…code, cg, electronics, 3d printing…

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Back on part 23 I added dual 12v 40x10mm cooling fans to the C-Bot: I’m guessing each was around 4cmf, for a total of 8cfm.  About the same cfm as the single 24v 40mm fan on my Replicator 1.  Thing is, the 1mm E3D-v6 Volcano nozzle I’m using is 2.5x as wide, and printing layers 2.5x as thick as the .4mm Mk8 nozzle on my rep1:  So, a huge increase in volume being extruded, but same cooling.  The results was, negligible:  Turning the fans on\off seemed to have no effect on the prints.

So, after much research online, I found a 12v ‘High Speed Delta Cooling Fan‘ on ebay, 40x30mm rated at 24cfm : I bought a pair of those, modeled a modified fan bracket based on what Carl Feniak had made (download the stl’s from Thingiverse), and hooked them up:

Pros:

• Huge amount of cooling, 48cmf combined.  If you point them towards the ground they act like hovercrafts.
• Don’t need any ducting, so much power.

Cons:

• Noise:  They sound like little turbines at full power.  Causes the stinkeye from the Mrs.
• On a torture test, the pressure actually blew a tower off the build platform (it was only anchored by a few mm of footing though).

Other:

• This could be a pro or a con based on how you look at it:  They cool so well, that the nozzle’s heater block couldn’t keep up:  Set at 210 degrees, it would steadily lower under 200 until I shut it down.  I had to use a spare strip of ceramic insulation tape (for a Replicator 2, fits great on the volcano though) to cover the heater block, then surround that with probably four layers of aluminum foil.  Now I can run the fans at 90% and not loose temp.

The Result:

• They definitely cool the pla down quickly, compared to no cooling at all.  Currently my biggest hinderance is that I’m low on filament, and the spools I have left have absorbed moisture, causing popping sounds during print, so I can’t get an accurate read on final quality.
• I can report though that bridging is much better:  I used to have to print three top layers to get a good finish, but I can drop that to two now.

Other things I’ve learned in the process:

• Hairspray : No good as a binder between the PLA and glass build platform:  The volcano prints pop right off within a few layers.  A 50/50 mix of wood glue & water though, like I have been using, works great.  On my rep1 I can use hairspray ok though, I figured it would work here too.
• Temp:  At 30mm/sec, I’ve been printing gray PLA at 210 deg successfully.  Tried lowering the temp to 200, but no dice:  The Bowden notched the filament.

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I wanted to print something a bit, “beefier” on my C-Bot, so I came up with this hexagonal shelf design in Maya:

Sliced in Simplify 3D, took just over five hours to print. Little under 12″ across, 5″ deep, printed in Makergeeks “Soulful Blue” pla.  Used the same 1mm E3D Volcano nozzle with 0.75mm layer heights. Intentionally didn’t print the roof to show off the cool infill. Weighs 630g, 1 shell, 15% ‘fast hexagonal’ infill,  which came out pretty organic looking since the slicer sort of ‘skips’ every other infill layer (as you can see if you inspect the close-up pic) and only prints half of what it should.

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Emboldened by the success on my previous ‘big print‘, I thought I’d go for a ‘really big print’:  Something that would really take up the whole build volume.  In Maya, I quickly modeled up a simple vase, sliced it in Simplify3D, and a few hours later, I had a… really big vase

Print specifics:

• Size:  20″ tall, base diameter of 11″.  Could go an inch larger in each direction, but didn’t want to push it (yet).
• Sliced in Simplify 3D, ‘vase mode’: 1 shell (plus no floor or roof, its a tube)
• Gray PLA
• 500 micron layer height, 1.0mm E3D Volcano nozzle
• 250 deg extruder temp, 50 deg bed
• Print bed:  Glass, slathered with wood-glue/water mix.
• Print speed:  45mm/sec
• Total print time:  3 hours, 9 minutes.  Adding a floor would have definitely pushed the time up.

Learnings:

• I’m happy with the print quality, but I can see where the neck narrows how the filament isn’t being cooled enough (gets slightly lumpier compared to the larger base):  I have a pair of 20cfm fans on order to see if this helps:  My current fans are around 4cfm each, which isn’t nearly enough considering this machine easily pushes out 3x the volume of material compared to my Replicator1, at a higher temp.  And the cooling fan I have on my Rep1 has around 8cfm.
• Once I bolt the printer down to the table it’s on, it should help lessen the vibration that comes from all that moving mass up on top, and get better quality.  On the todo list…
• Even though I have all my stepper voltages tuned in, my Bowden extruder stepper was still getting pretty warm after about an hour, so I pointed a fan at it.  Didn’t want a repeat of before…

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