How to make a grooved Extruder Idler Pully
Posted by Paul Wanamaker
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How to make a grooved Extruder Idler Pully February 25, 2015 06:59PM |
As part of my effort to make my Bowden extruder for Raptosaur more reliable I made a Grooved Extruder Idler Pulley, using a Dremel cutoff wheel.
This puts even pressure on one side of the filament and allows greater pressure without crushing and flattening the filament.
Making this turned out to be very easy to do and just took a few minutes.
The first step is to mark the exact place on the bearing where the groove will be. I did this by marking the side of some filament with a Sharpie (I use 3mm filament) and sliding the filament quickly into the bowden extryder, The still wet sharpie mark left a line on the bearing.
Next I inserted a bolt through the bearing and clamped the bolt in a vice.
Important: make sure to have someone help you by pressing something against the bearing so it does not over-speed and gall the ball bearings.
Wear safety glasses!
Then I used the Dremel to make a narrow groove right at the marked location. The Dremel was supported by the vice so it was easy to hold it securely.
Finally I placed the cutoff wheel at an angle to get the correct width.
Grind slowly and check it to make sure it's the desired width and depth. There is quite a bit of metal there, but it's not infinite, so don't go too deep (have a spare!)
BTW, the other thing I did to make my extruder completely reliable was to replace the extruder drive gear that I had made with a commercial Mk-7 gear which I had bored to fit the Nema-23 motor my extruder uses. The smoother teeth profile does not chew up the filament even with lots of retracts, and stays clean.
My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!
This puts even pressure on one side of the filament and allows greater pressure without crushing and flattening the filament.
Making this turned out to be very easy to do and just took a few minutes.
The first step is to mark the exact place on the bearing where the groove will be. I did this by marking the side of some filament with a Sharpie (I use 3mm filament) and sliding the filament quickly into the bowden extryder, The still wet sharpie mark left a line on the bearing.
Next I inserted a bolt through the bearing and clamped the bolt in a vice.
Important: make sure to have someone help you by pressing something against the bearing so it does not over-speed and gall the ball bearings.
Wear safety glasses!
Then I used the Dremel to make a narrow groove right at the marked location. The Dremel was supported by the vice so it was easy to hold it securely.
Finally I placed the cutoff wheel at an angle to get the correct width.
Grind slowly and check it to make sure it's the desired width and depth. There is quite a bit of metal there, but it's not infinite, so don't go too deep (have a spare!)
BTW, the other thing I did to make my extruder completely reliable was to replace the extruder drive gear that I had made with a commercial Mk-7 gear which I had bored to fit the Nema-23 motor my extruder uses. The smoother teeth profile does not chew up the filament even with lots of retracts, and stays clean.
My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
Can you answer questions about Calibration, Printing issues, Mechanics? Write it up and improve the Wiki!
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