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Mini 4th Axis - Seam left on finished part

Posted: Mon Apr 12, 2021 10:42 am
by SeaBiscuit
I have been using CNC in 3 axis for for a few years now and just purchased the 4th Axis Mini. I have the latest Firmware on the controller and the pendant... I have the Latest Post-Processing Files for VCarve (rotate on X and Rotate on Y [in inches]). I have carved a few things and they never seemed to turn out exactly how I expect them to... so I have moved to trying to carve some quick calibration type patterns so that I can validate that I have all the alignment and setup dialed in.

My Current issue is:

There Seems to be a SEAM down what I would Call the A=0 Line.... ("A" Being the 4th Axis Rotation value)

it is really just an annoying thing, as of this second it seems the finished product (other than the seam) appears correct.
Thinking maybe I was setting my 0,0,0 off I played around with cutting several versions after adjusting these settings... there seems to be little effect.

My Thought process of what is happening (which may not be correct) was the VCarve app is generating the file flat and then wrapping it around a 360 deg circle while scaling the flat plane to fit the size of the cylinder... i keep thinking that this "wrap" is not going the complete 360 deg... and so it is leaving a seam?!?!? but when i look at the calibration lines... they all seem to line up as expected, EVEN Across the Seam?!?!? if the wrap was short I would expect these lines would be off.... so now I am just at a loss...

anyone else seen this? is it normal? or is there something I can do to make it go away?

Here are some of my Settings that may come into play.
* i am doing everything in inches
* I create my V-Carve file with the wood diameter very close to the right size
* I tell V-Carve I want to have X=0 be the CENTER of the cylinder
* I do my tool path as RASTER

Thanks in advance for your time reading this and any help you might be able to provide would be great!

**here is an image of my sample carves (with either X adjusted or Z Adjusted

Re: Mini 4th Axis - Seam left on finished part

Posted: Tue Apr 13, 2021 5:44 pm
by SeaBiscuit

It seems to me that it is Not VCarve or the Post Processor (Tap Creation)
I looked over the TAP File and here is what I see...

#1 - The Tap File appears to be using Degrees when referencing the rotation of the A - Axis
#2 - The Rotation appears to start at 180 Deg (A180.0000) and then slowly reduces to 0 Degs then continues to decrease to -180 Degs (A-180.0000)

So to me that says... A180.0000 should be the same as A-180.0000 **Maybe this is the issue? but I would think this is normal

I will keep looking and testing...

next plan is to make a custom TAP file from scratch and have it mark degrees and then I will try to measure them and see if they are right on...

- Sea