Is there any way to monitor if a stepper motor is skipping steps?

3D Printing
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1

Is there any way to monitor if a stepper motor is skipping steps? I’m talking if I’m using repetier server and I’m printing away from home it would determine if the motor is skipping steps. It would be used on the extruder motor

2

For detecting extruded skipping you can use an encoder on the input filament and monitor it with repetier-firmware.

Also check out: http://tunell.us/

3

The problem I have with both of those is that the head will keep moving and mounting one of those devices will give a false reading. The filament moves WITH the extruder which means there will be a constant “forward” and “reverse” signal

4

So, yeah, you need something not mounted on the extruder but mounted on the filament – or, more likely, an encoder on a separate, sticky/rubberized roller sitting on the filament, so it sees the filament movement not the stepper movement. Interfacing that is going to be challenging, though, as it’s essentially a separate axis and will need its own quadrature decoder.

5

Counting skipped steps and not checking for grinding filament would be only a partial sollution. Check for filament movement.

6

@John_Bump yepp I think your right.
A extra wheel with a decoder pressed against the filament.

The best variant would be a pressure sensor in the printernozzle.
It would not only give us feedback of filament slipped in the driving gear.
But also would be the best variant for control of extrudet plastic and diverences in filament diameter.

But I have not seen a pressure sensor small enough so we can use it in the head.

7

@Sebastian_Schmidt lets say you did manage to get it in the head…you would still have to wire it up and it would have to be immune to the temperature. If the head is a part of the sensor though, things become more likely to work.

8

I have a suggestion. Ignore very small percentage errors or every minute touch of slippage will drive you crazy.

9

It’s more of knowing to be able to stop the print when I’m not home

10

It’s more of knowing to be able to stop the print when I’m not home

11

How constant is your spool rotation, @Branden_Coates ? I feel like mine is sort of jumpy and laggy because of the slack between the extruder feed and the spool. If you have a tensioner/drag on yours so it closely tracks the extruder movement, that could be a nice easy solution.

12

I think the 30 second rule should work.

13

Now the question is how do I hook it up, or how do know when it hasn’t moved? Use an arduino and light up a led?

14

The octoprint won’t work for me as I use repetier server. I do have a pi laying around though

15

@Branden_Coates I prefer an encoder over a potentiometer. Much less likely to go wrong. Of course for the real hardcore moneybags nutcases you could go the whole hog and use a synchro-resolver. I’ve considered printing my own encoder wheels on acetate sheet but commercial ones are always much better.

16

If you start grinding filament or skipping steps, the spool will probably hardly move. Using a potentiometer should be good to detect that. The trick is getting it to rotate infinitely instead of being stuck after x degrees.

17

My problem is that when the extruder moves, it moves the roll no matter the direction