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Reversing extruder stepper direction

Posted by Jeff B 
Reversing extruder stepper direction
December 04, 2009 11:09AM
I have a working stepper extruder, except it constantly turns in the wrong direction, I could fix this by a slight redesign of my extruder, but it seams that there should be a setting somewhere in the code.

I have looked through the config files of the 5d code (extruder and motherboard), I looked at the config files in the reprap host software, I even tried swapping the wires around (didn't work).

The motor direction is clockwise when looking at the shaft, needs to be counterclockwise.

Hopefully I can figure this out shortly and then ill try printing.
Re: Reversing extruder stepper direction
December 04, 2009 11:39AM
Typically, you can reverse the ABCD cable from the stepper driver to the motor (it might not fit exactly right, but will be OK). Then you can figure out a better solution later.
Re: Reversing extruder stepper direction
December 05, 2009 02:42PM
Actually, reversing the cable reverses both coils, and the motor turns the same way. You have to reverse one of the coils, and that will reverse the motor. Use a pair of tweezers to pop out the AB crimp connectors out of the plastic housing, and stick them back in the other way, ie BACD.

I'm pretty sure you can do it in the firmware, depending on your firmware, but this works for sure, as I did it on my old Darwin.

Wade
Re: Reversing extruder stepper direction
December 05, 2009 03:49PM
wade, I tried it your way and the motor seams to go the right direction and then it moves back. I believe i have tried every combination of wires.

Ive looked through all the firmware code that im using I have not seen any config for reversing the motor.

I may just modify my feeder assembly. Or go to a gear motor.
Re: Reversing extruder stepper direction
December 06, 2009 08:20AM
@Wade,
Actually reversing the plug does reverse both coils, but also swaps the coils over, so it does reverse the motion.

I.e. you can reverse either coil to reverse it, or you can swap the coils over. Doing all three will also reverse, which is what happens if you fit the plug backwards.


[www.hydraraptor.blogspot.com]
Re: Reversing extruder stepper direction
December 06, 2009 02:14PM
Heh, apologies GeertB and thank you Nophead! I did the experiment, and yes, reversing the stepper motor plug does reverse the stepper direction. Good to know, and a good reminder that one should actually test things occasionally. smiling smiley

Jeff B; I think you're using the extruder controller board, right? My stepper driven extruder is on the back burner, because I had a similar problem. My stepper is quite weak, and if there's too much friction and back pressure from the extruder, it behaves just like that - it goes forward 3 steps, then jumps back one step (full stepping) - it doesn't have enough torque to complete the revolution.

I've got some stronger steppers on order; you can also change the current setting on the extruder controller board, details in this thread:
[dev.forums.reprap.org]

If you're using a stepper driver for the extruder motor, you can of course just increase the drive current using the potentiometer.

Just for reference, Adrian's fast Mendel extruder uses a 4 kg*cm Nema 17 stepper, which is pretty torquey. I found some 5 kg steppers from Kysan; hopefully they'll be in soon.

I couldn't find any settings for extruder direction in the code either (I was thinking of reversing the axis, which is in there), but I haven't looked at the latest 5d code for a while.

Wade
Re: Reversing extruder stepper direction
December 06, 2009 05:47PM
I am using the extruder board.

I have the pwm in the code turned to the max of 255, assuming that is the max.

My motor seams to have odd steps no mater what orientation the wires are in, except when the motor is going counter clockwise.

supposedly my nema 17 steppers are 75 oz-in they are model number 4218 on this page [www.linengineering.com] and if I am correct is 5.4 kg-cm
Re: Reversing extruder stepper direction
December 06, 2009 06:36PM
Its going the right direction now, the erratic nature wasn't happening with a load, it seams that my problem is happening because I do not have the shaft properly supported when pressure is applied to the filament.

My tolerances when locating the bearing hole seams to be to loose or I wasn't taking enough time to do it correctly. So I'm going to remake some parts and try at it again.

