Wednesday, September 25, 2013

Testing Layer heights with Owls

Now that I have the printer working well, I wanted to test out how intricate I could make my prints. I found these owl earrings and printed them at 10% and 20% size. My layer height was 0.1mm and the prints took 15 minutes for the small guy and 2 hours for the lager one.

It is truly remarkable how well that they came out. The smaller owl is sitting on a US dime which is 17.9 mm in diameter! These are hard to see in real life and it was not trivial to even get my SLR camera to properly focus on the objects to take a picture.

A key development that made this possible was using hairspray to get the first layer to stick. I have tried many different methods of getting it to stick:

For PLA:
1) Blue painters tape- Does an average job especially without the use of a heated bed.

2) Heated glass- I wasn't able to get this to work on my Mendel Max but I did have luck with my Prusa previously. It could be that the Mendel Max uses a different type of heat resistant glass, similar to pyrex, which requires more playing around with the bed temperature to get it right.

3) Aquanet works really well. I spray it when the bed is cold (important to potentially prevent cracking) and warm the bed up to 70 C. I am sure to check with my extruder height that I can fit 1 piece of paper between the nozzle and the bed. Then, I can just print it and forget it!

In the US the hair spray can looks like this purple one:
The only issue I have now is that the parts almost stick too much so there probably is some fine tuning of the bed temperature that could ease that issue.

Slic3r Settings for a 0.4mm jhead nozzle:
Layer height: 0.1 mm
First layer height: 0.32 mm - Important! I had troubles sticking if this first layer was too short
Fill Density: 0.3 mm
Fill Pattern: rectilinear

Perimeters: 30 mm/s
Small Perimeters: 30 mm/s
External: 100%
Infill: 80 mm/s
Solid Infill: 50 mm/s
Top Solid Infill: 30 mm/s 
Support: 30 mm/s
Bridges: 10 mm/s
Gap Fill: 50 mm/2
Travel: 150 mm/s
First Layer Speed: 25%

Loops: 1
Distance from object: 15 mm
Brim: ~a few mm if needed on a large part

185 C first layer, 180 C after 
Bed: 70 C
Fan: 35 to as high as your ears can take! Disable it for the first layer

Start Gcode:

M301 P21.47 I2.24 D51.36 - set this based on your printer with PID tuning!
G92 E0
G1 E3 F1200
G1 E2 F1200
G92 E0

End Gcode:
G1 X12.0 F4000
G1 Y170 F4000
M104 S0
M140 S0 

No comments:

Post a Comment