Upgraded now Z is "not smooth"

[kasey_jones]

Hi Everyone,
I upgraded to the new motors (I have a PRTAlpha) and I have a 3D plaque I cut out. It uses two toopaths, a 1/8" ballnose (rough cut) and a 1/32" ballnose (finish). The 1/8" cut is smooth as glass but when I cut using the 1/32", the Z stalls and jerks when going up and down. I'm working on a video, but won't have it for a day or so (software issues). Has anyone had this problem or seen this type of behavior before??

Thanks,
Kasey

[Brady Watson]

It sounds to me like you have your XY and Z speeds too far apart from each other (EG 6.0,0.5) and/or your ramping values need to be tuned for the task at hand. If you are running a 3D file with that little 1/32" bit, try changing MS to something like 0.7,0.5 and adjust your ramping as follows:

3D threshold: 150
Min Dist to Check: .08
Slow Corner Speed: 30

See how this works for you. With very small bits, you have to adjust ramps so that things are a bit more cushioned. Any little jitter will result in tool marks. Make sure your pinions are in good shape, greased, and wipe your rails down with a brown scotch pad feeling for any bumps or jagged edges. These will transfer to the cut. Sand down any jagged edges with 100-150 grit paper or a 3M Roloc disc on a die grinder.

-B

[kasey_jones]

Brady -

Thanks for the advice, still new to all of this. I'll make these changes this afternoon and let you know.

Thanks again

[kasey_jones]

I also will need to soon replace or rebuilt my PC (75182) Router. Most of the work I do is small detailed plaques, I don't hog out lots of material with 3/4" bits. I realize I would have to address the different body size when mounting, but could I use a small router? 1 3/4 or 2 1/4? Just seems crazy to have all the HP and never use it.

[cnc_works]

Hey Kasey...I used a PC 690, then 890 for years before I got my spindle. The 890 especially was a lot quieter and powerful enough for everything I did with the SB though I'm sure I multipassed in some jobs where the 7518 would have been able to do single pass. I have a PRT so multipassing was kind of necessary anyway. Another small advantage of the PC 890 was a single wrench collet system.

I bought an adapter, I think from Shotbot, to account for the different diameters of the 7518 and the 890.

Donn

[kasey_jones]

Donn -

Sounds like a plan to me. I've priced them on Amazon at $157.98. The motor dia is 3.5 on the 690 and 4.2 on the 7518, a difference of .7 I didn't see an adapter listed on the shopbot page, how long ago did you get your adapter from them?

Thanks.
Kasey

[cnc_works]

Kasey, it has been probably 3 years since I got that part and, since I barely can remember what I had for breakfast, pushing more definitive recall out to 3 years is highly unlikely. But someone else on the forum or someone at Shopbot would likely remember.

Donn

[cnc_works]

Kasey, it has been probably 3 years since I got that part and, since I barely can remember what I had for breakfast, pushing more definitive recall out to 3 years is highly unlikely. But someone else on the forum or someone at Shopbot would likely remember.

Donn