"New build" Acorn swap in

All things related to the Centroid Acorn CNC Controller

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Sword
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Re: "New build" Acorn swap in

Post by Sword »

Scott
fbx
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Re: "New build" Acorn swap in

Post by fbx »

But the input really isn't sensing anything. The probe signal wire is 24vdc then goes to 0v when the circuit is completed with a ground.

But for some reason that made me think of another test...

1. I went out and hooked the probe signal wire to the positive lead of my multimeter.
2. Multimeter was set to xx.xx dc voltage.
3. I touched the negative lead of the multimeter to the common terminal shown in the acorn probe schematic (page 12)
4. The voltage read at 23.95 vdc

5. Next, I kept the probe signal lead attached to the positive lead on the multimeter
6. I touched the negative multimeter lead to various items on x/y-axis, observing the voltage
7. ALL voltages on the x/y-axis registered as 24.00 vdc

This suggests to me that there is a direct path to DC ground on the x/y-axis, much better than the common ground on the acorn board.

I also repeated this test with both steppers completely unplugged. Same result.


I then came to type these findings here, and decided to check the voltage at the column just to see if it too registered as 23.95 vdc since the probe common wire is attached here.

1. The voltage at the z-axis registered the same as the Acorn board common terminal. 23.95 vdc. As I had anticipated.
2. Then I rechecked the voltage at the x/y-axis components... Here's where it gets strange...
3. Voltage reading at the various x/y-axis components registered at 22.56 vdc. A smaller voltage drop to ground. Strange.

4. Waiting a short time (~5 minutes or so while typing) and I rechecked the voltage drop at the x/y-axis components again...
5. Voltage drop at x/y-axis components registers as 22.95 vdc.
6. Wait a few minutes and recheck... 23.05 vdc at x/y-axis components...
7. Wait a few minutes and recheck... 23.10 vdc at x/y-axis components...

8. Recheck the z-axis and common terminal...both steady and reading 23.90 vdc


There is definitely something going on with the x/y-axis area. There is a dc ground, but the voltage drop should be a consistent 24 vdc, not fluctuate between 24 vdc and ~22.50 vdc.
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Re: "New build" Acorn swap in

Post by fbx »

Chamfers and Fusion 360 CAM…

Has anyone ran into any issues with chamfers, Fusion 360 CAM toolpaths, and Centroid? Note - I am using Swissi’s post processor.


In fusion 360, there are two options for chamfers. The first, 2D chamfer, is used when the chamfer IS NOT modeled on the CAD model. The second, 2D contour, is used when the chamfer IS modeled on the CAD model. I have tried both methods, with and without the chamfer modeled. I continue to get the same result in the posted g-code - the chamfer tool path is 0.05” too deep.

I have checked the tool in the tool library - all measurements are correct. It is a 45 degree chamfer tool (90 degree overall), and comes to a point. There is no flat spot on the nose of the tool.

I have checked, tried, retried, rechecked my toolpaths. I have tried every option for cutter compensation. I have tried varying the bottom cutting plane. None of these seem to work.

The only thing that seems to work is using the 2D contour toolpath, then using stock to leave to offset the extra 0.05”.
For example, the modeled chamfer is 0.02”. I use the 2D contour, select chamfer tool which automatically registers the operation as a chamfer - when posted, the g-code shows a Z-depth of 0.07”. Using stock to leave, I enter 0.05”, check the g-code again, and see that the z-depth is now the desired 0.02”


Question is - is there some known issue with chamfers and Swissi’s centroid post processor? Or is someone familiar with the issue possibly being caused in fusion?
rk9268vc
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Re: "New build" Acorn swap in

Post by rk9268vc »

some things to check:

is there pretravel in your probe / tool height setter causing the part to be higher up than the mill thinks?

is the chamfer tool machined correctly and at expected angle, and truly to a point? I find it exceedingly rare to have a true point and not at least a 5thou flat

is the chamfer tool correctly modeled when you set up the tool in fusion?

when you program the chamfer in fusion, do you have a proper tool height offset and chamfer width?

I use 2D chamfer with the swissi probe app no problems. I also use a TTS probe and an automation direct tool height setter.
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Re: "New build" Acorn swap in

Post by fbx »

rk9268vc wrote: Tue Oct 04, 2022 3:56 pm some things to check:

is there pretravel in your probe / tool height setter causing the part to be higher up than the mill thinks?
No, x/y are fine with the kinematic probe, and I am setting z manually with a piece of paper.

is the chamfer tool machined correctly and at expected angle, and truly to a point? I find it exceedingly rare to have a true point and not at least a 5thou flat
It appears to be. I have even set the point diameter to .002" in the tool library with no change in outcome
is the chamfer tool correctly modeled when you set up the tool in fusion?
Yes
when you program the chamfer in fusion, do you have a proper tool height offset and chamfer width?
Adding width and height amplify the problem. This is what alerted me to the issue originally - setting the chamfer tip offset so that I am using the mid-area of the flutes rather than cutting at/near the point or the outside diameter of the shank.
I use 2D chamfer with the swissi probe app no problems. I also use a TTS probe and an automation direct tool height setter.
Are you using the 2D chamfer tool path with a modeled chamfer or without a modeled chamfer?
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Re: "New build" Acorn swap in

Post by fbx »

I removed the chamfers from the test block CAD model.

Next I use the 2D chamfer toolpath. I set chamfer width to .02". The tip offset is default at .04". Chamfer clearance is default at .025"

Here is what is posted to g-code - it shows a 0.110" depth of cut. There is an additional .05" depth being added to every chamfer I try to cut but I can't locate where it is coming from.

Here is the g-code and a pic of the simulation. The simulation height and spacing appears to be commensurate with a tip offset of .040" (I have made a mockup sketch in CAD to show the chamfer height/width as well as the additional tip offset).
Attachments
011 DEPTH THAT IS BEING POSTED TO G-CODE.JPG
CHAMFER TOOL TIP OFFSET VISUALIZATION.JPG
INCORRECT CHAMFER DEPTH.JPG
CHAMFER TOOLPATH SIMULATION CORRECT.JPG
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Re: "New build" Acorn swap in

Post by fbx »

Issue resolved - was not related to the post processor.
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