................................................................................. 10

4.0 Design and function ...................................................................................................................................... 11

4.1 General description ............................................................................................................................... 11

4.2 Constructive design ................................................................................................................................. 12

4.2.1 Technical data / main dimensions - power chuck type 3QLCLM ..................................................... 12

4.2.2 Design of power chuck .................................................................................................................... 14

4.2.2.1 Chuck complete ........................................................................................................................... 14

4.2.2.2 Centrifugal force accessories ..................................................................................................... 14

4.2.2.3 Body complete ............................................................................................................................. 15

4.2.2.4 Chuck cover complete.................................................................................................................. 16

4.2.2.5 Jaw complete ............................................................................................................................... 17

4.3 Function of the power chuck ................................................................................................................... 18

4.3.1 General information: ...................................................................................................................... 18

4.3.2 Centrifugal force compensation ..................................................................................................... 19

4.3.3 Lubrication ..................................................................................................................................... 19

4.3.4 Sealing of the power chuck ............................................................................................................. 19

4.4 Chuck jaw .............................................................................................................................................. 20

4.4.1 General information ......................................................................................................................... 20

4.4.2 Safety instructions for top jaws ...................................................................................................... 20

4.5 General safety instructions......................................................................................................................... 21

5.0 Clamping force .............................................................................................................................................. 22

5.1 General information ................................................................................................................................. 22

5.2 Clamping force FSp0 ................................................................................................................................ 22

5.3 Dynamic gripping force .......................................................................................................................... 23

5.4 Clamping force calculation ..................................................................................................................... 24

5.5 Determination of gripping force Fspz required for the machining process ............................................. 26

5.6 Permissible extension length ................................................................................................................. 28

6.0 Assembly ...................................................................................................................................................... 29

6.1 Actions to be taken before assembly ..................................................................................................... 29

6.1.1 Checking the spindle head for mounting the chuck flange ................................................................. 29

6.1.2 Checking the mounted chuck flange .................................................................................................. 29

6.1.3 Adjustment of the drawbar ................................................................................................................... 30

6.1.4 Adjustment of the drawbar ................................................................................................................... 31

6.2 Assembly of the power chuck .................................................................................................................. 32

6.3 Procedure for assembling the power chuck ........................................................................................... 32

6.4 Tightening torques of shaft screws ........................................................................................................ 34

6.4.1 Tightening torques of the chuck mounting screws: ............................................................................ 34

6.4.2 Torque of the jaw mounting screws ..................................................................................................... 34

6.5 Preparations for using the power chuck ................................................................................................ 36

6.6 Safety instructions ................................................................................................................................. 36

Table of contents

3QLCLM

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7.0 Initial operation ................................................................................................................................................ 37

7.1 Notes ....................................................................................................................................................... 37

7.2 Initial operation, operation ........................................................................................................................ 38

7.3 Unauthorized operating modes ................................................................................................................ 38

7.4 Safety instructions .................................................................................................................................. 38

7.5 Behavior in case of faults ......................................................................................................................... 38

7.6 Measures during longer standstill ............................................................................................................ 39

7.7 Measures after longer standstill ............................................................................................................... 39

7.8 Oil selection ............................................................................................................................................. 40

8.0 Maintenance ................................................................................................................................................... 41

8.1 Lubrication .............................................................................................................................................. 41

8.2 Maintenance plan ................................................................................................................................... 42

8.3 Disassembly of the power chuck .............................................................................................................. 42

9.0 Spare parts and customer service ................................................................................................................. 46

9.1 Spare parts ............................................................................................................................................. 46

9.2 Tools and accessories ............................................................................................................................ 46

9.3 Customer service ................................................................................................................................... 47

10.0 Declaration of incorporation ......................................................................................................................... 48

Table of contents

3QLCLM

Edition: 04/2014

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1.0 General information about the documentation

1.1 General information

This operating manual contains the required information for the intended use of 3-jaw power chuck with

balancing of centrifugal force type 3QLCLM. The manual is meant for technically qualified persons.

Qualified persons are:

• Persons, who are trained in handling of the power chuck as operating staff.

• Persons, who as commissioning and service staff possess educational qualification

required for commissioning and repair.

The instructions in this operating manual must be read and understood completely for

the operation, maintenance and repair of the power chuck.

We reserve the right to make technical changes necessary to improve the power chuck which may

result in deviations from the illustrations and information contained in this manual. This operating

manual may not be reproduced or copied, either in full or in part, utilized for the purposes of competition.

FORKARDT DEUTSCHLAND GMBH retains the copyright for this operating

manual.

The operating manual, prepared based on DIN V 8418, must be read, understood and followed by the

responsible operating staff.

Important details for the use of power chuck are pointed out in this operating manual. Faults in the

power chucks can be prevented and a trouble-free operation can be guaranteed only with the

knowledge of this operating manual.

• We would like to point out that we are not liable for damages and operational interruptions,

which may result from non-compliance of the operating manual.

• Please contact our customer service department if you still have any difficulties and they will be

happy to help you. Customer service - see corresponding section.

• This operating manual only refers to power chuck

Type 3QLCLM

• We reserve the right to make technical changes necessary to improve the power chuck, Type

3QLCLM, which may result in deviations from the illustrations and information contained in this

manual.

Table of contents 3QLCLM

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1.2 Explanation of symbols

Safety instructions for preventing mortal hazards or material damages are highlighted in this operating

manual through the key terms and pictograms.

Indicates possible hazard. Death, severe bodily injury or significant material damages

can occur if the precautionary measures are not taken or if the safety instructions are

not followed.

Indicates an important information to prevent material damages or unwanted

operational states.

Indicates an important information for handling or additional information.

1.3 Copyright

This operating manual is meant for the assembly, operating and monitoring staff. It contains

specifications and drawings of technical nature, which may not be copied, reproduced, either in full or in

part, or utilized for the purposes of competition without authorization.

The company retains the copyright for this operating manual.

FORKARDT DEUTSCHLAND GMBH

Lachenhauweg 12

72766 Reutlingen

Germany

Telephone: +49 7127 5812 0

Fax: +49 7127 5812 122

Administration and central warehouse: Lachenhauweg 12, 72766 Reutlingen

Made in Germany

© 2014 COPYRIGHT FORKARDT DEUTSCHLAND GMBH


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2.0 Safety instructions

2.1 General information

Power chucks may result in risks if their use and handling does not correspond to the safety

requirements. The power chuck has been built based on state-of-the-art technology and is safe to use.

However, the power chuck can pose certain risks if it is used improperly or not as intended by

unqualified personnel.

The following instructions are meant for personal safety and prevention of damages to the described

product or connected devices.

Read this operating manual before starting work with the power chuck and follow all safety

instructions. Non-compliance with the instructions contained in this manual may result in

mortal danger, severe bodily injury or severe material damages.

• Only qualified staff are allowed to work with the power chuck.

• Unauthorized modifications and changes to the power chuck are not allowed.

• Use the power chuck only in perfect condition.

• Switch off the machine before working on the chuck and secure the machine

against unintentional restart.

• Only use original components and spare parts of the manufacturer. Warranty shall

not be applicable if foreign parts are used.

• Before starting work with the power chuck, check whether all safety equipment are mounted

• The system "lathe-clamping device-work piece" is mainly influenced by the work piece to be

produced, which may result in a residual risk. This residual risk must be evaluated by the

operating company.

The manufacturer is not liable for damages resulting from non-compliance with the

operating manual!


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2.2 Intended use

The 3-jaw power chuck with centrifugal force compensation of Type 3QLCLM is engaged through a

rotary double piston clamping cylinder. Its axial actuating force must be suitable for the power chuck.

The power chuck 3QLCLM must be used only for its intended purpose. Intended use is the

clamping of work pieces on lathes and other tooling machines.

