ToolDocs/LaserCutter

The laser cutter charges 10p a minute of laser time to cover the operating costs (bulb, mirrors, lenses, and PSUs). We have already had to pay fro several replacement parts. The meter on the laser is currently underdevelopment so for now please time your own cuts.

= Where did the laser cutter come from? =

The laser cutter belongs to Tom Allen who funded it's purchase especially for the Hackspace. He is selling 8mm clear acrylic.

= How can I use the laser cutter =

Although quiet simple to use and very safe the laser cutter is also easy to damage with accidental mis-treatment. The tube, mirror's and lens all have an expected life and replacement cost, and cutting the wrong materials or in the wrong way reduces this massively.

For this reason we suggest that only people trained with what can damage it and how to use it safely operate it. If you are interested in using it, shout out on the mailing list and someone will probably be available to show you around at the regular Wednesday open nights.

Currently only paying members can be trained on the laser cutter. This is purely to encourage membership, to ensure the laser cutter has a home! Laser cutting to order for non-members is an option which could be open entirely depending on the project.

Here is a quick video introduction to using the LaserCutter.

= Materials =

The cutter can cut a wide range of materials but some cause hundreds of times more wear and tear than others. Generally anything which releases particles when burnt with the IR beam clog up the optics as the laser has very little optic protection, which then causes them to heat up instead of the target.

So far we have cut:


 * 1) Paper - use a weight to stop the extractor sucking it up! Low power and high speed
 * 2) Card - many types, higher power but still fast
 * 3) Laser ply - full power!
 * 4) Acrylic - settings table below
 * 5) Foam - high power very fast
 * 6) Rubber

Material should be no bigger than 278mm x 220mm to fit properly on the cutter bed.

= Acrylic stock =

The laser cutter loves acrylic, it cuts though it like butter leaving a lovely smooth edge.

The acrylic comes in sheets of 860mm x 210mm - this is the same as 2.9 sheets of A4 joined on the short edge. There are also a very much smaller number of sheets at 300mm wide if you really need it.

The 8mm clear acrylic and laser time is £5 for a whole sheet or £2.50 per A4 sheet, which is about the size of the bed in the laser cutter. This price is less than half you would pay retail, all profits are going towards repaying the credit card the laser cutter was bought on.

= Before lasing =

Before using the Laser Cutter:


 * 1) Check you are a trained, paying hackspace member
 * 2) Check you know where the fire extinguisher is and fire exits are open, it cuts by burning!
 * 3) Water is flowing into the water tank from the return hose
 * 4) There are no air bubbles in the laser tube
 * 5) The extractor fan is powered on
 * 6) The air assist pump is turned on

The Water Cooling System
The laser tube is cooled by deionised water that is pumped from a black plastic reservoir below the cutter into the tube and via a large chiller. There is a clear plastic tube that connects the reservoir to the cutter. There is also a black power cord that goes from the cutter to the pump in the reservoir. Both of these should be fully connected before applying the power to the system.

To ensure there are no bubbles in the laser tube, take the key from the top of the system and open the rear panel. You should see the laser tube as shown in the image below.

<< IMAGE OF LASER TUBE TO COME >>

Check there are no bubbles in the system, and if there are, gently tilt the cutter to let them safely exit the tube. Ensure the cutter is level on the table, close and lock the tube chamber and return the key to the top of the system.

= Air extraction system =

A high power fan sucks fumes out of the cutter up and out through the wall. It's pretty powerful, so you will hear that it's on.

= Air assist system =

The cutter has an air line going from an external pump (on the window sill) directly to the lens head. This should always be used and prevents any particles or convected heat from entering the laser head. It can be turned on and off with the switch's on the main panel. It should always be on when cutting, it's controlled by a button on the main panel and you can feel the pump vibrating when it's on.

= Preparing Your Design =

The laser cutter will only accept .DXF format files for cutting.

Software
Newlydraw 1.5 is the software and it likes dxf in mm. It run's on Windows XP and it needs a usb licence dongle to run but can be installed anywhere. The dongle should always stay with the machine. It's badly translated and bomb's out some times...If anyone wants to improve this situation please get in touch!!!

The laser laptop is attached to the machine and has NewlyDraw and dropbox setup so you can send DXF to it over the lan (ish) or from home.

