Press Tool Design - Tips for first time designer 2

[Finglas]

Designing a press tool at the moment for the first time. Any tips on how to make sure it works to a tee?

Think I need to add some guide rods so block punches line up with die. Tolerances are pretty tight.

http://www.box.net/shared/s78dqxyknn

http://www.box.net/shared/ao040zvvup

http://www.box.net/shared/qamn9s7ks6

http://www.box.net/shared/5975bl12fp

 

[MikeHalloran]

An arbor press is not going to work for this, and itty bitty guide rods won't be stiff enough to compensate for its deflections.

Start over with a real die set as a substrate. That includes the guide pins, and can be stored as a unit, and bolted into a punch press or a press brake for use.



Mike Halloran
Pembroke Pines, FL, USA

 

[ajack1]

I would agree with Mike you will need a die set, also the die will need one dowel if it is a slide fit in the lower bolster or two if not, the punches will need to be held in a punch plate that is also screwed and doweled or if not lined up by the stripper that is run on sub pillars and you will need to allow for the slugs to be removed, it is not clear if you have done that or not.

The locations are not great either and do you have enough stripping pressure?

 

[Finglas]

Hi guys,

Appreciate the feedback.

Workpiece material is Ticona Hostaform C 27021 Acetal Copolymer . It’s only 0.2mm thick. I think arbor press should be sufficient.

Mike - excuse, my ignorance, for I am not up to speed on presses and dies, but what’s a real die set? Is this an off the shelf set? Perhaps you send on a link to what you mean?

Ajack1 – have 2 dowels in place on die plate (Pic 5). Slight clearance on die hole in base plate so it’s a loose fit. Backing plate is also screwed and doweled (Pic 6) into punch mount plate. I think I need to add bushings in the bottom of the stripper plate to help align the punches with the die. There is a clearance hole in the base plate which aligns with another clearance hole on the press body.

Can you be more specific about locations not being great? Have done a calculation and rekon springs are sufficient.

http://www.box.net/shared/1iniyunmuk

http://www.box.net/shared/xn9tqi7bv3

 

[ajack1]

Fair enough finglas you could not see the dowels or drop holes in the previous views, it is also normal to have dowels as through holes so all dowels and cutting parts can be wire eroded in one set up after hardening, this helps greatly with tight cutting clearances.

The locations are not great as nothing is fixed (all slotted) so what ties the part to the position of the three piercings?

As for the die sets this is the sort of thing I and I assume Mike was referring too.

 

[Finglas]

I've never seen a thru all dowel hole in my short career but I can see your point of view when it comes to wiring the part all in one. I suppose once the 2 plates are doweled together, the dowel should not come out assuming it's a slide fit or tighter. Am I right in saying this?

“The locations are not great as nothing is fixed (all slotted) so what ties the part to the position of the three piercings”. You mean the red parts for locating the workpiece? Problem is, tolerances on the workpiece are not very fine so need adjustment here to settle on an average location for the workpiece.

http://www.box.net/shared/y455yn0z10

There are slight pockets on the underside of the workpiece which I think will locate on the shoulders of the die. Also, there is a profile on the workpiece which will guide the punches.

Appreciate the link.

 

[chicopee]

See if you can get the textbook " Die Design Fundamentals" by JR Paquin and RE Crowley published by Industrial Press Inc. That book should bring you to speed on die design. It explains all the components brought out by the above responders.

 

[Finglas]

Read a few reviews about the book and by the sounds of it it's not great.

 

[btrueblood]

"Read a few reviews about the book and by the sounds of it it's not great. "

Hunh? Where did you read those reviews?

 

[Finglas]

scribd i think, just googled the book and found a website with reviews. said it was rubbish really for the price of it.

 

[MikeHalloran]

Then consider the "SME Die Design Handbook".

Mike Halloran
Pembroke Pines, FL, USA