Sandvik Part_1.pdf

7/25/2019 Sandvik Part_1.pdf

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Within the die andmould makingindustry the develop-ment has been strongthe last years. Machinetools and cutting toolsget more and moresophisticated every

day and can performapplications at a speed and accuracy noteven thought of ten years ago. TodayCAD/CAM is very common and tomachine with so called HSM (High SpeedMachining) it is a necessity.

To manufacture a die or mould, manydifferent cutting tools are involved, fromdeep hole drills to the smallest ball noseendmills. In this application guide thewhole process of die and mould makingwill be explained with focus on the machi-ning process and how to best utilise thecutting tools. However, programming of

machine tools, software, workpiece mate-rials, the function of different types of diesand mould will also be explained. First letus take a look at a simplified flowchart tosee what the different stages are in the dieand mould making process.

INTRODUCTION

2

Contents


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DIE CONSTRUCTION WORK FLOW

3

1. Receiving - standard die parts,

steel castings, planning andscheduling

2. Model shop - tooling aideand checking fixtures

3. CAM-room - schedule,exchange reports DNC/CNCprogramme match, layout

4. 2D-machining - shoes, pads,

5. Blocking - die packs, die design

6.

3D-machining -sub-assembled dies

7. Polishing - standard partsand components

8. Tryout - sheet steel material

specifications check fixture.Inspection - Functional buildevaluation, stable metal panelproduct fixture

9. Die completion - die designhandling devices, productionrequirements, inspectionrequirements

10. Feed back - die history book,check list base

11. Shipping

Simplified, the die construction work flow can be explained as inthe illustration below.

1

2

10

3

4

5

8

7

6

10

9

11

10


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When a tool has to be made, for instance,to a hood of a car you do not make onepress tool and the material for the hoodgoes in on one side, gets pressed and comes

out finished on the other side. It is oftencomplicated shapes, geometries, which hasto be pressed, with different radii and cavi-ties, to close tolerances. To do this thematerial for the hood has to be pressed inseveral press tools where a small change inthe shape is made each time. It is not unusualthat up to 10 different steps are needed tomake a complete component.

There are 5 basic types of dies and moulds;pressing dies, casting dies, forging dies, in-jection moulds and compression moulds.

Pressing dies are for cold-forming of, forinstance, automobile panels with complexshapes. When producing a bonnet for a carmany pressing dies are involved performingdifferent tasks from shaping to cutting andflanging the component. As mentioned

earlier there can be over 10 different stepsin completing a component. The dies areusually made of a number of componentsnormally made of alloyed grey cast-iron.However, these materials are not suitablefor trim dies with sharp cutting edges forcutting off excessive material after thecomponent has been shaped. For this pur-pose an alloyed tool steel is used, often cast.

Example of a chain of process within theautomotive industry1. Blank die to cut out blanks from coiled

material.2.

Draw die to shape the blank.3. Trim die to cut off excessive material.4. Flange die to make the initial bend for

flanges.5. Cam flange die to bend the flanges

further inside.


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Material properties especially influencingmachinability are:

Surface hardness - to resist abrasive andadhesive wear

High content of carbides - to resistabrasive wear Toughness/ductility - to resist chipping

and breakage

Dies and moulds for hot work such as diecasting and forging are used for manufac-turing of for instance engine blocks. Thesedies and moulds are exposed to a numberof demanding conditions of which the

following are particularly critical for themachinability of the tool material.

Hot hardness - to resist plastic defor-mation and erosion

Temperature resistance - to resistsoftening at high temperature

Ductility/toughness - to resist fatiguecracking

Hot yield strength - to resist heat checking

Moulds for plastic materials include in-jection, compression, blow and extrusionmoulds. Factors that influnence the machina-bility in a plastic mould steel are:

Hardness Toughness/ductility Homogenity of microstructure

and hardness

Die and mould materialThe materials described and used as refe-rence-material in this guide are mainlyfrom the steel manufacturer Uddeholm,

with a cross reference list at the end ofthe chapter.

A substantial proportion of productioncosts in the die and mould industry isinvolved in machining, as large volumes ofmetal are generally removed. The finisheddie/mould is also subjected to strict geo-metrical- and surface tolerances.

Many different tool steels are used to pro-duce dies and moulds. In forging and diecasting the choice is generally hot-worktool steels that can withstand the relativelyhigh working temperatures involved.Plastic moulds for thermoplastics andthermosets are sometimes made from cold-work tool steel. In addition, some stainlesssteels and grey cast iron are used for diesand moulds. Typical in-service hardness is

in the range of 32 - 58 HRC for die andmould material.


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Hot work materialHot work material is typically used for: Die casting Forging Extrusion

When a die casting die is hardened andtempered, some warpage or distortion

normally occurs. This distortion is usuallygreater at higher temperature. This is wellknown, and it is normal practice to leavesome machining allowance on the die priorto hardening. This makes it possible toadjust the die to the correct dimensionafter hardening and tempering by finishmachining or grinding.

Distortion of the material can take place

because of machining stresses. This typeof stress is generated during machiningoperations such as milling and grinding.If stresses have built up in a part, they willbe released during heating. Heating releasesstresses, created through local distortionwhich in turn can lead to overall distor-tion. In order to reduce distortion whileheating during the hardening process, astress relieving operation can be carried

out. It is recommended that the materialbe stress relieved after rough machining.

Any distortion can be adjusted during finemachining, prior to quenching. The size ofthe die or mould often decides the hardnessof it, small moulds are 50 - 52 HRC and bigones are 45 - 48 HRC.

The amount of non-metallic inclusions and

the hardness of the steel are some factors thathave great influence on the machinability.

Typical failure mechanisms of hot worksteels are:Heat checkingHot wearPlastic deformationCrackingCorrosion

Optimum properties of the steel is:Good hot hardnessGood tempering resistanceLow thermal expansionGood toughness and ductilityGood thermal conductivity


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The Uddeholm steel grades for hot work are:Alvar 14Orvar 2MOrvar Supreme

Vidar SupremeQRO 90 SupremeHotvarDievar

As the performance of the die casting diecan be improved by lowering the impurities,i.e. sulphur and oxygen, all the hot work toolsteels are produced with extremely lowsulphur and oxygen levels.

