Questions about the engraver

[dirktheeng]

I'm considering going this rout but I'm not sure.

I do a lot of work with Autodek inventor to design parts. How do I tke a file and make it cutable? I can make DXFs of the file from inventor. Do I just import those into the software somehow? How do I make sure that the parts are cut exactly as I made them in the drawing (that is, how od I make sure it's 5mm wide if that is what I drew)?

Does the DSP account for kerf width like we can with CAM/Mach3?

[metalman]

I haven't used DSP but there are a few ways to accomplish kerf comp. Some software will do it automatically as long as the kerf parameter is entered properly. Then, you have to make sure the program knows which side the comp should be on. As an alternative, you can do an offset of the cut path before you send the DXF to the CAM program to get it to generate the G Code. That will effectively make the part bigger and holes smaller by half the width of the kerf on each side of the part. You also need to make sure the order of cut is correct. The center of a the letter "O" needs to be cut before the outside is cut or it may shift a little.

[dirktheeng]

I was specifically asking about how this gets done with the LightObject DSP controller. I am familiar with CAD/CAM methods, but not the DSP

[twehr]

I was specifically asking about how this gets done with the LightObject DSP controller. I am familiar with CAD/CAM methods, but not the DSP

The DSP cuts on the line. If you need to account for the kerf, you will need to do that in your original document.

If you are working from a ( kerf adjusted) DXF, you can simply import that to PHCad ( the DSPs native software ) and run the job.

The program I posted elsewhere to design finger joint boxes will adjust the kerf for you, if you enter it.

Over all, you are responsible for the kerf adjustments.

I am away from home most of this weekend. First of week I will write an article on measuring and adjusting for Kerf and how it relates to the DSP.

[bdring]

That is not uncommon for lasers. Even when submitting a file to Ponoko, all cuts are done on the line. Corel and AutoCAD both have offset features that could easily deal with that. Mach3 of course does not deal with kerfs. G-Code is all cut on the line. (Actually I think there are some tool radius compensation commands, but I would avoid them).

If you really want CAD control over kerfs you might be able to use a program like cut2d. It has post processors that can create importable drawings. I think it does HPGL and I believe I saw a DXF post too, but I don't see it in the list. I think you could write that post if not.

[dirktheeng]

That's what I figured I would have to do, but I thought i would ask if the cad program did that or not.

Also, I assume that the cad program can imprt any dxf file I can generate. I don't have autocad... I have Inventor. Is tha correct?

[bdring]

There are different versions of DXF. Usually importers are a rev or two behind, because it is always a game of catch up. Most exporters usually allow you to choose a few levels back for that reason.

I use AutoCAD LT for some 2D work, but Draftsight is almost a total clone and it works great. It allows you to work in many versions of DXF or DWG. AutoCAD always nags you to save in the latest revision. See my blog post on the subject.

http://www.buildlog.net/blog/2010/09/fr ... solutions/

[twehr]

That's what I figured I would have to do, but I thought i would ask if the cad program did that or not.

Also, I assume that the cad program can imprt any dxf file I can generate. I don't have autocad... I have Inventor. Is tha correct?

I have inventor 2012. I will test first of the week. I have not found any dxf that dsp chocked on but want to verify for you.