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Richard Rumancik
01-04-2008, 4:37 PM
In another thread Bob said:


Tell me, can you "cut" with a 20 watt laser and if so, how much lumber?
I wanted to make some steelrule dies. ( 3/4" plywood)
Maybe it's smarter to run the lser straight at em. Bob

Bob – thought we should start a new thread so we don't hijack the other one . . .

Making steel rule dies was one on the first applications of C02 lasers in industry. But you probably need a kilowatt+ laser to cut through the birch plywood that is normally used. It is often 15 laminations or so, and the glue really attenuates the beam.

To get a uniform width cut all the way through, you need a long focal length so you don't get a V-shaped cut. As a result you need quite a bit of power.

That being said, I did make a steel rule dieboard as a test with my 30 watt laser. The way I did this was to laminate several pieces of 4 mm birch plywood. I was designing for a 2pt rule (.028 thick steel) so I cut two offset lines to get the width correct to accept the rule. Then I cut 5 identical pieces. With a 40 watt laser you might be able to do it with 3 layers.

Now, the trick is to get them aligned exactly. In the layout I had added alignment holes in the corners. Theoretically two pins are adequate. For my sample, I applied wood glue and then pressed in .156" dowel pins to align the layers together. It is important to keep glue out of the slots. It is actually fairly quick once you do a few. It might be necessary to spend a few minutes cleaning out the slot with a suitable tool to "dress" it to the right tolerance.

Then you need to bend and install the rules.

I don't know if you can compete with commercial die makers, however, with this method. Commercial steel rule dies are generally not that expensive. (Simple shapes maybe $100 ruled.) But if you want to experiment for your own products or in-house work, and can bend the rules, it may be viable. I had the idea that I could supply dieboards to a local gasket company, but they wanted to have complete dies. I am not set up to bend and install the rules. There may be a market somewhere for blank dieboards . . .

The laser has the advantage over a jigsaw when doing multiple dies of the same shape. With the laser, you know they will be the same. When hand cut on a jigsaw, each die will come out a little differently.

William Johanson
01-04-2008, 7:23 PM
I am fairly new to the Laser engraving thing but I have been a Laser cut steel rule dimaker for the past 15 years. I am the production Supervisor for a medium to large sized Diemaker in Minnesota. We currently have 4 laser sytems we use. We run our dieboard thru 3 of them ranging from 500 to 2000 watts. Everything Richard says is accurate and the process he describes is very viable. In some ways this veneering method actually has some advantages over a single cut as even with a laser of 2000 watts it can be difficult to keep your slot width consistent and avoid angle. But, You really need to experiment with the glue you use as delamination can be a problem and I would definitely use a vacuum press to "clamp" the boards together for the same reasons. I really doubt anybody could make a go of supplying unknifed dieboards to a company for profit as the extra time spent burning 3 or 4 boards and laminating them would probably put you out of a good price range but for in house small run type work I think this would be an option. If anybody needs some help or advise in the steel rule die field feel free to contact me.

Bill

Peter Meacham
01-05-2008, 9:47 AM
OK, one of you guys is going to have to explain what a steel rule die is please - or a picture or two? Thanks, Pete

Richard Rumancik
01-05-2008, 10:41 AM
Peter, I will dig out a couple photos when I get a chance. Here's one below I grabbed from Google images. I also have the sample I made using the lamination idea so I will will post a picture later. A steel rule die is often compared to a cookie-cutter. Instead of cutting cookie dough, you cut plastic films, rubber sheet, cork, gasket material, paper, label stock, vinyl, thin wood, leather, foils, cardboard, etc.

A dieboard consists of a wood base with narrow grooves cut into it. Into the grooves you install steel rules (sharpened blades). The plywood board basically acts to hold the rules in place in the pattern, and keep them from bending sideways. If you need to cut small round holes you could install sharpened round tubes.

The die is installed into a press and the material fed underneath the die. You cut onto a softer material so you don't destroy the sharp die when it bottoms out on the material as the press closes.

The photo below shows a laser cut die. The blades go right through the plywood to the back surface. I'm not sure what the tool in the photo is doing. The cutting eges of the blades will be razor sharp. When you press this die onto a sheet of material you will get a shape. This particular shape looks like it could be a small fold-up box. The dies can have sections which just create a fold line (blade is not sharp) so you get a crease instead of a cut. For complex dies a CNC bender would be needed to get all the bends in the right place, as you want to minimize the number of joints.

The manufacturing industry uses tons of steel rule dies to make all sorts of flat products from sheet with inexpensive tooling.


http://www.barplate.com/media/4075/untitled40_193x164.jpg