2.5 carve roughing problem

[chip clark]

Hello - I'm having a problem with the tool plunging too deep when the roughing carve starts. I'm working with 1" material, depth of carve is set at .80, using a 1/4" spektra endmill. The tool has a set pass-depth of .125. When I start the carve the machine (Axiom AR8) plunges to 1/2" to begin the rough cut. A bit nervous about a cut that deep with oak. I attached a screen shot of the toolpath settings.

[Rcnewcomb]

Obvious question: Is Z-zero set to the top of the material, or to the table?

Beyond that, to eliminate a lot of random guessing, can you please upload your CRV file to a site like drive.google.com or Dropbox.com and provide us with a shareable like (copyright permitting)? That way we can inspect the actual file.

[chip clark]

Thanks for the reply, Randall! The Z is set at material height. Here is the link:

https://drive.google.com/file/d/1vNHhJ9 ... sp=sharing

[gkas]

As far as I can see via the preview, the carve is respecting the 0.125 pass depth. The feeds/speeds are very conservative for this machine. I would run @ 80 ipm and plunge @ 60 ipm for roughing @ 0.125/pass. That would knock about 45 minutes off your carve time. I cut red oak and maple on the machine all the time with no problems. Upping the plunge rate will cut a lot of times off the 3D carves.

[chip clark]

Thanks! You're right, the preview looks correct, but for some reason the machine is taking a 1/2" dive into the wood.

[gkas]

Puck setting correct? Try zeroing the old fashioned way, with a piece of paper between bit and work piece.

[Rcnewcomb]

Is it possible you are hitting the upper limit on your Z travel?
You have set home Z to 0.8" above the material which is 1.8" above the surface.
The bit probably sticks out 1.25", so now we are up to 3.05" above the spoilboard.
Your machine spec says it has 5.9" of Z travel, but I'm not sure how thick your spoilboard is, or if your router/spindle is mounted a bit lower than it needs to be.

Regarding the finish toolpath. Do not use an end mill. You will want to use a ballnose bit with a stepover of less than 10%.

[chip clark]

Not sure about all that. Still a bit new with this. I checked other successful carving files and they all have the same z setting at .80. I checked the calibration on the puck and it's correct. There's plenty of Z travel, and I'm touching off as I have on other projects. This has me totally baffled.

Yes, I prefer to use the Spektra tapered ball bit for the finishing cut, but it adds about 30+ hours to the run time.

[gkas]

Yes, I prefer to use the Spektra tapered ball bit for the finishing cut, but it adds about 30+ hours to the run time.

You should be using a ball nose or tapered ball nose for this cut, not a square end mill.

[martin54]

What version of the software are you using? If it's 10.5 then what post processor are you using? There have been a few problems with some of the PP within 10.5 & people have been advised to use there old post processor files from V10 if everything worked OK in V10.
Not sure it will help here but something else worth checking

[Bill_L]

What version of the software are you using? I ask because I opened your file in the latest version (10.505) and the only post processor that I can find for your machine (Axiom) is in "mm". Wonder if that might have something to do with it.

As far as your strategy for 3D toolpathing, I have a Shopbot PRS Alpha and have done extensive work with the following settings:

Roughing is 3D raster done with a 3 flute .375" BN at 3 ips (180 ipm) in X,Y, and Z. Step over is set at 30% with step down at .1875". With a 3 flute I almost never run the spindle over 9000 rpm. Remember, there will be ramping so the feed rarely achieves the full 3"ips.

For a file of this type/size a .125" BN will give you all the resolution that you need. I will run this file at the same feed (3 ips) and the same rpm for the finishing pass with a step over of 9% will achieve a nice smooth finish.

I don't know the capabilities of the Axiom so you might not be able to run it as fast but try tackling some smaller 3D projects and try different feeds/speeds to dial in the best results for your machine.

Bill

[chip clark]

Thank you to everyone who has responded! Interesting that my software is showing version 10.022. I thought I had recently installed the update to 10.5. I just tried to update it I got a prompt saying I had to install an earlier version of 10 before I can update to 10.5. ???

The post processor I've always used is Axiom-HHC-CNC (mm) (.mmg). I've never had any problems before this.

[Adrian]

10.5 is a download from your Vectric portal account.

The output from that post processor shows the first Z move is 3.175 mm which is 0.125".

Sounds like it's an issue at the machine/control software to me.

[gkas]

Thank you to everyone who has responded! Interesting that my software is showing version 10.022. I thought I had recently installed the update to 10.5. I just tried to update it I got a prompt saying I had to install an earlier version of 10 before I can update to 10.5. ???

The post processor I've always used is Axiom-HHC-CNC (mm) (.mmg). I've never had any problems before this.

You are using the correct one. There are only 3 official pp from Axiom, the one you're using, one for the laser, and one for the rotary.