strongest bowden coupler?

Hi,

Im testing some high speed/ high volume printing at the moment with a bontec V3 extruder, a e3dV6 and a 3d Solex 1.5mm matchless nozzle.
Everything works fine so far when I print .9 layerheight with 1.8mm width at 15mms, however the parts thats actually giving in when I push past 20mms is the bowden coupler. I already reinforced the e3d coupler with and additional m10 screw coupler on top but now the one thats coming out of the extruder is alse giving in.
So I was wondering if someone found a special super strong coupler already. I dont want to wire the extruder onto my hotend

Cheers

I finally went back to direct drive because of this problem.

sungod3k.

Are you perhaps just trying to melt more filament, at a faster rate than the hot end can cope with? It sounds to me that you are just building up too much pressure in the hot end by pushing the filament in faster than it can be melted. The area of a 1.5mm diameter nozzle is roughly 1.76 mm^2 and the area of a 0.5mm nozzle is roughly 0.2 mm^2. So, the area of your nozzle is roughly 8 times more than a 0.5mm nozzle. On top of that, you have a layer height of 0.9 mm which is roughly 3 times what you would normally use with a 0.5mm nozzle. So you are trying to extrude roughly 24 times the amount of filament than a more conventional nozzle at a given speed. All else being equal, you would therefore need to reduce your speed by a factor of 24. Or put another way, 20mm /s with your nozzle and layer height would be about the same as trying to print at 480 mm / sec with a conventional nozzle. 15mm/ sec would be the equivalent of (15x24=) 360mm/sec which is pretty damned fast so I'd say you've reached the limit of what is possible. Excuse the quick rough and ready maths which were just to illustrate the point and may be a quite a way out but you get the idea.

The math you did is roughly what I tried and came up with as well, but the upper end of the extrusion limits are not very well defined by the manufactures of the components. I tried e3d and bontec to give me their test data but all they gave me are theoretical values and not proper experiments. In addition the 3d solex nozzle increases the heatable area inside the hotend enableling much more heat transfer into the plastic, so the pressure should be reduced by that as well.

Therefore I can only compare it to my own experiences. I managed 10mms with the same .9LH and 1.8EW on a 1.2mm e3d volcano + nozzle. The limit I hit in this config was actually the ability to heat the plastic consistently but the bowden couplers were holding normally even if I pushed the speed to 20mms and only partially unheated blobs came out the hot end.

Also the extrusion looks quite normal, no skipped steps, no blobbing like before and I assume I would be able to push it to maybe even 30mms if it weren't for the couplers.

I had the idea of just glueing two of these couplers together. That could increase the holding force maybe...

Fair enough. I guess those E3d couplers might work - they aren't extortionately expensive to try. I presume you've tried the simple approach of pulling back the tube clip while pushing the tube in then fitting one of these [www.thingiverse.com] ?