The optimum structure for machining is auniform distribution of well spheroidizedcarbides in a soft annealed ferritic structurewith as low hardness as possible. The manu-

facturing process gives a homogeneousstructure and a hardness of approximately180 HB. The steels are characterised by avery uniform machinability.


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Cold work steelsCold work steels are used for: Blanking & shearing Cold forming Cold extrusion Cold forging Cold rolling

Powder pressing

If all areas where cold work tools are used,such as automotive, paper and pulp, generalmachining etc., the automotive industryamount to 40% of the total usage and isby far the largest segment. Within theautomotive industry the cold work toolsare mostly used for trimming tools. Otherapplication areas are low-alloyed steel for

holders and high alloyed steel for punchesand dies.

Typical failure mechanisms in cold workapplications are:(1) Abrasive wear(2) Plastic deformation(3) Chipping/cracking(4) Galling (built up edge)

The biggest problem with cold work isabrasive wear (scratching particles) andadhesive wear (micro-welds).

Adhesive wear is especially common onstainless steels in the automotive industrywhere a lot of components such as exhaustpipes and mufflers are made in stainlessmaterial.

Pressing tool for components to electrical stoves

Automotive

Mechanical engineering

Houshold appliances

Pulp and paper

Building

Electronics

Abrasive wear

Cracking

Built up edge

Chipping

Plastic deformation


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To come to terms with the abrasive wear,the carbon and chromium content can beincreased, however the material becomesmuch tougher to machine and wears heavily

on the cutting tools.

The steels for cold work have a highcarbon content and can be hardened to avery high hardness and as the alloy contentand hardness goes up the machinability

goes down, which will be explained in themachinability section in this chapter.

Short production series

Medium series

Long series

Arne 54 - 62 HRCGrane 54 - 58 HRC

Calmax 54 - 58 HRC

Rigor 56 - 62 HRC

Sverker 21 56 - 61 HRC

Sverker 3 56 - 62 HRC

Vanadis 4 56 - 62 HRC




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Cold work steels from Uddeholm are:ArneCalmax/CarmoRigor

Sverker 21Sverker 3Vanadis 23Vanadis 4Vanadis 6Vanadis 10


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Plastic segmentMoulds for plastic are used for a widevariety of products, for instance, in average11% of the total weight of a car is plastic

material and much of it is produced byplastic injection moulding. Another largesegment is the electronic industry, whichconstantly changes the models on televisionsets, computers and mobile phones, tomention some products.

A wide range of cavity sizes and shapes areproduced by the die and mould industrywhen producing plastic components. Radii

of 0.25 - 3 mm are typical in such cavitiesand many moulds require taper angles inthe range of 0.5 - 5 degrees to allow thewithdrawal of components. The dimensionalaccuracy required can be down to plus/minus 5 microns and the positional accuracyof cavities of same order to ensure nomismatch between mating faces in a dieset. Surface finish values of Ra 1 micronand less is necessary in many cases.

The steel types most commonly used inmouldmaking are; prehardened mould- andholder steels, through hardening mouldsteels and corrosion resistant mould steels.

Prehardened mould- and holder steel aremostly used for large moulds, moulds withlow demands on wear and high strengthholder plates.

Through-hardened steels are used for longproduction runs, to resist abrasion fromfilling agent, and additives in the plastic andto counter high closing or injection pressures.

Corrosion resistant mould steels are usedif a mould is likely to be exposed to acorrosion risk, then a stainless steel isstrongly recommended. Plastic moulds

can be affected by corrosion in severalways. Plastic materials can produce corro-

sive by-products, e.g. PVC, corrosion alsoleads to reduced cooling efficiency whenwater channels become corroded or com-

pletely blocked. Condensation caused byprolonged production stoppages, humidity,aggressive gases, acid, cooling/heatingwater, flow rate, plastic material or storageconditions often lead to corrosion.

It is important to have good surface finishin the cooling holes not to get corrosion,which can make the whole mould crack.The threads where the cooling hoses are

connected must also be made correct toprevent that corrosion occurs with acracked mould as a result.

Criterias for mould steel selection Moulding method Plastic material Mould size Number of shots Surface finish

The mouldmaker is primarily interested inthe machinability of the steel, its polishabi-lity, heat treatment and treatment properties.The moulder is looking for a mould withgood wear and corrosion resistance, highcompressive strength etc.

All aspects has to be taken into account,however, good uniform machinability is of

outmost importance considering that thecost of machining accounts for a largeamount of the total cost of manufacturinga mould.


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Uddeholm grades for plastic materials are:

Holdax

Impax SupremeRamaxOrvar SupremeGrane

Example of material and hardness for different lengths of production series

Calmax

Stavax ESRCorraxElmaxVanadis 4

For long runs > 1 000 000

For medium runs100 000-1 000 000 shots

For short runs < 100 000 shots

High hardness steel should be used 48 - 65 HRC,Calmax, Grane, Orvar Supreme, Stavax ESR,Corrax, Rigor, Vanadis 4, Elmax

Pre-hardened steel should be used 30 - 45 HRC,Impax Suprece, Ramax

Soft annealed steel of aluminium should be used160-250 HBCalmax, Gran, Alumec


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VANADIS 10

VANADIS 6

ELMAX

SVERKER 3

VANADIS 23

VANADIS 4

CORRAX

SVERKER 21

IMPAX SUPHOLDAX

RAMAX S

RIGOR

GRANE

CHIPPER

CARMO

CALMAXHOTVAR

ARNE

DIEVAR

UHB 11

STAVAX ESR

ORVAR SUP

QRO 90 SUP

FORMAX

14

Requirement

Favourable impact strengthand good polishability

Good wear resistance

Avoid subsequent heattreatment

Material properties

High purity

Hard carbides in steel matrix

High delivery hardness

Influence on machinability

Poor chip breaking

Considerable tool wear

High cutting edge tempera-ture, high tool wear

Machinability in different tool steels, facemilling whith carbide inserts

Go

od

Machinability

Low

0 100 200 300 400 500Cutting speed Vc m/min

Machinability in Tools Steels

Face Milling with Carbide


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Material for prototypes and short seriesALUMEC has an excellent machinabilityalso with high cutting speed, which leadsto lower mould cost and shorter delivery

time. This also makes ALUMEC suitablefor production of prototypes as well.

ALUMEC is a high-tensile aluminiumalloy that is produced in the form of hot-rolled, heat-treated plate. It is subjected toa special cold-stretching process for maxi-

mum stress relief. Because of its highstrength and good stability, ALUMEChas achieved widespread use within the

mechanical engineering industry. Thecharacteristics and advantages offered byALUMEC make it an ideal material forshort and medium-long series, which arenot subjected to very high compressiveforces, or for abrasive plastics.


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Cold work steels

ARNE

VANADIS 23

VANADIS 30

VANADIS 60

CARMO/CALMAX

CHIPPER /VIKING

FERMO

RIGOR

SVERKER 3

SVERKER 21

VANADIS 10

VANADIS 4

VANADIS 6

Hot work steel

HOTVAR

ALVAR 14ORVAR 2 M

ORVAR SUPREME

QRO 90 SUPREME

VIDAR SUPREME

DIEVAR

Mould steel

ELMAX

GRANE

IMPAX SUPREME

OPTIMAX

RAMAX S

STAVAX ESR

CORRAX

Holder steel

FORMAX

HOLDAX

UHB 11

DF-2

ASP-23

ASP-30

ASP-60

/635H/635

VIKING

-

XW-10

XW-5

XW-41

VANADIS 0

VANADIS 4

VANADIS 6

-

-8402

8407

QRO 90

-

-

ELMAX

-

718 SUPREME

-

168

STAVAX ESR s-136

-

-

HOLDAX

760

02.1

03.11

03.11

03.11

-

-

-

-

-

-03.11/03.22

03.11/03.22

-

02.1

-

01.2

01.2

2140

2725

2726

2727

-

-

2260

-

2312

2310

-

-

-

-

-2242

2242

-

-

-

2250

-

2314

-

2314

-

(2172)

-

1650/1672

1.2510

1.3344

(1.3204)

1.3241

1.2358

(1.2631)

-

1.2379

1.2436

1.2379

-

-

-

-

1.27141.2344

1.2344

-

1.2343

-

-

(1.2721)

1.2738

(1.2083)

-

(1.2083)

-

-

1.2312

1.1730

O1

M3 Class 2

-

-

-

-

A2

D6

D2

-

-

-

H13

H13

-

H11

-

-

(L6)

(P20)

-

-

-

-

-

4140

1148

Uddeholm grades SandvikCoromantCMC

ASSAB SwedenSS

GermanyW.-No

USAAISI/ASTM


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SKS3

-

-

-

SKD12

(SKD2)

SKD11

-

SKD4ModSKD61

SKD61

SKD7Mod

SKD6

-

-

SUS420

SUS420

-

-

90MWCV5

Z120WDCV06-05-04-03

ASP30

ASP60

Z100CDV5

Z210CW121

Z160 (CDV12)

-

-

-

-

Z5NCDV7Z40CDV5

Z40CDV5

Z38CDV5

-

-

-

-

40CMND8

-

Z30C17

Z40C13

-

-

40CMD8+S

XC48

95MnWCr5KU

HS6-5-3

-

-

-

-

-

X155CrMoV51KU

X25CRW121KU

X155CrVMo121KU

-

-

-

-

56NiCrMo7KUX40CrMoV511KU

X40CrMoV511KU

-

-

-

-

-

X41Cr13KU

-

-

-

-

-

F-5220

F-5605

-

-

-

-

-

F-5227

F-5213

F-5219

-

-

-

-

F-5307F-5310

F-5318

-

F-5317

-

-

F-5305

F-5303

-

-

-

-

-

F-5304

F-1142

VND

-

-

-

-

-

-

-

VC131

VD2

-

-

-

-

VMOVH13

VH13

-

VPCW

-

-

VCO

VP20

VC150

VP420IM

VC150

-

-

-

JapanJIS

FranceANFOR

ItalyUNI

SpainUNE

Brazil

B01

-

-

-

-

BA2

B06

BD2

-

-

-

BH13

BH13

BH11

-

-

UKBS


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HOTVARHOTVAR is a highperformance molyb-denum-vanadium

alloyed hot-work toolsteel which is charac-terised by high hotwear resistance, verygood high temperature

properties, high resistance to thermal fatigue,very good temper resistance and thermalconductivity. The steel is suitable forapplications where hot wear and/or plasticdeformation are the dominating failure

mechanisms. Suitable applications areWarm forging dies and punches, rollingsegments in roll forging, hot bending toolsand zinc die casting dies.

DIEVARDIEVAR is a high performance chromium-molybdenum-vanadium alloyed hot worksteel which offers a very good resistance toheat checking, gross cracking, hot wear and

plastic deformation. The steel is characteri-sed by excellent ductility in all directions,good temper resistance and good high-temperature strength. DIEVAR is suitablefor die casting, forging and extrusion tools.

CORRAXCORRAX is a precipitation hardeningsteel with exceptionally good corrosionresistance.

Compared with conventional corrosionresistant tool steel, CORRAX has someadvantages, flexible hardness 32-50 HRc,achieved by an ageing treatment, extremelygood dimensional stability during ageing,high uniformity of properties also for largedimensions, good weldability and no hardwhite layer after EDM.

ALUMECALUMEC is a high-tensile aluminiumalloy that is produced in the form of hot-rolled, heat-treated plate. It is subjected toa special cold-stretching process for maxi-mum stress relief. Because of its highstrength and good stability, ALUMEC hasachieved widespread use within the

mechanical engineering industry. The cha-racteristics and advantages offered byALUMEC make it an ideal material forshort and medium-long series, which arenot subjected to very high compressiveforces, or for abrasive plastics.

ALUMEC has an excellent machinabilityi.e. high cutting speed, which leads tolower mould cost and shorter delivery

time. This also makes ALUMEC suitablefor production of prototypes as well.

ORVAR SUPREMEORVAR SUPREME is a chromium-molybdenum-vanadium-alloyed steel,which is characterised by:

High level of resistance to thermal shockand thermal fatigue

Good high-temperature strength Excellent toughness and ductility in alldirections

Good machinability and polishability Excellent through-hardening properties Good dimensional stability during

hardening.

DESCRIPTION OF UDDEHOLM MATERIAL

Typicalanalysis %

Deliverycondition

Solution treated to ~34 HRC

C0,03

Si0,3

Mn0,3

Cr12,0

Ni9,2

Mo1,4

Al1,6


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ORVAR SUPREME is suitable for diecasting dies, tools for hot pressing andextrusion.

Good corrosion resistance Good polishability Good wear resistance Good machinability

Good stability in hardening.

STAVAX ESR is suitable for all types ofplastic moulding tools.

QRO 90 SUPREMEQRO 90 SUPREME is a high-performance,chromium-molybdenum-vanadium-alloyed hot-work tool steel which ischaracterised by:

Excellent high temperature strength andhot hardness

Very good temper resistance Unique resistance to thermal fatigue Excellent thermal conductivity Good toughness and ductility in longi-

tudinal and transverse directions Uniform machinability Good heat treatment properties.

QRO 90 SUPREME is suitable for diecasting- and extrusion dies and associatedtooling as well as forging dies.

STAVAX ESRSTAVAX ESR is a premium grade stainlesstool steel with the following properties:

Typicalanalysis %

Standardspecicification

Deliverycondition

Premium AISI H13, W.-Nr. 1.2344

Soft annealed to approx. 180 HB

C0,39

Si1,0

Mn0,4

Cr5,2

Mo1,4

V0,9

Typical

analysis %


Deliverycondition

None. Product is covered by patentworld wide


C

0,38

Si

0,30

Mn

0,75

Cr

2,6

Mo

2,25

V

0,9

Typicalanalysis %


Deliverycondition

AISI 420, modified

Soft annealed to approx. 200 Brinell

C0,38

Si0,9

Mn0,5

Cr13,6

V0,3

OPTIMAXThe rapid development in the high-techarea is putting higher and higher demandson the tool steel. Surface finishes, whichhave not been possible to achieve withordinary tool steel, are required. Forthese extreme requirements OPTIMAXhas proven to be the right choice.Characteristics found in OPTIMAX are:

Excellent polishability Good corrosion resistance Good wear resistance Good machinability Good stability in hardening.

OPTIMAX is suitable for applicationswhere extreme surfaces are required suchas lens moulds, moulds for compact discsand moulds for medical applications.

Typicalanalysis %

Delivertycondition


C0,38

Si0,9

Mn0,5

Cr13,6

V0,3


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HOLDAXHOLDAX is a vacuum-degassedchromium- molybdenum alloyed steelthat is supplied in hardened and temperedcondition.

HOLDAX is characterised by: Excellent machinability Good resistance to indentation Uniform hardness in all dimensions.

HOLDAX is suitable for holders/bolstersfor plastic moulds and die casting dies,plastic and rubber moulds, support platesand constructional parts.

ELMAXELMAX is a high chromium-vanadium-molybdenum alloyed PM steel with thefollowing characteristics:

High wear resistance High compressive strength Corrosion resistance Very good dimensional stability.

High wear resistance is normally connectedwith low corrosion resistance and viceversa. In ELMAX it has however beenable to achieve this unique combination of

properties by a powder-metallurgy-basedproduction method. ELMAX is suitablefor plastic moulding.

Typicalanalysis %

Deliverycondition

Soft annealed approx. 240 Brinell

C1,7

Si0,8

Mn0,3

Cr18,0

Mo1,0

V3,0

Typicalanalysis %


Deliverycondition

AISI 4130-35 improved

Hardened and tempered to 290-330 HB

C0,40

Si0,4

Mn1,5

S0,07

Cr1,9

Mo0,2

RAMAX SRAMAX S is a chromium alloyed stainlessholder steel, which is supplied in the har-dened and tempered condition.

RAMAX S is characterised by: Excellent machinability Good corrosion resistance Uniform hardness in all dimensions Good indentation resistance.

RAMAX S is suitable for holders/bolstersfor plastic moulds.

Typicalanalysis %


Deliverycondition

(AISI 420 F)

Hardened and tempered to ~ 340 HB

C0,33

Si0,35

Mn1,35

Cr16,7

S0,12


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FORMAXFORMAX is a low carbon steel that canbe supplied as hot-rolled or fine-machined

condition.

FORMAX is characterised by: Good machinability Easy to flame-cut Good mechanical strength Can be case hardened Good weldability.

FORMAX is suitable for bolsters, punch

holders, die holders, backing plates, guideplates, support plates, jigs, fixtures andconstructional parts.

CALMAXCALMAX is a chromium-molybdenum-vanadium-alloyed steel characterised by:

High toughness Good wear resistance Good through hardening properties Good dimensional stability in hardening Good polishability Good weldability Good flame- and induction hardenability.

CALMAX is suitable for both cold workand plastic applications.

Typicalanalysis %

Deliverycondition

Soft annealed approx. 200 HB

C0,6

Si0,35

Mn0,8

Cr4,5

Mo0,5

V0,2

Typicalanalysis %


Delivery

condition

(W.-Nr. 10050,SS 2172)

Hot rolled.

Hardness approx. 170 HB

C0,18

Si0,3

Mn1,4

VANADIS 4VANADIS 4 is a chromium-molybdenum-vanadium-alloyed PM steel, which ischaracterised by:

High wear resistance High compressive strength Very good through-hardening properties Very good toughness Excellent dimensional stability after

hardening and tempering Good resistance to tempering back.

VANADIS 4 is suitable for applications

where adhesive wear and/or chipping aredominating problems such as blanking andforming, cold extrusion tooling, powderpressing, deep drawing and knives.

Typicalanalysis %

Delivertycondition


C1,5

Si1,0

Mn0,4

Cr8,0

Mo1,5

V4,0


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VANADIS 6VANADIS 6 is a chromium-molybdenum-vanadium alloyed PM steel which ischaracterised by:

Very high abrasive-adhesive wearresistance

High compressive strength Good toughness Very good dimensional stability at heat

treatment and in service Very good through-hardening properties Good resistance to tempering back High cleanliness

VANADIS 6 is suitable for long run toolingof work materials where mixed (abrasive-adhesive) or abrasive wear and/or chipping/cracking and/or plastic deformation aredominating failure mechanisms. Such asblanking, powder pressing, plastic mouldsand tooling subjected to abrasive wearconditions.

VANADIS 10 is suitable for very long runtooling where abrasive wear is the domina-ting problem for example blanking andforming, gasket stamping, deep drawing,

cold forging slitting knives, powder pressingextruder screws etc.

VANADIS 23VANADIS 23 is a chromium-molybde-num- tungsten-vanadium alloyed highspeed steel PM, which is characterised by:

High wear resistance (abrasive profile) High compressive strength Very good through-hardening properties Good toughness Very good dimensional stability on heat

treatment Very good temper resistance.

VANADIS 23 is suitable for blanking andforming of thinner work materials such asblanking of medium to high carbon steels,blanking of harder materials such as harde-ned or cold rolled strip steels, plasticmould tooling subjected to abrasive wearcondition etc.

Typicalanalysis %

Delivertycondition

Soft annealed to approx. 280-310 HB

C2,9

Si1,0

Mn0,5

Cr8,0

Mo1,5

V9,8

Typicalanalysis %


Deliverycondition

(AISI M3:2/W.-Nr 1.3344)


C1,28

Cr4,2

M05,0

W6,4

V3,1

Typicalanalysis %

Deliverycondition


C2,1

Si1,0

Mn0,4

Cr6,8

Mo1,5

V5,4

VANADIS 10VANADIS 10 is a chromium-molybde-num-vanadium-alloyed PM steel, which ischaracterised by:

Extremely high abrasive wear resistance High compressive strength Very good through-hardening properties Good toughness Very good stability in hardening Good resistance to tempering back.


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ALVAR 14ALVAR 14 is a chromium-nickel-molyb-denum-vanadium-alloyed steel, which ischaracterised by:

Good toughness Good resistance to high thermal stresses Good stability in hardening Good through-hardening properties.

ALVAR 14 is suitable for hot workingtools such as support parts for extrusiontooling, hot forging tools, dies for tin, leadand zinc alloys and tools for hot shearing.

ARNEARNE general-purpose oil-hardening toolsteel is a versatile manganese-chromium-tungsten steel suitable for a wide variety ofcold-work applications.

Its main characteristics include: Good machinability Good dimensional stability in hardening A good combination of high surface

hardness and toughness after hardeningand tempering. These characteristicscombine to give a steel suitable for themanufacture of tooling with good tool-life and production economy.

Typicalanalysis %


Deliverycondition

W.-Nr. 1.2714, DIN 56 NiCrMoV7

1. Soft annealed to max. 250 HB.2. Hardened and tempered to 330-400 HB

(36-43 HRC; 1100-1350 N/mm2).

C0,5

Si0,3

Mn0,7

Cr1,1

Ni1,7

Mo0,5

V0,1

Typicalanalysis %


Deliverycondition

AISI o1, W.-Nr. 1.2510

C0,95

Mn1,1

Cr0,6

W0,6

V0,1

GRANEGRANE is a Chromium-Nickel-Molybdenum-alloyed steel, which is cha-racterised by:

High toughness

High hardness Good stability in hardening High resistance to wear Good polishing properties Good machinability.

GRANE is suitable for moulds in the plasticindustry and for a wide variety of heavy-duty tools exposed to severe pressure,shock loading or bending stresses.

Soft annealed approx. 190 HB

Typicalanalysis %


Deliverycondition

(L6)

Soft annealed to approx. 230HB.

C0,55

Si0,3

Mn0,5

Cr1,0

Ni3,0

Mo0,3


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SVERKER 3SVERKER 3 is a high-carbon, high-chro-mium tool steel alloyed with tungsten,characterised by:

Highest wear resistance High compressive strength High surface hardness after hardening Good through-hardening properties Good stability in hardening Good resistance to tempering-back.

SVERKER 3 is recommended for applica-tions demanding maximum wearresistance,such as blanking and shearing tools forthin, hard materials, long-run press tools,forming tools, moulds for ceramics andabrasive plastics.

SVERKER 21SVERKER 21 is a high-carbon, high-chro-mium tool steel alloyed with molybdenumand vanadium characterised by:

High wear resistance High compressive strength Good through-hardening properties High stability in hardening Good resistance to tempering-back.

24

RIGORRIGOR is an air- or oil hardening chromi-um-molybdenum-vanadium alloyed toolsteel characterised by:

High stability after hardening High compressive strength

Good hardenability Good wear resistance.

RIGOR is suitable for blanking, punching,trimming tools for forgings and tools forbending, raising, dies and inserts for moul-ding tablets, abrasive plastics etc.

Typicalanalysis %


Deliverycondition

AISI A2, BA2, W.-Nr. 1.2363

Soft annealed to approx. 215 HB.

C1,0

Si0,3

Mn0,6

Cr5,3

Mo1,1

V0,2

Typicalanalysis %


Deliverycondition

AISI D6, (AISI D3), W.-Nr. 1.2436


C2,05

Si0,3

Mn0,8

Cr12,5

W1,3

ORVAR 2 MicrodizedORVAR 2 Microdized is a chromium-molybdenum-vanadium alloyed steel,which is characterised by:

Good resistance to abrasion at both lowand high temperatures

High level of toughness and ductility Uniform and high level of machinability

and polishability Good high-temperature strength and

resistance to thermal fatigue Excellent through-hardening properties Very limited distortion during hardening.

ORVAR 2 M is suitable for plasticmoulding applications and extrusion tools.

Typicalanalysis %


Deliverycondition

AISI H13,W.-Nr. 1.12344


C0,39

Si1,0

Mn0,4

Cr5,3

Mo1,3

V0,9


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SVERKER 21 is suitable for toolsrequiring very high wear resistance, com-bined with moderate toughness (shock-resistance) for example blanking shearing,

cold extrusion dies, cold-heading tools etc.

UHB 11Uddeholms tool steel UHB 11 is an easymachinable carbon steel characterised by:

Good machinability Fair resistance to abrasion Good mechanical strength

UHB 11 is suitable for punch holders, die

holders, guide plates, backing plates, jigs,fixtures, simple bending dies and simplestructural components.

CARMOCARMO is a high-strength, flame-, induc-tion- and through hardening steel delive-red prehardened to 240-270 HB. The sur-face of the steel can be flame-hardenedwithout water cooling to a hardness of582 HRC. The depth of hardness is nor-mally 4-5 mm and the hardened and tem-pered matrix is a good base for the flame-

25

Typicalanalysis %


Deliverycondition

AISI D2, W.-Nr. 1.2379


C1,55

Si0,3

Mn0,4

Cr11,8

Mo0,8

V0,8

Typicalanalysis %


Delivery

condition

AISI 1045

As rolled. Hardness approx. 200 HB

C0,47

Si0,3

Mn0,6

S0.04

Typicalanalysis %


Prehardened to 240-270 HB

C0,6

Si0,35

Mn0,8

Cr4,5

Mo0,5

V0,2

hardened layer. The steel can be easilyrepair welded.

CARMO can be used in the flammable-

hardened or in the through hardened con-dition for blanking and forming of bothcar body parts (thin sheet) or structuralparts (thicker sheet).

IMPAX SUPREMEIMPAX SUPREME is a premium-qualityvacuum-degassed Cr-Ni-Mo-alloyed steelthat is supplied in the hardened and tem-pered condition. IMPAX SUPREME ismanufactured to consistently high qualitystandards with a very low sulphur con-tent, giving a steel with the following cha-racteristics:

Good polishing and photo-etchingproperties

Good machinability High purity and good homogeneity Uniform hardness.

IMPAX SUPREME is suitable for injec-tion moulds and extrusion dies for ther-mo-plastics, blow moulds, forming tools,

press brake dies and structural components.

Typicalanalysis %

Standardspec.

Delivery

condition

AISI P20 modified

Hardened and tempered to 290-330 HB

C0,37

Si0,3

Mn1,4

Cr2,0

Ni1,0

Mo0,2

S0,008


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26

Cast-iron is an iron-carbon alloy with acarbon content ofmostly 2-4% as well as

other elements likesilicon, manganese,phosphorus andsulphur. Corrosionand heat resistance

may be improved with additions of nickel,chromium, molybdenum and copper.Good rigidity, compressive strength andfluidity for cast iron are typical properties.Ductility and strength can be improved by

various treatments, which affect the micro-structure. Cast-iron is specified, not bychemical analysis, but by the respective

mechanical properties. This is partly dueto that the cooling rate affects the cast-ironproperties.

Carbon is presented as carbide-cementiteand as free carbon-graphite. The extentsof these forms depend partly on theamount of other elements in the alloy. Forinstance, a high-silicon cast-iron will bemade up of graphite with hardly anycementite. This is the type known as greyiron. The silicone content usually variesbetween 1-3%. A low amount of siliconewill stabilize carbides and the cast-iron

will be made up dominantly of cementitewith little graphite. This is a hard but weakbrittle type called white iron.

CAST-IRON


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27

In spite of the silicone content having adecisive influence on the structure, thecooling rate of cast iron in castings is alsoinfluential. Rapid cooling may not leave

enough time for grey iron to form, as thesilicone has not had time to decompose thecementite into the graphite. Varying sec-tional thicknesses in castings affect thecooling rate, affecting the state of carbon.Thick section will solidify into grey ironwhile thin ones will chill into white iron.Hence chilled cast-iron. Modern castingtechniques control analysis, cooling rates,etc. to provide the cast-iron components

with the right graphite structure. Also toprovide chilled parts where needed, forinstance a wear face on a component.Manganese strengthens and toughens cast-iron and is usually present in amounts of0.5-1%.

For this reason, a thin or tapered sectionwill tend to be more white iron because ofthe cooling effect in the mould. Also the

surface skin of the casting is often harder,white iron while underneath is grey iron.

The basic structural consituents of thedifferent types of cast-iron are ferritic,pearlitic or a mixture of these.

Types of cast-iron with ferritic matrixand little or no pearlite are easy to machine.They have low strength and normally a

hardness of less than 150 Brinell. Because

of the softness and high ductility of ferritethese types of cast-iron can be stickyand result in built-up edge forming atlow cutting data, but this can be avoided

by increasing the cutting speed, if theoperation permits.

Types of cast-iron with ferritic/pearlitic orpearlitic matrix range from about 150 HBwith relatively low strength to high-strength, hard cast-irons of 280-300 HBwhere pearlitic matrix dominates.

Pearlite has a stronger, harder and less

ductile structure than ferrite, its strengthand hardness depending on whether it hasrough or fine lamellar. The more fine-grai-ned and more fine lamellar the pearlite, thehigher strength and hardness. This meansit has smaller carbides with less abrasivewear but is more toughness demanding dueto smearing and built up edge formation.

Carbides are extremely hard constituents

whether they are of pure cementite orcontain alloying material. In thin plates, asin pearlite, cementite can be machined, butin larger particles which separate the con-stituents they drastically reduce the machi-nability. Carbides often occur in thin sec-tions, projecting parts or corners of cas-tings due to the rapid solidification, givinga finer structure, of these parts.


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28

Hardness of cast iron-is often measured inBrinell. It is an indication of machinability,

which deteriorates with increasing Brinellhardness. But the hardness value is anunreliable measurement of machinabilitywhen there are two factors that the valuedoes not show.

In most machining operations it is the hardparts at the edges and corners of compo-nents which cause problems when machi-ning. The Brinell test cannot be carried out

on edges and corners and therefore thehigh hardness in these parts is not discove-red before machining is undertaken.

A Brinell test says nothing about the cast-irons abrasive hardness which is the diffe-rence between the hardness on the basicstructure and the hardness of the constituente.g. a particle of carbide.

Abrasive hardness due to sand inclusionsand free carbides is very negative for

machinability. A cast-iron of 200 HB andwith a number of free carbides is more dif-ficult to machine than a cast-iron of 200HB and a 100% pearlitic structure with nofree carbides.

Alloy additives in cast-iron affect machi-nability in as much as they form or preventthe forming of carbides, affect strength and/or hardness. The structure within the cast-

iron is affected by the alloying materialwhich, depending on its individual character,can be divided into two groups.

1. Carbide forming: Chromium (Cr),cobalt (Co), manganese (Mr), vanadium (V).

2. Graphitizing elements: Silicone (Si),nickel (Ni), aluminium (Al), copper (Cu),titanium (Ti).


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29

Grey cast-ironThere is a large range of grey cast-ironswith varying tensile strengths. The siliconcontent/sectional area combinations form

various structures of which the low-sili-con, fine graphite and pearlite make thestrongest and toughest material. Tensilestrength varies considerably throughoutthe range. A coarse graphite structuremeans a weaker type. A typical cast-iron,where metal cutting is involved, often hasa silicon content of around 2%. Commonare the austenitic types.

Nodular cast-iron (SG)The graphite is contained as round nodules.Magnesium especially is used to depositthe gobules and added to become a magne-sium-nickel alloy. Tensile strength, tough-ness and ductility are considerably impro-ved. Ferritic, pearlitic and martensitictypes with various tensile strengths occur.

