extruder calibration

I have my reprap prusa mendel i2 running well, except for the extruder calibration.

I've been trying to get the extruder calibrated, but no matter what I change the steps per mm to in sprinter, I can not get the amount fed to change. It is always 5mm when I ask for 10mm. I've changed the config.h file to reflect different setting (and uploaded successfully), and I still get 5mm when asking for 10mm.

I'm not sure where to look for the problem. I'm assuming the extruder may be slipping, but I do not know how to tell. How many mm is one revolution of the bolt in the extruder?

If I ask for 10mm and only got 5mm, the math looks like this. 10mm = 700 steps/mm *10mm =7000 steps. So the controller sent 7000 steps. The measured amount extruded was 5mm. so 7000steps/5mm =1400 steps/mm. So I change it to 1400 steps in config.h upload using arduino software, then I go to pronterface and ask it to extrude 10mm (at temp), at 40mm/min rate, and it still does 5mm!!!

Any tips would be great.

thanks,


p.s. My first clue that something was wrong was the models I printed, had hollow walls and incomplete fill. I'm guessing this is because the extruder is not putting out enough to fill it in.

You need to look at this...

[reprap.org]

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Waitaki 3D Printer

I think the issue is the arduino software is not updating my sprinter. I have 10 teeth on the stepper and 43 on the large gear (ie. the hob bolt). Every time I tell it to run 10mm in pronterface the large gear only turns a quarter turn. So that would be apparent diameter of the hob bolt (in this case 7mm) times Pi (3.14) times a quarter rotation. = 5mm. Which is what I get when I measure the filament, so I know it is not slipping.

Why isn't it updating when I upload it in the arduino software. Do I have to hit a reset button or something? I updated the config.h file to reflect more steps per mm, but it doesn't work...

If you expect that the extruder is slipping, slow down the rate in Pronterface. If you are having trouble with the hot end, pull it off and see how much filament the extruder moves. If it moves 5 mm no matter what the steps / mm settings is, either your printer is haunted by ghosts or you are chafing the wrong line in the firmware (or not uploading it properly). One way to check the upload is to always change at least the time setting at the top of the file. You will see it repeated when Pronterface connects.

Most likely you have eeprom enabled in the firmware which means the new settings do not take effect. I personally recommend disabling eeprom in the firmware and always update the settings manually in the firmware and re-upload it. To test you can reset the eeprom to default values which should be the new values you set in the firmware.

Also the Reprappers section is to discuss "people using and building repraps" as the title says not for discussing technical stuff. There are specific sections for all types of technical questions.

Edited 1 time(s). Last edit at 11/24/2013 10:39PM by Sublime.

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