Thursday 8 August 2013

Inconsistent extrusion and a fix

Hi everyone, welcome to my blog. I'll be detailing all of the issues I've run into while printing from the viewpoint of a non-engineer so it might be easier for the layperson to understand, diagnose and hopefully fix whatever might be bogging down their Reprap.

Anyway, I've run into some problems regarding inconsistent extrusion. Take a look at the picture below:


The yellow arrow points to a few layers which appear 'spongy' and underfilled. I've also noticed the support structures generated would be very weak, which caused them to break and ruin rest of the print.

Since the coldend of the extruder is responsible for pushing the filament, I decided to take a better look by loosening the idler and this is what I discovered:


The hobbed bit of the hobbed bolt has gone out of alignment with the hole where the filament goes through. This means the filament would have been underextruded.

A potential fix for this problem would be to use a thicker washer on the right so when it is tight, the hobbed bit will be centered again. Since I'm too far away from a hardware store, I'll be making a quick fix by backing off the nut securing the big gear to the shaft of the hobbed bolt. This centered my bolt again, but I'd have to do this constantly until I can have a permanent fix.


There we go, a centered bolt, good to go.

If you have anything to add, please share it with us. We're all learning here

UPDATE: Even though the hobbed bolt wasn't aligned properly, the other reason why I couldn't print properly is because my filament was too moist. Don't forget to dry it out by baking on low or leaving it with a desiccant (e.g. silica gel).

UPDATE 2:
This problem was a lot bigger than I thought it was. Everything I've learned is covered in the next post.

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