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Extruder drive gear

The stock CupcakeCNC 3d printer plastruder, which I've been using, has a timing belt pulley to drive the plastic filament through the extruder. Unfortunately, it has an annoying habit of stripping the filament, getting plastic stuck in its teeth, and stopping extrusion.

Some folks have been experimenting with alternatives, like a small worm gear, and have reported great success. Since I've been frustrated at the extruder, I decided to make a small worm gear on my lathe. See the pic below.
photo.jpg

Comments

( 9 comments — Leave a comment )
momentrabbit
Mar. 22nd, 2010 01:05 am (UTC)
Niiiice. Use the hob-and-tap technique again?
revar
Mar. 22nd, 2010 02:15 am (UTC)
I shaped the general shape on the lathe, then mounted a 3mm tap in the lathe chuck, and held the brass part's groove to the tap in a free rotating setup. Amusingly, the tool holder that held the brass part was itself printed on the fabber.
cjthomas
Mar. 22nd, 2010 03:39 am (UTC)
If you're ever in a position to sell kits for the Cheesecake CNC, please let me know!

I've been investigating the Candyfab project, but it looks like the lead developers on that got busy with other things 6-12 months ago. They aren't offering kits of the original, mediocre fabber, and development on the much-improved fabber is to all appearances stalled (so kits remain a "we'll have this eventually" item).

Plan C is to download specs for the Candyfab parts and try using a halogen projector type system for the fusing, but I won't have the time or money to tinker with that for at least a year or two, and possibly longer.

Watching you tinker is fun as an interim activity!

-Deuce
dnellin
Mar. 23rd, 2010 05:19 pm (UTC)
Neat part! Boy, would your shop teacher be amazed.
revar
Mar. 23rd, 2010 07:29 pm (UTC)
I cannot comprehend how it is possible that younger-me really didn't like, and wasn't very good at either wood or metal shop classes.
dnellin
Mar. 24th, 2010 05:12 am (UTC)
There is something to that old saw "We live and learn."
chorca
Mar. 30th, 2010 05:10 pm (UTC)
D: Y helo thar. yippee pointed me over here, it is interesting to find another fur who's working on 3D printing and microcontroller stuffs! I've started building a RepRap Mendel.. build blag is here. A friend at my local hackerspace has a MakerBot and just got the heated platform for it, so we're going to build the pieces for the Mendel on it.

Your hobbed wheel is awesome! I'm using a similar thing with my extruder and it seems this is the way to go for extruders on these machines. I'm sure the pro machines use a very similar idea.

I'm trying a somewhat interesting idea on the heater bit, using a cartridge heater, so we'll see how it turns out. I'll keep an eye on your journal!
revar
Mar. 31st, 2010 01:19 am (UTC)
You're using a cartridge heater for the heated platform? Are you using a Solid State Relay to switch 120AC to it? I'd had thoughts along that line, myself, (with a silicone heater pad instead) but so far I've been put off because having to plug in a second power cable into the wall just seems inelegant. It'd allow for a lot faster platform heating, though.

The platform heater I currently have is a trio of nichrome wires under a 5mm acrylic sheet. 2.4ohms overall, which is probably more wattage (60W) than I should be pushing through the heatsinkless MOSFET. The platform is unevenly heated, and the acrylic warped and is now rippled and not very flat. I'm going to have to build a different heated platform soon.

I can't use the makerbot platform as my fabber's build area is 6"x7". So I need to roll my own. I'm thinking either nichrome on a pyrex sheet, or on the back of an aluminum plate, with Kapton film on the top.
chorca
Mar. 31st, 2010 01:11 pm (UTC)
Actually I'm using a cartridge heater to run the nozzle heat, I don't have a heated build platform set up yet. However, I wouldn't mind trying something like cartridge heaters, though the setup would be somewhat complicated, most likely drill out deep holes into an aluminum sheet for the bed and use 4 or more cartridge heaters to evenly heat it.
I'm going to try and run the output of the extruder controller into the SSR to modulate the 110V into the barrel heater. Should be able to keep all the control routines then and just use a better manufactured heating element. I guess the idea of heating the barrel using a threaded external part thing is gaining traction with MakerGear's new heater, and nophead's vitreous enamel resistor heater.

Otherwise, with the heated platform I think going with something metal is the best, due to heat transfer and such. Most people are using aluminum, I'm going to try copper, but I've seen at least one person mention trying to use something dense like steel/cast iron, due to it's ability to retain heat and keep it spread evenly throughout itself, making it easier to maintain temps. I haven't seen anyone try it yet, only mention it as a possible material.
( 9 comments — Leave a comment )