…code, cg, electronics, 3d printing…

I was recently approached by one of my co-workers, Diego Teran, if I could 3d print a zbrush sculpt he’d done of a pirate head.  Looking at it, I realized it’d be a perfect candidate to print life-sized on the C-Bot.  I’ve done a number of large format prints now (most recent), and am getting comfortable with letting the C-Bot run for extended periods of time.

To start, I did a number of 100mm high versions of the head, and had a back and forth dialog with Diego having him adjust the pose on the head from straight-on to “chin slightly lifted”, so that the only support needed was under the ear-lobes.  Happy with the tiny version, I fired off the “big head print” Friday night. On Sunday morning, it had finished:

Print Stats:

• 280mm / 11″ tall
• 683g of “Royal Pruple” Gizmodorks PLA, extruded at 225 degs on a woodglue-slurry-coated glass build plate (unheated).  Works out to be $17 in material.
• 31 hours, 32 minutes total print time (lol, the print estimate was 24 hours).
• Sliced in Simplify3D, the .gcode came to 69.6 megs.
• 2 shells, 5% ‘fast hexagon’ infill, no raft, supports under the ears only.
• 90mm/sec print speed.
• .6 mm E3d-v6 Volcano nozzle with 150 micron layer heights.

Overall I’m really happy with the results!

First, a disclaimer:  I modeled neither of these prints.  Everything up until now were simple designs I’ve come up with.  But after showing the work around the office, it piqued the interest of one of our extremely talented modelers, Franco DeRosa.  He had interest in turning his ZBrush sculpts into something physical, and I have interest in trying more challenging prints  Based on that, the below prints were born.  First, the final (painted) results from my Makerbot Replicator, then I’ll cover the process to get there:

Before any of the prints were started, Franco went through the pains of booleaning all the mesh together (since it was originally modeld for visual beauty, not 3d-printing consistency), making sure it was water-tight, and running it though both Meshlab and Netfabb Cloud to make sure of the consistency of the 3d models.

Innsmouth Monster

Franco did an amazing sculpt of the Innsmouth monster, based on the fiction of H.P. Lovecraft.  By the end, this print ended up being the largest one (volume-wise) I’ve done to date (but not longest print time).  Before I printed the large 9″ version, I printed out multiple smaller ones changing the print orientation : First I tried slicing it bottom to top, but this produced many artifacts under his chin I didn’t like.  So I laid it down on its back and printed it that direction, with support material:  While it deferred most of the errors to its back, the front looked great, so I decided to print the large version this way.  Here are 3.5″ examples I printed at varios resolutions to check how it would look:

Left: 3.5" 100 micron, printed back to front. Middle: 200 micron, back to front. Right: 200 micron, bottom to top.

After I figured out the back-to-front print direction was preferable, I set out to print the large versions, at 100 micron.  This process ended up being fraught with problems.  I had multiple “air print” failures on both of the prints, which I think came down to a couple issues:  A.  The orange Makerbot filament was tangled, a lot, on the last 1/3 of the spool.  I didn’t realize this until later, and ended up unspooling the remainder, and respooling it.  After that, no more print problems.  B.  The print didn’t seem to like printing the front flat base of the pedestal.  It would quit (air print) right at that location.  My only guess is that all the fine detail caused the printer to slow down, and somehow jammed the print nozzle(?).  In all cases I was able to catch it and reload the filament (by random luck), but on the print I kept for myself, I ended up having to fill in the errors with putty & sanded it, before painting.

The large 9″ 100 micron versions, in the printer:

The final painted version looks like a pewter monster-bust:

Print Info:

• Material: Makerbot Orange PLA
• Print temperature: 220c
• Slice height: 100 micron
• Print time:  25hr, 15 min
• Print weight: 183g, additional removed support weight : 53g
• Print surface:  Blue Painters Tape (hadn’t yet switched to removable Lexan)
• Print/slice software: Makerware
• Other:  Raft, support material

Hulk

Just like the Innsmouth Monster, Franco did an amazing job on Red Hulk.  And like the monster, there were a variety of “air print” problems on the Hulk.  To condense my findings, it came down to this:  I switched to some gray filament from ToyBuilderLabs (who I’d read a lot of good things about) that Franco had picked up.  And just like the previous orange filament, it had multiple tangles (when I reported to this to ToyBuilderLabs, the responded promptly and offered to replace the spool), but this time, the tangles were immediate (the tangles on the orange didn’t show up until the last 1/3 of the roll).  But I didn’t realize until another air print happened, and I noticed that the spool on the back of the machine was higher than it should be:  the stepstruder had physically lifted the whole spool against the strain of the tangle.  So, I again began to unspool the filament, and hit one tangle so strong it physically broke the line.  Ironically, that was the last tangle in the spool.  Secondly, I replaced the default Replicator delrin plunger with a prototype “grub screw” version (that the Replicator 2 now uses) Makerbot had shipped to me last year (before the Rep2 was released), so I could better control the tension of the filament.  However, even that failed on a print, when the vibration of the process vibrated the grub screw loose.  Frustrated, to fix it, I took an allen wrench, shoved it in the screw, then affixed the allen-wrench to the stepstruder via a rubber band.  50 hours of printing later, it still seems to be a good solution to anchor that thing in place

Final Thoughts