15mm error on Bottom Right Axis

[dlang]

Paul Modiano wrote:

@dlang

did you try grounding the encoder pin?

No. I don’t know how to do that. Are there any instructions you can point me to?

Soldering Floating Encoder Board Pin

There was a request for a more clear and easy to find set of instructions for how to solder the encoder boards (the previous answer was buried in a thread and not easy to search for or find) so this is duplicate information but in a more searchable way. The issue is that the encoder chips have a pin which can be used to set the direction that the encoder reads (IE is rotating counter clockwise positive or clockwise positive). We left this pin unconnected (our mistake) which seems to under some …

@dlang

As the Z axis moves away from the workpiece, the distance from the anchors to
the arms increases (the triangle of the x/y and Z is getting bigger), so the
motors spool out some belt to allow for this.

The xy movement that I witnessed when I manually told it to move z by 1mm was
far too great to have been compensation for a change of 1mm to the XYZ
triangle. Is there a setting somewhere that would allow me to adjust the
level of compensation that xy makes to a z movement?

it just calculates the desired belt length based on the x/y/z triangle from the
anchor point.

If the Z was not all the way down when you did the calibration, or the Z stop
value is not corred (or was not correct when you did the calibration), then the
anchor locations that were calculated are not correct and you will have errors

@dlang

If the belts remain tight all the time, this should not result in any movement
of the sled, but if you have a bad calibration and your belts are at all lose,
this could result in sled movement.

I have not been able to complete a calibration in a long time. It takes a long while but inevitably ends with WARNING FITNESS TOO LOW. DO NOT USE THESE CALIBRATION VALUES!

I think you may need to troubleshoot this more. what is the fitness that it
calculates? (the default cutoff was 0.5, I think bar lowered it to 0.45)

If your anchors move, if the Z offset values in the config don’t match the
reality of your machine, if the belts aren’t tight as you calibrate, those could
all result in bad anchor coordinates (i.e. a bad calibration)

you may also want to do a manual calibration check and see how close the result
is to what the auto calculated one gives you.

Maslow 4 manual configuration (onshape doc)

note that if the maslow thinks distances are X and your tape measure says they are Y, the maslow is correct (at least as far as getting good cuts are concerned) since the current calibration gives different coordinates on different runs of up to a couple of mm, that seems in the same ballpark as the errors of manually reading a tape measure, so I threw together this onshape doc that lets you enter measurements and it shows the frame and calculates the coordinates. I have you measure both diago…

some people have had better results with the manual version, but it depends
HEAVILY on how accurate your measurements are.

David Lang