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Behemoth prints 300mm tall PLA rocket section

This is the second PLA rocket I am building.  The first one flew well and is ready for another flight.  See it here.  The bottom section of this rocket is 300mm  tall.  I will print a 300mm tube and a 70mm nose cone for a total height of 670mm.

The layer alignment on this section is the best I have ever seen on any of the printers I have built.  I was worried about issues surfacing as I printed at higher and higher elevations.   So far I have not had any.  This one was printed at 0.35mm layer height and took about 2 hours to print.

I measured the Z height again and I can print 390mm high.

A challenge for the Behemoth

This spiral lightbulb is always a challenge to print.  It requires good retraction.  As the print gets taller the spirals get pushed around by the print head.  This makes the layer alignment difficult and as a result the surface finish suffers.  That said this is the best one I have printed to date on any of my printers.  The Behemoth is my 4th 3d printer.

I printed this one at 0.2mm layer height sliced with slic3r.  Fill was 0.15 with solid infill threshold area set to 0.  I also enabled cooling with min layer time of 15 seconds and min print speed of 10mm/s.  I printed using silver 1.75mm PLA from Ultimachine at 198C.  I used my floor fan on low to cool as it printed.


Behemoth 3d Printing

I have the Behemoth printing! I printed out the slic3r version of the tornado posted by Sound on thingiverse. I thought this would be a good test for the printer. This isn’t your typical first print. No calibration cubes here. Just right to business. It turned out very well. Layer alignment was excellent. I was a little worried that I might have issues with large objects This is the biggest object I have ever printed.  I’m relieved now and can spend time cleaning up the wiring and install the end stops for x and y.

Print specs:
– 210mm tall
– 0.31mm layer height
– 195 C
– Active cooling from a floor fan on low
– 2 perimeters
– 3 solid layers on bottom, 0 layers on top
– 0% infill density

– build envelope (350mm+ on X, 350mm+ on Y, and 400mm+ on Z)
– 0.35mm steep head nozzle with makergear hot end.

Behemoth update: Too much time to think

Man I wish my parts would get here already. I have too much time to think (over think) my original design. My main concern with the original design is whether the nema 17 (72 oz in) will be able to support a heavy 2.2lb table. I can go to a nema 23 if it does not work but I thought of an alternate design the other day. Instead of the rods moving with the table I would use a more traditional style bed where the rods are fixed and the bed moves on bearings. I can use 2″ aluminum channel to support the rods and I just need to cut some slots on the top to support them.

If anyone has any experience with running a heavy Y slide or nema 23’s let me know. I’d really appreciate some input.

The plan for the fan

I’ve been working on other parts of the Behemoth while waiting for the Y axis parts to arrive. In order to cool the ramps and the steppers I decided to place an 80mm fan at the end of the aluminium tube. It will pull air out of the tube. At the other end of the tube I made a mount for the ramps and the LCD click controller. This cooling arrangement will pull cool air from the ramps side and exhaust the hot air out the fan side.

I think I’ll work on some support legs next.