Pre Bid Meeting Clarifications

8/8/2019 Pre Bid Meeting Clarifications

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SUB: Replies to Queries related to BEML Limiteds Procurement of FlexibleManufacturing System (FMS) for Engine Cylinder Block machining raised by firmsduring the pre bid meeting held on Dt.17-08-10 at BEML, Corporate office, Bangalorechaired by DGM (CPC)

Ref: Tender #CPC/FMS/10-11 Dtd: 29

th

July2010.

The following are the replies/clarifications for the Queries -

Q 1. Please refer point 1 of 1.0 (page1), Point 4.2 of 4.0 (page 3) & point 1.0 ofAnnexure 1A (page 20), on Machine 1 Tender calling for Horizontal BoringMachine/head Changer/Horizontal Machining Center with Quill, Tool Magazineand with the capacity to handle Heavy Duty Angular Heads up to 350 Kg weightfor machining prismatic components in multiple axes and planes.

Please elaborate on the functionality of Quill on this machine process orapplication you think that this feature on the machine will have a major role toplay. Looking at the component & operations to be carried out, we are of theopinion that Quill is not required (it appears that it is made mandatory). Can anexception be provided if machines are offered without a Quill?

Ans: Functionality of Quill - Provision of Quill is mandatory keeping in viewof the following

1. Machining of Other Components BEML has identified some of the alternativecomponents for machining on the FMS which have inaccessible areas which

require Quill for machining.2. Optimization of Tool length To avoid lengthy Adopters, Tools to machine theareas which are not accessible directly or of small size.

3. We have also experienced the advantage of usage of Machine with Quill to haveTool Strain Mechanism which has helped in Rigid clamping of Lengthy BoringBars and Milling Cutters to avoid chatter and obtain improved surface finish.

In view of the above, no exception can be given for supplying machine without Quill.

Q 2. Please elaborate on the machine with Head changer & additionallyrequiring various Angular heads to perform different process/operations?

Ans. Head Changer Machines available with International Suppliers meeting our tenderspecification are also suitable for Machine1.The offer for supply of Horizontal BoringMachine / Head Changer shall be in line with the tender specifications.

Angular Heads are used on the Machine1 for operations like Crank boring, Cheekmilling, Notch Milling in Crank Bore etc.


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Q 3. The new generation of Horizontal Machining Centers can offer the samerobust construction as that of a Horizontal Boring Machine. Can a HMC ofequivalent rigidity be quoted instead of HBM. As we will not be able to achieve atorque of 5000 Nm on HMCs can we offer a spindle with suitable torque to

process the intended operations?

Ans: Machine 1 should be as per specifications provided in the tender. GeneralHorizontal Machining Centers which do not meet tender specifications are notacceptable.

Q 4. Angular heads up to 350 Kgs weight: In references to various places intender document as mentioned above, Angular heads up to 350 Kg weight isasked, also at point 15.4, page 10 under tooling specifies The Angular headsshould be of above 100 Kg Weight and should be carried by Special headchanger/ Tool pallet / Robotic tool handler. Angular heads should not be

Aluminum Body. Angular heads with light weight (


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Ans: Tender specifications indicates that the rough machining operations 1-5 shouldinvariably be tooled up and planned on the Machine 1 for regular production. Otheroperations to be divided between all the three machines including machine1 so as toachieve the Balancing of load on all the 3 machines.

Also, it is indicated that Machines 2 & 3 also should be equipped with tools (1 set of toolholders for each machine) for operations 1 to 5, and also other operations planned onMachine 1.

Also, it is indicated that the pallets should be interchangeable between all the threemachines. This will help in optimization of Fixtures and Setups.

Q6 . At this point 16.5 of page 12 under Fixtures, your requirement is formodular fixtures designed to commonise the fixtures only for the cylinder Blockmodels specified in point 1, does that mean that the remaining models specifiedin point 2 to 6 should have their individual fixtures w.r.t the no. of setups

required. We are of the opinion that manufacturer needs to be given a choice ofproposing the fixtures among the other cylinder blocks models ( 2 to 6) withchange parts or bringing in modularity. Please clarify.

