Y axis skipping Prusa i3
Posted by TERMINAL
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Y axis skipping Prusa i3 March 26, 2015 04:51PM |
Registered: 8 years ago Posts: 17 |
So i built a prusa i3.
Everything works well enough all the axis move fine, and the print starts off fine.
But about 5ish minutes in to the print my bed Y axis starts skipping.
The belt isn't slipping, i know that much, but for some reason after 5 minutes the bed just keeps stopping every turn and throws the print off.
I dont' know if anyone has experienced this or if they can help me.
Could it be the bearings?
Thanks in advance for ANY help or advice that you can give me.
Peter
Edited 1 time(s). Last edit at 03/26/2015 04:53PM by TERMINAL.
Everything works well enough all the axis move fine, and the print starts off fine.
But about 5ish minutes in to the print my bed Y axis starts skipping.
The belt isn't slipping, i know that much, but for some reason after 5 minutes the bed just keeps stopping every turn and throws the print off.
I dont' know if anyone has experienced this or if they can help me.
Could it be the bearings?
Thanks in advance for ANY help or advice that you can give me.
Peter
Edited 1 time(s). Last edit at 03/26/2015 04:53PM by TERMINAL.
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Re: Y axis skipping Prusa i3 March 26, 2015 05:15PM |
Registered: 8 years ago Posts: 38 |
Peter,
It seems I had an similar problem. After a bit of research it seemed that my Y-axis acceleration was set (by default) way too high in the firmware. It was over 1100mm/s2 as I can remember. I've brought this back
to 500mm/s2, which works fine for my printer. I had no more skipping on the Y-axis after lowering this vallue.
It seems I had an similar problem. After a bit of research it seemed that my Y-axis acceleration was set (by default) way too high in the firmware. It was over 1100mm/s2 as I can remember. I've brought this back
to 500mm/s2, which works fine for my printer. I had no more skipping on the Y-axis after lowering this vallue.
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Re: Y axis skipping Prusa i3 March 26, 2015 05:21PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 26, 2015 06:22PM |
Registered: 8 years ago Posts: 17 |
It seems to make no difference as fas as i can tell..
I changed this line in the code
#define DEFAULT_MAX_ACCELERATION {3000,3000,100,10000}
to this
#define DEFAULT_MAX_ACCELERATION {3000,1500,100,10000}
and then to this
#define DEFAULT_MAX_ACCELERATION {3000,800,100,10000}
and it made no difference.
after a few layers it just starts skipping again
I changed this line in the code
#define DEFAULT_MAX_ACCELERATION {3000,3000,100,10000}
to this
#define DEFAULT_MAX_ACCELERATION {3000,1500,100,10000}
and then to this
#define DEFAULT_MAX_ACCELERATION {3000,800,100,10000}
and it made no difference.
after a few layers it just starts skipping again
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Re: Y axis skipping Prusa i3 March 26, 2015 06:23PM |
Registered: 9 years ago Posts: 581 |
Also make sure that your Y axis pulley isn't slipping and that the Y axis stepper motor and driver aren't overheating.
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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 26, 2015 06:54PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 26, 2015 06:57PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 26, 2015 07:16PM |
Registered: 8 years ago Posts: 38 |
Maybe you can try to lower the amperage to this motor? I'm using RAMPS 1.4 on my printer and you can adjust the amperage to the motor by rotating the potmeter on the desired stepper driver. So if you're also using Ramps on your printer you could give it a try. Or otherwise search for an alternative of adjusting the stepper amperage of the control board you're using.
I would advise to make a mark (with an permanent marker for example) on top of your potmeter before adjusting. In this case you can "reset" to the current vallue it if necessary.
I would advise to make a mark (with an permanent marker for example) on top of your potmeter before adjusting. In this case you can "reset" to the current vallue it if necessary.
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Re: Y axis skipping Prusa i3 March 26, 2015 07:38PM |
Registered: 8 years ago Posts: 17 |
Yes, i am using RAMPS 1.4. The whole board is a Base V1.2
So i should just spin the screw marked Y counterclokwise?
