EMC repstrap from old printers and scanners

Now that my extruder is reliable, my DIY mill is officially an EMC repstrap :


The extruder is supplied trough a tube to a spool dispenser in order to avoid parasite forces caused by the extruder pulling the filament.
Some successful prints :
cylindre.JPG
The tape I print on is tesa N°4657 I borrowed from work, the PLA stick well to it but not too much, I can pull the printed part out without damaging it or the tape.

skin.JPG
left : resolution = 0.3mm
right : skin enabled with a division of 3, so external resolution = 0,1mm
Printed at 30mm/s

STL from [www.thingiverse.com]
overhang.JPG
Max overhang = 30° with this setting.

Quote

The extruder is supplied trough a tube to a spool dispenser in order to avoid parasite forces caused by the extruder pulling the filament.

Good idea, what sort of tubing did you use?

[www.hydraraptor.blogspot.com]

It was the insulation of a cable, not an ethernet cable but about the same diameter

Support structure test : support.JPG
After cleaning : support_2.JPG
Not that bad.
I set the support flow rate ratio to 0.5 (less didn't work well)
I didn't found a box to change the support structure angle in skeinforge, so I had to rotate the part 45° and change the infill direction to get that result.

vertical resolution test :
resolution_test.JPG
From left to right : 0.3mm, 0.2mm ant 0.1mm



Edited 1 time(s). Last edit at 11/19/2011 05:54AM by Petrus.

Would you be able to give reference of the blue attachments for the cable?
Thanks

Sorry, it was also salvaged so I don't know the reference, but they are not necessary in this configuration.

Cooling improvement :
duct_2.JPG
There is now only one powerful 40mm fan that cools the cold end and the print.
I found out the ventilation is very important for printing overhangs with 0.1mm layers.
duct.JPG
The duct is drown with google sketchup and print in PLA with 0.3mm layers.
The wall at the right is wasted material like the support structure. I printed it to absorb the inertia of the extruder between the printing of support structures at half the flow rate and the rest of the print.

Some test prints after this modification :
test_support.JPG
test_support_2.JPG
layer height : 0.1mm
Support structure : Cross hatch enabled, flow ratio : 0.5

test_support_3.JPG
After removal of the support structure and cleaning with a file :

I lighten the Y axis using 5mm MDF instead of the 8mm Plexiglas LCD screen light diffuser and replacing the glass with a failed PCB board, it's flat enough for small prints.
With theses modifications, I am able to multiply the acceleration and speed by 2.

I've also modified the raft plugin in skeinforge to add a "Support Feed Rate over Operating Feed Rate" setting.
my extruder tends to clog when extruding too slowly, with this modification I can print light, easily removable support structures that are printed faster and doesn't clog my extruder.

raft.py
If you want to use it it's at your own risk, it's the first time I modified a python script, I made it working using copy/paste and a lot of trial & error, I probably missed to do something.

Petrus, your results look amazing!!!

Would you be able to show better how you use the fan to cool down? (especially if that's the trick!) Is the fan blowing to the metal parts of the extruder or to the deposited material?

Thanks for sharing this.
Syncra

The fan cools down the cold end of the extruder and the printed part.
I made a picture from the part view :
duct_3.JPG
The hot end is insulated by the inner section of the duct, so the air only cools the printed part.

I noticed that active cooling is important when printing overhangs but not much for other stuff, for example the 3 domes I printed to test resolution are printed with the previous version of the extruder where the cooling was quite inefficient:
extruder_V2

I noticed it when I printer this sphere :
sphere_fail.JPG
The good bottom side was where the fan was, so I made a duct to cool all the sides of the part.

A time-lapse of my last print :
[www.youtube.com]

I made a small heated bed for printing with ABS :
heated_bed.JPG
It's a simple circuit board engraved by the printer with the spindle tool. I have to make an other one, The resistance is too high so it takes too long to heat up but I can get 100°C if I supply it with 12V continuously.
With this heated bed, I printed some clips to fix the new lighting system (fluorecent tubes from scanners):
clips.JPG
The PLA clips I made first were too fragile.

[edit]
Here is the new lighting system made from scanners fluorescent tubes :
light.JPG



Edited 1 time(s). Last edit at 12/30/2011 12:08PM by Petrus.

Hey,
very cool. Where can I find the EMC RepStrap Software, which can control the Extruder? Please give me a advice.
Thank you.

regards

I use the standard EMC2 software, you can download it on [www.linuxcnc.org]
The extruder stepper motor is controlled by the 4th axis (A axis) on EMC2.
Extruder and bed temperatures are controlled by a dedicated device I made : [forums.reprap.org]

Oh, and I made new time-lapses :
[youtu.be]
[youtu.be]
[youtu.be]



Edited 1 time(s). Last edit at 02/25/2012 09:41AM by Petrus.