Sunday, 10 November 2013

Filastruder Progress

I've been playing some more with my Filastruder this week, and I've made some discoveries.

First, the things it does not tell you in the manual, and some that are:

1) The manual states that you should clean the nipple (AKA tube) well before fitting to clear out any swarf. I blew mine out with a 110psi airline before fitting, but even that was not sufficient. I started finding bits of metal in the extruded filament:

This sort of thing will obviously choke an extruder. It is not a design fault of the Filastruder, just my failure to ensure the nipple was clean. Bear in mind you may need to flush some plastic through the unit to clear out any crap.

2) It is not made clear that the unit needs to be operated with a significant overhang. As the filament is extruded, if it snags on anything it affects the output quality. The radius of the filament as it coils from a height of approx. 1.3m is 1m. So the end of the Filastruder nozzle needs to be about 1.3m from any wall that could foul the filament as it falls. I also had an issue with the unit design. As the filament is extruded, it tends to fold underneath the machine as it coils on the floor. The problem I had was that it fouled on the wooden block that mounts the fan:

This caused the filament to back up at the extruder, resulting in a fatal kink:

After leaving the unit unattended on another occasion I came back to this:

I decided to design a new filament guide which would allow the filament to fold underneath the unit as it coiled. I came up with this:

It has an outreach of about 110mm, an inbuilt fan mount that allows the fan to be raised/lowered and moved forwards and backwards as needed. It also has multiple mounting holes to allow the distance between the extruder nozzle and the support bar to be adjusted. The support bar has been turned from some delrin bar I had lying around. It could easily be made from a length of copper pipe supported between screws.

Here it is fitted:

It clearly allows the filament to 'bend backwards' without fouling:

If anyone is interested, I'll upload it to Thingiverse. I now have a bounty of filament:

BTW Creating filament for 6 hours in the kitchen does not make you the most popular person in the house.


DDevine said...

I think what is written in the stickies in the forum is the real guide...

The metal in the filament is not from the nipple but actually from the auger rubbing against the rough surface of the barrel. The barrel has to be rough (the is an equation given to help explain why in the forums) but this also means that you have to run to run the Filastruder for a while after you first assemble it to wait for all the loose contaminates to be knocked off and pushed out.

Good work on the filament guide.

Tony said...

Yes. That makes sense. I've flushed about 1Kg trhough it so far, and it seems to have cleared now.