TUKI - 16 - Upgrades & Heated chamber prep.

Upgrades

I wanted the printer to be more precise. The roller skate bearings with 3d printed pulleys worked, however they still had some slop and uneven rotation. This would make the printer a bit more inaccurate.

To remedy this I decided to get some F626zz bearings. To break it down these are the specs based on the model number. I took the image from the seller. This is the dimension breakdown. I used two per pulley with a 6mm bolt.
D=6mm B=19mm A=6mm C=22mm

The original rostock style parts were printed in PLA and they were frankly thin. So I decided to design and build my own using the original parts as inspiration, omitting the unnecessary portions, and beefing up other portions.

This is the end result. NOTE: I need to take pics on a white background.

Note on the above image and the bottom tabs. The bottom tabs are there to create a barrier for heat, it should minimize heat loss through the sliders. No adjustment is built into these parts. The side walls are much larger and the whole thing has been printed with abs with a .5mm nozzle, it is exceeding the quality of the original PLA parts I purchased.

This part is the lower belt spreader which will help keep the motion even. It also uses the same kind of bearings and also has side tabs to keep the heat in the chamber. The bearing itself acts as a heat block on the bottom. I will be closing the rest of it off with other 3d printed parts.

These are the parts mounted to the printer. They are very smooth and should allow me to dial in some higher speeds.

Still experimenting with large nozzles.

I am still experimenting with larger nozzles as they truly do speed up print times. The parts do not look as nice as the finer nozzles but that is a sacrifice I am willing to take on larger parts. I enlarged one of my nozzles to 1.25mm or thereabout. The below bracket that will be used to hold the aluminum side plating took less than an hour to print ~48 minutes. The smaller nozzle .5mm can take over 3 hours to do the same job.

Further notes and thoughts.

  • My extruder is what is limiting my speed at this time. 25-30mm/s with the large nozzle before it skips. 55-60mm/s with the .5mm nozzle.

  • I am designing a 1:2 extruder that is belt driven and compact. I need more torque to print at higher volume as speed seems to be a rather poor term here. The current geared setup is good, but it’s noisy as well as underpowered. I would like to hit around 100mm/s with the .5mm nozzle and around 50-60mm/s with the 1.x+mm nozzle.

  • I am in the process of redesigning all the remaining parts from scratch as the original design makes too many compromises in the hope of saving a few grams of plastic. Plastic today is cheap enough to not make compromises like this.

  • Printing in with a large volume nozzle reduces warping significantly.

  • Printing with a large volume nozzle does affect the overall tolerance of parts, but no more than .1mm more than with a smaller unit. My printer holds a +- .1mm tolerance as is. With a 1.25mm nozzle it holds a =- .2mm tolerance, while not great, it is very acceptable for certain parts, I will continue to experiment and get better quality while keeping speed/volume up, the layer height was in the .4 - .5mm range.

  • That is it for now. If you like my work please subscribe to my youtube channel and check here often. I am planning on doing more youtube videos soon. See you soon!

Bruno M.

Engineer, Tinkerer, Technologist, Maker.

New York

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