Acrylic Cutting Help

[Tenson]

Slowing the spindle down shouldn't be an issue if I keep the feedrate proportional, right? The chipload is the important thing I think. Still, maybe it will cut smoother if it is faster, I should try.

I might also simply need to try another cutting bit, perhaps this one is slightly damaged.

[Lee Roberts]

Slowing the spindle down shouldn't be an issue if I keep the feedrate proportional, right?

I think that's right but dont see it would help for this, i could be wrong.

The chipload is the important thing I think.

Yea its a good indication that things are working well, i.e you want chips not dust, chips not spirals, though this is probably different for different materials.

I might also simply need to try another cutting bit, perhaps this one is slightly damaged.

Are you only getting this in soft stuff "plastics" or what, it could be the deflection/accuracy thing seen in climb vs conventional.

.Me

[Jonathan]

From the images in the first post it looks like the machine slightly lost position after a few passes, then continued as normal. Tricky to explain, but what I think happened is at the depth of the poor finish the machine lost position and moved further away from this cut, but not by much, such that on the subsequent passes the cutter didn't quite touch the first bit that was cut, but did stick hot swarf to it, hence the poorer finish. Meanwhile the cutter would have cut more from the waste piece, over the full height - hence the better finish on that part. I've seen this happen on my machine when a part hasn't been clamped well, so it moves ever so slightly giving the same effect. Could be the same here...

Slowing the spindle down shouldn't be an issue if I keep the feedrate proportional, right? The chipload is the important thing I think.

Spot on...

Precisely what feedrate, spindle speed and depth of cut were you using?