Hy Forum
as some of you know, i still don’t have a 3D printer, these are theoretically considerations.
Often i read on several pages that the materialflow is a problem.
first of all i think the problem is that the environment is not stable, so a printer case is necessary.
(Making perfect means temperature controll for same conditions every time printing- ABS-, PLA-rolls included)
Mechanically a ‘material reserve loop’ construction in any way, could help. The filament must be stabilized before it enters the ‘printhead area’ .
Connecting the Material from the roll directly to the printhead leaves no room for mechanical tolerances. If it it goes from the roll to the printhead through the air there is no guidance that takes care to the bending characteristics of ABS/PLA. “it breaks accidentally”
A pre-heat-section, that heats and maybe forms the material before it enters the extruder, to counter varying material diameters could also help.
I give the rod to the practitioners…
p.s. sometimes i read the material is not consistent in its mixture, maybe a melting pot above the ‘printhead’?.. have to sleep about this…
Hi HotteKrempel,
it’s beneficial, but not for the material flow - it helps to prevent warping of the printed object.
For PLA, the usable temperature range is low and the warping nearly not existent anyways, so encasing the printer is usually done only for printing ABS or similar materials.
ABS won’t break like that, since it’s quite flexible compared to PLA. PLA usually won’t break while printing, but when left in a strained position (between spool and extruder) over night.
[quote=“HotteKrempel”]A pre-heat-section, that heats and maybe forms the material before it enters the extruder, to counter varying material diameters could also help.
[…] maybe a melting pot above the ‘printhead’?[/quote]
Using solid instead of (hot) liquid material is what makes FDM/FFF such an easy method. You can add a filament extruder before the printer extruder, if you feel up to the task …
Cheers,
kuraasu
Hy Kuraasu
[quote]
“You can add a filament extruder before the printer extruder, if you feel up to the task …”[/quote]
Sounds interesting.
i understand it like this, the filament intruder has to provide a continously flow of material, independently wich ‘material situation’ has been before.
After the filament leaves the filament extruder the various filament tolerances are flattened (additional software control is needed)
This means, bouncing, thickness, temperature… (and mixture fluctuations) ‘are under control’.
(The last point is different to handle, except you mix the filament at this time or a 10kg meltingpot is needed.
(means filamentmixing problems are mixed :-))
If this is done and the filament reaches the head, a solution is needed to controll the printing dots.
Do i understand it right?
Cheers,
Hotte
P.S.: At the end of the day my printer prints with drops of PLA instead of ink drops, but can i produce colours with mixing PLA base colors(CMYK)?
Hi HotteKrempel,
[quote=“HotteKrempel”]the filament intruder has to provide a continously flow of material, independently wich ‘material situation’ has been before.
After the filament leaves the filament extruder the various filament tolerances are flattened (additional software control is needed)[/quote]
it’s not only the software. The filament extrusion process, at least on the home-brew scale, is quite unstable. Using a simple extruder with easy control mechanism is possible, but only because you can check the extruded filament manually before using it in the printer. When you want to feed the extruded filament directly to the printer extruder, you need constant high quality, or in other words: much better control. The usual way to do this is to use contactless diameter measurement, and a sophisticated feedback loop for the drive unit.
Let me put it another way: a company that produces filament will usually have a professional filament extruder for this task. You want to add something to the printer that produces better filament quality compared to said professional filament extruder. I don’t want to keep you from doing it - by all means, go ahead and build this machine. However, you should expect to spend more time, money and material on this machine than a filament company - otherwise you won’t reach the quality that you want.
Nothing new, unfortunately. There’s for example a company in Baden-Württemberg called Arburg; they designed a combined print head which includes a “filament” extruder and a (if I remember correctly) piezo-actuator to control the actual extrusion through the print nozzle. There’s no filament any more, it uses plastic pellets straight away. There’s a patent for this extruder, so details can be found in the usual databases.
You can, but it again adds one order of magnitude (or more) of complexity to the system. Due to the viscosity of the material, you cannot simply print two “dots” at the same spot for color-mixing like an inkjet printer does, but you have to mix the molten filament from multiple sources before the nozzle. The RepRap forum’s German section has some info on projects like this, and there are surely several more people around the world working on such an extruder.
Cheers,
kuraasu
Hy Kuraasu
do you know where a can get a skecthup model of the K8200 ?
Cheers,
Hotte
I just got my K8200 up and running about two weeks ago.
A few days ago, my filament just broke on its own (at night, while the machine was off). I tried to run another job the next day, but I couldn’t get the filament inserted–the feeder was jammed. Not only that, but the extruder stopped extruding material. I also noticed that the filament would snap easily in my hands.
What I did:
- Took the whole roll of filament (only a little filament left on the roll) and put it in the oven at 170 degrees F for about 1/2 hour.
- Unscrewed the extruder head and cleared the filament that was jammed in the teflon cylinder
After the bake out, the filament was much more flexible. When I reassembled and ran a print, the printer worked better even than Day 1!
What it fixed:
- not enough filament coming out of the extruder
- filament breaking
- filament jammed in the extruder
- filament coming out in spurts
- filament not sticking to the heat bed
I live in Houston, and it’s been REALLY humid here recently. It’s amazing what a difference a bake out made in my printing, and it seemed to fix all the frustrations I had during my first two weeks.