I need to die cut small rectangles approximatley 6mm x 4mm out of 1/16 and 1/8 thick plastic and fiberglass sheet. We need to do at least several rectangles at a time. Having virtually no experience in designing dies, I spent about 10 minutes cooking up this design. Would something like this work? Can anybody lend any design advise for a rectanglular die?

http://www.cnczone.com/gallery/data/500/medium/Isometric.jpg
http://www.cnczone.com/gallery/data/500/medium/Side2.jpg
http://www.cnczone.com/gallery/data/500/medium/Top.jpg

Next you are going to tell me they need to be perfect squares!
Drawing dies like this is easy, the hard part is making the die. Your prpblem is going to lie in the banding material. It is going to be tough to locate the banding material in a small grid like that. The thickness of what you are cutting is another huge factor. 1/8 inch with a die like that is going to be rough. How will you extract the parts after they are cut? You will also have a tough time creating cuts at every corner without the material getting stretched.
I would make an adjustable shearing jig and cut my material in strips. After you cut the strips I would then readjust the shearing jig for the other dimensions cut. It is not elegant but a lot more practical. Even a jig on a band saw where you can adjust for the kerf of the saw blade would be good.
This is not to say the die cannot be designed as you drew it. It will just be a mess to piece it all together and maintain strength throught the cut.
The working materials is tough also. The part is going to be almost as thick as it is wide at 1/8. The plastic is going to most likely 'smear' rather than cut (depending upon your tonnage). The fiberglass will be hard to sever the strands. You are going to end up with a lot of fiberglass particles and unclean cuts. Take precautions.

The first and most important question is how many of these do you need to produce. I can give you some advice but the amount you need to do is important to justify the means of doing it, against cost.

Regards,

Scott

If you want to learn about making dies that's one thing but for many of our applications we use Apple Die, www.appledie.com . You might want to check them out. They are very affordable and they will let you know if it is practical or not.

I''' be needing several thousand of these rectangles. Now I've been considering a shear, or by means of cnc to produce these. Laser cutting won't work for me.

A small shear and a jig would probably work. I think that the work would go pretty slow though.

Now I'm thinking the cnc mill might be the best way to accomplish this in a reasonable amount time. A custom vacuum clamp with a vacuum hole for each center of the squares and a small diameter endmill....

It seems like there should be a simple way to diecut these though.

The question mark on your post is very appropriate. Your best path to solving this problem is to work out a precise feed method to position the material to be "sawed".