The maximum gripping force and maximum speed of the chuck must not exceeded. The permissible

speed or the required gripping force must be determined for the application in accordance with the

applicable technical rules (e.g. VDI 3106). In case of doubt or accessories not provided by the

manufacturer, the threshold values must be approved by the manufacturer or redefined.

The following factors must be taken into consideration:

• Variable friction coefficient between work piece and top jaw

• Proportion of clamping diameter and working diameter

• Magnitude of the cutting force on the cutting tool

• Swing of the top jaw from the clamping point

• Decrease of the gripping force through centrifugal force due to external clamping

Even adherence to the assembly, commissioning, operating and repair conditions prescribed by the

manufacturer are part of intended use. Any and all other usage is considered improper use. The

manufacturer cannot accept liability for damage resulting from such use.


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2.3 Operating instructions

Rotary clamping devices must be secured with suitable covering hood or safety door before touching

in accordance with the regulations of the trade associations.

The machine must be stopped immediately in case of any faults in the power chuck

during operation. It can be operated again only if the fault is fixed.

After switching off clamping energy, loosen the work piece from the power chuck. The local safety

provisions and accident prevention regulations of the respective trade associations in their applicable

version are applicable for the operation of the power chuck.

2.4 Maintenance and repair

In case of maintenance work or inspection work on the power chuck, stop the machine and switch off

power supply to the clamping cylinder.

The power chuck is exposed to high loads when it is subject to speeds that are normal on rotary

machines. In case of occasional collisions between the tool and power chuck, e.g. faults in program

sequence, the power chuck can be damaged.

After a collision stop the lathe immediately and check the power chuck for damages. In

addition to easily identifiable damages, the tool may also have hidden damages such as

hairline cracks in the chuck head and damages to the sealing elements.

Check the affected parts of the power chuck in such case with a suitable and non-destructive test

method and check for cracks and replace the chuck in case of any damage.

Only use original FORKARDT spare parts.


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2.5 Safety conditions for power chucks

The safety conditions for the operation of power chucks are defined in the testing principles of the trade

associations as well as DIN, VDE and VDI guidelines. The individual test conditions are guaranteed

through following measures:

Test conditions guaranteed by

The machine spindle can start only when the

complete clamping pressure is built up in the

clamping cylinder

1. Pressure switch in the clamping lines2. Pressure indicator manometer

The machine spindle can start only if the tension is

in the permissible range of the jaw stroke

chucking stroke monitoring on the actuation

cylinder through electrical limit switch.

The clamping can be released only when the

machine spindle is stationary

Standstill monitoring at the

machine spindle

The work piece remains clamped up to spindle

standstill if there is failure of clamping energy

Non-return check valve in the actuation

cylinder

There will not be any change to the switch position

in case of electricity failure and return

Impulse-controlled way valve with

locked end positions

A signal will be sent for automatic or manual

spindle stop in case of failure of clamping energy

Pressure switch in the clamping line

2.6 Instructions

The operating manual, prepared based on DIN V 8418 and DIN EN 292, must be read, understood and

followed by the responsible operating staff.

Important details for the use of power chuck are pointed out in this operating manual. Faults in the

power chucks can be prevented and a trouble-free operation can be guaranteed only with the

knowledge of this operating manual.

We would like to point out that we are not liable for damages and operational interruptions, which may

result from non-compliance of the operating manual.

Please contact our customer service department if you still have any difficulties and they will be happy

to help you.


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3.0 Transport and storage

3.1 Packaging, disassembly level

The weight of the product and transport route are also decisive for the packaging type. The power

chuck are wrapped in oil paper or clear foil to protect against dirt.

Power chuck up to size of 315 mm 0:

- Packaging in folding cartons, with corresponding padding or - in case of longer transport route - by

filling the folding carton with foam.

Power chuck up to size of 400 mm 0:

- Packaging in wooden crates, with suitable filler material (e.g. Styrofoam chips) and with the

inclusion of accessories such as top jaws and chuck key.

Power chuck are delivered in completely assembled condition, intermediate or chuck flange

separately.

3.2 Transport, handling and storage

Report transport damages to the freight forwarder. Please report missing parts to the manufacturer

immediately by phone and in writing.

If the power chuck is not mounted immediately after delivery, it must be stored in a safe location. In

such case, cover the parts properly and protect against dust and moisture.

All blank parts of the power chuck as well as accessories are coated with preserving material to

provide better protection (e.g. Metal protector Plus, Molykote brand).

The scope and contents of the delivery is listed in the delivery notes and its completeness must be

verified when the power chuck is received.

The icons (in accordance with DIN 55402 Part 1) on the packaging must be followed, e.g.:

Top Keep dry Keep away from heat Hand hooks

prohibited

Center of gravity Attach here


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4.0 Design and function

4.1 General description

3QLCLM power chucks are wedge hook chucks with large through hole, centrifugal force

compensation and integrated lubricant reservoir. Thanks to hermetic sealing, these are

maintenance-free and insensitive to dust. They are suitable for use as universal chucks for almost all

lathe operations:

- for heavy duty machining of disc and rod-shaped parts- for delicate finishing of easily deformable work pieces.

The new series of 3QLCLM power chucks is a result of consistent development of existing power

chuck (QLC) and has proven design elements. Type 3QLCLM power chucks were developed by using

computer-assisted calculation methods and are manufacturing using high-quality steel with most

advanced production technology (developed and manufactured under ISO 9001). Power chuck sizes

of 160, 200, 250, 315 and 400 mm diameter. The main features of Type 3QLCLM power chuck are

described below:

• Innovative master jaw profile with optimal guide length.

• Jaw guides customized to profile to avoid loss of lubricant.

• Improved efficiency due to the multiple jaw guides and shortened jaw radius.

• Integrated lubricant reservoir with improved forced circulation.

• Zero backlash wedge hook mechanism for maximum gripping force and accuracy.

• Centrifugal force compensation for maximum speeds.

• Large through hole for rod works.

• Selected material pairing - all force-transmitting parts are hardened and polished

• Simplified form through piston connection in the chuck and not sliding in the rear side.

• Base jaw connections based on European and international standard.

• Developed and manufactured under ISO 9001.

• Thanks to suitable accessories - actuation cylinder, hard or soft top jaws matching the work piece

and drawbar or the pull rod as connection element between power chuck and actuation cylinder -

complete solution as modern and powerful power chuck device.

The zero backlash wedge hook mechanism (domestic and foreign patents) guarantees maximum

clamping accuracy, irrespective of functional and manufacturing-related dimensional differences of the

individual parts. Counterweights behind the master jaws reduce the centrifugal force of the jaw and

allow use of 3QLCLM - chuck with high or delicately reduced gripping force in all speed ranges. The

lubricant reservoir in the sealed chick body ensures the force-transmitting sliding surfaces with each

chuck stroke and ensures constant gripping force with extended maintenance intervals.

The jaw profile (patented) offers an optimal guide length for inner and outer clamping, reduces the

load and wear and tear and prevents entry of coolant fluid as well as spinning of lubricant grease. The

manufacturing of all chuck components in highest FORKARDT quality guarantees a long service life

and reliable function (monitoring with the most modern testing equipment / quality assurance in

accordance with ISO 9000).


