3d milling question

Machines (Original/PRO)
1

Hello everyone.

I have a problem with “3d” milling in several steps.

I have altitude offsets between millings.

Let me explain, I surfaced my board, made a pass with a straight cutter to rough up the work then a ball nose cutter.
Until then, no worries.

For the second ball nose milling cutter, the milling having become too long, I separated my file into several pieces to be able to mill in several stages.
I do the first, everything is fine. I turn off the machine (too late to make any noise).
The next day I started again doing a prob xyz with a cylindrical cutter and a prob z with the ball nose cutter.
milling begins and it is lower than the day before, as if prob z was not identical.
I don’t know if the problem comes from me (this is the first time I’ve done this) from the machine or from the software (carveco).
If anyone has any ideas or knows what’s going on.

THANKS

2

I would leave the controller on overnight.

1 Like
3

Over a week or two without problems?

4

I used the Onefinity black box controller for a little over a year and other than an occasional reboot it was never powered off. It should not be an issue to leave it run overnight.

2 Likes
5

Hey Fred,

if you probe Z again, you should be at identical bit tip position, in relation to the workpiece. At least if the workpiece position where you probe has not changed.

This must be an inaccuracy of the probing procedure. That could have different possible causes. There could be a different amount of dust under the touch plate.

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6

That’s also what I thought, which is why I do a Z test every time.
I did not move the workpiece and it is screwed to the scrap board.
I check the cleanliness of the piece and the probe each time.
Could it have an impact if the sounding plate is in one direction or the other?

Leaving the controller running constantly could be a solution but I’m not thrilled but I have no choice.
Afterwards I do not understand these shifts and given the capacities and the functioning of the machine they should not happen.

7

Hey Fred,

I am not sure, maybe if the surface is not milled flat. I have read in another thread that the Onefinity touch plate has no fantastic tolerances

Does it change something if you leave the controller on? Do you mean, does the difference in Z height then not occur?

8

Hi Aiph5u

When I do several millings in a row without turning off the controller I don’t have this problem.
For me the problem comes from prob Z which seems not always to be identical.

But in my mind doing this prob z again should re-adjust the machine in the same way as the previous one.

9

Hey Fred,

If probing repeatability is the problem, turning the controller off should make no difference.

10

I m not sure I understand correctly.
To be sure.
When the machine stays on between two jobs: no worries.
When I turn it off between two millings (with a new prob): problems

11

Do you think I should contact onefinity to report the problem to them?

12

Hey Fred,

If you do exactly this (changing the bits and reprobing as you described), but without shutting the controller off in between, does the error occur too?

13

I don’t know, I have to try to answer you.
I’m going to go to the workshop this morning, I’ll test

14

Hey Fred,

I just can’t imagine how turning the controller off would change something.

No hurry, got to terminate sleep first :slight_smile:

15

In case i was a bit terse in my first reply, i meant that by not switching off the controller one would not need to do any more probing; x,y or z.

Depending on the size of your job 3d milling can show up tiny variances from probing errors in your work piece.

16

I understood your idea, no worries.
When you say tiny, what order of magnitude are you thinking of?
For me the difference is largely visible to the naked eye. I would say of the order of a millimeter.
I will take a photo when I am at the workshop.

17

Here is a photo of the offsets, we are talking about 0.4 0.5 mm. It’s not huge but you can see it.
I was wondering in the software there is a milling tolerance adjustment, if I set it to 0 will it help?

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18

Hey Fred, hey Andy @AndyP,

good morning!

0.4 to 0.5 mm is not tolerable. So the “step” appears after changing the bit and probing, but not when you don’t probe, is that right?

Where do you put the touch plate to probe?

Do you probe on machine bed?

19

So I took the test
-roughing

  • passage of the ball nose milling cutter on a first zone.
  • xyz prob with the cylindrical cutter.
  • prob z with the ball nose cutter.
  • passage of the ball nose cutter on the 2nd zone.

Result a shift but not visible to the eye only by passing the finger.

But that’s where I’m an idiot. I realized that the wood had obviously been worked to the point of removing the screws (or I hadn’t tightened enough).

I’m going to finish this work just to see what it can produce, even if for me the result won’t be what I want.

I would then do it again by doing a double surfacing of the panels (both sides) before gluing and again on the side to be worked.
And I’ll put more screws to hold it and we’ll see.

For the moment I will consider that these are errors on my part and not on the machine.

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20230923_1157201920×2560 526 KB

1 Like
20

Hey Fred,

I agree, I would check if your workpiece moved a little bit in height.

As I actually cannot acquire experience with my touch plate at the moment, I would be very interested in knowing what accuracy/repeatability the touch plate can deliver