How does the tension in your belts feel? If it’s too high this could be the motors fighting each other
Great to know. The tension was low so I bumped it up to 1500 from the standard 1200 if memory serves.
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I’m still seeing this error on the plunge. I’ve tried changing the tension to 1200 and 1300 but it seems like it’s still doing that shift after the initial plunge.
It’s almost like the bling starts wide/off then it slides into it’s path. Any ideas? Always seems to be a right to left movement error.
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The tension setting doesn’t matter during the cut, only during calibration.
are the belts tight as it is moving?
check that the bit you have is a plunge bit (has a cutting surface across the entire bottom) Compression bits usually aren’t as they are designed for side cutting.
Have you tried reducing your plunge rate. If the bit is plunging to fast, it could be acting as a pivot point for a moment until it reaches full depth. Couldn’t tell from the video, but if the sled is tipping a little bit you could definitely see what you are experiencing, and it doesn’t have to tip much.
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Ramping your plunges so it doesn’t have to go straight down can make a big difference.
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Yeah. Totally understand that and set it up that way. I think the first plunge was. 2mm or so and I still saw the same result even on first pass.
The video above is really bad bc my hand shakes but in it, it moves to the position, then begins the plunge and right before the clip ends you see the smallest of slides of the sled.
It’s like it’s releasing a small amount of tension or something.
The belts seem tight to me. Pressing on them things seem great. Not a ton of deflection.
I’m just at a loss. This was true before v.81 as well.
Looking at my previous cuts I noticed it was happening on the top right of a path when it drops into the cut. This one was bottom left, but same thing. Could this be a gcode issue on the plunge data for some reason? It’s almost like it is doing this on purpose
That sounds like it might be trying to compensate for the length of the belts changing as the carriage moves down on the z, which would introduce slack if the belts didn’t tighten at all as it happened, and that it might not be tightening enough, allowing for a momentary bit of slop.
Yeah that’s what I was thinking. I don’t know how I’d fix this. Before the plunge it doesn’t seem to have slack at all.
Shot in the dark…try reducing your travel height and plunge depth so that the z axis has less movement during a plunge. Also try reducing plunge speed
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Good idea. I’ll give it a shot. Although my plunge death isn’t too crazy. 2mm
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Some CAM software will offer different settings for lead in or a ramped step down to address marks like that. Basically what it will do is either spiral down or ramp down which helps with keeping the edge of the part clean
@bar Any idea about these settings on the KrabCam? I create my SVGs in Inkscape or Onshape and then load to KrabCam. I’m a HUGE newb to KrabCam.
There is an option for choosing between plunge and ramp on profile and pocket operations in KrabzCam.
The property is called “Attack method”.
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Gosh everyone is so friendly and helpful. Thanks for tackling this with me
So I found that little guy today (Ramp) and tested him out. To no avail. (Sorry forgot to photo that one. ). But it looked the same as the other photos. And the ones attached.
Of attached , first is just me plunging about 1.5mm and then coming up and back down. Then traveling right 3mm, coming up and down, then right 20mm, stop, 20mm to right and then up.
So at least I know it’s happening when I come up.
To the touch I noticed my bottom two cables ( I am setup vertical) are a smidge less tight than the above. Maybe this is a culprit.
Ideas?
On @TimS idea of plunge rate and clearance height, I think I can rule that out with the fact it was wonky on the way up.
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Paul Prociv wrote:
To the touch I noticed my bottom two cables ( I am setup vertical) are a smidge less tight than the above. Maybe this is a culprit.
Yes, if the belts are not tight, bad things happen.
I think you will need to do the calibration again, make sure you ahve the Z axis
all the way down when you do the calibration.
David Lang
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A 2mm plunge should be well within the limits of the maslow. Check the feedrate, bump it down.
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Interesting - I’ve never tried this myself, but I’m about to make some tweaks to my frame so I’ll give it a go to see if this has a significant effect on the calibration results.
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Seems the same each time I do the calibration, but I can def do it again.
Some other questions trying to get to the bottom of this.
After a successful calibration on your spoil board, has anyone found that adding a 3/4 work piece messing with performance? Too tight? This is how I have done calibrations, always with the z bottomed out.
Second question: after setup, retracting and storing, does everybody extend then raise z to put in the bit. OR do you raise the z, put in th bit extend and do your cut? Does this matter?
Of course I set the z home before every cut, just wondering if the order of operations on the extension matters
Paul Prociv wrote:
Seems the same each time I do the calibration, but I can def do it again.
Some other questions trying to get to the bottom of this.
After a successful calibration on your spoil board, has anyone found that adding a 3/4 work piece messing with performance? Too tight? This is how I have done calibrations, always with the z bottomed out.
there is a difference, the way to deal with this would be to adjust the Z offset
values (possibly down for the calibration on the spoil board and then up when
you add your workpiece.
the difference is expected to be small enough to not make a noticable
difference, but you can play with this. (it’s going to depend on how close to an
anchor you get, if you are 24" away from the corner, the difference between the
triangle that’s 24" on the hypot and 2" on one side (23.917 on the other) and
one that’s 3" on that side (23.811) is small, but not zero
Second question: after setup, retracting and storing, does everybody extend then raise z to put in the bit. OR do you raise the z, put in th bit extend and do your cut? Does this matter?
Of course I set the z home before every cut, just wondering if the order of operations on the extension matters
It should not matter.
David Lang
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