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4.2 Constructive design

4.2.1 Technical data / main dimensions - power chuck type 3QLCLM

3QLC 315-LM-Z11-KDIN max 4000 U/min

Fmax 60KN


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Technical data / main dimensions

Power chuck Type 3QLCLM

Chuck type 3QLCLM 160-38 200-54 250-72 315-88 400-126

Ident-No. 191203000 191216000 190476000

Max. actuation force - F max daN 4000 6000 6000

Max. gripping force - Fsp max daN 7000 9100 12000

Max. speed - n max min-1 6300 4500 4000

Mass moment of inertia J kgm2 0.138 0.81 0.81

Moment of inertia GD2 kgm2 0.552 3.24 3.24

Weight G 22.6 38.1 57.3

Dimensions

Spindle connection ØC Z5 Z6 Z8 Z8 Z11 Z11 Z15

Chuck size ØA 175 215 265 330 415

Bore ØB 38 54 72 88 126

Jaw connection (DIN 6353) D KDIN KDIN KDIN KDIN KDIN

Centering drawbar ØB2 42 65 77 93 134

Chuck centering ØE 140 170 220 220 300 300 380

E1 6

Piston bore ØF 52 76 90 110 150

Fixing screws G M12x95 M16x110 M20x90

Thread connection drawbar G1 M45x2 M68x2 M82x2 M100x2 M140x2

Jacking screw standard sleeve G2 M4 M5 M6 M6 M6

Chuck height H 101 101 111 111 141

Chuck height up to jaw support H1 111 124 124

Mounting depth H2 5 6 6

Cover height H3 6 8 8

Thread length mounting bolt J 20 23.6 30

Thread length actuator J1 17.5 24 24

Pull length actuator J2 23.5 34 34

Actuator stroke K 20 20 20

Actuator position K1 21.5 20 20

Pitch circle-Ø Fixing screws

L 104.8 133.4 171.4 171.4 235 235 330

Jaw stroke 4.5 5.4 5.4 5.4 8

Jaw position to the center of chuck

Nmax. Nmin.

52 47.5

70 64.6

88 82.6

100 94.6

133 125

Jaw mounting bolt O M10 M12 M16 M16 M20

Distance jaw mounting bolt P1 12.5 15 20 25 35

Minimum distance to jaw mounting bolt

P2 12 12 16 16

Distance ti jaw mounting bolts P3 25 30 40 50 70

Length of cross tenon P4 70 84 96

Jaw width Q 35 35 45 45 60

Groove width Q1 16H7 16H7 20H7 20H7 25H7

Feather key width / slot width Q2 10g6 12g6 16g6 16g6 25g6


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4.2.2 Design of the power chuck

4.2.2.2 Centrifugal force accessories

Chuck-Ø Centrifugal force weight

Lever

160

200 191062009 156122010

250 191216009 156584010

315 190476009 156584010

400

CHUCK BODY

JAW COMPLETE

CHUCK COVER COMPLETE

4.2.2.1 Complete chuck

CENTRIFUGAL FORCE ACCESSORIES

ACTUATOR COMPLETE

CHUCK FIXING SCREWS

Lever

Centrifugal force weight


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Chuck-Ø Cylinder screws cover fixing 1

Cylinder screws cover fixing 2

Cover O-Ring 1 O-Ring 2 Protective sleeve

Countersunk screw

160 - -

200 701C004320 701C005350 191062005 - - 191062002 703D004030

250 701D006350 701D006370 191216007 - 711A022030 191216004 703D004030

315 701D006350 701D006370 190476007 711H015037 711A030193 190476004 703D004030

400

Chuck-Ø O-Ring 3 O-Ring 4 Frame Locking screw

Sealing disc Actuator O-Ring 5

160 -

200 - 711A020849 191062001 709C212150 171594044 191062003 711A020055

250 711A015050 711A015033 191216001 177821008 191216002 711A030112

315 711A015123 711A015123 190476001 709C212150 171594044 190476002 711A030127

400

4.2.2.3 Chuck body complete

COUNTERSUNK SCREW

ACTUATOR

O-RING 5

LOCK SCREW

SEALING DISC

CHUCK BODY

O-RING 4

O-RING 3

O-RING 2

O-RING 1

PROTECTIVE SLEEVE

CYLINDER SCREWS COVER FIXING 0

CYLINDER SCREWS COVER FIXING 0


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4.2.2.4 Chuck cover complete

Chuck-Ø Cylinder screws Chuck cover O-Ring 1 O-Ring 2 O-Ring 3

160 - -

200 701B010360 191204001 711A020107 711A015015 711A015014

250 701B010380 191216005 711A030191 711A025075 711A025012

315 701B010380 190476005 711A030198 711A025026 711A025012

400

CYLINDER SCREW

CHUCK COVER

O-RING 3

O-RING 2

O-RING 1


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4.2.2.5 Jaw complete

Chuck-Ø Cylinder screws top jaws

Cylinder screw top jaw

Sealing frame O-Ring A Adapter jaw O-Ring B Cylinder screw(s) sliding block

Sliding block Base jaw

160

200 701B012340 191064002 711A015028 191203001 711A020047 701C005320 191064003 191064001

250 701B016360 701C008360 191216008 711A178051 701B004340 190476010 191216003

315 701B016360 701C008360 190476011 711A020055 190476008 711B178054 701B004340 190476010 190476003

400

CYLINDER SCREW

O-RING A O-RING B

ADAPTER JAW

CYLINDER SCREWS FOR TOP JAWS

BASE JAW

SLIDING BLOCK

SEALING FRAME

CYLINDER SCREWS FOR FIXING THE ADAPTER JAW


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4.3 Function of the power chuck

4.3.1 General information:

The power chuck is actuated through a standard hydraulic cylinder with monitoring of chucking stroke, by

using machine hydraulics or a separately provides hydraulic unit.

Depending on the type of work pieces to be machined, the following are used:

Partly open chuck a hydraulic actuating cylinder

e.g. Type OKRJ...

or

Open chuck a hydraulic hollow cylinder

e.g. Type OKHJ...

.

In some cases, hydraulic cylinder of

type PZRAJ or PZHAMJ is used.

The power chuck, fixed to the spindle head of a lathe, is actuated axially through a hydraulic clamping

cylinder and has the function to generate a gripping force to hold the work piece to be clamped through

the axial force generated by the clamping cylinder.

The pressure at the clamping cylinder must be adjusted such that the max.

permissible actuation force of the power chuck is not exceeded.

The axial actuation force of the clamping cylinder, which is spread on the actuator surface through

pressure, is transferred to the corresponding wedge guides of the master jaw through the wedge surfaces

laid out in the chuck actuator and these wedge guides wedge into each other during the clamping process.

The corresponding gripping force builds up radially on the work piece through the top jaws.

Clamping force at the chuck actuator causes jaw stroke to the inside (outside clamping). Compressive

force at the chuck actuator causes jaw stroke to the outside (inside clamping of hollow work pieces). The

power chuck type 3QLCLM is equally suitable for both clamping devices.

The monitoring of the clamping path is done through radially arranged limit switch on the clamping

cylinder.

Partly open chuck

Open chuck


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If the top jaw is adjusted to a specific clamping diameter, the jaw mounting bolts must be loosened

through two rotations with the Allen wrench (in accordance with 911) and the top jaw must be pushed

into the corresponding clamping diameter with the sliding blocks and screws.

If there is a change of top jaws from outer to inner clamping,

watch out for change in the direction of movement of the top jaws,

or if the top jaws are changed for example from hard top jaw type HB for roughing operation to soft top

jaw type WBL for finishing, then the jaw mounting bolts must be loosened through two rotations (with

Allen wrench) and the top jaw must be removed completely from the master jaw.

Clean any chips or dirt from the chuck bore and master jaw before removing the top

jaw from the master jaw!

If the processing of the clamped work piece is interrupted for many hours, the power chuck and/or the

clamping cylinder must be actuated again.

4.3.2 Centrifugal force compensation

Each master jaw is assigned to a counterweight through a reversing lever. When the chuck is rotated, it

uses its centrifugal force to balance the centrifugal force of the base and top jaw, which otherwise may

result in significant loss of gripping force. This simple, robust and direct centrifugal force compensation

system ensures high gripping force of the 3QLCLM power chuck in the entire speed range on the one

hand and allows selective processing with reduced gripping force on the other hand even at maximum

finishing speeds.

