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i know this is a very common issue and i am currently searching old threads but figured i would post my own also
i did a few minutes of adjusting on xcarve today v wheels and no change
but i did notice something
regarding losing steps y axis real bad…seems to be on larger projects
only that go towards the center of work area and past…
for some reason on my y axis on the right side only (farthest away
from my electronics) my motor makes a very odd sound at same spot
…approx 400mm loction
if i bring machine to fronjt left and just jog it 1 inch at a time its
perffectly fine until it gets to about 400mm and then the right y
motor makes an odd sound and machine loses steps bad …i have repeated
this several tim3s and its same spot every time
and it does seem when i machine larger projects is where im getting my
step loses…when i do small projects in the front part of the machine
it seems ok
there is nothing inrerfering with y motor bracket and machine is fairly square…nothing visually looks out of wack…all the v wheels move when jogging machine and the belts are tight not loose
and my xcarve is older version 2016 model 1000mm and its been doing this since on and off since day 1 of owning this machine
i just now came to conclusion becasue i have been trying to do a larger project and its failing…and most of my projects were small in the past so no issues…and i am now recalling that every time i have lost steps it was on larger projects…so im confident this has always been exisiting and is not a new issue
If one motor stall on the same location over and over => mechanical binding or more friction than rest of the travel.
If you disconnect the belts and move the gantry by hand over the offending portion do you feel anything?
yes gshield stock…i just assembled this about 6 months ago and has had this issue since day 1 off and on
forget my last response…i tried machinging a part closer to the front just now and it lost steps immediatley…with basically no tool load…1/8 inch bit at .025 25ipm
i aborted job …i give up…have no clue whats goping on…its very aggravating
Double check the mechanical before going to the electronics.
I was having an issue with the X gantry dragging and discovered it was a combination of grit in the wheels and compressed grit on the gantry ways. This issue showed up after some sessions cutting plastic and urethane foam board. I needed to clean the ways and the wheels, ans the space between the wheels and the body of the X slider.
Something else to check mechanical - the belts drop into a slot in each of the ways. Check to see if there is something holding the belt down and not allowing it to lift out of the slot.
If you do not find anything mechanical, do a clean restart of all electrical systems. Disconnect the X-Controller form the computer and from the main power source. Wait 60 seconds and hook back up. Clean reboot the PC.
The gshield only have three drivers so the two Y-motors share a single driver (they each have half the power as X&Z)
Also the driver isnt capable of providing the motor the power they can handle, so the drivers are a weak link.
Wether the driver is your core issue I dont know but overdriven/overheating Y-driver can cause a lot of issues.
hi haldon like i said this happpends even doing air cuts…no tool load at all…so overheating or not capable moving in air would be pretty ridiculous design…my cheap ■■■ 3d printer doesnt do this nor does my cheap ■■■ laser engraver…both were under 100$ each…neither have3 ever lost steps period…and i use my 3d printer a lot and both are similar belt design…as a matter of fact my cheap ■■■ 3d printer and laser printer use the same size belt as my xcarve lol…now thats sad
Simplified:
Stepper motors receive full power even sitting still (required to make them reach holding torque). This current is passing through the driver regardless what the stepper is actually doing. So the driver do heat up.
This is not something that applies only to the Xcarve but any stepper system out there.
So yes, it is entirely possible that the driver can overheat during “air carve” if its current limit is set too high or driver receive insufficient cooling.
Bottom line, the gshield poses a performance limitation - especially on the Y axis. I fully believe your machine issues lies within the driver and/or rapid and acceleration rates - provided the mechanical aspects are sound
Change:
$111=2500
$121=100
Does this change anything in machine behaviour?
BTW:
If your machine loose steps without any grinding noise detected => most likely driver overheating
If your machine/steppers make sudden grinding noises (short bursts or prolonged) => mechanical or feed/acceleration issues.
Regarding Vref, check out this link for detailed information:
As the motor speeds up it cools a bit while it’s running. As it slows down it starts heating back up. That’s the reason for the “reduced torque” selection option on the fourth switch. You can choose max holding torque, or some cooling when the motor is at rest.
ok understood however when there is a tool load during machinging that does create much added force on the machine…so air cuts dont have all the extra forces …
thaks when i get time i will investigate with your advice cant do it now too cold out
and like i said my cheap 3d printer and cheap laser engraver have never ever lost steps …they use same type system and i use them many many hours especially 3d priner
thats comparing a $100 machine to a $1600 dollar machine…the $1600 machine should be in theory more reliable
i didnt know thqt larry very interesting drivers get current all the time and not on demand…when needed…that seems wasteful and unnecessary wear and tear on the drivers to me…
haldor i dont believe it is the speed of the machine as i was only moving at 25ipm and lost steps on the 2nd pass doing a cutout in plywood at .025 depth
and i slowed my rapid down substantially so that when it goes to first mahining point it takes its time ni9ce and slow and did not lose steps going to first point…it lost steops this last test during the slow machinging process
Steppers are very different from a standard brushed electric motor.
The power need to come from somewhere, an idle/non-rotating brushed motor require nothing - because it is doing nothing, and you can spin it easily by hand. A stepper motor at “idle/non-rotating” is forced by the driver to stay put and will resist hand turning. This require power.
Your stepper based 3D printers and laser do the very same.
thanks for all the info…im going to try to tinker with it today a bit doing some testing and changing and adjusting
one noe though
if i have machine disconnected powered off…and i push the gantry back and forth at a fairly high feed rate, at the right y motor area there is a grinding sound …not the entire way but just random as pushing.
Disconnect power AND disconnect the belts one way or the other, so the only thing that would cause friction are the wheels. Motion should be smooth with uniform friction.
