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elastic filament transport

Posted: 28 Oct 2015, 08:56
by rallef70
Hi there,
I am a quite glad owner of a tuned 3dtouch machine.
Recently, I have bought some Ninjaflex filament for Smartphone cover usage.
The transport mechanism does not accept the filament - no, it likes to eat the filament itself.
Has someone here solved such an issue?

Re: elastic filament transport

Posted: 12 Nov 2015, 22:34
by Isaac_alaska
yes. you need to eliminate any distance between the drive gear and the hole that the filament goes into. on my typeAmachines series 1, i drilled a .125" hole into the aluminum block just past the drive gear, and then machined a delrin bushing with a 1.76mm hole in it, and a taper that fits up between the drive gear and the support bearing. there is less than 1mm between the filament leaving the drive gear and entering the hole

Re: elastic filament transport

Posted: 16 Nov 2015, 00:48
by PenskeGuy
Isaac_alaska wrote:yes. you need to eliminate any distance between the drive gear and the hole that the filament goes into. on my typeAmachines series 1, i drilled a .125" hole into the aluminum block just past the drive gear, and then machined a delrin bushing with a 1.76mm hole in it, and a taper that fits up between the drive gear and the support bearing. there is less than 1mm between the filament leaving the drive gear and entering the hole
This doesn't seem possible with a 3D Touch/3000 transport. There is no "drive gear". It is a threaded rod that rotates, with the filament pressed against and into it by spring-loaded rollers The action combination moves the filament downward into the heater/nozzle.

Re: elastic filament transport

Posted: 16 Nov 2015, 01:22
by Isaac_alaska
can you post a pic? i'll try to post detailed photos of mine when it's done printing, which should be in a couple hours

Re: elastic filament transport

Posted: 17 Nov 2015, 00:52
by PenskeGuy
Isaac_alaska wrote:can you post a pic? i'll try to post detailed photos of mine when it's done printing, which should be in a couple hours
This should do it: http://ametameta.com/drhugh/3dprint/bfb ... sembly.htm
Filament goes in though the curved slot marked "A" in the third photo; propelled by the screw, into and through a PTFE tube, seen in the detail below that, that leads directly into the hot end. The path can't be shortened without redesigning the entire mechanism.

Re: elastic filament transport

Posted: 18 Nov 2015, 17:06
by Isaac_alaska
here's what i did to mine to be able to extrude ninjaflex at an acceptable speed. i also had to change the idler bearing so it was the same diameter as the drive gear, so that the "cone" that fits up between them as as tight as possible of a fit on both sides. it's actually such a tight fit that to get the cone out, i have to loosen the set screw on the drive gear and slide them both out at the same time.

stock, there is no black plastic insert, it's just a flat aluminum block and the filament is unsupported from where it leaves the drive gear to where it enters the block, a distance of maybe 4mm. to eliminate this, i counter-bored the aluminum block and machined a delrin insert (the black cone) for the filament to slide through

Re: elastic filament transport

Posted: 15 Dec 2015, 04:46
by rallef70
Ok, that IS impressing. And I am envy because you have a solution.
As PenskeGuy stated, we have a different feeder system.
But: you wrote about avoiding holes, and that gives me a hint for a new (and maybe simple) solution.
It consists of a bended baffle with a defined cutout that is placed between the holde of the bearings/guides and the block.
Hmmm, too bad I am at work and not near my machine...