#MakiBox A6 Pellet Drive - Hot End Plastic Action
2021-09-04 20:35 by Jonathan Buford (comments: 0)
#MakiBox A6 Pellet Drive - Hot End Plastic Action
Now that we have a final direction on the pellet drive, we are systematically starting with the final design process for it. Instead of starting with the drive itself, we are working with a proposed hot end design that would accomodate a single pellet stream to test our existing heater layout compatibility.
We manually pressed the pellets into the hot end to get the output, and you can see the resulting filament (1.0mm diameter) is very smooth and consistent. In fact, it is so consistent that the measured tolerance is +/- 0.01mm deviation. For reference, commercially available filament has a typical tolerance of +/-0.05mm typically, but can wander beyond that.
The temperature during extrusion did not dip, but we will need to adjust the settings for the feedback for controlling the temperature to be more in line with our system for best performace.
So, heating works, extrusion works, next we will build a drive and a hot end output.
Stay tuned til next update.
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Comment
My understanding is that the device above will be connected to a teflon-lined tube that goes to the print head.
I think you'll want to test that you don't get any jams when the extruder is allowed to cool and then restarted. I'm worried that when restarted, the filament might develop a break in it, and the two sides of the break might overlap and jam.
The filament will be running through a cool metal tube prior to the Teflon tube that will act as a die for final sizing and would prevent this from being an issue.
As far as the drive goes, have you attempted larger blades on the auger? I noticed in the earlier updates, you guys were using something with very small blades.
of different options. We will be trying out some different methods for
this new barrel and see what works best, since it is a pretty
different problem to solve. Part of it is getting the material into a
small column and the other is putting enough force behind it to keep
it moving.
Shatter the pellet as very small and supply to the head's hot nozzle.
in Addtional for the shatter method also may needed melt the pellet can be shattered as easily.
It may will be a good way and easy to supply to head as more smoothly without a zam.
1. Melt the pellet such can be easy to crumble and Shatter the pellet as more very small.
2. Push the sand of pellet to the head.
3. Melt the sand of pellet at the hot end to printing.
Sorry for my bad english jon. just it's my idea. ^__^ Hope you may found more good way. Cheer up! jon.
here is no way to modify my comment... T__T sad....
I hope it getting cold when it being pressured.
actually grind make a loud noise. anyone would be do not want it.
so any guys knowing that plastic can't be crumble when it heated. ^__^;
just It a way to make a weakness can be crumble.
Yes... it may getting more difficult a way to solve... sorry ignore me.
I have been using printrbot for 3 weeks now. just to let you in on some details. printrbot is very well done but has allot of pitfalls, so before you get any good results allot of testing and tuninig is required. it prints ABS at 0.1mm but:
- lots of x y z speed tuning required
- the printerbed needs to be prepared with special tape (that is the most anoying aspect)
- very cumbersome filament handling (the role of filament is large)
- external power source (big pc powersource block extra on the table with open cables...very ugly)
can a print that is not used any more be transformed back to pellets and recycled for other prints? (this is simply cool if this works)
also did you concider the printer bed to be ready and no tape or any preparation is requried prior to printing?
any way :-) looking at our design is very refreshing looks so professional, i can't wait to get one :-)
For our unicorn plot, there was no calibration done to the machine. We did have to configure it properly to get the scale correct and we tested various speeds, but those will be known quantities for our end users. Actually, it will be just load and print, from what it looks like, with just the table calibration and leveling being the only calibration needed.
We do have an external power supply, basically similar to an XBox 360 or large laptop supply. But, this plugs into the side of the case using a nice looking socket, and the supply itself is just one wire to the wall and one to the printer.
Yes, bad prints could potentially be recycled by turning them into small pieces that are the right size for the pellet drive. This is something we will work on or someone will come up with a good solution in the community.
Print bed and tape, etc. We will need users to apply Kapton tape to print on. This lasts for many prints and currently gives the best output. We will look at other potential print bed materials in the future, but this is currently the best solution.
Rather than tape, it uses plastic bases which can be removed from the printer and easily swapped over. This approach works well (and the bases can be bent to snap the printed part off) but obviously the bases require a significant amount of work to manufacture - they won't be cheap enough to use with a Makibox.
Perhaps one option would be to have a removable aluminium sheet that acts as the printing base. I would imagine that even if it can't be bent to remove the part, it could be dropped into the freezer and the different rates of thermal contraction would do the job nicely.
The key question is whether the base will be reusable, or just so cheap that you can discard it after a single print. For example, if you could clamp down a piece of paper then that might provide an adequate printing surface, and you'd just stick a new one in each time. Alternatively, if you had something like a flexible steel surface (eg. like a conveyor belt, so it can be flexed easily with no permanent damage) then that could be quite expensive to produce but reusable for hundreds of prints.
Anyway, I'm sure you'll come up with something. Starting with tape sounds like a fine option to me, and then alternatives can be offered as upgrade options as they're developed. No point trying to solve every single problem facing 3D printers in the very first Makibox design.