Bowden Extruder Installation Recommendations

Hi All,
I'm building my own large-format printer (1m X, 500 mm Y, 500 mm Z) and I'd like to have some general recommendations about installing a Bowden extruder.
Should it be made to tilt as the Z axis rises?
Should I mount it on the Y axis gantry so the tube will not have to be so long as to move in both Y and Z?
What would be the longest distance I should run a Bowden tube?
I purchased an Airtripper's Bowden extruder and Mk. 8 direct drive gear.
Any recommendations will be most appreciated.
Thanks!

Put your extruder up as high as you can, and point the tube out horizontal, that seems to work best on deltas of this size as per my own testing.
Once you have your bowden roughed out, then you can figure out if there is someplace to strap it down, but odds are you won't find anything. Some have used retractable keychains to add support.

Really there isn't a limit on bowden length, you just need more retraction and power. Using a direct driven extruder like yours, I would advise not going below .4m nozzle size. Even a high torque motor will strain a bit on a .4mm any decent speed or in your case, even at lower speeds due to bowden friction. They have great retraction, but lack power for higher speeds or if anything at all gets into the nozzle.

I agree with sheepdog... If going bowden, you may have issues with .4mm nozzles and smaller. An all metal hotend will only make it worse if printing PLA.

I've run into issues where the difference between a direct drive working or not is how smooth the PLA filament is. If it had a rough texture, I was not able to generate enough pressure without loosing steps. I have since switched to a geared extruder and have not had any issues.

Either way, my favorite tip if using push to connect fittings is to print some PTC shims to better lock the tube in place. It prevents premature wear and tubing disconnects under heavy retractions.

I can only speak from my experience with my delta. I have a bowden airtripper extruder, with an all metal hot end, a .4mm nozzle, and I print only in PLA. I print great. With all metal hot ends, it is just keeping them cool with fans (I use dual 40mm fans) and using cooking oil when using PLA, as well as increasing the temperature at the hotend if the filament is not melting fast enough.

For the length of the bowden tube, I lowered the machine and checked that it touched all areas of the bed with enough slack in the line. When it rises, the bowden will recoil up, so you will not have issues of the tube falling below the nozzle and on to the print.

Edited 1 time(s). Last edit at 09/02/2014 07:52PM by Wildcard.

Would you recommend it to be mounted on the Y axis structure?
Could it be mounted on the frame? Actually, it may counterbalance the Y-axis motor.
Thanks for the advice.

Great! Thanks, that's the best kind of advice.
I was thinking of putting the extruder on a pivot that would keep the bend radius of the tube from getting too radical, and therefore allow a shorter tube.
The extruder could be central or off to one side of the frame. It may help with feeding filament up from under the printer.
Thanks again!

Good idea. When you mentioned locking the fitting in place I immediately thought about the Teflon-lined braided metal brake lines on my car. Maybe that would provide an adequate lock.
Thanks for the advice.

Thanks for the advice, all. I'll try to remember to quote the post I'm replying to. A bit of a noob. O well.

There is an older topics about optimum placement of the extruder motor in the General section.
You can also see how I solved the mounting of the extruder motor on my delta here.

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Quote
DinoK
There is an older topics about optimum placement of the extruder motor in the General section.
You can also see how I solved the mounting of the extruder motor on my delta here.

I would have probably run the filament out horizontal, but same placement.
Look at the attachment, this is the best routing on minis I have found, but I do have more pushing power than you do so friction isn't as much of an issue.

Quote
Wildcard
I can only speak from my experience with my delta. I have a bowden airtripper extruder, with an all metal hot end, a .4mm nozzle, and I print only in PLA. I print great. With all metal hot ends, it is just keeping them cool with fans (I use dual 40mm fans) and using cooking oil when using PLA, as well as increasing the temperature at the hotend if the filament is not melting fast enough.

Not all all-metal hot ends are the same, or even really all metal (the E3D V6 for 1.75mm is not). I have an E3d V4 that does okay with PLA and I have another all metal head that was an absolute nightmare. It would lock up after each print no matter how much air it got. As for the oil, that just sounds like a hassle and a mess. I haven't tried the E3d V6, but not only do I feel it's a lie (as mentioned), but I've blown out so many pneumatic fittings (and bowden tubes) that the idea of it being built in, just makes me cringe.

That's one good thing about direct drive, you don't have to worry about destroying the bowden system, then again, you also can't exactly print very fast either.