4.3.3 Lubrication

The movement of the centrifugal weight in the rear part of the chuck is used to supply lubricant to all

sliding surfaces during each chucking stroke. The excess lubricant inside the chuck is centrifuged to

the required points through the rotation of the chuck and is available again for the next chucking stroke.

When compared to the traditional chuck guides, the 3QLCLM type power chucks can use lubricants

with low viscosity, which can reach the sliding surfaces in a better way due to centrifugal capability.

This improves the reliability of the lubrication function and makes cleaning and maintenance of the

3QLCLM power chuck much easier.

4.3.4 Sealing of the power chuck

Type 3QLCLM power chucks maintenance-free thanks to their sealing and are sealed against entry of

lubricants and functional disruptions caused by the entry of coolants, dirt and chips.


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4.4 Clamping jaw

4.4.1 General information

The power chuck is a connecting element between the lathe and the work piece to be processed. The

power produced by the lathe is transmitted to the spindle nose by the power chuck and

to the transfer point between power chuck and work piece by the positive driving of the

closed chuck jaws.

Wide chuck jaws must be avoided

because they come to stop at the work

piece unevenly and cause radial

run-outs.

The power chuck is a connecting element between the lathe and the work piece to be processed. The

power produced by the lathe is transmitted to the spindle nose (by the power chuck) and

to the transfer point between power chuck and work piece (by the positive driving of the

closed chuck jaws). Chuck jaws are the radially moving elements of the power chuck, which hold the

work piece during machining. The chuck jaws consist of the master jaw (the connecting

link to the power-providing part of the power chuck) and the top jaw which is positively attached

(by serrations) to the master jaw and can thus be exactly positioned. The chuck jaws

have to be changed to suit the type of machining or the differences in size and shape of the work

pieces. The chuck jaws must be trained separately for optimal use and to prevent run-outs.

For the type QLCLM power chuck, the top jaw may have different holders for fixing to the

master jaw depending on the design:

• Cross tenon

• Different quick change systems

4.4.2 Safety instructions for top jaws

• Recalculate the strength of self-manufactured top jaws using the gripping force.

• Only use ORIGINAL mounting bolts for fixing the top jaws with due consideration of the

prescribed quality! (Cross tenon)

• Set the speed limiting device on the lathe to the permissible speed determined for the special

top jaws, as otherwise the centrifugal forces occurring at the jaws at higher

speeds will reduce the gripping force to such an extent that the work pieces will

no longer be securely held!

Comprehensive jaws come to stop unevenly at the work piece on one side and cause radial run-outs.

Power chuck center = workpiece center or center of rotation

Center of eccentric chuck diameter


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• When inserting the work pieces into the power chuck, one top jaw must always be placed at

the bottom so that jamming of the work piece between two top jaws is avoided.

• When the work piece is inserted, the travel of the top jaws should be 3 mm or less. Design

top jaws in such a way that the jaw travel required to reach the gripping position is not more

than 3 mm.

• Check the strength of the jaw mounting bolts. Recalculate the tensile strength (static and

dynamic). Use only good quality bolts of grade 10.9 to DIN 267!

• For external clamping, arrange the mounting bolts as far as possible to the inside!

4.5 General safety instructions

• A chucking pressure monitor must be provided to ensure that a minimum chucking pressure is

available.

• The pressure monitor must be set and then locked to prevent any further adjustment so that

the machine can only be started when the chucking pressure exceeds an adequate minimum

value

• The pressure at the clamping cylinder must be adjusted such that the max. permissible

actuation force of the power chuck is not exceeded.

• The test regulations of the industrial safety authority demands that not only a pressure monitor

but also a stroke monitor is provided for the actuating cylinder. The stroke monitor must ensure

that the spindle and feed drives cannot be started or are automatically stopped if the power

chuck is opened or the actuating cylinder reaches the end of its stroke.

• The lathe spindle must be prevented from starting when the power chuck is either fully open or

fully closed as the lathe will be stopped by the safety limit switches when the chuck is in its limit

positions. The machine spindle must not start until the chucking pressure in the actuating

cylinder has been built up and the power chuck has gripped within its permissible working

range.

• In the event of failure of the hydraulic power supply, a signal must be triggered to stop the

spindle and the work piece must remain securely gripped until the spindle has come to a

standstill.


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5.0 Chucking force

5.1 General notes

The connection of the power chuck to the work piece is force-locking, i.e. the force transfer happens by

pressing the chuck jaw (master jaw with top jaw) to the work piece. The contact pressure required for

creating this force locking is called as gripping force.

Various influences have direct or indirect effect on the gripping force:

• Variable friction coefficient between work piece and top jaw

• Proportion of clamping diameter and working diameter

• Magnitude of the cutting force on the cutting tool

• Swing of the top jaw from the clamping point

• Decrease of the gripping force through centrifugal force due to external clamping.

Rotating work holding equipment is subject to centrifugal forces that increase with the square of the

speed of rotation. The centrifugal force opposes the gripping force in the case of external chucking

and increases it in the case of internal chucking. The residual dynamic gripping force at high spindle

speeds depends on the static gripping force, the mass of the chuck jaws and the radius of their center

of gravity.

5.2 Gripping force FSp0

The max. gripping force FSp0 is only achieved under favorable conditions.

These are: • A well maintained power chuck• Optimum lubrication of all sliding surfaces• Application of maximum actuating force• Short overhang of top jaws• Spindle static n = 0 ( or low spindle speed )

The static gripping force is measured with a static gripping force meter, e.g. SKM 1200 / 1500, SKM

1200 / 1500, see publication 930.10.02D. The values of FSp0 can be used for stress calculations, e.g.

for the design of special jaws.


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5.3 Dynamic gripping force

The dynamic gripping force FSp is the total force (daN) supplied by all of the jaws under dynamic

conditions and represents the minimum value of the available gripping force under normal operating

conditions.

These are:

• • well maintained condition and

• • adequate lubrication of all sliding surfaces

of the power chuck. In really good condition, power chucks will exceed the calculated value of FSp

The static gripping force is a function of the chuck design data. But does not solely determine the

gripping force under dynamic conditions. The gripping jaws appreciably effect the performances of a

chuck. They have to be selected to suit the specific application.

The gripping jaws effect the gripping force and hence the maximum permissible speed. The centrifugal

force of the jaws of power chucks can have such a significant effect on the gripping force that this

effect has to be taken into consideration at higher spindle speeds.

The centrifugal force generated by the master jaws and top jaws which reduces the gripping force of

the chuck is countered in Type 3 QLCKT power chucks by counterbalancing levers so that the gripping

force acting on the work piece remains practically constant.

The gripping force to be applied at standstill, FSp0, must be correspondingly high so that the gripping

force required for cutting is still available at the selected spindle speed. The effect of the

counterbalancing weights actuated by the levers is taken into consideration for Type 3 QLCKT power

chucks by the chuck constant C4.


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5.4 Gripping force calculation

Calculation of the dynamic gripping force and the actual loss of gripping force

ΔFSp following formula is applicable for Type 3 QLCKT:

whereby the available static gripping force Fspo (at spindle speed n = 0) is:

and the loss of gripping force A Fsp due to the jaws:

and the influence of the lever-actuated counterbalancing weights:

The dynamic gripping force Fsp: is thus

The total centrifugal moment can be calculated as:

Terms used in the formulas:

Fsp = Dynamic gripping force [daN], the total dynamic gripping force applied by the jaws

C1, C2, C3, C4 = chuck constants

Fax = Max. actuating force [daN]

n = Spindle speed [min-1]

Ma = Total centrifugal moment of the jaws [kgm]

Dsp = Gripping diameter [mm]

YAB = Distance of center of gravity of top jaw from

gripping diameter [ mm]

a = Jaw overhang [mm]

i = Number of jaws

G = Mass of each jaw [ kg]

Ra = Distance of center of gravity of jaw from center of

chuck [mm]

Table of contents

3QLCLM

Edition: 04/2014

25

For each application it is necessary to check that

the available dynamic gripping force is adequate.