Design

 * SolidWorks
 * Inkscape
 * FreeCAD

= Things to make =

BoxMaker
Link: http://boxmaker.rahulbotics.com/

This script has been tested to created a 50mm cube from 7.5mm clear acrylic, here are the settings used. Interestingly, the cube had an internal width of 42mm and external width of 57mm - this was due to the DPI, the generator assumes 100 DPI, the Inkscape default is 90 DPI. Once set correctly, it is highly accurate.



I'll upload the DXF's once zip upload is enabled.

Boxer
Link: https://bitbucket.org/hudson/boxer/overview

This is untested. May work well with wood but will not play nicely with the 7.5mm acrylic.

= Burn Baby Burn the fun part= To prolong the life of the laser tube and power supply, we request the:

MAXIMUM LASER CURRENT TO BE 20mA !

Going above this just generates a lot of extra heat for small cutting improvement.

Etching
Undocumented. Though many have had great success with surface etched designs especially on wood and acrylic.

Also

We made some safety signs for the space using this yellow laminate: 908.com

We used scan mode with a speed of 300mm/s, power at 12mA, and 62mm height. Etch with top protective plastic film off, but cut with it on (bit smokey !).

Also available in white and other colours. Looks better (blacker) after a gentle wash in soap and water.

= Help / Issues = We've found that if you try cutting with the underside's protective film removed, you will find 'swirl marks' after cutting. These are caused by the heat/smoke being extracted from the cut. To fix this, simply leave the protective film in place until you are finished cutting.



= Things We've Made =

Here's a few pictures of some things made in the space... As nothing has been made yet, these are from messing around..



= Using SketchUp - Notes from User Michel aka Buserror =

Sketchup 8 has a plugin that will export whatever is selected as DXF... One thing to remember is that it will export it as it is /viewed/ -- so align your object on one axis, select them and then export them. + One important thing is that you need to make sure only the /faces/ are selected, not the components for example. My first try had like 8 'layers' of the same line over each others.. It looked fine when importing it, but it was in fact completely ruined. + Another thing to note is that the "Find Overlap" button doesn't really work. If you have lines on top of each others, they will be ignored and will still generate multiple cuts in the same place (BAD) + I don't know of a tool that will simplify a DXF to make sure the file is 'clean' -- wouldn't be hard to make one tho...

Other than that, the DXF generated by the plugin was loaded without problems in the cutter software.

Some more random bits from the experiments: + You can cut acrylic by scoring both side, and using large stompy boots to snap it. Works pretty well. I used a "Stanley knife" but the tool to use is the one one use to score/cut ceramic tiles. + the surface of the cutter is *not* A4 -- it's a bit shorter (28cm, I think) and a bit wider (23 or so) + If you cut an acrylic sheet that is near the maximum size, strange things happend... We're not entirely sure of whats goign on /exactly/ but I had issues with lack of precision, non-perpendicular cuts, and Al had a cut that was semingly missed... + A A5-ish sheet cut /perfectly/ tho... + You can make holes of passing screws, and these come out beautiifuly. I did cuts of R=1.6mm and I can pass M3 screws perfectly in them + You can drill, and screw in the thickness of the acrylic. I used a Archimedean drill to drill a thin guide hole, and then a M2.5 drill bit, slowly so as not to melt the plastic. Wiggle it a bit to make it a notch wider, and you can then screw a M3 bold straight into it.

Now, the best bit is that you can sand down rough edges and get a /perfect/ crystal clear edge again by flaming it. Use a butane torch and pass it on the edge, it just cleans up to perfection. You need to make sure the edge is sanded to "opaque" and is clean of course, but the butane torch makes you a nice prism like finish, like the laser cutter does.



= Using OpenSCAD to create a 2D DXF from a 3D model. =

In a recent post on the rlab google group (here ) regarding the laser cutter, a query about creating a dxf arose. David Price posted a solution using OpenSCAD and I thought the content was valuable. So I post it here for reference.

THE POST CONTENT FOLLOWS:

WRT stl to dxf conversion, OpenSCAD can do this - you arrange the object such that the section you want is on the XY plane at Z=0 and use the projection function, compile (F6) then export as a dxf file. The result is compatible with the laser cutter software (newly draw), at least the object I did this with was.

Here's an example - F6 has been pressed and the section at z=0 is ready to export as a DXF;



Here is the dxf imported in to Inkscape;



Note the edges are made up of multiple line segments so will need tidying up.

This worked adequately to cut an acrylic microscope stage on the laser cutter from an OpenSCAD master a couple of weeks ago.

David