[CarveOne]

Do I just add the G61 at the start of each file?

I guess if that's it I can put it in the post processor file so it goes in each header.

Hey, they made ships out of concrete, so an MDF strike fighter might be ok.

The test pilot's initial reaction to it might be comical.

CarveOne

[Quiff]

Hi Arbo,
Enjoying your build. You might want to look at what your setting is for acceleration. If it isn't high enough you will get "Not Rounded" corners. Not sure if that was your problem or the reverse.
Can you please attach a close up of the rack & pinion for both X & Y so I can see how it attaches etc.
Thanks

[ahren]

Quiff,

There's an installation video on my website that shows how everything goes together if you're interested:

http://cncrouterparts.com/product_in...products_id=65

Best regards,

Ahren
www.cncrouterparts.com

[debetto]

Do I just add the G61 at the start of each file?

I guess if that's it I can put it in the post processor file so it goes in each header.

Hey, they made ships out of concrete, so an MDF strike fighter might be ok.

Yes, adding it to the start of each file should do it. Also, a G64 command--which I think is constant velocity mode--should undo the G61, if desired.

Great machine, by the way. I'm thinking of having a similar design for my build.

debetto

[Arbo]

That G61 does the job, and you are correct, G64 goes back to the other mode.

I wish Mach had some sort of "average cut speed for the whole piece" that it kept track of, would be handy.

Been cutting some positive glider tails out of MDF to test things. Here is one a friend did the other day, then soaked in epoxy. Another layer of epoxy and finishing sand and it will be good for him to make molds with.

[ger21]

If you can accurately reference the part, machining it after the epoxy cures gives a fantastic finish that is much easier than sanding the rough surface you get after just epoxy coating. Ideally, you'd want to rough it about .005 oversize first.

[Arbo]

If you can accurately reference the part, machining it after the epoxy cures gives a fantastic finish that is much easier than sanding the rough surface you get after just epoxy coating. Ideally, you'd want to rough it about .005 oversize first.

Didn't think about that. Thanks. Would you finish with a ball end with very small overstep?

[ger21]

Didn't think about that. Thanks. Would you finish with a ball end with very small overstep?

That's stepover. Yes.

[Arbo]

Added a rod to the dust boot, to attach the suction hose to, it helps keep it out of the way far better.

Also a picture of clamp down.

And a piece I was experimenting with in a paint program and mesh program. I think in the end it should be reversed from what I did, but it's ok for a test piece.

Also hooked up a logitech gamepad and have it set to jog the machine. Quite nice.

[CarveOne]

Hey Arbo,

Are ya having too much fun to talk to us anymore? How's your R&P drives holding up for you?

CarveOne

[Arbo]

Been trying to learn, it's a lot of information overload.

Trying to figure out the whole accelleration, feed speed, CV mode vs not CV mode and all that. Seems that running in CV mode the machine is of course smoother, but if the feed speed get's too high, it cuts corners, but you go out of CV mode and have a lot of curves (3d relief stuff) and it's painfully slow. I'd like to find a resource that shows pieces, and talks about speeds and bits used to cut it, how many different passes used and what style, as well as modes used (cv, etc). Stepover needed to produce a smooth finish, etc. Right now my machine is running on a piece I drew up, it's an 8x10" piece, with a relief in it. Running a finishing pass with a 1/8 ball nose, at 10% stepover, set to 80ipm but not in CV mode so it's slow and stuttery for all the stops and starts. It's been running about 2 hours and about half way done. Is this sort of time frame normal? That's yet another bit of information that would be nice to see along with the above information.

I've searched CNCzone and only found a spec of information here and there.

The R&P drives are good, but as I mentioned before, the rack I got was not all the same. After looking closer it is obvious on the 6' lengths the teeth are longer, so the pinion doesn't seat all the way down. The faster the machine moves, the more you notice (and feel) the vibrations. I need to pull the 6' racks off and grind the teeth down.

Your machine is looking good with the R&P. Been watching that one.