In the case of gripping jaws made from self-made

jaws or other special jaws, the actual centrifugal

moment has to be determined from the weight

(by weighing) and the distance from the

center of gravity Ra, from the center of the

chuck.

The weight of special top jaws for high spindle speeds must be reduced as much as

possible and the overhang of the jaws should be kept short.

The weight and position of the center of gravity of the finished jaws have to be determined, whereupon it

must be checked that the residual dynamic gripping force of the power chuck is adequate for the

intended machining operation.

If the calculated dynamic gripping force Fsp proves to be inadequate for the machining

operation, then the spindle speed or the weight of top jaws must be reduced.

The permissible spindle speed for the power chuck equipped with appropriate top jaws or the variation

of gripping force with speed has to be calculated for each application.

Safety instructions:

Check that the gripping force of the chuck is adequate for the machining operation

under the chosen operating conditions.

Maintain the chuck properly to attain the calculated values of the gripping force (the

actual gripping force can be higher in the case of a freshly lubricated chuck).

Use light top jaws at high spindle speeds.

During rotation of the power chuck, use a dynamic gripping force meter, e.g. FORSAVE

D, to determine the dynamic gripping force.

Determine the loss of gripping force under dynamic conditions at every changeover to

ensure that the gripping force is adequate for the desired operation.

If the gripping force falls below the specified value, lubricate the power chuck.

Auxiliary roller

Even surface


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Determination of the gripping force Fspz required for the machining process

The gripping force required for each

application has to be determined. If this

gripping force cannot be provided by the

chuck with the factors of safety given by the

guidelines of the German Association of

Engineers VDI 3106, then the permissible

spindle speed or the permissible chip cross-

section has to be determined.

An example:

A solid steel work piece (i.e. without bore) has to be machined. The gripping diameter dsp=60mm, the

turning diameter dz =60mm and the cut requires a tangential cutting force Fs=1200daN at a spindle

speed of 2760 rpm.

Soft jaws turned to the gripping diameter are used to avoid damaging the work piece. This gives a

gripping coefficient of |isp=0.1. A safety factor Sz is allowed for the cutting data with Sz=2.

The reduction in gripping force ΔFsp amounts to 2000daN.

This example shows:

When taking into account the reduction in gripping force ΔFsp the minimum static gripping force

required is

= 2000 + 2000 = 4000daN. The main variable affecting the gripping force is the tangential cutting force

Fs, which can be determined from the chip cross-section and the specific cutting force.

The gripping force necessary for the machining operation is given by:


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Terms used in the formulas:

Gripping coefficient μsp

Jaw design Material Material surface at the gripping point

la = Overhang of the work

piece

a = Depth of cut Steel 0.1 0.15 - 1 )

s = Feed AI 0.1 0.14 -

Ks = Specific cutting force Ms 0.09 0.14 -

GG 0.08 0.12 -

dz = Machining diameter Steel 0.12 0.20 0.32

dsp = Gripping diameter AI 0.11 0.19 0.30

μsp = Gripping coefficient Ms 0.11 0.18 0.27

Fs = Primary cutting force GG 0.10 0.16 0.26

Steel 0.25 0.35 0.50

AI 0.24 0.33 0.48

Ms 0.23 0.32 0.45

GG 0.20 0.28 0.40

1) Avoid, smooth jaws are only suitable for gripping machined surfaces

2) Indentations will be produced on the work piece.

The cutting forces increase as the cutting tool becomes dull. An additional factor of safety

Sz=2 is recommended to allow for all uncertainties in the machining process.

The gripping force must be increased to

allow for the tilting effect caused by the

overhang.

Specific cutting force Ks (N/mm2) for feed s and

Adjustment angle 70° (Source König, Essel )

Material no. Material Tensile strength

B N / mm2

at m/min

Feed s (mm)

0.16 0.25 0.40 0.63 1.00 1.60

1.0401 C15G 373 100 2482 2169 1916 1687 1481 1298

The tilting force need not be taken into

account if the work piece is supported by a

tailstock or if the work piece does not

project beyond the jaws by more than 0.5 x

dsp. The gripping force Fspz required can be

found approximately from the formula:

1.0501 C35G 490 100 2577 2237 1927 1668 1441 1241

1.0532 St50-2 559 100 2561 2248 1959 1716 1499 1307

1.0632 St70-2 624 100 2877 2492 2142 1851 1595 1371

1.0711 9S20 371 100 1609 1553 1497 1444 1393 1342

1.1181 Ck35V 622 100 2574 2266 1962 1741 1527 1339

1.1191 Ck45V 765 100 2524 2253 1999 1781 1584 1405

1.1221 Ck60V 673 100 2548 2296 2058 1851 1662 1490

1.3505 100Cr6G 624 100 2904 2551 2239 1968 1726 1510

1.4113 X6CrMo17G 505 100 2378 2107 1854 1638 1445 1272

1.4305 X12CrNiS18.8 638 350 2596 2192 1835 1545 1296 1065

1.5752 14NiCr14BF 658 100 2249 2012 1790 1598 1424 1266

1.5919 15CrNi6 510 100 2271 2051 1842 1661 1494 1342

1.5920 18CrNi8G 578 100 2360 2095 1847 1636 1446 1276

. Tilting factor: 17131 16MnCr5G 510 100 2641 2244 1891 1603 1354 1141

1.7147 20MnCr5G 568 100 2452 2174 1915 1694 1495 1317

1.7225 42CrMo4V 1138 100 2428 2249 2075 1919 1773 1635

1.8515 31CrMo12V 1060 100 2678 2419 2173 1960 1764 1565

1.8519 31CrMoV9V 931 100 2507 2265 2036 1836 1653 1485

3.1354 AlCuMg2 15Hv10 200 953 649 752 66» 593 525

This equation cannot be applied to stepped

work pieces whose gripping diameter is

appreciably smaller than the machining

diameter.

- G-AlMg4SiMn 260 200 829 729 636 558 - -

3.3561.01 G-AlMgS 75HV10 200 886 797 713 641 574 514

0.4020 GG-20 178HB 200 1637 1444 1227 1047 892 757

0.6030 GG-30 206HB 100 1919 1595 1313 108» 899 740

0.7050 GGG 50 194HB 200 1840 1606 1392 1213 1053 913

The feed thrust component Fv and passive thrust Fp are not entered in this

formula. They are taken into account with safety factor S z!

Simple jaw FNC 50

FNC 51 Stone jaw

Roughing jaw FNC 52


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5.6 Permissible overhang length

X = 0.75 Dsp

= Total gripping force = I Jaw forces

Simple safety against the work piece flying out of

the chuck from the cutting force component P is

ensured when the friction force |isp x Fsp/3 and P

are in equilibrium.

The gripping force required to

prevent tilting out of the chuck:

The gripping force required for

driving:

The gripping force required: (S =

safety factor)

Permissible overhang length with

given gripping force:


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6.0 Assembly

6.1 Actions to be taken before assembly

6.1.1 Checking the spindle nose of the chuck flange

The mounting surfaces on the spindle nose have to be

checked with a dial gage to ensure that high accuracy in

respect of radial run-out of the power chuck is achieved

Radial run-out of

register: max. 0,005 mm

Axial run-out of the register: max. 0.005 mm

• The flatness of the face has to be checked with a straightedge.

