Recalibrating ToM - Extruder running at 2x speed?

[Michael Cook]

Last year I upgraded my Thing-o-Matic from a MK6+ to a Qu-BD extruder, and I've never had it running well since. I always end up getting frustrated trying to calibrate it and give up. I'm using a Makerbot gear, not the Qu-BD one.

So I started over a few days ago, with a clean install of the latest versions of ReplicatorG and Sailfish. When I tried a basic test cube with Print-o-Matic (non-accelerated) and I had to quickly abort the print as it was putting out way too much plastic, which always seems to be my problem.

So I got an idea and decided to check the extruder motor speed. I used the control panel in RepG to run the extruder at 1 RPM for 60s and sure enough the extruder stepper made TWO revolutions. I'm going to assume this isn't right. My stepper says it's 1.8 degrees per step, which seems to be what the Makerbot steppers are (it's hard to find solid numbers). I'm using the stock Thing-o-Matic HBP MK7 Sailfish machine in RepG, all other axis work at the correct speeds.

Is there a place to adjust this? I looked all over and couldn't find any settings that looked like they would apply. Should I just change the steps-per-mm in the machines.xml file to make up for this difference? I checked the stepper controller and it's set to 1/8 microstepping like all the others.

I'd really like to get my bot working again. 

[Dan Newman]

On 17 Mar 2013 , at 11:16 AM, Michael Cook wrote:

> Last year I upgraded my Thing-o-Matic from a MK6+ to a Qu-BD extruder, and
> I've never had it running well since. I always end up getting frustrated
> trying to calibrate it and give up. I'm using a Makerbot gear, not the
> Qu-BD one.
>
> So I started over a few days ago, with a clean install of the latest
> versions of ReplicatorG and Sailfish. When I tried a basic test cube with
> Print-o-Matic (non-accelerated) and I had to quickly abort the print as it
> was putting out way too much plastic, which always seems to be my problem.
>
> So I got an idea and decided to check the extruder motor speed. I used the
> control panel in RepG to run the extruder at 1 RPM for 60s and sure enough

> the extruder stepper made *TWO* revolutions. I'm going to assume this isn't

> right. My stepper says it's 1.8 degrees per step, which seems to be what
> the Makerbot steppers are (it's hard to find solid numbers). I'm using the
> stock Thing-o-Matic HBP MK7 Sailfish machine in RepG, all other axis work
> at the correct speeds.
>
> Is there a place to adjust this? I looked all over and couldn't find any
> settings that looked like they would apply. Should I just change the
> steps-per-mm in the machines.xml file to make up for this difference? I
> checked the stepper controller and it's set to 1/8 microstepping like all
> the others.
>
> I'd really like to get my bot working again.

1. I've never trusted RepG's control panel. Once upon a time I did,
but at some point comprehensive QA largely disappeared on RepG and I
stopped trusting many pieces of it. So, I take with a grain of salt
anything I learn from using RepG's control panel. Instead, I write
gcode and run that through the bot.

2. When the stepper drivers fail, they often fail in a way that has
them not using the correct micro stepping. You might, WITH THE BOT
POWERED OFF swap the A axis stepper controller with another axis.
Swap both the "input" ribbon cable and the "output" wiring to the
stepper motor. Then see if the behavior changes.

Dan

[Michael Cook]

2. When the stepper drivers fail, they often fail in a way that has
them not using the correct micro stepping.  You might, WITH THE BOT
POWERED OFF swap the A axis stepper controller with another axis.
Swap both the "input" ribbon cable and the "output" wiring to the
stepper motor.  Then see if the behavior changes.

Bingo. Swapped A and Y. A runs at the right speed now, Y runs too fast.

Thank you Dan. 

[Dan Newman]

So either the DIP switches are wrong, the DIP switches are broken, or
the stepper driver is ill. Unfortunately, you already checked the DIP
switches so its the harder-to-rectify latter choices.

Dan

[Tim]

Did you clear the EEPROM before/after installing sailfish?

Op zondag 17 maart 2013 20:16:13 UTC+2 schreef Michael Cook het volgende:

[Michael Cook]

Yes, I did a full factory reset.