I talked to a friend and he suggested fixing a small pc fan to the side of the motor. Good idea?
Anyways, i'll try lowering the amperage tomorrow(it's getting late) and i'll keep you updated.
Thank you all very much for the help. This is the best support i've had on a forum for quite a while.
Peter
So i should just spin the screw marked Y counterclokwise?
I talked to a friend and he suggested fixing a small pc fan to the side of the motor. Good idea?
Anyways, i'll try lowering the amperage tomorrow(it's getting late) and i'll keep you updated.
Thank you all very much for the help. This is the best support i've had on a forum for quite a while.
Peter
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Re: Y axis skipping Prusa i3 March 26, 2015 07:50PM |
Registered: 9 years ago Posts: 581 |
Quote
TERMINAL
Yes, i am using RAMPS 1.4. The whole board is a Base V1.2
So i should just spin the screw marked Y counterclokwise?
I talked to a friend and he suggested fixing a small pc fan to the side of the motor. Good idea?
Anyways, i'll try lowering the amperage tomorrow(it's getting late) and i'll keep you updated.
Thank you all very much for the help. This is the best support i've had on a forum for quite a while.
Peter
Counterclockwise by about an eigth of a turn. Here's the reprap wiki guide to tuning your stepper driver current: [reprap.org]
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 26, 2015 08:01PM |
Registered: 8 years ago Posts: 38 |
Peter,
A fan would also be a possibility. But I should try to lower the current to the motor by rotating the potmeter on the stepper driver counter clockwise first. Less current means less heat. So it would save you some money.
From the other side, to few current to the motor will also result in skipping. So you have to try to fine tune this by adjusting the potmeter on the stepper driver with little turns. Also keep the Y-axis acceleration in the firmware in mind.
Maybe you have to adjust both.
A fan would also be a possibility. But I should try to lower the current to the motor by rotating the potmeter on the stepper driver counter clockwise first. Less current means less heat. So it would save you some money.
From the other side, to few current to the motor will also result in skipping. So you have to try to fine tune this by adjusting the potmeter on the stepper driver with little turns. Also keep the Y-axis acceleration in the firmware in mind.
Maybe you have to adjust both.
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Re: Y axis skipping Prusa i3 March 27, 2015 05:49PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 28, 2015 10:16AM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 28, 2015 12:15PM |
Registered: 9 years ago Posts: 581 |
Friction might be the problem. How easily does the Y axis move with the power off?
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 28, 2015 12:35PM |
Registered: 8 years ago Posts: 17 |
It's not the friction.
When i move it i hear the smooth motor sound just fine.
When i noticed it started skipping i touched the motor and it was terribly hot just like before.
It just took longer this time.
I'm 100% sure that the bed is setup correctly and the motion is fine, only the motor heating up is the problem.
When i move it i hear the smooth motor sound just fine.
When i noticed it started skipping i touched the motor and it was terribly hot just like before.
It just took longer this time.
I'm 100% sure that the bed is setup correctly and the motion is fine, only the motor heating up is the problem.
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Re: Y axis skipping Prusa i3 March 28, 2015 12:44PM |
Registered: 9 years ago Posts: 581 |
If the motor is too hot it's either working too hard or the vref is too high. Have you tried the adjustment method in the wiki post I linked to, or did you just turn the pot down a little bit? Do you have a multimeter you can use to check the current vref setting?
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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 28, 2015 03:02PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 28, 2015 05:57PM |
Registered: 9 years ago Posts: 581 |
That's the right method. If you unhook the belt on the Y axis, does it travel freely - meaning, if you push it with a finger will it continue sliding after you let go, or does it stop immediately?
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 28, 2015 06:09PM |
Registered: 8 years ago Posts: 17 |
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Re: Y axis skipping Prusa i3 March 29, 2015 10:45AM |
Registered: 9 years ago Posts: 581 |
What speed are you printing at?
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.
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Re: Y axis skipping Prusa i3 March 29, 2015 11:45AM |
Registered: 8 years ago Posts: 17 |
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