• The surface of the face has to be clean and the holes in it

must be deburred.

6.1.2 Checking the fitted mounting flange

The power chuck has a central register. An appropriate

mounting flange (see also Section 5.8.1) is attached to the

spindle nose of the lathe for direct mounting of the power

chuck on the machine spindle with short taper to DIN, ISO and

ASA standards.

If the adapter flange is manufactured by the user, it must be

finish-turned on the machine spindle and balanced before the

power chuck is mounted.

After fitting of the mounting flange, the radial and axial run-out

must be checked!

• Remove dirt or chips from machine spindle. Clean the

centering collar and locating face of the adapter flange.

• The flatness of the face has to be checked with a straight

edge.

• The tapped holes for the mounting bolts must be

countersunk, so that the thread is not stripped.

• The mounting surface for the power chuck must not be

concave or convex.

• The flange must be in contact over the whole surface!

Wrong!


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Attention:

Do not allow the outer rim of the power chuck to

rest on the mounting flange.

Threaded bores must be drilled in the mounting flange for

attachment of balancing weights which, depending on the

size of the power chuck to be mounted, should be

be-tween M8 and M16 with a thread depth of max. 2x0.

The outer diameter of the mounting flange must be relieved

so that it is approx. 1 mm less than the register diameter

for the power chuck.

Correct!

6.1.3 Fitting and alignment of the draw tube

The actuating cylinder and the power chuck are connected by a draw tube.

Particular attention has to be paid to the following points when fitting a draw tube:

• The draw tube dimensions have to be adequate for the loads imposed.

• The draw tube must be turned all over to avoid imbalance.

• Manufacture the draw tube from a material with a tensile strength of at least 1000N/mm2 ,

e.g. 42CrMo4V.

• The draw tube has to be balanced dynamically in two planes, so that the residual imbalance

in each plane is not equivalent to more than a mass of 5g at the outer diameter.

Attention:

Make sure that the draw tube is in alignment! The draw tube is in alignment when both

threads are concentric! Skew threads are not permissible!

The extreme right position of the chuck piston of the chuck must always be determined by the

actuating cylinder and not by the power chuck itself.

The piston of the actuating cylinder there-fore has to be moved into the extreme right position

before mounting the power chuck!


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Attention:

The length of the draw tube has to

be arranged so that

the setting dimension "E" is obtained in the

position shown.

Dimension "E" is the measured distance

between the contact surface of the power

chuck and the back edge of the register

diameter in the chuck piston (chuck piston

of the power chuck in the right hand

position).

Secure the draw tube

in the piston rod of the

actuating cylinder with

Loctite 242!

Chuck type 3QLCLM --> 160 200 250 315 400

Setting dimension "E" + 0.2 mm

-->

6.1.4 Fitting and alignment of the draw tube

The high spindle speeds necessitate accurate balancing of the rotating parts. An imbalance in the chuck

body will cause free centrifugal forces when the spindle rotates; these centrifugal forces can cause

vibrations which have a negative effect on the product quality. Since the centrifugal forces per unit of

weight increase with the square of the spindle speed, the demands on the precision of balancing

increase with increasing speed of the parts.

For this reason, the lathe spindle, the actuating cylinder, the power chuck, the cylinder flange, the chuck

mounting flange or adapter plate and the draw tube must be balanced.

The power chuck is balanced dynamically, whereby any imbalance is corrected by screwing balancing

weights into the chuck body and the balance quality G = 2.5 to 4.3 (depending on chuck size) in

accordance with VDI 2060 (or DIN ISO 1940) is observed. Cylinder flanges or chuck mounting flanges

delivered by us and the draw tube are also balanced. The actuating cylinder is therefore balanced

dynamically in two planes, whereby any imbalance is corrected by screwing balancing weights into the

cover and the cylinder body of the actuating cylinder and the balance quality G =2.5 in accordance with

VDI 2060 (or DIN ISO 1940) is observed.

Right hand stop

Draw tube length L = A + B + C + D – E – F


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6.2 Mounting of the power chuck

Remove any chips from the machine spindle before mounting the power chuck. Clean the register

and locating faces of the adapter flange!

6.3 Procedure for mounting the power chuck

Attention:

If a mobile hoist which can be moved in all directions is available for mounting the power

chuck, observe the following points: The working load of the hoist must be at least the weight

of the power chuck!

Attention:

Use the mounting hook to mount the power chuck on the hoist and

level it with the spindle.

The mounting hook must correspond to the conditions in accordance with DIN 6890

!

Attention:

Remove any chips from the machine spindle before mounting the power chuck.

Clean the register and locating faces of the adapter flange (adapter disc)!

However, in case the machine’s chucking equipment is frequently changed, the draw tube should

be screwed into the thread of the 3QLCLM power chuck and Loctite 290 should be used to

secure it against loosening!

When screwing the draw tube in the chuck piston, take care not to damage the O -ring!

Machine spindle

Power chuck including screwed draw tube

Chuck and mounting screws


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Screw the draw tube into the thread of the chuck

piston. Secure the draw tube with Loctite 290! When

screwing the draw tube in the chuck piston, take care

not to damage the O - ring!

Securely screw the chuck piston with fitted draw in

the thread of the cylinder piston. Push the mounting

recess of the power chuck on the mounting spigot of

the chuck flange. When doing this, make sure the

mounting bolts are at the correct angle to the

threaded bore holes in the chuck flange. Tightly

screw the power chuck on the chuck flange with the

socket head screws.

Before finally tightening the socket head screws in a

clockwise direction, align the power chuck so that

after completing mounting, the run-out at the test

surfaces of the power chuck does not exceed 0.01

mm.

Draw tube

Po

wer

ch

uck

Machine spindle with intermediate flange

Power chuck including screwed draw tube

Chuck and mounting screws


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6.4 Tightening torques of shaft screws

6.4.1 Tightening torques of chuck mounting bolts

Bolts in accordance with DIN 912 Quality 10.9 Manufactured in accordance with DIN 267

Thread M 5 M 6 M 8 M 10 M 12

Tightening torque Nm 8.7 12 25 43 56

Preload Fv N 9300 10560 16940 23100 25200

Thread M 16 M 20 M 24 M 30

Tightening torque Nm 124 244 420 840

Preload Fv N 42400 66400 95600 154000

6.4.2 Tightening torques of jaw mounting bolts

Bolts in accordance with DIN 912 Quality 10.9 Manufactured in accordance with DIN 267

Thread M 6 M 8 M 10 M 12 M 16

Tightening torque Nm 15 29 50 75 155

Preload Fv N 13200 19360 26950 39200 74200


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After mounting the complete power chuck system, check for imbalance and compensate any

remaining imbalance by screwing in corresponding threaded studs to DIN

914

• on the cylinder side into thread d of the cylinder flange,

• on the chuck side into the mounting flange

. The thread on the cylinder body of the actuating cylinder or on the body of the power chuck must not

be used for this purpose as the exact dynamic balancing of the actuating cylinder or power chuck will

be lost.

Check the proper mounting (using a dial gage) on the test faces of the power chuck.

The chuck body may be distorted if the chuck without

gripping jaws does not operate freely.

• In that case, remove the chuck from the spindle of the machine.

• and check the flatness of the chuck mounting flange and

• the diameter of the taper register!

Radial run-out: max. 0.01 mm (Guide value)

Axial run-out: max. 0.01 mm (Guide value)


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6.5 Preparations for using the power chuck

After the chuck has been mounted but before it is used, the following steps must be taken to ensure

trouble-free operation:

• Clean everything from the machine that does not belong to it (e.g. assembly tools).

