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.




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.

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