Complete EDM Handbook_8.pdf

8/14/2019 Complete EDM Handbook_8.pdf

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8

W re EDM ng ne-P eceStamp ng D esBlanking Die

W re EDM as ma e t poss e to pro uce g qua ty es rom one p ece o

oo stee . T s met o s o pro uc ng es w t w re EDM can resu t n su stant a

savings. Following is a description outlining this method.

A. Desired Stamping

T e es re stamp ng can e e t er t e s ug or t e an as s own n F gure 8:1.

B. Preparing the Tool Steel Blank

Dr , ream an tap a o es or punc , e an str pper as s own n F gure 8:2.

Figure 8:1 Desired Stamping: Slug or Blank


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108Complete EDM Handbook

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C. Placement of Starter Hole

T e starter o e can e p ace n e t er t e punc sect on or t e e sect on. T e

small line created with wire EDM is in most cases negligible; however, the line

should be placed in the part which will produce the scrap.

. Punch Shape is the Desired Stamping

f the desired stamping will be the shape of the punch, then the starter hole shouldbe in that punch. The part will take the shape of the die section. Place the starter hole

a out rom t e cutt ng e ge.

Rule:Starter o es s ou a ways e p ace n t e es re s ape t at s n t e

e. Ex: I t e punc s t e es re s ape, t e starter o e s ou e put n t e

punc sect on o t e e. See F gures 8:3,4.

Figure 8:2 Part to be Wire EDMedDrill, ream and tap all desired holes.

Fi ure 8:3 Desired Stam in is the Slu .


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Wire EDMing One-Piece Stamping Dies 109

. Blank Shape is the Desired Shape

t e es re stamp ng w e n t e s ape o t e rema n ng an , t en t e

starter o e s ou e p ace n t e e sect on. T e part w ta e t e s ape o t e

punc . See F gure 8:5,6.

igure 8:4 Placement of Starter HoleIf punch is desired shape, place starter hole in the punch section of the die.

Fi ure 8:5 Desired Stam in is the Blank


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. Harden the Tool Steel Blank

ter a o es ave een put n, t e too stee an s ou e eat-treate an

tempered to desired hardness. In close fitting dies, the steel should be stress relieved

and double or triple tempered. Air hardening tool steels should be used. Oil harden-

ing steels have more internal stress after heat-treating and tend to move more.

. Stripper Plate

Trans er a o es nto t e str pper p ate, nc u ng t e starter o e. Remove t e

str pper p ate.

. Punch Holder

Trans er o es rom punc to punc o er as ustrate n F gure 8:7. Dr an

ream a punc o es. Remove punc o er.

Figure 8:6 Placement of Starter Hole

If the remaining blank is the desired shape, place thestarter hole in blank section of the die.

Figure 8:7 Mount Hardened Punch SectionThe unch section is mounted to the unch holder with screws and dowels.

.


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G. Mount Die Blank on Die Set

Drill and ream the die block to the bottom die set as in Figure 8:8. Bolt and dowel

he die blank to the bottom die set. Do not remove the bolted die section from the

die set.

H. Mount Punch Holder onto the Die Set

Bo t an owe punc mount ng p ate to punc sect on t at was prev ous y one.

ut on upper e s oe an r an tap or o ts, t en r an ream or owe p ns

nto t e punc mount ng p ate.

Mount ng t e punc o er e ore t e e s w re cut e m nates t e nee or t e

cu t tas o n ng up t e punc w t t e e sect ons. T s met o pro uces a

per ect a gnment as ustrate n F gure 8:9.

Figure 8:8 Mount Hardened Die SectionThe die section is mounted on the die set with screws and dowels.


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Com lete EDM Handbook M.com

. Mount Stripper on Bottom of Die Section

y mount ng t e str pper on t e ottom o t e e sect on, t w e cut at t e

same t me as t e regu ar e sect on an ave proper c earance a aroun . T e

owe p ns can e use to ne up an o t e str pper. See F gure 8:10.

igure 8:9 Mount Die Section on Upper Die Set ountedWith the die section mounted on the die set, and the punch holder m

eamed in place.on the hardened blank, the cold roll punch holder is screwed and bolted and

nch and die sections.Now when the die is wire EDMed, there will be a perfect alignment between the p

igure 8:10 Wire EDMing Stripper with Die section.

112 om liments of www.ReliableE


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J. Wire Cut the Punch, Die and Stripper

The EDM programmer calculates the exact taper needed to produce the proper

clearance. With one cut, the punch, die and stripper will be produced as in Figure

:11. The stripper slug may be used to extend the punch. Land can be easily done

on the die section with a skim cut. See Figure 8:12.

igure 8:11 Punch, Die and Stripper Can be Made with One CutExample: Material14 gauge cold roll steel with 12% clearance per side.