Climbing that learning cliff, I am.

[Arbo]

Oh, order some brushes for the dust boot as well. The plastic didn't last long after a few snags on parts.

[CarveOne]

I shoulda known that you have your head buried in the documentation by now. When you learn it all, you can impress those of us that don't, yet.

CarveOne

[Arbo]

I'm not sure how far I'll get, but I hope to get there, even if it takes brute force experimenting.


Here's an idea I have been working on, getting better each iteration as I learn...

First in MDF....



Then I figured out the text (so I got the cutouts in the o and a and such).. but used a CV mode in there, and that make it less than perfect....

And for some reason it set the 'work' down into the wood (hence the rectangle set down into it)...



So I tried again, but it once again went down below the top, even though the part was set to the top of the block for generating the gcode.... and because of that I set the z wrong for the last pass which was for the corners of the letters and such, so that goes too deep.



I'm almost there, just need to figure out why parallel finishing is going below the 'top' of the piece...

[jimalb]

Arbo,
Nice job on this machine!
I built an engraving machine and use EMC2 and in the header for the Gcode I use A

G64 P0.005

This tells EMC2 to use CV mode but not to deveate more than 0.005 from the tool path.
For me this smooth the running a lot and still has sharp cornners.
So check the Mach documents and see if it will accept a P word or some such and then play with the settings till you find something that works for you.
Jimmy

[Arbo]

Jimmy, thanks, I'll give that a try tomorrow and see how it works/if it works for me.

[Arbo]

I found the CV settings information about setting tollerance, set it to .005, and jacked up my accelerations to 20. I'm rerunning the last piece shown above to see results. It definitely looks faster already. Will be watching the time.

[Arbo]

Jimmy, mach doesn't use the p command for tolerance, it has a setting in the configuration (so I found out).

Also set my accelerations up around 20.

Made some zig zag patterns in CAD and tested. With the 0.005 and acceleration set, I could whip through at 600+ ipm without missing anything. Far more than I'll ever need. The pauses that do occur are a lot less harsh that previously.

That in mind, I went to the sketchup gallery, found and eagle, downloaded it, converted it to my cad program, imported it, resized, squeezed down the z to flatten it, and then generated some gcode.

The piece is 14.5" x 4.87". Ran roughing at 250 ipm with a 1/4 end mill. Ran perfect.

Ran finishing pass with 1/8" ball nose at 200 ipm, again flawless.

While the finishing pass was running I decided I wanted to add some text, so I made some text, cut it out of my 'base', then copied the 'base' down .2 below the current one, and generated gcode just to finish that area (thus giving me cut down in letters).

I am very happy with figuring out the whole acceleration/CV thing. The other piece I recut (as mentioned in last post) came out better and in less than 1/4th the time.

All in all a good day for my knowledge and forward progress. Perhaps I should relax with a beer now.

edit: The dark spot on the one wing is CA glue, as I went through the MDF so fast, it had split and was peeling up there. That's ok, it was just a test.

[Arbo]

Attempted my first litho today. Used a 1/4" plastic cutting board bought at walmart for 4 bucks.

1/16 inch bit, 8 ipm. Fiddled with router rpms. Still need to fiddle more to get cleaner cuts without melting the plastic.

This piece hasn't been cleaned up of all the little clingon pieces of plastic, so it will look better when done...

[CarveOne]

Attempted my first litho today. Used a 1/4" plastic cutting board bought at walmart for 4 bucks.

1/16 inch bit, 8 ipm. Fiddled with router rpms. Still need to fiddle more to get cleaner cuts without melting the plastic.

This piece hasn't been cleaned up of all the little clingon pieces of plastic, so it will look better when done...

Now do that in Plexiglas and make the bottom border a little wider to drill four or five holes for white LEDs facing upwards. Wire them to a battery with the appropriate resistors, and put it in a frame so that the LEDs aren't seen until turned on.

Heaps better than a black velvet Elvis.

CarveOne