Wacky Tool Path

This forum is for general discussion about Aspire
Post Reply
vonbergmann
Posts: 2
Joined: Mon May 20, 2019 2:40 pm
Model of CNC Machine: Camaster Stinger 1

Wacky Tool Path

Post by vonbergmann »

Howdy,

I have been using Aspire for about 6 months, and I have gotten the hang of a lot of it. Most of my questions have been solved by searching here, or other sites. This one has me stumped. I am not even sure how to search for an answer.

I am tool pathing a guitar neck I modeled. when I do a 3D finish pass, the bit wants to jog up and down at the heel of the neck. I ruined a few test blanks until I actually looked at the toolpath. THis has come iup in other models I have built. Any help in helping me to understand this would be appreciated. Thanks so much, MelImage
Attachments
Bit Jog.jpg

User avatar
adze_cnc
Vectric Apprentice
Posts: 929
Joined: Sat Jul 27, 2013 10:08 pm
Model of CNC Machine: AXYZ 4008
Location: Vancouver, BC, Canada

Re: Wacky Tool Path

Post by adze_cnc »

Some will call this “sewing machiing”. It happens when the finish toolpath is riding along the edge of a near vertical plane. When calculating the position in space sometimes the maths say the z is at the bottom of the “cliff” and other times that math says it is at the top.

You could create two separate boundaries: one for the nech and one for the heel. You would 3D finish the neck as you do now and the heel using a raster path perpendicular to the length (that is across the heel).

There are many other methods to try such as using a boundary that prevents the toolpath going over the “cliff” and then following up with a 2D profile path.

User avatar
Rcnewcomb
Vectric Wizard
Posts: 3947
Joined: Fri Nov 04, 2005 5:54 am
Model of CNC Machine: GCnC/WinCNC
Location: San Jose, California, USA
Contact:

Re: Wacky Tool Path

Post by Rcnewcomb »

Here is an example of the problem, and how I handle it.

I have a design where you will notice the toolpath preview shows the finish tool path occasionally dropping off the edge.
Screen Shot 2020-06-29 at 2.33.20 PM.png
Normally I use a boundary vector, and my boundary offset is slightly over 1/2 of my bit diameter. But in the case that causes the tool to occasionally drop off the edge.
Screen Shot 2020-06-29 at 2.52.55 PM.png
Therefore I would reduce the offset to something smaller until the problem disappears. In this example an offset of 0 works fine.

You can even specify a negative offset. Try an offset of -0.5 and preview it, just to give you a better understanding of how the offset works.
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

vonbergmann
Posts: 2
Joined: Mon May 20, 2019 2:40 pm
Model of CNC Machine: Camaster Stinger 1

Re: Wacky Tool Path

Post by vonbergmann »

Thanks for the info gents. Very kind!

Post Reply