• Check whether the fill level of lubrication is OK (see also Maintenance)

• Carry out a no-load operating cycle (without work piece) of the chuck to distribute the grease.

• Check all visible screws and bolts for tightness.

• Check the movement of the jaws.


The test regulations of the industrial safety authority demands that not only a pressure monitor but also a

stroke monitor is provided for the actuating cylinder. The stroke monitor must ensure that the spindle and

feed drives cannot be started or are automatically stopped if the power chuck is opened or the actuating

cylinder reaches the end of its stroke.

• Use limit switches to VDE 0113 / 12 with mechanically operated positive-acting NC contacts to monitor

the actuating cylinder stroke.

• If other control elements, e.g. proximity limit switches, are used instead of the safety limit switches, the

same degree of safety must be assured.

• Use a safety margin of 1 mm. in each direction when setting the limit switch actuators to the permissible

stroke.

Right hand stop

Left hand stop

only here!

Spindle rotation is permitted

Safety margin

Safety margin

Safety margin

Safety margin

Working stroke

Working stroke

Total stroke

Total stroke


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7.0 Commissioning

7.1 Notes

The initial period of use has a marked effect on the satisfactory performance of the power chuck. The

mounting of the power chuck should be checked at this stage.

Mount the top jaws centrically and then connect to the master jaws (observe the marks

on the chuck body and master jaw)!

Do not overload the power chuck! Set the pressure at the actuating cylinder so that the

maximum permissible actuating force is not exceeded! (See section Design and function - Technical data)

• The power chuck must open and close at approx. 1/10 of the permissible actuating force!

• Binding of the power chuck may be the result of strained master jaws or top jaws. Unbolt the top

jaws and inspect the cross tenon.

• If the power chuck binds without top jaws, the chuck body may be strained. Check the flatness

of the chuck mounting flange!

• Check the jaw movement and chuck piston stroke!

• Check the gripping force Fsp0 with a static gripping force meter, e.g. SKM 1200 / 1500

The stop of the cylinder piston is on the right, always in the actuating cylinder - not in the

power chuck.

The extent of movement of the chuck piston towards

the left must be limited by the chuck body or its

mounting flange.

Right hand stop

Left hand stop


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7.2 Operation

Insert and grip the work piece in the power chuck. Start the machine and wait for the machine

program to enable the spindle rotation.

Do not start the machine spindle until the actuating cylinder has built up sufficient pressure and

the work piece has been gripped within the permissible working range!

Machine work pieces at high spindle speeds only under the protection of an adequately

dimensioned safety guard!

Make sure to fit safety devices and close safety guard!

• The safety guard must be locked as long as the machine spindle is running and

should only be opened when the spindle has come to an absolute standstill!

• Operation of the power chuck must always comply with the local safety and

accident prevention regulations! Reference is expressly made to the specific

accident prevention regulations of the local industrial safety authority.

• Local safety instructions must always be observed when operating systems and machines.

• Check sample work pieces!

The precision of the power chuck is illustrated during repeated chucking of a work piece and

by its running precision when the work piece was machined in several consecutive

chucking. If the center of the gripping cross-section deviates from the lathe centerline

beyond the specified tolerance, this will result in faulty work pieces and consequently to

scrap!

7.3 Unauthorized operation

In the event of system imbalance at the actuating cylinder or power chuck, eliminate the

imbalance immediately!


• During rotation of the power chuck, use a dynamic gripping force meter, e.g. FORSAVE D, to

determine the dynamic gripping force.

• Determine the loss of gripping force under dynamic conditions at every changeover to ensure

that the gripping force is adequate for the desired operation.

• In the event of a loss of chucking power, stop the machining operation and the machine spindle

immediately!

• In order to maintain the gripping force over long production runs, operate the chuck periodically

under no-load (without a work piece). A uniform gripping force of the chuck is assured only if the

lubrication films are maintained and the grease is distributed to the loaded parts.

• Release the work piece from the chuck only after stopping the machine spindle!

• Do not leave the work piece in the chuck overnight as the chuck releases the work

piece after the power chucking system has been switched off!

7.5 Procedure in the event of malfunctions

Irrespective of the instructions given below, the power chuck must always be operated

in accordance with the local safety regulations!


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We recommend that a lockable switch be fitted which prevents an inadvertent starting of the machine

spindle during repairs or in the event of a malfunction. The following table lists the symptoms, causes

and the measures to be taken into the event of any malfunctions of the power chuck. We cannot

guarantee for the exhaustiveness of this list due to wide range of influencing factors (level of

knowledge of the operating personnel, etc.).

Symptom Causes Measures Severe vibration of the machine Out-of-balance forces due to the mounting

flange or cylinder flange and possibly the chuck

or the actuating cylinder due to incorrect mounting

Check run-out on the reference surfaces of the

power chuck. Correct imbalance on power chuck

or actuating cylinder immediately. Rebalance

mounting flange or cylinder flange, if necessary.

Readjust spindle bearings.

Inadequate gripping force Soiling Inadequate lubrication Clean power chuck, check lubrication. If

lubrication is not sufficient, dismantle, clean and

lubricate the power chuck.

Full movement of the jaws is not attained Master jaws incorrectly mounted or reversed. Check and replace if necessary

Wrong length of draw tubes Check setting dimension "E"

No gripping force Master jaws strained Inspect locating faces, possibly

use of jaws from a different

manufacturer

Top jaw cannot be adjusted Serrations of master jaw soiled Clean

Possibly difference in pitch with

self-manufactured top jaws

Run-out error with ground soft top jaws too

large

Master jaws reversed, possibly also top jaws Check and replace if necessary

7.6 Measures during longer standstill

• Move the piston of the actuating cylinder to the right!

• Remove the work piece from the power chuck!

• Clean and grease the power chuck!

• Coat bright metal parts with a corrosion inhibitor. Observe the safety instructions of the

corrosion inhibitor manufacturer!

Do not clean the power chuck with compressed air because chips and coolantmay get in the eyes!

Risk of injury!

7.7 Measures after longer standstill

• Clean corrosion inhibitor from the chuck parts.

• Lubricate the power chuck. Remove any excess grease which emerges!

• Operate the chuck without gripping a work piece to distribute the lubricating grease!

• At standstill of the machine spindle, check the static gripping force Fspo with a static

grip-ping force meter,

• e.g. SKM 1200 / 1500!

• Grip a work piece.


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7.8 Oil selection

All hydraulic oils with a viscosity of approx. 30 to 50 centi-Stokes at 40°C are suitable for the operation of

chuck cylinder. For normal operation, we recommend a viscosity of 46 centi-Stokes at 40°C. This

corresponds to ISO recommendation VG 46 in accordance with DIN 51519, e.g.:

ARAL TU 524 (VG 46)

ARAL TU 508 (VG 32)

SHELL TELLUS C 46 (VG 46)

SHELL TELLUS C 32 (VG 32)

or other branded oils of above qualification.

Attention:

If a VG 32 oil type is used, then it may result in higher leakage of oil supply to the

chucking cylinder (see also operating manual of the manufacturer of chucking

cylinder).

Recommended oil

Operating temperature

Viscosity Viscosity Viscosity Viscosity Viscosity CSt at CSt at CSt at CSt at CSt at 50°C 50°C 50°C 50°C 50°C

25-54 cSt At working condition

Heat

60-80°C

Aral oil GFY

Aral oil TU 524

Aral oil TU 528

49.0

49.0

68.0

Energol HLP 150

Energol HLP 175

49.0

65.0

Esstic 55

Teresso 56

Hydraulic oil 49EP

Nuto H 64

49.0

49.0

49.0

62.0

Mobil D.T.E.Oil

Heavy

Mobil D.T.E.26

51.0

37.0

Shell Tellus 137 Shell Tellus 537 Shell Tellus 33 Shell Tellus 41

Shell Tellus 141

49.0 49.0

ca. 38 60 60

Lubricant for the power chuck

Name Type

FORKARDT special grease PF2

FORKARDT special grease PF6

Mobil oil Vactra Oil No.4

Product numbers see in Section Spare parts and customer service


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Foreign matter penetrates into practically every power chuck during machining. Chips, scale and

foundry dust increase the friction between moving parts and coolant washes away the lubricants

The chuck sealing can only delay it, therefore the power chuck must be checked regularly and cleaned

if required and filled with fresh lubricant.

