Hi ! As result of the previous post, I performed an upgrade of the Z Nut holders, the parts are stiff not any problem there.

I was curious about the shape of the linear infill, so I cut the part and actually it is mostly a waste of material for any structural part.

However there was still a bit too much play but this time it was coming from the expensive brass nuts.
So I bought the IGUS ones and they have an acceptable play. Of course they do not have the same size, so another minor iteration on the design and 16 hours of additional print (with a bit of warping).

I checked also the Z stepper motor support and I was not happy too, it is a potential source of flexing due to length of the screw and the weight of the heatbed. I was looking for the weakest point and it was not so difficult to break it: so time to redesign and make a biffy part for this.

The result of the failure test, the dense linear infill is too weak, and the surface of the pillar is too small too.

I slightly increase the surface of the pillar part and I added two horizontal places to put additional screws.

I checked for any design alternative, but it is very tight and there is not so much choice on the anchor points for the support. In general 3D printed stepper motor supports are attached on the side of something that provides the needed strength, but it is not my case. Also, I want to keep as small as possible any offset between the linear rods and the screw and the original design was good for this parameter.
The part is using a strong hex infill at 30%, you can see here on this failed part (puking nozzle), the zigzag things are the supports. The strong hex infill has wall of 0.8mm and 1.6mm that are not rotated like it is done for a line infill, this slightly improves the strength of the part.

It takes 17hours to print for each, its weight is about 160 grams, for the scale the stepper motor is 48mm long.

Lesson learned

Sometimes you pay a lot for not good enough parts, wasting time and resources. I strongly undersized many of the designed parts on the Z axis and I am paying few times those bad design choices. It is part of the learning process and 3D printing allows to iterate quickly even if it takes several hours to print some parts.

Result and forthcoming part

I am waiting the end of the print of the other big boy to perform the assembly and check if some else is wrong ;-)
I have printed new lighter and stronger parts for the XY gantry to test.

Previous Parts

• https://steemit.com/technology/@boucaron/why-building-yet-another-3d-printer-part-1
• https://steemit.com/technology/@boucaron/why-building-yet-another-3d-printer-part-2
• https://steemit.com/technology/@boucaron/why-building-yet-another-3d-printer-part-3
• https://steemit.com/technology/@boucaron/why-building-yet-another-3d-printer-part-4
• https://steemit.com/technology/@boucaron/the-hotend-head-3dprinter-part-5
• https://steemit.com/technology/@boucaron/xy-stepper-motor-supports-3dprinter-part-6
• https://steemit.com/technology/@boucaron/z-stepper-motor-supports-3dprinter-part-7
  -https://steemit.com/technology/@boucaron/test-assembly-3d-printer-part-8
  -https://steemit.com/technology/@boucaron/lcd-support-3d-printer-part-9
• https://steemit.com/technology/@boucaron/x-y-optical-end-stops-3d-printer-part-10
• https://steemit.com/technology/@boucaron/small-heat-bed-assembly-3d-printer-part-11
• https://steemit.com/technology/@boucaron/power-supply-unit-holder-3d-printer-part-12
• https://steemit.com/technology/@boucaron/cable-management-for-the-hot-end-head-3d-printer-part-13
• https://steemit.com/technology/@boucaron/firmware-first-heat-first-moves-xy-gantry-alignment-3d-printer-part-14
• https://steemit.com/printing3d/@boucaron/induction-probe-on-the-z-axis-aluminium-brackets-3d-printer-part-15
• https://steemit.com/printing3d/@boucaron/failure-with-adjustment-tolerance-and-the-need-to-re-designing-few-parts-3d-printer-part-16
• https://steemit.com/printing3d/@boucaron/tb6600-stepper-drivers-support-quick-test-of-drivers-3d-printer-part-17
• https://steemit.com/printing3d/@boucaron/design-improvements-on-the-gantry
• https://steemit.com/printing3d/@boucaron/changes-on-the-bed-support-3d-printer-part-19