Some basic advice needed re: Laser Cutting

[Zaheer]

Hello,

Recently I've started tinkering with Google Sketchup (and learning Autocad for my masters degree), and have played around with making some buildings with the vague aim to get them made in the back of my head.

To finally get to the point, what format of files are any use for laser cutting services, can any work from the 3d model or will I have to convert these into another format myself. I'm sure that if there's a service that can do it for me they will be an awful lot quicker.

Any other basic advice would be greatly appreciated.

Chris.

[Elk101]

I'm not overly familiar with laser cutting other than what a learned while drawing up some stuff to send to Warbases, but I have used CAD for years. A dwg or dxf file should be fine as long as your cutlines are properly layered, the parts are set out to reduce waste and lines aren't repeated, although I think some laser cutting people will sorry that out for you.

I'm sure someone with way more knowledge will be along to help. I'd love access to a laser cutter, I have all sorts of drawings done!

[Gary Peach]

Hi

Most of the MDF type laser etching machines have come from the integration of plotting - vinyl sign cutting and steel fabrication.  The Graphics side use Illustrator and that type of program, where the Fabrication side came with CAD-CAM software liked to CAD.

Basics, you’ll find most will accept DXF and DWG AutoDesk AutoCAD files.  Best in 2007 and earlier.  R12 DXF is most stable.

As for layering -  Layering is more about the ability to work with the file in CAD.  Where its interchanges to the Laser software this is mainly a Graphic issue and the difference in colour is important.  The colouring is based on the engineering side where the laser needs to cut to an exact side of the line, allowing for the Curf - Taper of the laser when cutting through.  Where engineering tolerances are important for fit the colours define whether the cut is on the inside or outside of the object or cut centrally.

Check with who ever you go with as to their preferred layer-colours.

3D cannot be used.  Polylines may not be seen.  Circles created from exploded lines may not be visible in the laser software so send a PDF plot with your files to compare what you send with what they import.

Sketchup.  This is really not a CAD package.  It has its uses but not really as a tech tool.  The circles in sketchup are not true and will be faceted.  I know that the laser by dint of its motor action will 'facet' some curved but at a lesser rate with a CAD produced curve. 

The main difference between CAD tech software and Sketchup is again its route purpose.  Sketchup was a rendering package that has gone on to try to be more than it is.  As such the difference is.

CAD packages work in a Vectored way x'y.  Sketch Up is Scalar as used in the print industry.

As for getting them cut etc, its as much a to and fro exercise.  Also not the tolerance of the base materials is not tight - MDF so don’t expect the same level of precision form 1 cut to the next.  Plastics and steel is a different matter as they are not so prone to environmental distortions.

You will also find that each laser has its own foibles and the cuts will vary again, machine to machine, and depending on the age of the laser tube and the cleanliness of the lenses and the machines.

Hope this helps.

[zizi666]

DXF or AI files should do the trick.
Personaly I create drawings in Coreldraw and then export them as AI (as asked for by the friend that has the lasercutter )
In one case the file needed editing because 1 piece was cut out instead of being grooved.

[Elk101]

That's really useful info Gary. I figured that if it was st least clear what was intended for each layer then it would become easier for anyone doing the actual cutting to sort a drawing out for use on their particular laser. I was keen to see the replies to this for my own information too, hence my earlier post (so I didn't miss responses!).

[Zaheer]

Thank you, that's very helpful, certainly a lot to mull over!