EDM programmer will determine the proper angle to cut the die section.

igure 8:12 Calculating Desired Clearance

(Clearance is exaggerated)

l


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otal Burr-Free One-Piece Blanking Die

or most es, p ac ng t e starter outs e t e punc or e an eav ng t e

narrow er or cutt ng as a neg gent e ect on t e part. On t n mater a s

e ow 1 32 t c , t ere may e a ra se area t at or prec s on stamp ng parts

may e o ect ona e.

T ere s anot er met o n ma ng a one-p ece e w ere t ere s no er at a .

T e starter o e s r e on an ang e w ere t ntersects rect y n t e m e o t e

punc an e sect on. See F gure 8:13 an 8:14.

t ere are ot er punc an e o es n t e part, t e starter o e s ou e

prec se y ocate . In t e ot er met o o us ng a stra g t starter o e an eav ng

a er , t e p acement o t e starter o e s not cr t ca .

Figure 8:13 Burr-Free One-Piece Blanking DieRecommended for precision stampings.

The path of the wire will leave a kerf halfway on the top of the punch and

alfwa on the bottom of the die where stam in does not take lace.


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Compound Blanking Dies

Fo ow ng t ese nstruct ons can re uce costs ramat ca y n pro uc ng

compoun an ng es.

A. Desired Stamping (Figure 8:15)

B. Prepare Tool Steel Blank

Dr , tap an ream a necessary o es, nc u ng starter o es. See F gure 8:16.

emem er: Put starter o es n t e es re s ape. Har en an temper.

gure : es re amp ng

Figure 8:16 Prepare Tool Steel Die SectionPut in all desired holes before hardening.

Starter hole


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C. Mount Punch Holder

ount punch onto a punch holder as in Figure 8:17. Make sure the punch holder

is large enough to hold the stripper bolts and springs. Remove punch holder.

. Mount Die Block on Bottom of Die Set

r an ream a o es or sect ons t at w e mounte on t e ottom o t e e

sect on as s own n F gure 8:18.

Figure 8:18 Mount Die Blank on Bottom Die Set(Mount both the inside and outside sections of the die.)

Figure 8:17 Mount Punch on Punch Holder(Mount middle punch section onto the die.)


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E. Mount Punch Holder on Top of Die Set

Mount punch on the punch holder with dowel pins as illustrated in Figure 8:19.

rill, ream and tap holes from top of die set to punch holder. Now the die section

can be removed for wire EDMing. Mounting the punch holder before wire EDMing

creates a perfect alignment for the clearance between the punch and die.

. Stripper Plate

Since this is a compound blanking die, parts of the stripper will be on both the

op and the bottom of the die shoe. Drill no holes on the stripper except for the two

starter holes.f the angle of the cut is relatively straight, then the stripper can be clamped on

e e sect on an w re EDMe at t e same t me. Ot erw se, t e str pper may ave

o e cut separate y.

G. Wire EDM Compound Die

The EDM programmer will calculate the exact angle for proper clearance.

rom one piece of tool steel, a high performance inexpensive compound die can

be produced. See Figure 8:20.

igure 8:19 Mount Punch HolderMount Punch on punch holder, then bolt and dowel

punch holder to upper die set. This procedure will guarantee a

perfect alignment of the punch and die sections after the die is EDMed.


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. Completed Die

. Stripper with Springs

Mount str pper w t str pper o ts an spr ngs on ot top an ottom o e set.

See Figure 8:21.

Figure 8:20 Compound Die from One Piece of Tool SteelFrom one piece of tool steel, a high performance

nexpensive compound die can be produced.(Clearance is exaggerated.)

persFigure 8:21 Completed Compound Die with Spring Mounted Stri


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. Stripper with Knockout

T e a vantage o a noc out e s t at t e scrap an part w e separate . See

gure 8:22.

igure 8:22 Completed Die with KnockoutKnockout removes slu from art.


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Wave of the Future

Wire EDM has revolutionized machining. With todays high-speed cutting

machines, wire EDM will increasingly replace work performed with traditional

methods.

Today, manufacturers, designers, engineers, and those responsible for determining

machining methods should endeavor to understand the wire EDM process in order

to maximize its great potential. Their knowledge of this process will result in their

company saving money, time, and effort while increasing quality product.

et's exam ne anot er un que met o o EDM ng. W t to ay's sop st cate

ram EDM mac nes many new poss t es ex st.

Documents

Complete EDM Handbook_8.pdf