My software is not getting the job done

[CRITTERBOARDS]

My software is not getting the job done, or I’m not going about it the right way.
I’m new to the world of CNC I recently purchased a small CNC router that runs a trim router as a spindle. My purpose is very single minded the only thing I wish to accomplish is making inlays in wood, these inlays for example are walnut inlayed in maple and they are at lest 1” thick. The problem I’m encountering is I can’t seem to get a good fit the software I’m using to create the vector / plotter file is Corel 12. The G code seems to jerk or leave flat spots. The way I try to make the file is create a ¼ wide line Trace it on outline thus creating two parallel lines which I separate to create two files. Seems like is should work, but its just not coming out clean. I can’t determine if its my plotter file or the G code that’s causing the problem. Now is this a good way of pursuing this problem or dose somebody know of a better way of creating inlay patterns.

[HuFlungDung]

Can you post a sample file? Some of us can maybe backplot it and see how it looks in a real cadcam program.

Are you getting gouges? Does the tool lift when it needs to? Are all the movements lines, no arcs?

[CRITTERBOARDS]

Originally Posted by HuFlungDung Can you post a sample file? Some of us can maybe backplot it and see how it looks in a real cadcam program. Are you getting gouges? Does the tool lift when it needs to? Are all the movements lines, no arcs?

What format would you like, Plotter or the G code?

It goes from one point to the next in a strait line and in a curve I end up with a small flat maybe .005”. The other pattern will have the save flats thus not lining up, and I do have it set at 0. I’m thinking if there is software that will generate the code to the right of left of the line not the center it would probably solve my dilemma.

[HuFlungDung]

Gcode please

[CRITTERBOARDS]

I couldn’t seem to attach the g code file. So i rename the extension to TXT, hope it works

[CRITTERBOARDS]

Hears a sample of what I’m trying to do this one is the first test so it not the best but gives you an exaggerated example of the problem

[HuFlungDung]

Well, I backplotted the gcode (using OneCNC), and I would say it looks okay. I'd cut it

If you are having machine jerk problems, it may be due to lack of processing power in your cnc, attempting to run very short segment code at high speed.

Turn down the decimal place accuracy on your posting program, you don't need 6 significant digits This alone may improve processing speed on your cnc.

Then, after reposting at 3 or 4 digit accuracy, then if you still see the machine jerking, then reduce the feedrate (maybe in half) and see if the machine can process it fast enough to keep the drive buffer full.

[HuFlungDung]

Btw, if you can figure out how to do G41/G42 tool radius comp on your machine, then you can perhaps make do with one centralized profile and cut on either side of it. But, there could be a problem with entry/exit to/from the profile.

I'd recommend for that type of work that you might take a demo of OneCNC Express. This will allow you to pocket the interior, as well as profile offset either side of a line, choose different tools on a mere whim, etc. It'll put the fun into your work

[CRITTERBOARDS]

Ok my manual says G41 left G42 right. If I’m reading this correct I add G41 or G42 in the code and it should give me the offsets I’m locking for?

[Dave's_Not_Here]

... what, if any difference, will the ability to "read ahead" on the toolpath have on smoothing out the transitions... coupled with possible feed rate adjustments, etc...

[HuFlungDung]

You're right, Dave. Several lines of "look ahead" are required of the controller. It needs to keep the command buffer to the motors full, so that continuous motion is possible.

G41/G42 could certainly be used on a centralized toolpath for your purpose. However, applying tool comp requires a bit of practice, to see exactly how the machine begins and ends when it starts onto the profile, and leaves it. This is because the machine begins at some start position, tool comp is called, and it then has to get into position to the right or left of the profile. The amount of the movement will be the tool's radius. This is called the "lead in" to the radius compensated path.

You'll have to insert the tool's diameter (or radius, depending on how the controller is set up) in its tool comp register. Then, you have to call for the comp to be applied, typically with a
G41 D1
for tool #1

When the path is completed, the compensation should be cancelled with a G40 in the code.

[CRITTERBOARDS]

Manual combination is going to be way more involved than I want to get into. I’m just going to pursue the software that will do it for me.