Ans:

A. As indicated in the point 16.5, the common fixtures are acceptable only for4D105, 4D105 HPD and 6D105 Components.

B. All other components should have separate fixtures.

C. Modular fixtures by combining more than one of the above components areacceptable. However, each setup for each component should have separatefixture as per tender specification.

Q 7. At point 2.1.12 of page 23 Pick up magazine: Need elaborateunderstanding on the various possibilities that can be considered to handleHeavy Angular Heads/Boring Bar/Special attachments, as this clause ask for apick up magazine, but at clause 15.4 of page 10 under Tooling the same needs tobe handled in various options of Special head changer/Tool pallets/Robotic toolhandler, Need your comment on to it.

Ans: 2.1.12 of page 23 refers to Pick up Magazine for use with Horizontal MachiningCenters (Mc 2 & 3) .

Where as clause 15.4 of page 10, indicates handling of Angular Heads on Machine 1where various options of Special Head Changer / Tool Pallets / Robotic Tool Handler are indicated.

Suitable Heavy Tool Handler should be provided as required.


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Q 8. For MC1 (horizontal boring mill):

a. 2.1.6: Swing diameter of 2500 mm unnecessary large for the machined

component: to be reduced to max. 2200 mm.

Ans: Swing Diameter of 2500 mm is essential keeping in view of the other

components planned for machining on FMS. Swing diameter of 2200 mm not

acceptable.

b. 2.1.9: CNC: shop mill option unnecessary for this automated line.

Ans: Requirement reviewed and Shop Mill is necessary for our future plans. Shop

mill with provision for 4 axes programming to be supplied.

c. 2.1.11: This description is mixing milling head fixation and toolstrain

device.i. External clamps with min 150 kN is necessary for angular

heads.

ii. Spindle flange diameter of 220 mm is desirable for the tool

strain tools. External clamps (annexure 1G) are not compatible

with those tools as the flange is rotating with the spindle.

For those tools a clamping force of 20 kN has been proven

satisfactorily.

Ans: i. Milling Heads to be clamped by a fixation by bayonet and conic centering.

Min. 150 kN necessary for angular Heads.

ii. Spindle flange diameter of 220 mm is required for tool strain tools. Mainly used for

Lengthy Boring Bars and Heavy Tools like large milling cutters etc.

As an alternative, fixing by 4 external clamps operated automatically is indicated in

the tender.

d. 2.1.11 - 2.2.4 - 2.2.9:

In 2.1.11 and annexure 1G a fixation system with 4 clamping unit is suggested.

In 2.2.4 and 2.2.9 a fixation by bayonet and conic centering are specified.

The freedom of choice of the fixation system has to be given to the machine

tool manufacturer with respect of the necessary accuracies, fast attachment

changing time and high clamping force.


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Ans: As indicated above, Milling Heads to be clamped by a fixation by bayonet and

conic centering and Rough Boring Bars and lengthy boring bars to have tool strain

mechanism.

Alternately fixing by 4 external clamps operated automatically is suggested.

Q 9. For MC2 & 3 (machining centers):

a. 2.3.1 (acceleration 4 m/sec2) & 2.3.3 (feed 40 & rapid 50 m/min)

This is unnecessary limiting the machine choice / technology.

The choice should be kept open as long as the production capability

of 2400 blocks/year is warranted.

Ans: The parameters of Acceleration of 4 m/sec2 and Feed of 40m/min. and Rapid

feed of 50 m/min. for Horizontal Machining Centers are essential and no relaxationcan be given for above parameters.

b. 2.3.2 The torque of 2000 /2500 N.m is not compatible with the 50KW / 5000

rpm / 2 speed gearbox specification: please change to 1400 N.m

Ans: The torque values of 2000 / 2500 Nm (100% / 40% load), Spindle Power 50 KW

, max. Speed of 5000 rpm specifications cannot be relaxed. Firms have to indicate the

values of range of Speed ( RPM ) for Constant Torque ( Max. torque 2500 Nm) and

Constant Power 50Kw.

c. 2.3.6: Swing diameter of 2500 mm unnecessary large for the machined

component: to be reduced to max. 2200 mm

Ans: Swing Diameter of 2500 mm is essential keeping in view of the other

components planned for machining on FMS. Swing diameter of 2200 mm not

acceptable.

d. 2.3.9: CNC: shop mill option unnecessary for this automated line.

