DXF export for laser

I'm exporting drawings to .dxf or .dwg from ProE for use on a small laser we've just purchased.
The laser driver runs as a 'print driver' from within vector based graphics
software [Corel, Adobe Illustrator, MicroGrafix].
My problem is that the export from ProE does not seem to be 1:1 even though the drawing scale is - I've imported to Corel and MicroGrafix with the same effect.
Any ideas?
Cheers, Sean
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~ Sean Kerslake Dept. of Design & Technology Loughborough University LE11 3TU
01509 228317
~~~~~~~~~~~~~~~~~~~~~~~~~~
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Well, no problem, so far. Pro/e can take a drawing view of top/plan view of a part and turn it, quite adequately, into a DXF that any laser machine can read.

Okay, now you've got me completely lost. Are you saying that the DXF from Pro/e is not readable by your laser? that it needs to be, first, read into Corel and reinterpreted? 'Printer driver' to re-output this information? this seems altogether strange to me, nothing here that is standard procedure with Pro/e output. Maybe do a file compare ('Beyond Compare' file check) to see what the Pro/e export is missing!?! You shouldn't need a 'second opinion' to get to the simple 2-D outline you need.

The scaling problem could simply be the drawing format that was originally used. In Pro/e, stupidly or not, it scales to the format/drawing size. So, use E or Custom (drawing size to suit) for all big stuff at non-scaled values (i.e., make the drawing to the size of the universe, if this is what it takes to hold the model outline at 1 to 1.)
David Janes
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Also, check out a message on a similar topic from Carl, 1/19/05, which gives hints on how to make sure stuff gets scaled properly. At very least, make sure Pro/e's units agree with the default import units of the laser software. For example, if your laser is importing in inches and Pro/e is exporting in centimeters, you'll have a scaling problem. DXF doesn't communicate information on either scaling or units of measure. To DXF, a line is a line and it am what it am. You supply all the intelligence, DXF ain't got none. So, if you had a choice of export formats, you might be better off with something like IGES or STEP which have some intelligence built in, providing the laser software is smart enough to take advantage.
--
David Janes



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Hi SeanK!
Ive just read your quests. Im coming from Germany and I am working as an Laser-Engineer. We do produce all kind of Laser-graphics on nearly all kind of surfaces. We do use YAG and CO2 Lasers with 1024n/m up to 150Watts. We use dxf files, too. The format for the Laser output is .plt or .prnt - in case you are sending laserdata from a CAD Software to your Lasersoftware. The CADfiles always are converted into .plt (plot) files by our software (and I guess many other machine demand so, too)
To reach a maximum or the best result when "plotting" with a laser - I use to scale my CAD (dxf) file 100:1. I mean you just have to scyle your picture (true vector lines with no string wirdth) hundred times bigger than the endproduct - here : your lasered surfaces,object etc..)
I know that the format .dxf is not a ISO-standard. That mean that all software applications may use the suffix .dxf. Its either implemented with any world wide standards or compatible with other .dxf suppliers. That mean that the only variables in an .dxf-file are x,y,z coordinates. Nothing else. If yolu are using Coreldraw to prepare your vector graphics, you cannot say that your lines have a witdth of zero, or just use no line.strength. You can test the different screen outputs by switching your view-modes. Always use the outline mode online. Everything you see here is "Real" in any other mode you cannot trust the screen. All CAD software or .dxf producing apps are handling the unimplemented .dxf-standard different,generating of .dxf files is a mess!
My hints for you: You have to know that the Laser do have an own streamwitdh. In my Case a Laserline have the strenght/width of 0,02mm. That means if you are Lasering for example: the letter : a - the a also have an inline and an outline graph and these lines will be lasered with the strength of your specific laser. Remember that good sign-cutting or engraving software always have the abbility to calculate exactly this diffrences between screen and tool generation.
You have to use the Inline-Fuction on every objects you are exporting to Autocad(later you will understand) to match the Laserlinewitdths. Use the half of the real Laserwitdh e.g 0,02mm if your Laser is 0,04mm. Copy the corrected cloned,smaller object and create a new CAD-dokument in your CAD software and paste that clone. After that go on like this:
Always use an easy simple CAD software to construct your graphs. ALWAYS Use Coreldraw to export (via export-option) your .ps, ai, eps etc files into that special format: eps-format . There are one or two more eps formats Corel allows to import. Only use the eps interpreted style for reimporting your just exported .eps. The other .eps only format dont work with software like Autocad. The imported data ist always scub or sucks. After exporting into .eps and reimporting as .eps interpreted you should use that simple CAD programm I was talking about(the option to import eps data is recommended!!) Ok, know import your 100:1 eps data and watch the output with the maximum zoom. If your lines are smooth and exactly as they where when xporting from Coreldraw - you might be happy.
Now use the CAD software and export your file into the dxf-format. IT IS RECOMMENDED THAT YOU EXPORT THE DXF-FILE with the subinfo or headersuffix R12.Not R13 or R14 or else...) Now open that dxf file in Autocad. I use AutoCad LT2000. previous or later versions do not work! Now use for example a simple 90 0,04mm hatch to fill your Texts or symbols or what ever.
After that step generate a new output file from that -using generate function. Choose .dxf-format and the 2nd Options should again be R12 Format.
Reopen your CAD-Software and Import your dxf format (change the filetype from eps to dxf again in your import dialog scene.) The best way to continue now is to export it to your Lasermachine Software.
Its not easy at all. But after 15 jears in the Laser signing business I should have testes every kind of possibilities and I come to a final result: There is no cheap solution to creating exact dxf images for a Laser.
I use the software CASmate 6.5 by amisoft (signmaking and engraveing steering and cutting software) That software is the best. But the support has ended cause its an 16Bit application. The Software group know offering a new Version called: FLEXISIGN. Search in Google for Flexisign or amisoft and you will find better information. The bad thing is that the software is very expensive and rare.
I hope I could help you a little bit - I know how confusing it is working with dxf formats.
Just have a look at our Website : http://www.optimark.de
For sure I am out
Daniel
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