Steppers not as strong as they age?

I’ve noticed recently that when changing bits mid-carve the carriage was fairly difficult to move by hand as the steppers were energized and resisted movement. However, lately they seem to allow movement easily. The machine carves just fine, but it just seems a bit too easy to move it now when energized.

Thoughts?

I have some advice that I got from Phil of ‘Designs by Phil’ that really changed my XC’s performance and stopped it from losing steps when carving hard woods with high feed rates or changing bits. I hope this helps you.
The only negative is the motors are fully powered on when idle and as a result are hotter than before disabling the torque reduction feature. The X-Controller also is running hotter than before because of the increase current needed for the motors. I tend to turn off the XC when not using it now or use the $SLP command (1.1 Firmware needed) to turn off the power to all the motors when not using the XC for a while. I have not seen any problems over the last year running this way. I recommend you try it.

From Phil:
For some strange reason, Inventables decided to activate the auto torque reduction from the factory. This is a useless and harmful setting to have active. It reduces the holding torque of the axis to only 30% when not receiving a move command. This is above and beyond the $1=255 setting. So when you are cutting straight on the x or y axis, the other is at only 30% power. A recipe for disaster. The Z axis is also affected. Z goes down to depth, then is at only 30% holding torque.

http://www.designsbyphil.com/x-carve-tips.html

Good Luck

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Yes, set $1=255 and switch#4 = OFF for all axes.
Only then will you have full power available for steppers that are holding position.

Regarding weaken over time its unlikely as the only two factors at play is 1) friction, bearing failure and 2) magnets have been overheated and weakened.

Most stepper data sheets indicate max case temperature at 80degC / 176degF
Magnets loose their strength when they reach about 140degC / 285degF.

So if you have kept your steppers touchable in terms of heat they have not overheated. If you can place your hand on it and hold for 3s then you are at about 55-60degC / 135degF.

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I’ll check my settings…and thanks for the science! :wink:

Careful, moving the gantry by hand while the machine is on can overload the stepper drivers and make them go up in smoke.

@RohanSingh you know, I keep reading about people’s comments about moving the gantry by hand. I NEVER move it by hand when the machine is powered on, however, I move it all the time when it’s turned off. It’s never been an issue when powered down, so I trust that’s ok.

actually, the back feed protection circuit is only active when the x-controller is powered on. so you’ll want to push it very slowly or you will eventually fry something.