Sunday, 16 March 2014

Cheap Ebay Lasers

You can buy a 40W laser cutter for less than £1000 and I recently acquired one of these cheap machines. There are many internet horror stories about these things and even though this one was provided in a non functional state it's still easy to see why the horror stories exist. I've given it a quick look over and these are my first impressions. I'm just going to talk about the actual hardware because the reviews of Moshidraw say that it is unintuitive, poorly translated and largely unusable, I haven't even bothered to install it because I want this machine to have an open source controller anyway.

The Good
  • The Price, similar models are priced about £500 on ebay.
  • The layout, it's a sturdy metal box all wired up nicely
  • Complexity, it's a very simple machine which should make it easy to spot any issues. 

The Bad - minor niggles that you can live with but shouldn't have to
  • Manual Power, manual power gives you a lot of control but software control is easy and allows you to complete entire jobs in a single procedure.
  • 10 Turn Dial, the manual power dial rotates 10 turns with no indication which turn you are actually on.
  • The lightbulb, in a time where LED's cost pennies this should be using them.
  • Poor exhaust fan, these little fans just don't shift enough air out of the machine.
  • Exhaust fan location, the fan blocks access to the laser tube especially if you seal the gaps around the fan with gaffa tape to make the extraction work.
  • No Red Dot, with a cutting area this small maximising the material use is pretty important.
  • No Locks, you can open the panels at any point during the lasers operation, "my advice? Don't!"
  • No cable guides, the stepper motor wires rub against the rails as it moves.
  • Poor sticker translations, It's a short job to get a native speaker to correct the English. 
  • A5 Cutting area, I'm still unsure if I should include this, it is small but that's the price trade off.

The Ugly - Real issues with the machine
  • No Z Axis, The final lense of the assembly focuses the laser beam into an hourglass shape, the material needs to be at the centre to cut effectively, no Z axis means that the work will always be outside of this focal point.
  • The Weird Clamp thing, the centre of the work area is a large hole, work is supposed to be clamped into place with sprung loaded thing which jams as it goes in and out. Fragile items and thin materials (which should be bread and butter work for these lasers) just can't be placed inside it.
  • No Interlocks, the case can be opened while operating and there is no water flow detection on the laser tube, this could result in damage to the tube or even worse yourself.
  • Frame Collision, the XY frame collides with the exhaust port at the back of the machine, it will do this every time the laser tries to return to the zero position. 

Touching briefly on the Moshidraw control software. When user forums offer advice such as "Don't move objects around in Moshidraw if you want them to remain the same size" it really puts the final nail in the coffin for these machines.

So there you have it, a brief overview of a cheap laser cutter. You can buy a laser cutter really cheaply but for my recommendation, if it costs less than £1000 you need to be asking what it's missing.