The SG cast-iron is also a graphite structu-

re with properties in-between that of greyand nodular cast-iron. The graphite flakesare compacted into short ones with roundends through the addition of titanium andother treatment.

Malleable cast-ironWhen white iron is heat treated in a par-ticular way, ferritic, pearlitic or martensiticmalleable cast-iron is formed. The heat

treatments may turn the cementite intospherical carbon particles or remove thecarbides. The cast-iron product is malleab-le, ductile and very strong. The siliconcontent is low. Three categories occur:ferritic, pearlitic and martensitic and theymay also be categorized as Blackheart,Whiteheart and pearlitic.

Alloyed cast-ironThese are cast-irons containing largeramounts of alloying elements and, generally,these have similar effects on properties of

cast-iron as they do on steel. Alloying ele-ments are used to improve properties byaffecting structures. Nickel, chromium,molybdenum, vanadium and copper arecommon ones. The graphite-free whitecast-iron is extremely wear resistant whilethe graphite-containing cast-iron is alsoknown as heat resistant ductile cast-iron.Corrosion resistance is also improved insome types. Toughness, hardness and heat

resistance are typically improved.

The main difference in these types is theform in which carbon, mainly graphiteoccurs.

The general relative machinability of thefour main kinds of cast-iron is indicated ina diagram where (A) is grey cast-iron, (B)malleable, (C) S.G. iron and (D) chilled,

white cast-iron.

A B C D

1009080706050403020100

Relative machinability


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30

Machinability of cast-ironWhen establishing machinability characte-ristics of cast-iron grades, it is often usefulto note the analysis and structure:

Reduced carbon content results in lowermachinability since less fracture-indica-ting graphite can be formed.

Ferritic cast-iron with an increased sili-con content is stronger and less ductileand tends to give less build-up edge.

Increased pearlitic content in the matrixresults in higher strength and hardnessand decreased machinability.

The more fine lamellar and fine-grainedthe pearlite is, the lower is the machina-bility.

The presence of about 5% of free carbidesin the matrix decreases machinabilitysubstantially.

The effects of free carbides with respectto machinability is more negative incast-iron with pearlitic matrix, becausethe pearlite anchors the carbide particles

in the matrix. This means that it isnecessary for the insert edge to cutthrough the hardest particles instead of,as can be done with a ferritic structure,pulling out or pushing into the softferrite.

The top of the casting can have a some-what lower machinability due to im-purities such as slag, casting sand etc.which float up and concentrate in this

surface area.

Generally it can be said that: the higher thehardness and strength that a type of cast-ironhas, the lower is the machinability and the

shorter the tool-life that can be expectedfrom inserts and tools.

Machinability of most types of cast-ironinvolved in metal cutting production isgenerally good. The rating is highly relatedto the structure where the harder pearliticcast-irons are somewhat more demandingto machine. Graphite flake cast-iron andmalleable cast-iron have excellent machi-

ning properties while SG cast-iron is notquite as good.

The main wear types encountered whenmachining cast-iron are abrasion, adhesionand diffusion wear. The abrasion is produ-ced mainly by the carbides, sand inclusionsand harder chill skins. Adhesion wear withbuilt-up edge formation takes place atlower machining temperatures and cutting

speeds. This is the ferrite part of cast-ironwhich is most easily welded onto theinsert but which can be counteracted byincreasing speed and temperature. On theother hand, diffusion wear is temperaturerelated and occurs at high cutting speeds,especially with the higher strength cast-irongrades. These grades have a greater defor-mation resistance, leading to higher tempe-rature. This type of wear is related to the

reaction between cast-iron and tool andhas led to some cast-iron machining beingcarried out at high speeds with ceramictools, achieving good surface finish.


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31

Typical tool properties needed, generally,

to machine cast-iron are high hot-hardnessand chemical stability but, depending uponthe operation, workpieces and machiningconditions, toughness, thermal shock resi-stance and strength are needed from thecutting edge. Ceramic grades are used tomachine cast-iron along with cementedcarbide.

Obtaining satisfactory results in machining

cast-iron is dependent on how the cuttingedge wear develops: rapid blunting willmean premature edge breakdown throughthermal cracks and chipping and poorresults by way of workpiece frittering,poor surface finish, excessive waviness, etc.Well developed flank wear, maintaining abalanced, sharp edge, is generally to bestrived for.


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32

Materiel

type

Grey

Cast-iron

Alloyed

grey-iron

Alloyed

grey-iron

Nodular

cast-iron

Nodularcast-iron

Hardness

HB

150-200

220-260

210-240

200-260

230-300

Area of

use

Frames

Dies

Dies

Dies&

stamps

Dies&stamps

Japan

JIS

FC250

FC300

FC350

Not

available

Not

available

FCD450

FCD550

FCD600FCD800

France

ANFOR

Ft25

Mn450

Mn450

FGS400

FGS600

Italy

UNI

G25

GNM45

GNM45

GS370-17

GS600

Brazil

GG25

GG26

GG26

GGG60

GGG60

Materiel

type

Grey

Cast-iron

Alloyedgrey-iron

Alloyed

grey-iron

Nodular

cast-iron

Nodular

cast-iron

Hardness

HB

150-200

220-260

210-240

200-260

230-300

Area of

use

Frames

Dies

Dies

Dies&

stamps

Dies&

stamps

CMC

Coromant

08.1/2

07.2

07.2

09.1

09.2

Sweden

SS

0125

0852

0852

0717-12

0732-3

Germany

DIN

GG25

GG26

GG26

GGG60

GGG60

USA

ASTM

A48

Class 40B

-

-

-

A536

Grade 80-55-06

UK

BS

BS1452

G150

G250 +Cr % Mo

BS1452

G250

BS2989

600/3

BS2989

700/2


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33

FROM QUOTATION TO A FINISHED PRESS TOOL

Finding good solutionswith little materialFirst of all the die andmouldmaker has to do

a quotation on thejob, which can be hardmany times since theblueprints from thecustomer often is

pretty rough outlined due to their ownongoing development of the product.

Often the tool maker receive CAD drawingsof the finished component, which looks

far from the different tools that has to bemanufactured to produce the component.This phenomenon has much to do withthe integration of computers within themanufacturing and the companies evershortened lead times on products.

There are often complicated shapes andgeometries with deep cavities and radii,which has to be pressed to close tolerances.

