Z wobble taken care of, and nice fat 0.8mm nozzle attached.

3D Printing
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1

Z wobble taken care of, and nice fat 0.8mm nozzle attached.

Core-T is ready for bulk part production.

Total build size: 250x200x250mm

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2

Some final thoughts on Core-T:

Advantages:

  • Part count reduction over core-xy
    – (only two linear bearings on Y, plastic-on-rod bearing for X)

  • No critical alignments required, so long as the bed is flat and Z is 90 degrees to the X/Y plane.

  • arm can be lifted up
    – this allows for hotbed inspection, prevents head crashes onto the bed, and “travel” over globbed up plastic

  • single open belt

  • 9 idler bearings

Disadvantages:

  • can’t go as fast as Core XY designs due to ringing concerns

  • requires a Bowden extruder (or very lightweight extruder) to reduce ringing

  • requires Z probe for bed leveling

  • 9 idler bearings :neutral_face:

  • less than 7 hour total run time - no data on wear patterns of the rod-on-rod and plastic-on-rod bearing

Takeaways for other projects:

  • investigate plastic-on-rod bearings for standard core-xy, for designs where there is no rotational torque on the hotbed carriage

  • bed levelling is very good in modern firmwares - this can be used to reduce part count, if considered carefully.

  • Melanine covered MDF is a useful material for making printers - its dimensionally stable, and much cheaper than aluminum extrusions.

  • thick (3mm) glass plates make good cantelivered Z beds for PLA printing with glue stick.

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I love this

4

@Jason_McMullan Do you think the ringing problems can be solved by adding linear guides to the other side of the arm?

5

@Thomas_Balu_Walter

The wobble is due to my super crappy cantilevered platform that flops up and down by nearly 1mm at the far edge

I need to make a much stiffer mount

6

I was thinking about the “can’t go as fast as Core XY designs due to ringing concerns” and “requires a Bowden extruder (or very lightweight extruder) to reduce ringing” disadvantages you mentioned. My idea is to build this using V-Slot extrusions, but I am not sure about the mechanical disadvantages compared to other Core-XY implementations with two belts.

7

This was totally an experiment in “what can I make with the scraps laying around my shop”, but i find that the arm based motion control is quite usable, so long as the far end is supported.

Torque on the arm is primarily on the slide, not the far end, and so long as your infill isn’t aligned to Y, I rarely see ringing in X/Y at the 30mm/s speeds I run.

A stiffer arm may help for higher speeds, as would a V slot rest instead of just floating on a rod.