Ans: Requirement reviewed and Shop Mill is necessary for our future plans. Shop mill

with provision for 4 axes programming to be supplied.


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e. 2.3.11: This description is mixing milling head fixation and toolstrain

device.

i. External clamps with min 150 kN is necessary for angular heads.

ii. Spindle flange diameter of 220 mm is desirable for the toolstrain

tools. External clamps (annexure 1G) are not compatible with those

tools as the flange is rotating with the spindle.

For those tools a clamping force of 20 kN has been proven

satisfactorily.

Ans: i. Milling Heads to be clamped by a fixation by bayonet and conic

centering. Min. 150 kN necessary for angular Heads.

ii.Spindle flange diameter of 220 mm is required for tool strain tools. Mainly used

for Lengthy Boring Bars and Heavy Tools like large milling cutters etc.

As an alternative Fixing by 4 external clamps operated automatically is indicatedin the tender.

f. 2.3.11 and annexure 1G:

a fixation system with 4 rotating clamping unit is suggested.

The freedom of choice of the fixation system has to be given to the

machine tool manufacturer with respect of the necessary accuracies,

fast attachment changing time and high clamping force.

Ans: As indicated above, Milling Heads to be clamped by a fixation by bayonet

and conic centering and Rough Boring Bars and lengthy boring bars to have toolstrain mechanism.

Alternately fixing by 4 external clamps operated automatically is suggested.

g. 2.4.3 (guide ways with anti-friction material)

2.4.6 (form rail & roller bearing units for the guide-ways)

Guide ways with anti-friction material insure high stability and

movement smoothness long tool tip lifetime.

This insures also a longer machine lifetime without heavy

maintenance.

We recommend removing of the 2.4.6.

Ans: 2.4.3. In case of Boring Machines - Guide ways with anti friction material is

recommended.


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2.4.6 Refers to details of axis drives with LM Guide ways for Horizontal

Machining Centers (Mc 2&3).

h. 2.4.4: 3 bearings.

We recommend system with a higher number of bearings (4) that

warranties a longer life time and higher stiffness for stable machining.

Ans: As indicated, minimum no. of bearings should be 3. Higher numbers as per

design requirements are acceptable.

i. It is mentioned under Ref No. 1.0 sl. 2 that, two numbers of Horizontal

machining center / Horizontal boring machines (Mc 2 & 3) as per

specifications in Annexure 1B -For complete machining of cylinder blocks.

Annexure 1B contains specifications for Horizontal machining centers only

and no specifications for Horizontal Boring machine furnished.

Ans: All the parameters like X, Y and Z Travel, Spindle Speed, Spindle Power,

Max. Torque, Pallet Size etc. should be as per the specifications given in

Annexure 1B.

Variations in parameter Acceleration (given as 4 m/Sec2 for HMC ) as per

Standard Boring Machine Spec. is acceptable. Cutting Feed - 1-30000 mm/min.,

Rapid Feed 32m/min. acceptable for Boring Machines.

Q 10. 7.7- Identification system for Fixture / pallet / Setup may be

elaborated?

Ans: As per tender specification System should have facility for identifying the

fixture / Component / Setup by physical inspection by suitable means like Video

Camera / other fool proof means for identification of setups. The system should be

fool proof and should avoid wrong component going into the machine.

Video Camera should be quoted as an option.

Firms should explore providing Fool proof system for identifying fixture, component,

setup using probing and other alternate means like providing sensors for identifying.

Documents

Pre Bid Meeting Clarifications