parametric mendel z-axis top holder

Before easter I tried to print some presents for my daughter and her cousin.
To make it personal I printed her names on the designated presents.

Text on things comes out better when printing with 0.2 mm slice thickness.
The printed objects looked quite ok, but I was wondering why there was a strange repeating relief on the side of the objects.



This relief results from a little wobbling of the z-axis.
One can only see this when printing with high quality.



After re-centering the z axis the wobbling disappeared for a while.
At the end of the print the z axis was wobbling again.

It was caused by the high printing speed.
When printing very small parts the printer shakes very much.
Because the z axis is only fixed at the bottom, the top has enough space to move out of the center.

A quick look at thingiverse showed I was not the only one having this problem.
Thing no. 4101 was exactly the kind of fixation I was looking for.

The original part is a substitute to one z-axis clamp. Also it didn't have anything to fix the z axis.
Some little changes for perfect fit, a hole for a 608 bearing and the possibility for an upgrade without disassembling the z axis and my mendel was fixed.

The holes were perfect - I even didn't need any screw to fix the bearings.



The wobbling is much better now and the relief is also reduced but still visible.

If anybody also needs this part - you can download the design on thingiverse.

Greetings from the lake of constance
BonsaiBrain

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printable belt with T-profile

An idea during a print - and another universe opens :-)

Sounds like something from the '70s but is from 2011.
This morning I printed another mendel spring. When removing it from the glass printbed it jumped on the x-axis belt.

In the dark corner, where my printer is placed, the soft PLA and the belt looked the same color - even if the one is more light grey and the other one more blue grey.

But this similarity encouraged myself to copy the shape of the belt with soft PLA. OpenSCAD again proofed to be very good for things like that. I made a singel pattern of one tooth and the following gap and copied it 20 times.
The print was amazing - it was strong, it was not springy as expected - it streched not even with force.
The comparison to the original showed the possibilities of soft PLA:



This was the proof of principle. