Filament pre-heater

[antiklesys 3]

Hi all,

I was thinking that the curvature of the filament may cause a lot of stress in being fed to the machine, this may be even more noticeable during long prints.

My idea would be to put some sort of pre-heater before the feeder in order to reduce the plastic curvature stress.

In order to do this another brass pipe and aluminium block together with thermocouple and resistor could be used. Set the temperature somewhere around 70-80C and see how it goes.

Do you think this would be a good idea?

[Daid 306]

I'm wondering what problem you are trying to solve really... my filament doesn't seem to have a problem to bend to the weak curve of the bowden tube.

You could however, remove the "stress" of the tube by hanging your extruder drive from a string on the ceiling above your machine... (I still hope to see photos of this silly idea some day)

[antiklesys 3]

Hahah I like the ceiling idea but I'm afraid the issue won't be resolved.

What I'm saying is:

The tube bends from the hot end till the feeder.

The filament is curved in a different way than the tube as it's curved to follow the spool profile.

While the filament is being consumed and the spool "spins" the filament may assume a different curvature which is opposite as the one of the bowden tube.

This would cause additional stress and force required from the feeder motor.

By heating the filament we could remove the mechanical stress generated by the form of the spool which was generated at the time the filament was wound on the spool.

Do you think it would work?

[joergen 2]

Hahah I like the ceiling idea but I'm afraid the issue won't be resolved.

What I'm saying is:

The tube bends from the hot end till the feeder.

The filament is curved in a different way than the tube as it's curved to follow the spool profile.

While the filament is being consumed and the spool "spins" the filament may assume a different curvature which is opposite as the one of the bowden tube.

This would cause additional stress and force required from the feeder motor.

By heating the filament we could remove the mechanical stress generated by the form of the spool which was generated at the time the filament was wound on the spool.

Do you think it would work?

Me thinks you are overthinking an issue that really isn't an issue, and introduce all sorts of other problems.

the filament really has no problem following the bowden, and will internally twist itself to it's original shape. you can see that if your bowden is a bit longer than the stock (i.e. mine) and also when you take the filament out, you'll see how the tooth marks aren't in a straight line, but in a helix.

secondly, heating the filament makes it soft, and it will 'bunch up' in the bowden,and cause more problems, potentially getting stuck in the bowden, or even worse before the hotend. the force necessary to conform the filament to the bowden is orders of magnitude smaller than the force necessary to push it through the hot end.

in my opinion, stay cool.