After wiring everything up and running electronics and motion testing, I am happy with with general design of the corexy system and the hotend mounting.
I ran the machine through some paces last night for several hours without any failures or signs of warping due to heat.
What was extremely disappointing was the Z axis and build platform mounting design – I had my doubts about this during construction and yesterday’s testing confirmed that there is a lack of rigidity in the whole setup. Getting the bed level is proving to be a large challenge given the amount of flex in the design.
I might be doing some more work to try to hack this into testing operation but ultimately it needs to be redesigned.
The heated bed platform is constructed using a standard RepRap heated bed which is bolted flush to an aluminum heat spreader and insulated on the bottom to retain heat. A 12″ x 12″ mirror tile from the hardware store provides a strong flat surface to extrude plastic onto.
It’s heavy. The base heating module weighs in at 970g and then jumps up to about 1620g once the mirror tile is added.
The net result of all that weight on the poorly designed LM10UU clamps and the skinny aluminium channel I used to hold it all up is a lot of flex and it’s very sensitive to vibration.
I plan to make a revised version with stronger bearing clamps as well as stronger support arms. I am seriously considering adding another 10mm thick linear guide rod or two to the design as well to enforce rigidity.
I’ll need to look at seeing what can be done to alleviate some of the weight if possible as well.
Otherwise, everything seems to be working well. There are a few more pieces which need to be added to the filament pushers so that it can actually start feeding plastic into the hotends but I don’t anticipate those will be too hard to design.
Update: I did a bit of disassembly on the build platform base – removing the glass bed guides from the assembly reduces the overall weight by 130g for a total of 1490g. Not really a significant savings overall in terms of performance of the current design. I might still try to press this into service in order to get the filament pushers finished and the printing abilities of this build tested. If I can get it printing some parts it may be easier to use the larger build volume (compared to my little Prusa Mendel i2) to create a new Z axis.
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