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Laser Cutter

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laser

(Mark Hanford) #1

We have now officially acquired our first laser cutter!

@Cylindric has created an SHM Laser Repository in the SHM GitHub for any documentation and plans etc that might become useful, and has been building a SketchUp model, so if anyone wants to incorporate it in any plans, go nuts.

Specifications

  • 50W of CO2 laser power.
  • Bed size: ~A3 (290x420mm)

Induction

This is scary equipment, and as such you’ll need to be inducted to use it first. Please ask on the forum if you wish to learn how to use this, or ask one of the @laser_users for more info.

Materials List

This is a list of various materials that may or may not be allowed. If the material is not on this list, assume it is not allowed! This list is subject to change. If you want to cut something not on this list, check with one of the Laser Wizards, and we’ll find out what the implications are.
Thanks to the ATX Hackerspace for the detailed information.

Can Cut

  • Acrylic, Lucite, Plexiglass, PMMA
  • Plywood - avoid cheap stuff that might contain gobs of horrible glue
  • Solid Wood
  • Delrin
  • MDF, LDF
  • Paper, card - caution, very flammable!
  • Cork
  • Thin polycarbonate <1mm - can burn, not a good choice
  • Polyurethane Foam
  • EVA - Ethylene Vinyl Acetate - leave the lid shut to fully ventilate once finished
  • Kapton
  • Mylar - best if thin
  • Styrene - very smokey, and keep it thin!
  • Depron - can be a bit messy, but give it a go
  • Natural-fibre cloth
  • Vegetable-tanned Leather stinks the space out, keep the lid shut for a good while after finishing
  • Magnet sheet
  • PTFE - only if thin, and keep the lid shut even after you take your part out! We don’t want to all die.
  • Silicone - this has been tried, but it is almost indestructible on our laser. You might be able to get through 1mm sheets of silicone, but any more than that it will just char the surface. Not banned, but not much point.

Can Etch

  • Anything you can cut
  • Glass
  • Ceramic
  • Stone
  • Anodized aluminium
  • Painted metals

BANNED

  • Everything not on any of these lists
  • Chlorinated plastics (PVC) - This will damage the optics, corrode the metal in the laser, and kill the electronics.
  • Polycarbonate >1mm - mostly just pointless, as it absorbs the laser. It’s what the laser window is made of for a reason.
  • ABS - melts
  • HDPE - burns, melts and spreads gooey mess all over the place.
  • Polystyrene Foam - Number one cause of fires in laser cutters. Don’t even try it.
  • Polypropylene Foam - cause of fires in laser cutters. Don’t even try it.
  • Fibreglass - It’s made of two components, and you can’t cut the glass, and mustn’t cut the resin.
  • Carbon Fibre
  • Pressure-treated wood - It’s pressure-treated with all sorts of nasty chemicals. Don’t do it.
  • Galvanised metal - Pointless.
  • Anything mirrored - Can hopefully guess why not.

Notes and Specific Details

Here are some specific notes and guidance on some of the materials, and possible sources to get them from…

Acrylic

  • Clear Acrylic Perspex Sheet, eBay, price depends on size, but an A4 sheet of 3mm is about £2.85 (£4.57/m2)
  • rLab recommended the supplier Kitronik. 600x400x3 is £6.24. (£2.60/m2) They also do a nice 9-pack of coloured A4 sheets.

Plywood

  • Kitronik sell Birch and Poplar plywood in various sizes. An A4 sampler is convenient, and dirt cheap (about £1.20/m2).

Polyurethane Foam

  • This material cuts and scans very nicely, leaving a clean edge the same as from the factory. When scanning, it smokes a lot, so make sure to keep the lid down and the fans on for a good minute or two after finishing your job to ensure all the nasties have fled the space.
  • ShadowFoam sell PU foam in a variety of colours, pre-cut to whatever size you want. A 1200x550x30 standard sheet is £20. An A4 10mm sheet with a coloured top is £10, but subsequent sheets are only £2.
  • It doesn’t take much power to cut through this foam, so high speeds and low power are called for. The 10mm thick, purple-topped foam cut all the way through at 80% power and 100mm/s, with a neat and precise depth possible when Scanning. A fast 200mm/s and very low power scan ot 15% creates a shallow depression of about 1mm.

(Mark Hanford) #6

We have added three new materials to the “allowed” list!

  • Polyurethan Foam - I had great success with this material recently, and it looks like it could be useful for those wishing to make foam inserts or shapes, such as for lining tool boxes or equipment cases etc.

  • Ethylene Vinyl Acetate - @Jagmills has had success with this type of foam, details to follow. Note it can be a little unpleasant, so keep the lid shut for a while once you’ve finished your job.

  • Silicone - well, it won’t kill anyone, but you probably won’t get it to cut much. It’s on the list because you might get success with really thin samples, but anything more will probably just char.


(Malcolm Napier) #7

Hi Mark,

Where did you get your Polyurethan foam from?

Regards,
Malcolm


(Malcolm Napier) #8

Duh! Next time I will read the whole thread before posting…


(Sarah) #9

Hello! I am still lurking, and planning a visit back to the space soon I hope!

I’ve come across a site with some interesting plastics, mostly for guitar making but am curious about whether they could go into the laser.

This one https://www.rothkoandfrost.com/materials-c25/sheets-c26/incudo-pearloid-celluloid-sheet-p402#attribute[3]=79 claims to be laser safe (it’s a Cellulose nitrate (celluloid) sheet) - but not on the list above as far as I can tell.

This one doesn’t mention lasers at all: https://www.rothkoandfrost.com/materials-c25/sheets-c26/incudo-shell-cellulose-acetate-sheet-p60#attribute[3]=288 and is a Cellulose Acetate Sheet so I really have no idea.

Does anybody have any thoughts on these ones and their likely safety?

Bw
Sarah


(Chris) #10

Hello Sarah! Good to hear from you, hope the new job is treating you well :slight_smile:

I am suspicious of cellulose nitrate being laserable - my first thought (with my limited chemistry knowledge) was “surely that’s flammable”, and in fact it is supposedly explosive! Have fun reading the Wikipedia article on its alias, nitrocellulose - that might not go down well. I would suggest you check with the manufacturer as it’s possible there’s some additions to the plastic that make it more laser friendly due to their wording on that website.

Cellulose acetate sounds safer but not pleasant. I looked at the MSDS sheet and it supposedly is non toxic, but it’s likely to make acetic acid vapour which might not be too laser friendly. I found this site that seems to show it’s possible though, albeit with some scorching to the plastic.


(Matt) #11

The laser cutter now has a shiny new bed.


(James Donovan) #12

Interesting question relating to metal… I have access to some stainless steel “silk” and fine mesh. Hoping that the laser will be able to heat tint/engrave/cut through the wires (24micron - 236micron). If there is any effect, I can post the results on here.