What is your favourite way to hold down thin material when laser cutting?

[Aras Balali]

I recently found your awesome forum and joined. Looks like one of the few nice places left on the Internet. This is my first post, so hello everyone!

We recently purchased a 120W CO2 laser for our makerspace in Kamloops, Canada. Some of our members are interested in cutting thin materials such as veneer and leather. I am wondering what kind of setup people use for these type of material. Veneer is specially challenging since it is very brittle and also will pop off once a piece is cut.

I noticed a discussions around here about a vacuum hold down. That design looks interesting since it uses acrylic which is a relatively safe material for the laser. We have built a vacume hold table for our large CNC router using ultralight MDF. However I was a bit worried about using MDF as spoiler in laser. Is it safe?

Please let me know what setup you would recommend. Thanks!

[Keith Downing]

If you have a metal honeycomb table magnets work wonders for me. I have 4 smaller magnets for light material or corners and 2 stronger magnets for heavier or warped material. Haven't found much I can't control with those placed strategically.

[Aras Balali]

Thanks for the quick reply Keith. I have a bunch of 10mm neodymium magnets around as well as a few hard drive magnets, I may give that a try.

However, I read in this in the manual that came with the machine from China:

The environment for the machine should be dry. free of interference and influences from pollution, vibration, high voltage and strong magnet.

At the same time I see several posts here in which people recommend using magnets. Any idea why they are saying strong magnet away from the machine? It might be that the original intended meaning got lost in translation. As far as I understand unlike plasma, CO2 laser does not interact with electromagnetic field. So what would possibly be the concern?

[Rich Harman]

Any idea why they are saying strong magnet away from the machine?

Perhaps because there are limit switches that could be affected by magnets - but having magnets on the table will not interfere with those.

[Bill George]

Ditto what Rich said, I use magnets on my steel honeycomb table all the time.

[Matt McCoy]

I have aluminum honeycomb tables, so I use flat steel bars.

[David Somers]

I also use magnets. I buy mine from KJMagnetics.com. There is nothing around the head assembly in the laser that would be effected by a laser. I use a variety of sizes, but always in the N52 grade which is the strongest grade of magnet in Neodymium. I tend to use 1/2" x 1/2" by 1" or 2" long magnets for most things. I also keep a number of flat circles in case I need to hold an item down in the center area. I have set places setup on the laser that I use and have templates in Corel that mark where the magnets will go so my designs avoid them if they are in the center.

I will use metal bar for some things.

One idea on veneer if it would help you. I buy PSA veneer in 2 x 8foot and 4x8 foot sheets. That is adhesive backed. I will take two sheets and adhere them together with the grain at 90 degrees to the other sheet. That still keeps the veneer .05" thick, but makes it very durable. I have been doing some very delicate cuts on that and it holds up great. You might be able to safe a bit of $$ (canadian of course <grin>) by buying 1 sheet of paper backed and one sheet of PSA and adhering those together. I think the paper backed will be a bit less $$ per sheet.

[Caroline Watson]

Hi aras, i work in leather and use micropore tape to tape the leather to the base. It is paper type tape that doesn't leave residue on the leather. Since leather usually won't site flat, i tape around the whole piece with about 3mm on the leather and the rest on the base. cheers

[Gene Jameson]

All of mine are aluminum, where do you guys get steel honeycomb material? Being able to use magnets would improve my life. I just bought .5" square grid used in the hvac and lighting industries. They work well, are less fragile but they are aluminum just like the honeycomb that came with the lasers.

[Rich Harman]

All of mine are aluminum, where do you guys get steel honeycomb material?

It's common on the Chinese lasers. I think all the mainstream lasers use aluminum honeycombs. The only benefit to aluminum that I am aware of is that is is lighter, but then my 55" x 35" steel honeycomb is not difficult to handle so that makes me curious why the mainstream lasers don't use steel. Being able to use magnets is a huge advantage.

[Gene Uselman]

All of mine are aluminum, where do you guys get steel honeycomb material? Being able to use magnets would improve my life. I just bought .5" square grid used in the hvac and lighting industries. They work well, are less fragile but they are aluminum just like the honeycomb that came with the lasers.

Again- I am an interested party. Where can you obtainthis material?

[John Blazy]

HI Gene and Aras,

I am storing my steel honeycomb at the moment because it flashes the edges of acrylic when cutting, so I made a grid from 1/8" HDF (Duron tempered hardboard) and ran steel inside the grid to hold magnets. It works superior to the steel honeycomb for flash reduction, but if I were cutting veneer exclusively, I would switch back to my steel honeycomb.

I would offer the steel honeycomb to sell to you, but I use it for flattening veneer under my heated oven.

If you want a steel honeycomb, I would suggest giving Ray Scott from Rabbit Laser a call, since all his Chinese lasers come with steel honeycomb.

Grid-clsp.jpgGrid-noFlashCut.jpg

For ornery panels, I use wire "C" clamps that hook to underside of the HDF grid, otherwise I use ND magnets that Dave Somers suggested (Thank a ton, Dave!).
IMG_20160308_154311.jpg

[Mark Taylor2]

Depending on the size you need for the bed, take a look at lightobject.com. The honeycomb is steel while the frame is aluminum.

[Mohammed Issa]

HI Gene and Aras,

so I made a grid from 1/8" HDF (Duron tempered hardboard) and ran steel inside the grid to hold magnets.

The HDF table you made looks pretty cool John, have you posted any plans or more pictures of these tables?

[Gene Jameson]

I would like to know more about hdf. I assume it holds up pretty well based on your photo. Did you fabricate the c clips or are they purchased.