Shop Vac and lost steps?

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This topic contains 13 replies, has 6 voices, and was last updated by Profile photo of Jason Jason 5 months, 2 weeks ago.

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  • #26594
    Profile photo of John
    John
    Participant

    I am trying to determine if I need to be more careful with the shop Vac.

    so I noticed that there were massive lost steps along the y axis on a couple of recent cuts. I ended up looking about 10 inches off the y axis cut. At this time, I did not notice much obstruction of movement at the time so I am wondering if it could be due to somthing electronic. Specifically, I happened to be cleaning up the saw dust from my cut with the shop vac. Could the shop vac have generated static or other electrical noise causing loss of steps?

    #26597
    Profile photo of Ryan
    Ryan
    Keymaster

    What are your settings, what are you cutting, how big is your machine?

    Questions in the sticky?

    #26598
    Profile photo of KronBjorn
    KronBjorn
    Participant

    -Could the shop vac have generated static or other electrical noise causing loss of steps?

    No, not near the motors, currents are too high. If you were vacuuming the control PCB you could potentially break something, but not likely loose steps.

    #26605
    Profile photo of Matt P.
    Matt P.
    Participant

    Might be power supply problem? Is your shop vac plugged into same outlet as Ramps/Arduino power supply? The slight voltage drop when adding load (turning on shop vac) to circuit might be causing an issue with power supply to Ramps/Arduino.

    #26606
    Profile photo of Ryan
    Ryan
    Keymaster

    Lost steps and a finished cut are a gcode issue. If it is a random event the cut will get completely shifted and screwed up. So either it is moving too fast or a gCode issue.

    Without seeing the resulting cut or knowing more it is best not to give to many hypothetical scenarios and confuse the issue.

    #26763
    Profile photo of John
    John
    Participant

    info below:

    4′ x 4′ build on EMT
    feed rate: 25
    bit: 2 flute 1/8
    depth 1.2mm
    plung rate: 3
    Tool: standard dewalt

    it was definitive missed steps on the Y axis. it was a complete shift on the y axis. I was able to repeat the same gcode later with no issues.

    I did have my shop vac on the same outlet so I swapped it.

    Its possible that there was a y-axis obstruction that I just did not see. I have ear muffs on when I do the cut, so I would not hear the motors complaining if that did happen. I did not see anything but I guess you never know.

    #26764
    Profile photo of Ryan
    Ryan
    Keymaster

    A feed rate of 25mm/s at 3mm depth of cut is pretty high if you are cutting wood. You might want to slow down until you are sure your machine can handle it. Try 12 or 15 and work up from there.

    #26772
    Profile photo of John
    John
    Participant

    sorry, I think that I wrote that wrong.

    my depth of cut was 1.2mm. my plunge rate was 3.

    #26773
    Profile photo of Ryan
    Ryan
    Keymaster

    I would still go a little slower. I print at 30mm/s, and that is next to no load. I would stick to 12-15 and just vary the depth according to material density.

    #26789
    Profile photo of John
    John
    Participant

    awesome, I will try reducing for next cut!

    #26791

    For a 1/8 flute I think it is a bit too fast. But for a 1/4 it should be fine though.

    It will depend of your motors and the size of your pulleys too, but I’ve cut wood yesterday at similar speeds and depth with a 1/4 bit and it worked just fine.
    I have bigger pulleys that the ones that were recommended, so I could even have a bit more torque if I change them for the appropriate ones. So I guess in your case it may not necessarly be a speed issue (because it apparently worked fine on the X axis).

    From my opinion, you may want also to check the temperature of your motor drivers. It is possible that the Y driver overheated and entered into protection mode. Or that your Y motor was underpowered. Either way, check your drivers current first.

    #26792
    Profile photo of Ryan
    Ryan
    Keymaster

    Smaller bits can cut faster due to lower loads than a larger bit on our machine (rpm’s, diameter, kerf, ect. all come into play). Larger the machine the larger the bit it can throw around.

    Larger pulleys = less torque higher top speed, ya got this one backwards as well.

    I agree it could be a driver voltage issue as well.

    #26801

    “Smaller bits can cut faster due to lower loads than a larger bit on our machine (rpm’s, diameter, kerf, ect. all come into play). Larger the machine the larger the bit it can throw around.”

    Well I’ve done many tests on my machine and I couldn’t reach the same speeds with the 3mm bit than I was reaching with the 6mm one without having the router slow down and the motors missing steps.
    I undestand your point and it seems perfectly logical, but it completely contradict my experience. So there may be other parameters involved.

    “Larger pulleys = less torque higher top speed, ya got this one backwards as well.”

    That’s what I’ve said actually if you re-read carefully 😉
    Maybe I was not clear (sorry, English is not my mother tongue), I said I have biggers pulleys, which is why I lose torque. I could have a bit more torque if I change them for the appropriate ones. If I remember correclty, my pulleys are 14 tooth, I think the ones your recommended were 10 tooth.

    #26823
    Profile photo of Jason
    Jason
    Participant

    I can say that my shop vac most definitely was the cause of some strange and random movement during cutting on my machine. It was not even plugged into the same circuit as my MPCNC. There was no mechanical interference either. Once I turned off the shop vac the same gcode file ran fine after 3 straight fails in a row. I tried again this time with the shop vac as far away as the hose would allow and I had no issues.

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