Filling through the oil holes in the chuck body (see above). Oil quantity max. 75% of the cavity volume.

This will ensure uniform chucking force, accuracy and high service life.

The lubrication of the - actuated by the hydraulic oil cylinder - power check must be

done at regular intervals. Due to this reason, carry out many empty runs (without work

piece), to distribute the lubricant evenly.

8.0 Maintenance

8.1 Lubrication

FILL THE POWER CHUCK WITH LUBRICANT AT THE MARKED HOLES

WHEN FILLING MAKE SURE THAT BOTH OPENINGS ARE POINTING UP AT THE SAME ANGLE


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42

8.2 Maintenance plan

After 24 hours; during initial

operation or repair.

Operate the chuck without gripping a work piece to distribute the

lubricating grease.

Check the bolts for firm seating.

Weekly Check the Fsp0 with a gripping force measuring device, e.g.

FORKARDT SKM 1200 / 1500.

Weekly Functional test of the power chuck system.

Monthly / quarterly / semi-annual Check the master jaw, chuck actuator, lever and sealings for wear.

Depending on the load of the power

chuck.

Use new sealings if required during assembly / disassembly of the

power chuck and fill actuator and jaw guides with PF2 grease and

fill power chuck with Mobil Vactra Oil No. 4.

8.3 Disassembling the power chuck

Open the locking screws on the body

and discharge lubricant oil.

Loosen the fixing of the

drawbar/cylinder.

Fix the power chuck to crane so that it

can be pulled later with a suitable hoist

...

(e.g. hoist or special lifting device)

. . Remove the mounting bolds for

the power chuck.


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43

After pulling the power chuck from the machine,

screw the drawbar from the actuator

Remove screws for top jaw mounting bolts and

screws for intermediate jaw mounting bolts.

Now you can remove the intermediate jaw and

the O-rings

Remove screws for cover bolts.

Now you can removed the cover and O-ring.

Note:

O-ring will not be present in certain chuck variants. Here

the chuck is sealed with a sealant (e.g. "Hylomar

Universal Blue").

When assembling note that the sealing areas are

cleaned off grease and the area between cover and

body has sealant.


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44

Countersunk screws

Remove protection sleeve.

Now you can remove the protective sleeve and

the O-rings

Remove the cylinder screws for sliding blocks.

Now the sliding bolts can be removed. Even

the sealing frames at the master jaw and

associated O-rings can be removed as next

step.

Remove the cylinder screws for

chuck cover.

Remove chuck cover including all O-rings and

centrifugal weights from the body of the chuck.

You can now remove the centrifugal weights

and O-rings from the chuck cover and lever

from the chuck body.


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45

Pull the actuators from the chuck body. The

master jaws will move into the center of the

chuck.

When the actuators are removed, the master

jaws can be pushed into the center one after

another and then removed from top.

Pull the covers of QLC guides only in case of

repairs.

Auxiliary threads can be used in this case. The

removal requires certain force because the

covers are used with a sealant.


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46

9.0 Spare parts and customer service

9.1 Spare parts

For safety reasons, use only ORIGINAL - FORKARDT spare parts.

Take the product numbers of the components from the component list in Section Design and function.

Manufacturer's warranty is applicable only for original parts from FORKARDT. We are not liable for any

damages resulting from the usage of foreign parts.

A regular stocking of important repair spare and wear parts at the installation location is very important

for constant function and readiness of the power chuck system. The parts list can be used for ordering

spare parts.

• For safety reasons, use only ORIGINAL FORKARDT spare parts!

• The use of parts from other sources on our products relieves us from our obligations regarding

product liability, in so far as any damage can be attributed directly or indirectly to the use of

such parts.

• Our warranty only extends to ORIGINAL spare parts supplied by us.

Please note that special specifications frequently exist for parts manufactured or bought out by us and

that we always supply spare parts that meet the latest technical standards.

9.2 Tools and accessories

The following tools and accessories are used for carrying out maintenance work:

All pin wrenches in accordance with DIN 911 for the cylinder screws.

To be provided by the customer:

Degreasing agents, preservation agents and lubricants must be provided by the client, but can also be

supplied by us on order.

Name Type Ident-No. Container

FORKARDT - special grease PF2 4101400085 Can 1 kg

FORKARDT - special grease PF6 4101400089 Can 1 kg

Mobil - bed track oil Vactra Oil No.4 4101400078 Canister 20l


Edition: 04/2014

9.3 Customer service

Following data must be specified when ordering spare parts:

Description Quantity Ident-No.

FORKARDT DEUTSCHLAND GMBH

Lachenhauweg 1272766 Reutlingen

Telephone

Fax

+49 7127 5812 0

+49 7127 5812 122


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48

10.0 Declaration of incorporation

According to EC Machinery Directive EG-RL 2006 / 42 / EC

The manufacturer

FORKARDT Deutschland GmbH

Lachenhauweg 12

72766 Reutlingen

herewith declares the following incomplete machines with designations:

Type designation: Three jaw power chuck, maintenance-free with centrifugal force compensation

Type: 3QLCLM

• The general health and safety requirements according to Appendix I of the aforementioned directive have been referred to and observed.

• The special technical documents according to Appendix VII B have been prepared.

• The aforementioned special technical documents will be submitted to the responsible authority as required.

• Commissioning is forbidden until it has been verified that the machine in

which the aforementioned machines are to be incorporated comply with

the specifications of the machinery directive.

• Responsible for the documentation:

Date/manufacturer's signature: Location:

Declaration of incorporation number: 3QLCLM.D

Since we are constantly striving to improve our products, the dimensions and information may not correspond to the recent designs, therefore

such information is not binding.

(Management)

Reutlingen04.06.2019


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49

UniqueFirst-cl

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� Experienced.

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FORKARDT LOCATIONSFORKARDT DEUTSCHLAND GmbHLachenhauweg 1272766 Reutlingen-MittelstadtPhone: (+49) 7127 5812 0Email: [email protected]

FORKARDT USA2155 Traversefield DriveTraverse City, MI 49686, USA Phone: (+1) 800 544-3823 (+1) 231 995-8300Fax: (+1) 231 995-8361Email: [email protected]

FORKARDT INDIA LLP Plot No. 39D.No.5-5-35 Ayyanna Ind. ParkIE Prasanthnagar, Kukatpally Hyderabad - 500 072, India Phone: (+91) 40 400 20571Fax: (+91) 40 400 20576Email [email protected]

FORKARDT FRANCE S.A.R.L.28 Avenue de BobignyF-93135 Noisy le Sec CédexPhone: (+33) 1. 4183 1240Fax: (+33) 1 4840 4759Email: [email protected]

FORKARDT CHINAPrecision Machinery (Shanghai) Co Ltd1F, #45 Building, No. 209 Taigu Road,Waigaoqiao FTZ CHINA 200131, CHINAPhone: (+86) 21 5868 3677Email: [email protected]

WWW.FORKARDT.COM

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Documents

3QLCLM POWER CHUCKS - FORKARDT Inc....Table of contents 3QLCLM Edition: 04/2014 6 2.0 Safety instructions 2.1 General information Power chucks may result in risks if their use and