To Bowden or not to Bowden.....

Hi RepRap Forum,

I've been on the search for maximised print quality over the past few weeks and I am considering changing to a Bowden set up. I have no desire to print flexible materials, so I feel a direct drive extruder is a bulky mass adding additional. The added speed benefits also point me towards a Bowden system. I already have a good deal invested in 1.75 mm filament, so I would be reluctant to move to a 3mm Bowden system (which I have read is more effective). What are your opinions on this situation? If it comes recommended, what bowden system would you recommend, I'm running a acrylic i3. (links would be apreciated)

Happy Printing,
Kev

If I got it correctly another benefit from a Bowden set up is a more even pressure in the hot end.

Hi,

I'm a bowden fan too.
Bowden minimize filament traction on the printhead.
The printhead have less mass and can move faster.
Trough, the print quality is better with a bowden.

I use RichRap's wade gear extruder and a E3Dv6.

++JM

What are the experiences with 3mm bowden. Ultimaker is the only name that comes to my mind that is doing that. I get the argument for it, having my self the 175 bowden, but is it worth the trouble and the disadvantages from 3 filament?

All metal hot ends are not that good with Bowden extruders as they don't agree too well with the longer retraction that is needed.

Quote
SlowFoot
All metal hot ends are not that good with Bowden extruders as they don't agree too well with the longer retraction that is needed.

I don´t get that.
Sure you have to retract more filament to cope with the backlash in the tube, but the length of filament retracted in the heatbarrier is the same ( or should be, if done right ).

A Bowden setup for a Prusa i3 doesn´t make much sense, because in my experience the y-table is the weakest link in the chain.
I´d choose Bowden for a dual extruder for sure, but not for a single extruder.

-Olaf

Edited 1 time(s). Last edit at 09/23/2015 05:51AM by o_lampe.

I've converted my i3 to bowden and I can print at higher speeds with beter or similar quality. The x carriage mechanics is more complex than the y carriage which is better supported. Dangling a relatively heavy motor, hobbed bolt and nuts, a idler bearing and the wades extruder printed part from the x carriage makes it difficult to keep the print quality high at higher speeds. It sticks out to the front creating a lever that can set the x carriage in motion/vibration at higher speeds. I've now upgraded the y carriage from wood to aluminium, about 300 grams and still keeps up with the x axis. Because it's much stiffer the print quality went up even more. I had to tighten the belts more which was a problem with the z axis smooth rods bending inward. I solved it temporarily by glueing the x smoothrods to the x motor and x idler parts. The force of the x belt tension is now on the x smoothrods instead of the z. In the next iteration I will add a different belt tensioner that will transfer the force directly to the x smooth rods. I don't like glueing them as maintanance will be more difficult.

Oh and I'm using 3mm filament, and I print with flex65 filament with no problems, but at lower speeds of 30mm/s, normally abs or hips at 60/80mm/s for perimeter/infill.

First layer at 15mm/s to make it stick better. I have very little blobs now that I run the extruder motor with 2000mm/s2 acceleration (down from 3000) which allows a speed of 65mm/s instead of 28mm/s. Retraction length 4.5 to 5mm.

I'm running with a custom geared extruder, loosely based on the greg wades extruder, mounted behind the frame at the top for a shorter bowden tube. The custom hotend part is very light weight yet includes a cold end cooler, parts cooler and bed leveling servo and can optionally have some leds for lighting the printed part.

I've been running this setup for 4 months now and I really enjoy the inceased speed.

The only thing I might want to change is the top of the bowden tube swinging to and fro freely. This may have a lever effect on the hotend introducing some wobble in the prints when the print head makes rapid back and forward motions. Mostly during infill which will not be visible on the ouside anyway. I could constrain it with a smooth rod and linear bearing.

I'm planning to add a second extruder in the future.

I went bowden with my OrdBot.
I have twin Wade extruders bolted to the top frame and short 300mm long tubes to the hotend. The secret is keeping the tubes as short as possible to minimise hysterisis. I am using 1.75mm filament. I have no experience of 3mm.
Reasons were to try twin colours (still trying) and and also to get the moving weight down /printing speed up.
I print usually at 100 -150mm/sec but I have had it up to 250mm/sec for simpler objects. The carriage really flies about.
Once the settings are optimised quality is as good as when my extruder was non bowdenised I think.

I also converted my i3 to bowden with wade gear. It has improve the print quality and speed. Plus the stock setup was always giving trouble. Filament jam on stepper gear everyday with the stock setup. That's from folger tech

Edited 1 time(s). Last edit at 09/26/2015 07:51AM by deaconfrost.

I've frankensteined together a bowden setup from a Hesine kit and several pieces I've bought on Aliexpress. The direct drive was just giving me too much trouble and grief as it seems every time the blasted thing wanted to retract, it would pull the filament all the way out of the throat and then jam trying to feed it back through. Now that I relocated the motor elsewhere, I've had much more reliability when printing and my print quality has increased dramatically.

I simply bought 2 pneumatic fittings with the appropriate sized PTFE tubing to fit the M6 hole on my extruder motor mount and got an M6 coupling nut to attach the other to the throat on the hot end. Slide the hotend into the groove on the X-carriage mount and tighten up an M6 nut on the bottom to sure things up and it's been zipping away better than ever! I had to secure the motor originally with some tape until I was able to print the motor mount featured in the pictures (I just found a NEMA 17 end cap on thingiverse and drilled a hole in it to mount it to the acrylic frame).

I've also since taking these pictures rigged up the original cooling fan from the extruder motor to blow on the coupling nut and pneumatic fitting to keep the top end cool and that has worked wonders as well.

Everyone should experiement to find what setup works best for them, but I highly recommend a bowden setup after the success I've had.

Picture Links
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[drive.google.com]