Herkermer-Jerkermer

[kubotaman]

Okay I am a little puzzled. I have a file made in Aspire that is a gable vent 30 inches in diameter and is completely round and is made as a three rail sweep in Aspire. I felt it was the perfect time to do the toolpath, 3D roughing, in a circular motion. Of course I was also going to do the finish toolpath in the same manner. When I started cutting, roughing toolpath, the machine was jerking enough to make the cut quite poor. I changed just about all the ramp settings but they made little difference, if any. I stopped the machine and then proceeded to draw and cut a simple circle of the same size that was giving me trouble. It cut as smooth as silk. This proved to me that it was not the machine giving me the problem. I then went back to my Aspire drawing to see if there were quite a bit of nodes in the original circle. That was not the problem. In fact there were only four nodes in the 30 inch circle. I ended up cutting the three rail sweep in the usual manner along the X axis. You also have to realize that I am just learning the way to use the ramping settings so I could be wrong in that department. Is there anyone that can point me in the correct direction so I can cut the second vent the way I would like? It certainly would be easier for me. Also understand that when I cut it in the X axis it still jerked but noting compared as to cutting in the circular motion. Thanks!

[knight_toolworks]

are there any vertical parts? they can cause that. I was doing some moulding and all along the edges I would get a lot of z plunging. but even going around the part there is z movement in the fiel when the height does not change.

[Gary Campbell]

Daryl...
Can you post a pic of the preview and your tool settings? Someone may be able to help, but we need more info.

[myxpykalix]

Daryl,
I think the correct term for your problem is "Herky-Jerky":D

I have seen circles comprised of bunches of short straight lines that might cause that but if you don't have that then you need to look at your speeds.

What is causing it to go to its speed, then have to slow down or stop, its possible you have hidden vectors.

When it does this does the Z move up or down? Do you have other vectors hidden underneath that you just don't see?

Like he says post a dxf so we can see what you're trying to do.

[bleeth]

You can do a work-around by making the outside vector of your part a little larger than you want and create your model from this and then do a second vector offset slightly inwards that is the size of your part. Then do the 3-d cutting in the inner vector and use it as a cutout line as well. It doesn't take much of an offset to pull this off.

[tmerrill]

Gary is correct, we need the file and more info. There is a lot of speculation going on here based on some bad info.

Aspire does not offer a 'circular' roughing pass, only a Z level and 3D Raster, both of which are raster toolpaths. So I can't tell exactly what toolpath is being used and how it was set up.

If one does get into a situation with many Z level retracts, changing the stepover by a couple of percentage points normally eliminates them.

If the issue is vertical side cut quality, taking a few minutes to create "machining bases" around the design will reduce the time of the 3D toolpaths and leave the vertical surfaces to be better cut with a 2D profile toolpath.

Tom, sounds like that would have been better info to place on the beta forum instead of blind-siding the program on a public forum.

Tim

[bleeth]

Who's Tom?

[tmerrill]

The guy who decided to delete both his posts.

[srwtlc]

Tim, I'm not sure how Daryl has done this in Aspire, but could it be (sounds like) the situation of not having a flat plannar surface around his circle where the program doesn't get the edge information. Don't know if I described that in the right terms, but I think you know what I mean.

Scott

[gene]

That would be a good feature if aspire could do a circular toolpath . this would make making arch moulding much faster, or can it already?

[kubotaman]

Thanks for the comments. I was out of service as far as telephone and DSL till just now. I will post some pictures tomorrow and the file that has given me the trouble. I redid the file today and made sure all was correct but it still does the same "Herkermer Jerkermer" actions. Maybe someone can explain it to me as to why it does it. I looked for hidden vectors but haven't seen any. Post tomorrow. Thanks!

[kubotaman]

Sorry guy's this site won't let me upload my files since they are too big!!??

[kubotaman]

I can e mail them to you personally if you want. Just let me know. Thanks!!

[Gary Campbell]

Daryl...
You can snap a pic of the 3D prieview. You can also save as a new file, delete the toolpaths and post the file, as it will be much smaller. Also, post your tool speeds and feeds.

I would have you email file to me, but no Aspire here.

[bleeth]

You can e-mail them to me Darryl. I'm pretty sure though that the whole Herky-Jerky thing is caused by vertical walls and can be fixed by changing your toolpath strategy as suggested below.
daver at professionalmillwork dot com