Bowden or Wade Extruder

Hey,

I am thinking of upgrading my RepRap to a dual extruder rather than the standard single extruder.

I am currently using Wade's extruder on my X carriage.

However, If I want to put 2 on the same carriage, 2 Wade's would not fit.

The only other options I can see are either having 2 Wade extruders off the carriage and connect them up to the hot end via pneumatic fittings.

Or, I could use 2 Direct Bowden extruders on the same carriage (much like the replicator 2)

Does anyone know of any pro's and con's with these extruders and their possible set up.

Thanks

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

replicator 2 does not use bowden. it uses tubes only to prevent tangling of feedstock.


pros of bowden are light weight, faster acceleration. cons are you need a smaller nozzle size and good retraction settings to prevent oozing. works best with cura software because of built in comb feature that cleans the ooze insize part walls.also available for skeinforge, but not in slic3r.

I feel that software has matured enough to give bowden a try, especially with issues of dual extruder weight.

Edited 1 time(s). Last edit at 01/01/2014 09:27AM by jamesdanielv.

So would you recommend using 2 wades connected via pneumatic fittings which are located off the x carriage?

Thanks

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

Yes, as long as you use ptf/ptfe tubing at a slightly larger inner diameter. 3mm feedstock , should have a 3.1mm diameter, and 1.7 feedstock should have a 1.8 diameter inside the tube. outer diameter should be whatever the fitting size is. you want it only slightly larger.




also you want to slightly drill the side of the tube where the feedstock flows into, so it has a funnel shape going into the tube, many jamming issues can be avoided by doing this, also the reason for PTF tubing is that any other tubing does not have enough strength to stay attached to the fitting.


if all else look at how ultimaker does it.

make sure hot end has a fan where feedstock flows out of tubing. die swell becomes impossible to manage without proper active cooling on these types of designs.

Edited 2 time(s). Last edit at 01/01/2014 01:53PM by jamesdanielv.

Hey,

Would I need to add this fan if my PTF tubing went straight into the top of the hot end [www.ebay.co.uk]

(1.75mm Filament)

And this would be the Extruder set up (the other end of the PTF tube) [hannahnapier.co.uk]


This is the extruder I am looking at buying/using.

However, this may be my other option [thingiverse-production.s3.amazonaws.com]

Thanks

Edited 3 time(s). Last edit at 01/01/2014 02:55PM by ayouden.

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

I have just converted my Ord Bot Hadron to twin extruders. I am new to all this but I have fitted twin Wades on the top with short PTFE bowden tubes to twin jheads on the x carriage. I am using 1.75 mm filament in 2 mm id / 4mm od tube with pneumatic fittings. Tubes are about 15" long. I tried to keep them as short as possible to reduce compression effects or slack in the system.
The reduction in weight was one of the reasons for doing it. Twin extruders flying about at high speed would be a problem I think.
1.75mm filament is more flexible than 3 mm. Still a project being developed. I have got a single extruder working so far and had some good single colour prints. I have 10mm retraction to minimise oozing. Next I need to solve the problem of how to set the bed height for twin extruders.

Hey,

When you say getting the bed height right, I am guessing you mean that you need both the extruder nozzles to be at the same Z height as one another?

If you could keep me posted on your project that would be really useful!

Thanks

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

If you want to go Bowden, maybe first try out a setup with just one Bowden extruder? Last week I have finished my 2nd printer. First one was normal extrusion and the 2nd one uses Bowden. I can't really compare because the Bowden printer uses PLA and the other one uses ABS plastics.

It's a journey, because there are more factors involved in printing, the compression of the filament along then length of material between the extruder and hotend, springiness of the Bowden tubes, etc etc. Therefor retraction settings take a while to configure, I myself am now at 3mm retraction, but I think it needs just a little bit more maybe 0.2mm more or something.

My heatbed is an aluminum heatbed, 2 layers, pretty heavy but on a very smooth linear bearing system I designed myself so it can still be fast. The X-axis is not working on it's full speed, but thats ok, I think that if I would print faster with the PLA at the moment, the precision will be lower again anyway.

The reason why I did it was just because I wanted to have this Bowden system because it looked cool (I admit, I'm guilty), but if it would have a real function (like using it for a dual extrusion setup) I could only encourage it. I see double extruder setups on thingiverse, but it looks too bulky and probably is.

ayouden: yes I meant getting both nozzles exactly the same Z height. I think they must be closer than a single layer height, unless anyone else knows better. I don't know whether to shim one to level them or devise an adjustable screw system. If they are not exactly the same the second extruder is going to catch on the print.
I have also got the nozzles spaced 40mm apart in the X axis. About as close as I could get them.

It sounds as though I am using too much retraction at 10mm. Just slows down the print I guess.

Regarding the tubing: in an ideal world it would be nice to get 1.8mm id tube but I have never seen it available. I used 2mm id ptfe tube. I found it is possible to gently push and pull the 1.75mm filament backwards and forwards at one end so it moves a bit and yet it does not move at the other end until a point is reached when the force is increased. Like a hysteresis effect. It gives the impression that the filament is compressing (I am using ABS) but I think it is also because the filamant sort of snaking inside the tube as well. The design is all a compromise so I kept the Bowden tubes as short as possible. They are now 38cm or 15".

I have also found some of the pneumatic fittings (4mm / 1/8"bsp) allowed the tubing to move backwards and forwards. I swapped these out to make the whole thing as tight as possible.