Cut3d - roughing marks

[rhfurniture]

Hi,
I am getting some very minor marks from the roughing cut, only on vertical edge surfaces, in spite of setting "machining allowance" to 1mm. Does this allowance only apply to Z?
This was using an 8mm ball - no other problems, so it has held up on its axes position.

R,

[rcnewcomb]

Can you post a photo?

[rhfurniture]

Will do Monday.
Thanks, R.

[paco]

Tell us/vectric how large was your project please.

[rhfurniture]

Hi:

4255
The artefact is about 2mm across, and was part of the roughing cut. The upper vertical machined edge to the left is 50mm high. The whole project is 700mm x 300mm x 120mm approx and was cut with an 8mm ball spiral in Rampf raku-tool board - an easy-cut plastic based cnc modelling board,
R.

[rhfurniture]

Bump - any ideas?
It was a single surface imported to cut3d from rhino via a 3ds file, and worked "fit to material" on page 2 of the wizard.
R.

[pfulghum]

Collet marks?

[Brady Watson]

Ralph,
I'm not familiar with the tooling board that you mention, but my experience has been that some of those composite boards move around a bit as you remove material. It depends a lot on the shape that is being cut out.

Did you use an 8mm ball for the roughing as well as the finishing? If so, did you tell Cut3D that you were using a ball end tool or an end mill? If you changed tools, there is a possibility that there could have been some debris under the zero plate or deviation in Z from the zzero location of the roughing tool.

To answer your question, the 1mm allowance that you specified for roughing is in all 3 directions, not just in the Z.

-B

[paco]

I had a "similar" problem once but it was with a much larger project. The whole (nested) models where over 48"X48". The problem, according to Tony at Vectric, was that I was well over the "proper" resolution for Cut 3D. Like Cut 3D was better suited for smaller scale project. Zooming in at certain angle could reveal the roughing toolpath was cutting "through" the finishing one.

If you assume the tool didn't lost position anyhow and that you material block didn't move then you may want to contact Vectric support to inquire about an issue with Cut 3D.

I'm not familiar with the tool bit you are referring to. If the tool bit shape isn't support by the Cut 3D tool data base, it might be the problem...

Any chance you can upload the Cut 3D file for us to study?

[benchmark]

Ralph,

I am having similar problems with some scrolled keystones that I am making at the moment..... are you getting any machine vibrations when the spindle changes position from a tall vertical edge to a horizontal plane.

My keystones have nearly 1 million lines of code so when I increased the feed speed the jerky motion caused iregular tool marks similar to the those you have shown.

Maybe some slop in the pinnions ?


Paul

[rhfurniture]

4256

4257

4258
I used "use model silhouette" on page 2 (not "fit to material" as earlier post). Both machine and material were dead firm, and both roughing and finishing were with 8mm spiral. Feed speeds were in the 50mm/sec range, and stepovers were 3mm and 0.2mm. The tall vertical edges were cut afterwards - there was no registration or toolpathing problem as the item was not moved and the final shape was spot on. Given that I had 1mm machining allowance, the cutting position got to be at least 2mm out of where it should have been. On the roughing page, I had it set to "raster Y" / "Z level" / "none" (profile).
It is possible that it was confused by only using a top surface for a model.
Anyway, thanks for replies - I will be more careful to look at the full combined preview in future - currently I just check the finished preview for surface quality.

R.

[rhfurniture]

Addendum to above: I used an 8mm BALL spiral for ruf + fin.
Sorry for being a bit bitty with the info.
R.