Rubber / Foam Rubber Question

[Walt Langhans]

So I got one of the odds request, but after thinking about it I figured it might work but I need some help. What I need to do is cut 1.5" Hexes but they need to be 5/16" thick, and out of some kind of rubber or foam rubber (kind of like the stuff that kitchen mats are made out off).

So is my 80Watt going to have any issues cutting that, also I haven't had much luck finding a supplier so if someone could point me in the right direction that would be helpful, and lastly is there anything I should know about cutting / engraving on rubber or foam rubber?

Thanks!

[Dave Sheldrake]

Lots of possibles Walt, foam can be from great to highly toxic junk. Without an MSDS for the material it's like playing with a loaded gun.

cheers

Dave

[Walt Langhans]

Do you know which ones are safe Dave?

[David Somers]

Walt.....As Dave mentioned, the MSDS is the key to knowing. It all depends on the material that makes the foam, and the material that is doing the expanding. Most foams are urethane based, which by itself should be OK in a laser, depending on what they used as the expansion/foaming agent, plus other add ins. There are even a number of PVC based foams out there which would obviously be something to stay far away from on a laser.

For what it is worth....I did a quick google search on foam rubber and came up with lots of suppliers and manufacturers out there. I think the trick is finding materials that have the characteristics you want, and then going on line to look at the MSDS.

Unfortunately, Other than having stood on some nice foam rubbers, I have no experience with them directly or I would be happy to share info. I am just relating what I saw on some quick searches.

Has your customer shown you what he is thinking of for a material? Those are pretty loose specs you quoted. For example...does he want closed or open cell foam? He did spec the thickness of course, but has he given a firmness? Durability? In other words, is this foam to be compressed and uncompressed frequently and therefor more subject to cell breakdown? Or is it not going to be stressed in that way much? Is fluid absorbancy an issue? Resistance to stains? UV? Stuff like that. With that info you start to have enough info to talk to suppliers and manufacturers about what they have that meets those needs, and then the MSDS comes in.

By the way....Thomasnet and Graingers can be good references when you are looking for manufacturers and suppliers in the US. Obviously not everyone lists with them, but they are about as complete a general listing as you can get and can be pretty hand. Our contracting and facilities management folks use those sources all the time when looking for things.

Hope it is warmer your way than here in Seattle Walt. I just had a wicked cold bicycle commute at 5:30am. I haven't actually sipped my cup of Starbucks yet and am dipping my thumbs in it instead!!

And if you are thinking of coming to Seattle today.....think again! The Seahawks parade is today to celebrate the Superbowl win. They are predicting 500,000 people along the 2 mile parade route at 11am. The whole city only has 620,000 people! Holy cow! And the pep rally in the football stadium is sold out and they are now selling overflow tickets to the same pep rally in the adjacent baseball stadium! Double holy cow! Pretty amazing!!!

Dave

[Keith Upton]

So much is going to depend on that type of foam rubber you end up using. I've been having foam cut for the past several years and will be doing it on my new laser in house going forward. It took me a while to track down the right type of foam for me and them a little longer to find the right supplier. A few things I've learned while testing different foams in the laser...



Controlling melt and kerf angle on thicker foams can be tricky (I'm still trying to work this out).
Even when safe to cut, they really smell when you pull them out of the laser
It takes a lot of power and low speed depending on the type and density of the foam.


For the 1 inch foam pictured below, I'm at around 20 speed and 100 power on a 60w laser (single pass to cut).

http://www.wingsofwar.org/forums/attachment.php?attachmentid=116919&d=1385916864

http://www.wingsofwar.org/forums/attachment.php?attachmentid=118403&d=1388544517

[David Somers]

Keith,

I am curious....have you played at all with compressing your foam where it will be cut? Just wondering if that would help give you a vertical cut, and or change the characteristic of the cut? Obviously this would only work well on a straight cut. Any complex shapes would be too difficult/impossible to do this with.

And of course...keep in mind you are being asked this by someone without a laser. I represent a variant of that old adage, "those who can't do, ask silly questions." <grin>

[Keith Upton]

The shapes I'm cutting are pretty complex:

http://www.wingsofwar.org/forums/attachment.php?attachmentid=116922&d=1385916866

http://www.wingsofwar.org/forums/attachment.php?attachmentid=118404&d=1388544518

That last shot is of the old foam I was having them made out of. It was very compressible but the new foam gives next to nothing. I can stand on it with out it compressing much at all... maybe an 1/8 of an inch.

[Dan Hintz]

Keith,

Looks like a HDPU foam you're working with now... nice stuff. Holds heavy tools well, assuming you get the cutout size snug enough to the tool.

[Keith Upton]

Dan, i've not heard it called that, only a mico XPE foam. That pic with the blue and black foam is different though (I'm not using it, that was just for testing). It was really nice. It cut nice and engraved nice. It also has a nice finish. But I could not find it in 3" thickness with out it being custom made or laminated. Neither of those options would work for me.

[Dan Hintz]

Ah, cross-linked PE (XPE)... PU is a PE, but LDPU is a closer match to XPE than HDPU.

[Matt McCoy]

Try http://toolfoam.com/valueline.asp

The 4# XPE is suitable for laser cutting.