Stop laminate warping

[Riki Potter]

Hi everyone,

I've posted a couple of times but this is my first topic, I work at an engraving/trophy shop with the aim of using the laser to expand the business further into custom jobs.
I use laminates alot to make plates for trophies and plaques and stuff but I've been coming across a frustrating problem recently. When I print a logo or anything else that has large areas of black the laminate often warps due to the heat, This is normally ok because it normally doesn't affect the engraving much at all and their stuck firmly to a flat surface anyway. At the moment I'm trying to re-do a plaque someone made a mistake on a few years ago and the logo keeps on warping the laminate, the original I have is on thicker laminate than I currently have which explains why it hasn't warped nearly as badly.
When I run it though at 50/50 on 500dpi it warps the heck out of it, I managed to reduce the warping by lowering the dpi but this results in poorer quality, the logo is all clean lines and I need to get it to the standard of the original to satisfy the customer.

I hope that's intelligible, to recap how do you engrave large solid black areas on laminate without warping the material?

[Martin Boekers]

First are you sure it is lasered and not rotary engraved?

Next try speeding it up and increasing the power (you want the p[ower to where it
is just breaking through the cap of the laminate.) If you go to slow it builds up more
heat in a concentrated area.

Maybe 2 passes at lower power will work.

Large black areas can be difficult though.

[Riki Potter]

The original is definately lasered, I fiddled with the speed/power a bit but still couldn't get it to the quality I want. We've just ordered the thicker laminate so I can use that tomorrow insteead of wasting more material trying to get it to work. There is also some warping on the original but it's quite minor.

[Joe Pelonio]

When running 50-60 items on a sheet with lots of large areas to engrave, I will have the laser cut a small hole near the middle of the sheet between where the item in that area will be, and wire it down to the honeycomb. Another option is tio use very thin double sided tape to adhere the back to a scrap (sheet from which items have been cut out) of 1/4" acrylic.
The disadvantage to that is that some pieces of the laminate will semi-weld to the acrylic and take a little longer to remove.




Most of the time a little masking tape around the edges will help when the material comes warped, but for the engraving heat you have to take steps to account for it.

[Mike Null]

If the material warps then you may be using too much power. I think you're on the right track going to a thicker material but are you sure you're engraving laserable material? If you are laser engraving rotary material you'll find that it has a thicker cap and takes more power to engrave and could cause it to warp.

[Riki Potter]

Mike, the materials have "Laserables" written all over them, from Innovative Plastics Inc. I managed to get it to work fine by upping the speed to 70 with a power of 50 and using the thicker material (1.5mm I believe), this managed to get through the cap with only a couple of patches with very faint colour still showing. It also worked alot better on the thinner material with a lower DPI, but I always go for the best possible clarity which I rarely get with a lower DPI.

Thankyou all for you advice. Joe, wiring the plate to the honeycomb is a great idea! I also like taping it to something more sturdy, we have alot of steel/brass scrap plates laying around as we're an engraving store so I may try using that to avoid the welding. Martin, your advice worked well for me, I still haven't had a chance to give each material a good test for ideal power/speed settings but this is something I hope to do in the near future.

[Bob Davis]

How about putting a piece of steel plate underneath the plate and using some magnets to hold it flat? Works for me.

[Scott Challoner]

Another thing to reduce the heat affected area is to use a shade of gray rather than 100% black. I usually use 70 or 80% gray but you can experiment. I also drop my table by 2mm. I don't know if this helps with the heat, but it makes the engraving a little smoother