Rostock Max finally getting results

I picked up a Rostock Max 3d printer a few weeks back.  I wanted one to gain experience with a bowden hot end setup and a delta arm configuration.  The build was pretty straight forward for me as I have built many 3d printers and even designed my own.  I found the stock power supply did not provide enough power for me to heat the bed and maintain a constant temp on the hot end.  I replaced it with a quality Corsair 600W supply that has a single 12V rail.  Other than this and the fans I added the rest of the RMax is stock.  If I had to pick one thing about the build that I did not like it would be the fitting of the arms to the aluminum u-joints.  This required a lot of sanding, scraping and countless refits to get them to move with minimal friction.

My first prints turned out a lot worse than I was hoping for.  However I was expecting more tuning than usual as I had read that Bowdens and delta’s required it to make decent prints.  I was starting with PLA instead of ABS so it was even harder to tune the bowden setup.  I needed to add a fan to cool the peek part of the hotend to stop the PLA from oozing up and causing a jam.  I spent a lot of time on PLA prints and tuning but could just not get a result I was happy with.  I decided to switch to ABS as it was supposed to be easier with the Rmax and its Bowden setup.  Well I spent an equally frustrating amount of time trying to tweak the settings and not getting acceptable results.  I was basing my tuning on the nozzle size of 0.5mm.  In order to be sure I confirmed with John at SeeMeCNC that mine was indeed shipped with a 0.5mm nozzle.

Well it turns out my 0.5mm nozzle was not actually a 0.5mm nozzle. It was most likely a 0.7mm or larger.  I figured out the nozzle wasn’t 0.5mm by extruding slowly into open air and waiting for it too cool then measuring the diameter. I was between 0.9 and 1mm in diameter.  Normally a 0.5mm nozzle would measure about 0.6mm or so.

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0.7mm nozzle on the left and 0.??? on the right

 

 

 

DSC00860I was unable to print infill without making a mushy mess. (rmax on right with 0.5mm nozzle settings and Behemoth on right with proper infill extrusion width)

The mush was caused because I was using 0.5mm nozzle settings for extrusion and infill width in KISS. If you try and print infill with a width less than the nozzle diameter it won’t work. It makes sense why if you think about it. How can you possibly extrude infill at a diameter less than the nozzle diameter keeping in mind that infill typically bridges itself in open air. Mine would just fall apart as the flow calculation was wrong.
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Once I dialed in the correct extrusion width into KISS the results were amazing.  Infill was perfectly connected and layered.  No more mushy mess!

 

 

 

I’d really like to be printing with a 0.5mm nozzle but I’ll have to wait until SeeMeCNC sends a replacement. For now I put on the 0.35mm nozzle. In this video you can see me printing the golvend tornado. I sliced it with KISS slicer at 0.25mm layer height. Printing at 20mm/s with feedrate at 150% and temp set to 230.

 

 

 

More pics using PLA

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3D Printed Planetary Gear Bearing

I found this on thingiverse the other day.  I wanted to see how it would print on the Behemoth.  The only way it can be made is on a 3d printer.  It can’t be assembled or dissambled (at least without breaking it).  It printed great and it was very easy to break the gears free and start rotating it.  I ran it in a drill a little bit and it loosened up very nicely.  I’m not sure how long they will last but I intend to use them in the smaller 1 pound spools.

You can see the results here

Behemoth 330 x 360mm print bed

I picked up a piece of 41cm x 35cm x 3mm float glass at the local glass shop. It weighs in at a hefty 1029grams. I’m printing a 300x300mm square picture frame just as a test of the large surface area. The glass does sag a bit in the center but that can be easily remedied with some supports underneath. So far it doesn’t seem to effect the print.

I think I’ll work on a system to make these print beds easier to interchange. I’d like to be able to put the smaller bed back on there when I need heat on the bed.

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:
- http://www.thingiverse.com/thing:33344
- 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

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