Welcome! Log In Create A New Profile


I am having a problem with the Stepper extruder

Posted by paulharrington 
I am having a problem with the Stepper extruder
December 25, 2011 09:36AM
Hi there,
First of all Merry Christmas. I hope some of you can help me with this problem. I bought a prusa kit from taobao (the chinese ebay) and am all but complete. Tho I am having a problem working the extruder. The motor just seems to make a sound and doesn't actually turn the motor at all. when i connect this motor to a different connection on the board (say the X-axis) it works perfectly.
I am using repsnapper to test and control my machine and the circuit is ramps 1.2 . The speed is 115200 and using COM4, I am not sure of the firmware as it was uploaded to the circuit by the supplier. I have yet to try the heated bed or the extruder heat.
I hope someone can get onto me ASAP and help me sort out this mess as I hope hoping to be printing before the night is out. (Wishful thinking i know but it is Christmas.)
Hope someone can help me
Re: I am having a problem with the Stepper extruder
December 25, 2011 11:30AM
I don't know the ramps circuit, but does it have a potmeter where you can control the amount of power that the motor can draw? If it works on another port, it seems like the motor, wires and so on is working. If it is making a sound, it sounds like it is trying to turn, but doesn't have enough power to do so. Just take care, that you don't give them too much power, because it will skip steps, because of the thermal shutdown in the stepper controller and the stepper controller will get very hot. It's part of the trimming to set the amount of power "Just Right"(tm).

Happy Christmas and good luck.
Re: I am having a problem with the Stepper extruder
December 25, 2011 01:43PM
Also check that all the jumpers are installed under the driver.

You can switch the driver with another (Z) and see if the issue follows the driver. Make sure to disconnect power and USB first.
Re: I am having a problem with the Stepper extruder
December 25, 2011 05:42PM
The hint for me is that you say you don't know what RAMPS firmware you are using. Since you've proved that the motor is working, and your communication is working (or you wouldn't have been able to test the motor in another driver connection), I'm guessing that the settings in your firmware are wrong. The firmware is probably trying to make the extruder motor move much too fast.

You have to be able to flash your firmware. There are essential things (like e_steps_per_mm) that you have to tailor for your particular printer, and you do it by editing the configuration.h file in the arduino editor. You sometimes need to change some of these values when you change filament type or even colour!

So you have to get the arduino IDE set up. And you have to choose which firmware you want to use. For my MakerGear Mendel Prusa kit, I started with sprinter as the firmware, and pronterface as the control software on my windows 7 laptop.

Don't start playing with the setting of the driver pot yet. If it worked when connected to the X-axis driver, then it should work with the same pot settings for all motors, especially if you haven't loaded any filament yet.

Try using pronterface (instead of repsnapper) to move the extruder motor, with no filament loaded. You can change the mm/minute value in the graphical user interface, and find out whether it works with slower or faster speeds. You don't need the arduino software to do that, but you do need a working python 2.x setup.

If you are using windows, you can try the software setup instructions at [groups.google.com]

Andrew Roberts
Re: I am having a problem with the Stepper extruder
December 25, 2011 05:51PM
I didn't read your issue well enough earlier.

The manual extrude command in repsnapper is way too high for the way extrusion is currently controlled. Use the slider by the extrude button to reduce speed to something close to 200mm/s.

Pronterface is currently more up to date and will, by default, send manual extrude commands w/ sane speeds.
Sorry, only registered users may post in this forum.

Click here to login