Motorcycles, tools, and garages! A little bit of everything mechanical and technical.

Wednesday, March 18, 2015

Mendelmax 2.0 / enable Raptor Hand

Playing around again. Downloaded the Raptor hand from Thingiverse. Got most of the parts printed. I *really* need to get a .5 nozzle, it's taking forever. I think I'll have about 13 hours of print time into all the parts by the time I'm done, but I did make a couple of extra fingers and they are definitely NOT an "easy" print.

I tried doing the entire thing in one set but I had some bed adhesion issues. It was going to take waaayyy too long anyways. The first piece I printed was the palm.

Came out pretty nice. I'm still getting some warping on overhangs but everything else seems decent enough. Still not sure why I'm printing at 174 deg. C though (PLA). Pulled my extruder apart to check the thermistor but nothing seems out of place.

Few more pics of the palm.

Worst of the warping.  Maybe Mr. Flood can chime in and give me some more ideas of what to try here?

I thought this was pretty impressive though. Haven't done much with anything that has a serious overhang but it turned out nice.

And the gauntlet. Notice the two slots where it bridged. A little bit of goo but really it cleaned up nice.

Sure is a teeeeeny little hand. Makes me kinda sad- Don't know what I'd do if I lost the use of one of mine (knock on wood)...


Frankie Flood said...

A couple of possible things might help:
if printing in PLA then utilize a glue stick for bed adhesion. I just "draw" all over the surface and this helps adhere the print to the bed. Using this on a sheet of glass helps. Blue Painters tape also works wonders with PLA (then skip the glue stick). Just make sure you place nice flat strips of blue tape to your glass bed. 60-90 degrees on the bed temp should work if using a heated bed and PLA.

If printing in ABS use 3M Kapton heat resistant tape and place the tape on a sheet of smooth glass (1/8" from the hardware store) and set this on the aluminum bed and clamp it with black paper clip/clamps. Heat the bed to between 110 and 90 degrees when printing.

You can use borosilicate plate glass but honestly the regular hardware glass works fine as long as you don't "shock" the build plate from cooling and heating too fast.

Aquanet hairspray over the Kapton tape will work wonders with adhesion of ABS prints. Just mist a thin layer on before printing. You'll have to pry the print off the caption tape when finished.

I like to extrude:
ABS at 230 degrees
PLA at 185 degrees (if not using a fan to cool the print)

Also selecting to use a "Raft" or "Brim" in Slic3r when printing in ABS helps keep the part down and from lifting. A nice Raft can help adhere the print to prints with small contact area.

ABS warps bad so I usually try to print in a pretty stable location with no drafts or moving air. I've heard of people using a cardboard box over the printer to help hold the heat from extruder and bed inside to stabilize the print conditions. Stratasys printers actually use a heated build chamber for this reason 9 they own all patents on this).

dorkpunch said...

Sorry, my mistake... I'm not really having adhesion issues- on one of the attempts I just had my nozzle too high for the first layer. Didn't stick well.

My question was on the warping on overhangs. My theory is that as the nozzle goes out over the overhang and comes back, the filament is being laid down on a pretty thin base. The loop back is pulling the filament tighter, pulling the whole overhang up a bit more on every pass. Who knows though, I could be clear out in left field.