Design of Simple and Progressive Dies
DEPARTMENT OF PRODUCTION ENGINNERING
BY- KELIFA SEID
11/24/2014 1KELIFA SEID
Progressive die design
• As already noted, the overall production requirements are the main factors in
considering the size of a die and the number of finished products per stroke of
the press. Let us consider a requirement for 1,000,000 washers per week, to
be produced in a press capable of delivering 150 strokes per minute.
• We may easily calculate that 150 hits per minute equals 9000 strokes per hour
and 72,000 blows per workday. This means that if we run a strip through the
die, producing one part with each blow, at the end of the week we will have
11/24/2014 KELIFA SEID 2
Progressive die design…
• For that reason we should increase the output of a press by producing
more than one part at a single stroke.
• To further shorten the length of production, we may want to build a die,
producing four parts at a time, or a four-up die.
• The output from such a tool will certainly satisfy the basic demand, and
there will still be some time left.
11/24/2014 KELIFA SEID 3
• With washers and other round blanks, the strip layout for a four-up die
will look as shown below.
• The punches are not mounted along a straight line, as their shanks and
heads will never fit the distance in between, aside from the fact that such
a crowded arrangement will considerably weaken the punch plate and the
• Instead, the tooling is spaced along an angular axis, the angle of
inclination off the horizontal being either 19.5° or 30°, which is an
industry standard.11/24/2014 KELIFA SEID 4
• Such an arrangement gives us a comfortable distance between the stations for
placing punches and dies without any interference. It also provides for the
strip engagement along its whole width at the same time.
FIGURE a ---- Strip layout for a round washer, 19.5° inclination.11/24/2014 KELIFA SEID 5
FIGURE b --- Strip layout for a round washer, 30° inclination.
11/24/2014 KELIFA SEID 6
Support bracket, second strip layout.
11/24/2014 KELIFA SEID 8
Support bracket, third strip layout.
11/24/2014 KELIFA SEID 9
Support bracket, fourth strip layout.
11/24/2014 KELIFA SEID 10
• The 19.5° strip inclination is shown in Fig.a above. The formula to use for
calculation of the feed, or progression is
• The 30° strip inclination is shown in Fig .b above and the formula to use
for calculation of the feed, is
11/24/2014 KELIFA SEID 11
Design or/selection of finger stops, automatic stops,
pilots, stripper plate, punch, punch plate, pillar die
• Finger stops, or primary stops are used in progressive dies having two or
more stations. They register the strip for performing operations prior to
strip engagement by the automatic stop.
• The number of finger stops used depend upon the number of stations in
the die. For hand feeding it is always one less than the total number of
stations but for automatic feeding only one finger stop is required.
• Finger stops are made of cold rolled steel.11/24/2014 KELIFA SEID 12
• Finger stop A is in position to stop the strip for the piercing operation.
11/24/2014 KELIFA SEID 13
• Finger stop in pulled position allows strip to be moved to the automatic
11/24/2014 KELIFA SEID 14
• Recommended front spacer thicknesses are tabulated which allows a
minimum of 1/16 inch clearance between the top of the strip and the under
side of the stripper plate to provide for possible curvature in the strip.
11/24/2014 KELIFA SEID 15
• Proportions of these fifteen finger stops enable ready selection for almost
any die design and they assure positive stopping of the strip.
• In both the forward and return positions the maximum thickness of the
stops remain confined in the front spacer for strength.
• For example ,if 3/32 inch thick strip is to be run, and the die hole contour is
smooth and curved, it would fall in the second line: strip thickness A-1/16 to
1/8. and recommended front spacer is 1 ¼ inches ,and finger stop number 2
should be used .
11/24/2014 KELIFA SEID 18
• Automatic stops, or trigger stops used to register the strip at the final die
station, they differ from finger stops in that they stops in that they stop the
strip automatically ,the operator simply keeping the strip pushed against the
stop in its travel through the die.
11/24/2014 KELIFA SEID 19
• All necessary dimensions are given for making automatic stops ranging
from number one to six . From this table the designer can apply
dimensions, or the automatic stop can be specified by number.
11/24/2014 KELIFA SEID 20
• Every strip design should begin with an assessment of the location of pilot
holes. These openings must be pierced at the first station, because they
serve afterward as guides and locating arrangements for the strip on its way
through the die.
• Pilot holes may be extra openings placed beside the parts, or they may be
holes included within the part itself and serving at the same time as the
• The location of pilot holes should always be at the far opposite sides of the
strip, with the greatest possible gap in between. This is to secure the best
fixation and positioning of the strip, once the pilots engage in their
• Pilot holes may not be necessary where producing complete parts from the
strip in a single station of the die, as with production of washers.
11/24/2014 KELIFA SEID 24
• The frequently used shoulder pilot A is retained in blanking punch B by
socket pilot nut C. pilot holes are pierced at the first station. The strip is
then located by pilots at the second and succeeding stations.
• The automatic stop is positioned so that the strip is stopped with a
previously pierced hole 0.010 inch past its final location. The pilot moves
the strip back this amount to bring it into correct register.
• This over travel prevents possible cramping of the strip between pilot and
automatic stop as shown below ,the pilot is just contacting one side of the
hole in the strip preparatory to bringing it back to true position.
11/24/2014 KELIFA SEID 25
• The shoulder pilot is used for holes A from ¼ to ¾ inch diameter ,and it has
the following general proportions straight engagement length B should be
from 1/3 to 2/3 of stock thickness ,engagement D is made three times pilot
diameter C. clearance relief diameter E is usually 1/32 inch larger than body
diameter C of the pilot.
11/24/2014 KELIFA SEID 26
11/24/2014 KELIFA SEID 28
• Punch plates hold and support piercing, notching and cut off punches. They are
usually made of machine steel, but can be made of tool steel, and ranges from
small simple blocks for holding single piercing punches to large precision-
machined plates for holding hundreds of perforator
• Important design considerations are:-
1. Adequate thickness for proper punch support.
2. Good dowelling practice to insure accurate location.
3. Sufficient screws to over come stripping load.
Compound and Combination dies
• Some compound dies are used just for trimming, others are specialized for
• There may be compound dies with interchangeable inserts, which can
produce several different products just by switching between them.
• Several compound dies can be involved in production of a single part, which,
during the manufacturing process, is transferred as in progression from one
die to another.
11/24/2014 KELIFA SEID 30
• There are many variations of compound dies, all of them having one feature in
common ,with each stroke of the press, a minimum of one operation is being
• Combination dies combine at least two operations during each stroke of the
press. Otherwise these two types of dies are so similar in their construction
and application that their names are often considered interchangeable.
• Some shops, however, are making a distinction between the two types calling
any cutting and forming die a combination die, while the compound die is
considered only a cutting die.
11/24/2014 KELIFA SEID 31
• Compound dies produce very accurate parts, but their production rate is
• These dies consist of a single station where the part is most often blanked
out and either formed, embossed, pierced, or otherwise adjusted in a
single stroke of the press.
• No progression of the strip is involved, as each stroke of the press
produces a single, complete part.
11/24/2014 KELIFA SEID 32