donhuevo's E3D Bowden fed X-Carriage

The files are up on Thingiverse. You can find them here: http://www.thingiverse.com/thing:343995/#files. I wouldn't recommend attempting it if you don't have your printer dialed in well. Early on, I tried printing with support material but it turned into an ugly mess. I drew support material in for the upper housing so that it could be easily removed. Because the bearing channels are printed parallel with the bed, they'll need a fair amount of cleanup after. It's by far the lesser of all the evils I encountered. Here are some pics of the disassembly...


I'm still working out some kinks with the LED. For the most part, it works the way I want it to. When printing though, it goes out from time to time. I'm thinking it's because I'm pulling my 5V from Aux 1 on the RAMPS board. I have a buck converter coming from Adafruit so I can pull 5V right from the power supply. We'll see what happens...

 

A quick video. Pretty sure I'm running at 200% printing the retaining clip...

 

Pretty cool. I don't know much about bowden feeding but I assume that it makes faster speeds possible? Also, the LED is cool but you should put it under the hotend so you can see your prints better. Can't really see anything printing in the video you uploaded

 

Yep... black plastic on a black bed recording video with a cell phone. Not the smartest move. I have a couple white LED strips up inside the top of the printer. In real life, the part is visible. To answer your question, yes you can print faster. Taking the weight of the stepper motor off the carriage makes it a whole lot more nimble.

 

Biggest limitation on speed is feeding the filament I've found. You really need a high torque, direct drive, cold end.

 

I'm running a NEMA17 with 5:1 planetary gears and its keeping up. Getting warm but keeping up.

 

Yeah I'm also running those planetary gears. I had to tune them down because they were getting so hot they'd melt the filament before entering the bowden tube. It puts out great torque but there's an upper speed limit. I still need to try and push it but I noticed at 120mm/s it was starting to show it's limits.

 

Where did you guys source your parts/information from?

 

I got mine here: http://www.omc-stepperonline.com/ratio-51-geared-stepper-motor-for-nema-17-stepper-motor-p-140.html

 

Cool, thanks. How about the whole filament feeder assembly? It looks like Donhuevo has an assembly that isn't printed. And forgive all my questions, but does the motor plug right in to where the old filament feeder motor went or will I have to make modifications to my software to get the gearing to match up correctly?

One of you guys should do a full write up for this in the modification section. I know a lot of us would be interested. Seems like minimal cost/work for a nice speed upgrade.

 

His pictures blurry but to me it looks like he printed a bracket for mounting the EZStruder on. It normally mounts directly to a Nema17 stepper motor, so you'd need an adapter bracket for securing to the stepper and ezstruder together.

Mine also required drilling out the hobbed pulley to 6mm to fit on the drive shaft.

The geared stepper/ezstruder will plug in directly to your old port, but as it requires significantly less amps you'll need to tune down your stepper driver so as to not heat up the geared stepper. You need to adjust your steppers per unit in the firmware to be around 510.

 

yep, sorry about the blurriness. The bracket is a simple square loop I printed that clamps around the middle of the motor. Here's a better picture...


Mine is also a NEMA17 5:1 from stepperonline. I stole one of the four case screws and its nut and attached the clamp to the spool holder that came with the printer. I also use an EZstruder from seemecnc.com. I got by hobbed pulley from trinity labs to fit the 8mm shaft coming out of the planetary gears. Both Filastruder and Printed Solid both sell the E3D hot end. As far as tuning the steps per mm in firmware, I started with 95.9 for the EZStruder multiplied by 5.18 (the value from the planetary gears). Then I cut the filament flush at the end of the EZstruder and had Repetier extrude 10mm. Cut flush again and took that piece of filament to the calipers. I'm at work right now so I can't check for sure but I think my final number was around 470 steps per mm.

Mike, what did you tune your stepper down to? I think mine is still at .45V from rheostat to ground when only usb powered.

I bought ancillary electronics stuff from sparkfun & adafruit. I think my LM8UU linear bearings came from China via Ebay - 10 for less than $10. (The x-carriage needs four of these BTW).

On an unrelated note, here's another vid of the hot end heating up. Kinda boring but the LED goes from blue to red.

 

Yeah I meant the plate that joins the geared stepper to the ezstruder

That's cool I didn't know there was options for different bores: http://trinitylabs.com/products/hobbed-pulley though they look to be going out of business

I did a "dumb" tuning. Tell the printer to extrude a lot of filament. As it's extruding turn back the rheostat on the stepper driver until the motors begin to stall pushing the filament, then turn it up just slightly to get above that minimum torque requirement. I can measure the v_ref later if it's of use.

What circuitry did you use to get the colors? Really neat.

 

The LED is a neopixel from Adafruit. I went with this one because of it's size... https://www.adafruit.com/products/1612 They have an Arduino library. The three wires are 5V, Gnd and one to an Arduino digital pin. They can be strung together and you can tell which LED to do what. I picked up D44 from AUX 2 on the RAMPS board. I wrote a little function that varies the color depending on where the temp is between 30C and target temp. Conceivably, one could add another for the bed and it would still take commands from D44 but independently of the extruder LED. Even one for a second extruder.

This is the Ezstruder -> planetary adapter I found on Thingiverse... http://www.thingiverse.com/thing:131310

If you think of it the next time you have it tipped over.

 

I just ordered this. I think it's going to do wonders for the extruder heat... http://www.amazon.com/30mm-25mm-Heatsink-Dissipate-Cooling/dp/B008OTKW3E/ref=pd_ybh_1

 

I measured around 130 to 160mV on my stepper drivers

 

Wow! I tried taking mine down to 200mV and it was stalling badly. I finally did what you did and started extruding and adjusting simultaneously. Thank you!

 

So this has been my first experience with Bowden-fed printing. I've almost had to learn how to print all over again. I've fiddled with temperature, speeds, other settings like 'Avoid Crossing Perimeters' and Slic3r's new feature - 'Wipe'. Turns out the one thing that made the biggest difference was to set my Lift Z to zero for retraction. The second biggest thing was to up my retraction speed to 40 and my retraction distance to 3mm. Hardly any strings or blobs now. Also, I'm going to have to actively cool my extruder motor. I have a 40mm fan on the way and will get something designed to hold the motor and mount the fan to.

 

Are you still running at 200mV?

 

I have no idea now. I just adjusted until it smoothed out.