Tuesday, February 7, 2017

Prusa i3 improvements

As I've been posting here, I have a prusa i3 on loan for a couple of months.

A few weeks ago, I got a piece that had no plastic deposited on one specific area, and was fine on the rest. This was very odd, so I had it reprinted and stayed around to see what happened. Immediately I saw that the extruder stepper motor was not turning. I looked around to try to see the reason for this, and found the culprit: a damaged cable:

Extruder stepper broken cable

I tried fixing it, by taking out the small metal tab in the connector, but that didn't work for long.
I talked to the owner of the printer and he had a spare cable. According to him this had happened before, and was a common problem.
The issue here is that a lot of stress is put on that particular cable as it travels left and right along the X axis all the time, plus vertically, although that is a slow and much less often travel.

Since I don't like problems that reoccur, I thought of a solution: a cable holder that transfers the stress from the connector to the cable, which is a point much less prone to failure. So I designed a cable holder that holds not only the extruder stepper cable, but all the cable for heating the extruder and for the fans. Here it is, printed in glow-in-the-dark PLA:

Extruder stepper cable holder
Extruder stepper cable holder

This makes the whole cable behave much better, and I think will also prolong the life of the extruder heating connections. I also printed one for the X-axis stepper motor which travels up with the Z-axis:

X-axis cable holder

You can find these models in the warehouse here.

While discussing this problem, I also realized the cable proving the heated bed with power also keeps traveling back and forth along the y-axis and so it would also fail sooner or later, so I also designed a little holder for this. You can find it in the warehouse here:

Heated bed cable holder

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