To be able to create these shapes severaldifferent press tools has to be manufactu-red. If one company can come up with asmart solution that has fewer steps in thepressing process they have a clear advantage.

If the component to be machined is verylarge, a model of foamed plastic (styrofoam)is made with the shape of the component.The model of foamed plastic is then packedin sand and chill cast. When the meltedmetal is poured into the casting mould thefoamed plastic evaporates and you will geta blank with an optimised shape to have aslittle material to remove as possible to thefinished shape of the component. About

10 mm and sometimes even less stock isleft to the final shape of the die, which savesa lot of time as much rough machining iseliminated.

A model of foamed plastic, which is close to the shape of the component to save time in rough machining


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34

The next step is to start up the machiningof the component. Usually this is donedirectly on the optimized blank of thetool. However, sometimes the customer or

the tool manufacturer himself wants tomake a prototype of the tool to see thateverything is correct before starting to cutchips out of the optimized blank. Which isboth expensive and can take a long time toproduce.

The prototype is normally machined inaluminium or kirkzite. Only half the toolis machined, the lower part, and is then

put up in a Quintus press. This type ofpress has a rubber stamp working as theupper part of the press tool, which pressdown on the sheet metal which forms afterthe prototype tool half. Instead of a rubberstamp there are also press techniques whereliquid is used to press the sheet metal overthe prototype tool. These procedures areoften used within the automotive industry

in order to produce several prototypecomponents to crash test to see if anychanges has to be made to the component.There are several advantages with this type

of prototype methods when it is used inlow volume part production:

Only a single rigid tool half is requiredto form, trim and flange a part.

Tool cost reductions of up to 90%. Reduction in project lead-time. Reduction in storage space for tools. Increased design and material

possibilities.

The single tool half can easily bemodified to accommodate part designchanges.

No matching or fixing of tool-halves. Several different parts can be formed in

one press cycle. Prototype tools can often be used in

series production tools.


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35

The machinist can, in fact, decide thewhole milling strategy by the machine in aWOP-station (Workshop OrientedProgramming).

The machining is often structured to per-form the roughing and restmilling opera-tions during the day shift, while attendedby a machinist. The time consuming fini-shing operations are often done unmannedduring the nights and week ends. Whendoing this it is important with a goodmonitoring system on the machine toprevent that the component gets damaged

if a cutting tool breaks. If a good tool wearanalysis has been made and the tool lifehas been established, automatic tool changescan be made to utilize the machine tool evenfurther. However, this calls for very accu-rate tool settings especially in the Z-axis toget as small mismatch as possible.

However, it is also very common that bothhalves of a tool is machined as the onlydifference is that it is made of aluminium.Which is easy to machine and cheaper than

the real tool steel.

While the blank is being cast the machi-ning strategy and the tool paths are beingdecided with the help of CAM equipmentat the programming department. When theblank arrives the CNC-programme shouldbe out by the machine tool in the work-shop. In some work shops the machinetools are connected to a CAM work-sta-

tion, which enables the machinist to makechanges in the programme if he realisesthat there is too much material to removein certain places or another tool might bemore suitable.


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36


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When the machining is finished the die ormould has to be ground, stoned or polishedmanually, depending on the surface require-ments. At this stage much time and moneycan be saved if more efforts and considera-tion has been put down on the previousmachining operations.

When the press tool is thought to be finishedthe two halves must be fitted, trimmed,together. This is done by spotting, the sur-face of one of the halves is covered withink, then a component is test pressed inthe tool. If there is a clean spot somewhereon the sheet metal there might, for instance,be a radius which is wrong and need someadditional polishing done to it. You alsocheck that there is an even sheet metalcolumn all over the test piece. This spot-ting-work is time consuming and if thereis a tool, e. g. 3000 mm x 1500 mm and itshows that there is a corner 0.1 mm lowerthan everywhere else, the whole surfacehas to be ground and polished down 0.1mm, which is a very extensive job.

The die for a cutting tool after manual polishing A pressed and Spotted Workpiece


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38

PROCESS PLANNING

The larger the compo-nent and the morecomplicated the moreimportant the process

planning becomes. Itis very important tohave an open mindedapproach in terms ofmachining methods

and cutting tools. In many cases it mightbe very valuable to have an external spea-king partner who has experiences frommany different application areas and canprovide a different perspective and offer

some new ideas.

An open minded approach to thechoice of methods, tool paths, millingand holding toolsIn todays world it is a necessity to becompetitive in order to survive. One ofthe main instruments or tools for this iscomputerised production. For the Die &Mould industry it is a question of inves-

ting in advanced production equipmentand CAD/CAM systems.

But even if doing so it is of highest impor-tance to use the CAM-softwares to theirfull potential.

In many cases the power of tradition inthe programming work is very strong. Thetraditional and easiest way to program toolpaths for a cavity is to use the old copymilling technique, with many entrancesand exits into the material. This technique

is actually linked to the old types of copymilling machines with their stylus thatfollowed the model.


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This often means that very versatile andpowerful softwares, machine and cuttingtools are used in a very limited way.

Modern CAD/CAM-systems can be usedin much better ways if old thinking, tradi-tional tooling and production habits areabandoned.

If instead using new ways of thinking and

approaching an application, there will be alot of wins and savings in the end.If using a programming technique inwhich the main ingredients are to sliceoff material with a constant Z-value,using contouring tool paths in combina-tion with down milling the result will be:

a considerably shorter machining time better machine and tool utilisation

improved geometrical quality of themachined die or mould less manual polishing and try out time

In combination with modern holding andcutting tools it has been proven manytimes that this concept can cut the totalproduction cost considerably.

Initially a new and more detailed program-ming work is more difficult and usuallytakes somewhat longer time. The questionthat should be asked is, Where is the costper hour highest? In the process planningdepartment, at a workstation, or in themachine tool?

The answer is quite clear as the machinecost per hour often is at least 2-3 times

that of a workstation.

After getting familiar with the new way ofthinking/programming the programmingwork will also become more of a routineand be done faster. If it still should takesomewhat longer time than programmingthe copy milling tool paths, it will be madeup, by far, in the following production.However, experience shows that in the

long run, a more advanced and favourableprogramming of the tool paths can bedone faster than with conventionalprogramming.

Contents

Documents

Sandvik Part_1.pdf