Advice for Compression Die Design
Advice for Compression Die Design
(OP)
I would appreciate some feedback on a compression die design that I am leading. My background is electrical engineering and I have never designed a die before. This is in an academic environment so there is little practical experience with this sort of thing. I have met with a tool and die maker but I still have a number of design questions that I am unsure about.
The intent of the die is to compress copper coils in prototype quantities (~20 units produced) under fairly high loads, ~300 to 400 tons. I am trying to design something that will work the first time because I don’t really have budget to make a second but it doesn’t need to be overly fancy since it is only for making very limited quantities.
The final compressed dimensions of the coil are ~5.23” x 2.26” x 1.09” with the compression surface being 4.84 in^2. The pressure on coil will be 61 kPSI - 165 kPSI.
An exploded view of the design as it currently stands follows:
Link

1) The design current uses a yoke, die, bobbin, and punch. The compressed coil is formed in the cavity created by the die, bobbin, and punch. The yoke surrounds the die to add strength as there are concerns that the die might crack given the pressures and forces. There is a taper on the outer die perimeter and the yoke inner perimeter for the yoke to contain the die as the coil tries to force it outward.
11) Any idea of what you would estimate is a reasonable cost for this so I don’t get taken to the cleaners trying to get it made?
Any comments or feedback would be greatly appreciated.
The intent of the die is to compress copper coils in prototype quantities (~20 units produced) under fairly high loads, ~300 to 400 tons. I am trying to design something that will work the first time because I don’t really have budget to make a second but it doesn’t need to be overly fancy since it is only for making very limited quantities.
The final compressed dimensions of the coil are ~5.23” x 2.26” x 1.09” with the compression surface being 4.84 in^2. The pressure on coil will be 61 kPSI - 165 kPSI.
An exploded view of the design as it currently stands follows:
Link

1) The design current uses a yoke, die, bobbin, and punch. The compressed coil is formed in the cavity created by the die, bobbin, and punch. The yoke surrounds the die to add strength as there are concerns that the die might crack given the pressures and forces. There is a taper on the outer die perimeter and the yoke inner perimeter for the yoke to contain the die as the coil tries to force it outward.
- Does it make sense to use a yoke? Would the yoke be better replaced with just a larger die?
- Is this likely the correct steel to use? I need high hardness to avoid deforming the die and have the copper extrude between the die, bobbin, and punch but I am also concerned about the die cracking. I was also considering S7 steel.
- Does this tempering temperature seem correct?
- Do I need to specify anything further on the print in terms of hardening, tempering, quenching, etc.?
- Is this the correct/best tolerance to use?
- Would it be better to have an additional diamond locating pin or an additional bolt?
- Should the diamond pin be located diagonally across from the round locating pin or collinear through the part?
- Any recommendation which type of locating pin to use? Press-fit or threaded shank?
- Is there any other source for threaded shank locating pins than Misumi?
- Do you think the die and yoke are thick enough? Is the die big enough? If I can make it smaller that would be great from a cost and handling perspective.
- How long should the die set guide pins be above the top die plate when the die is fully closed?
- Is there any disadvantage of using short should bushings? They give more flexibility for reusing the die set.
- What surface or polishing level would you recommend?
11) Any idea of what you would estimate is a reasonable cost for this so I don’t get taken to the cleaners trying to get it made?
Any comments or feedback would be greatly appreciated.