Thanks for all the help.
Re: Reversing extruder stepper direction
December 08, 2009 07:48PM
I had the same problem with a DC motor.
The problem is that the firmware is wired to a specific direction.

i.e.
process_string.pde
set_direction(1);



So I modified the code with in parameter.h

///////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// Extruder direction
//
// If your extruder motor is going backwards when it should be going forward and vice versa swap this over
//
//#define EXTRUDER_FORWARD true
//#define EXTRUDER_REVERSE false
//
//
#define EXTRUDER_FORWARD false
#define EXTRUDER_REVERSE true
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////

and process_string.pde


case 101:
ex[extruder_in_use]->set_direction(EXTRUDER_FORWARD);
ex[extruder_in_use]->set_speed(extruder_speed);
break;

//turn extruder on, reverse
case 102:
ex[extruder_in_use]->set_direction(EXTRUDER_REVERSE);
ex[extruder_in_use]->set_speed(extruder_speed);
break;


If you want the firmware files with the changes already made download

[dev.forums.reprap.org]
its's the offical code with a few bugs removed.

I have made a few more changes since my v1.9. If anyone else wants it I can post it up.

Version change log (of v1.17)

//////////////////////////////////////////////////
// Version history
//////////////////////////////////////////////////
//
// Arduino v1.0 by Mike Ellery - initial software (mellery@gmail.com)
// v1.1 by Zach Hoeken - cleaned up and did lots of tweaks (hoeken@gmail.com)
// v1.2 by Chris Meighan - cleanup / G2&G3 support (cmeighan@gmail.com)
// v1.3 by Zach Hoeken - added thermocouple support and multi-sample temp readings. (hoeken@gmail.com)
// Sanguino v1.4 by Adrian Bowyer - added the Sanguino; extensive mods... (a.bowyer@bath.ac.uk)

// v1.05 by SG - Feature 10/2009 - Added #define EXTRUDER_stepper_motor and #define EXTRUDER_DC_motor in parameteres to reduce memory overhead
// v1.06 by SG - Feature 10/2009 - Changed to accept ; as terminators and other debug code for the Serial Monitor program in Arduino Compiler
// v1.07 by SG - Bug fix 10/2009 - Changed extruder to work with dc motor as per source [dev.forums.reprap.org]
// v1.08 by SG - Bug fix 10/2009 - Changed to reverse extruder motor. Forward becomes backwards and vice versa.
// v1.09 by SG - Bug fix 10/2009 - Changed process_string.pde:ex[extruder_in_use]->set_direction(1); to set_direction(EXTRUDER_FORWARD) and EXTRUDER_REVERSE
// v1.10 by SG - Feature 11/2009 - Added enable/disable of extruder valve - (#define EXTRUDER_enable_valve) - to reduce memory overhead for config without extruder valve
// v1.11 by SG - Feature 11/2009 - Turn heat on at startup so we don't have to wait - (#define EXTRUDER_startup_temp 200)
// v1.12 by SG - Feature 11/2009 - Added sleep mode to turn off the steppers when not in use. - (#define ENABLE_STEPPER_SLEEP 20000)
// v1.13 by SG - Feature 11/2009 - Added a wait when the microcontroller is reset. (#ENABLE_WAIT_AT_RESET)
// v1.14 by SG - Feature 11/2009 - Added debug statement to M101 to say why it is pausing (#DEBUG_M101_why_have_you_stopped)
// v1.15 by SG - Feature 12/2009 - Added define in parameters.h to remove drilling software (#ENABLE_DRILLING) to reduce memory overhead for config without drill
// v1.16 by SG - Feature 12/2009 - Set to zero when minimum endstop encountered. (#ENABLE_ZERO_HOME)
// v1.17 by SG - Bug fix 12/2009 - Plastic blobs appear when a M101 was reached due to wait occuring for heat up (see notes.h & Problems and solutions section

regards

Stephen
Re: Reversing extruder stepper direction
July 10, 2016 04:08AM
ho do i edit my firmware thanks sorry for jumping in ust done some ugrades now my extruder is going in reverse haaha its crazy
i have a prusa i3 ctc (ebay special )
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