4th Axis Incomplete Finish Cut

Topics related to wrapped rotary machining in Aspire or VCarve Pro
HBruns
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Re: 4th Axis Incomplete Finish Cut

Post by HBruns »

SteveNelson46 -
I am importing & using the larger OBJ file and not an STL file.

When either the STL or the OBJ file is used, and a raster angle of 0-degrees is used, this problem manifests.
When either the STL or the OBJ file is used, and a raster angle of 45-degrees is used, this problem does not manifest.


I wonder....
Since the problem shows up when the Y & Z axes increment and the next command is to rotate 1 full turn
Either
- from A0.000 to A360.000 - OR
- from A360.000 to A0.000
Could the controller be interpreting that as a NULL motion?
Do I need a controller firmware update?

Code snippet -
...
N64100G1A0.000
N64110G1Y88.639Z22.494
N64120G1A360.000
N64130G1Y88.798Z22.465
N64140G1A0.000
N64150G1Y88.957Z22.434
N64160G1A360.000
N64170G1Y89.116Z22.396
N64180G1A0.000
....

Greolt
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Re: 4th Axis Incomplete Finish Cut

Post by Greolt »

I see you have an axiom machine. That usually means you either have a DSP controller or UCCNC

Take a look at a setting called "Rollover on 360" in UCCNC. "Rot 360 Rollover" in Mach3. No idea what it is called on the DSP.

You gcode calls A360, A0 repeatedly after the crown section. See snippet.


N63080G1A360.000
N63090G1Y80.530Z17.037
N63100G1A0.000
N63110G1Y80.689Z17.228
N63120G1A360.000
N63130G1Y80.848Z17.420
N63140G1A0.000
N63150G1Y81.007Z17.611
N63160G1A360.000


I would suggest that the controller is just taking the shortcut between 0 and 360
Attachments
Rotational.jpg
Rotational1.jpg

HBruns
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Re: 4th Axis Incomplete Finish Cut

Post by HBruns »

Pretty sure it's a DSP controller
It's a RichAuto B18
Image from the Internet - Mine has all english writing on the buttons
Image

I have heard of no rollover equivalent for this controller

Greolt
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Re: 4th Axis Incomplete Finish Cut

Post by Greolt »

It should be there somewhere. Look at the manual or ask the manufacturer.

HBruns
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Re: 4th Axis Incomplete Finish Cut

Post by HBruns »

Greolt wrote:
Tue Mar 16, 2021 2:59 am
It should be there somewhere. Look at the manual or ask the manufacturer.
Just looked through the Axiom 4th axis manual.
There are controller changes described for the B18, though there is nothing about "rollover on 360" or anything similar.

Greolt
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Re: 4th Axis Incomplete Finish Cut

Post by Greolt »

It would surprise me if there is no way to control that behaviour.

One way around this would be to change your finishing strategy.

Have the cutter travel along the length of the piece with the rotary turning a small amount each pass.

That is the way I do most rotary jobs.

HBruns
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Re: 4th Axis Incomplete Finish Cut

Post by HBruns »

Greolt wrote:
Tue Mar 16, 2021 9:21 pm
It would surprise me if there is no way to control that behaviour.

One way around this would be to change your finishing strategy.

Have the cutter travel along the length of the piece with the rotary turning a small amount each pass.

That is the way I do most rotary jobs.
This does work.
With the same RASTER finishing pattern and changing the default raster angle from ZERO to any non-zero value will successfully finish the piece.

Greolt
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Re: 4th Axis Incomplete Finish Cut

Post by Greolt »

It would still surprise me if the controller has no way to control that rotary axis behavior.

If that is so then the controller is quite deficient for rotary axis use. IMO

Tailmaker
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Re: 4th Axis Incomplete Finish Cut

Post by Tailmaker »

Not sure what PP you are using but on my machine the "regular" G94 post processor (feedrate=distance/min) does not work well when cutting mostly rotation moves because the machine interpretes that as feedrate=degrees/min. If I am lucky it works but often the axis stalls because the commanded angular speed or acceleration exceeds the machine's capability.
Using a "G93" post processor (feedrate=1/(move time)) is supposed to fix that but many machine controllers can not handle the G93 (or not properly).
For that reason I try to lay out the tool paths mostly along the rotary axis and then the G94 method works perfectly.
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HBruns
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Re: 4th Axis Incomplete Finish Cut

Post by HBruns »

Yes -
The machine was going from 0.00 degrees to 360.00 degrees via the shortest path... which is no movement at all along the rotary axis.
Talking to Chad at Axiom Precision got me through this.
There is a setting buried DEEP in the controller settings, and it is not mentioned in the 4th axis documentation.
Change that setting from “NEAR” to “NORMAL” resolves this issue.

There are a few “GOTCHA’s” to changing this setting, so I advise making the call to Axiom Precision and have them walk you through the process if you are having this problem.

Tailmaker -
The post-processor is supplied by Axiom Precision.
They have 3 PPs for their ARx machines:
- 1 for 3-axis projects
- 1 for rotary (4-axis) projects
- 1 for LASER projects

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TReischl
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Re: 4th Axis Incomplete Finish Cut - FOUND A BUG

Post by TReischl »

HBruns wrote:
Fri Mar 12, 2021 4:00 am
I'm pretty darned sure I found the problem.
Short answer - There is a bug in the software.
.....
Many posts later HBruns wrote: "There is a setting buried DEEP in the controller settings, and it is not mentioned in the 4th axis documentation.
Change that setting from “NEAR” to “NORMAL” resolves this issue."


This is an example of why I am hesitant to call something a "bug".
"If you see a good fight, get in it." Dr. Vernon Jones

HBruns
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Re: 4th Axis Incomplete Finish Cut - FOUND A BUG

Post by HBruns »

TReischl wrote:
Sun Mar 21, 2021 12:49 am
This is an example of why I am hesitant to call something a "bug".
Certainly a problem in the process.

BTW -
I like my eggs with hot sauce. :oops:
:mrgreen:

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JoeBlow
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Re: 4th Axis Incomplete Finish Cut - FOUND A BUG

Post by JoeBlow »

JoeBlow wrote:
Sat Mar 13, 2021 12:52 am
As far as why this might be occurring...could be due to Axiom rotary users needing to change the RT Type parameter in the Rich Auto controller.
and even sometimes the answer is there all along :D

Also mentioned on the Axiom forum in a couple places.
Beautiful Things Function Better

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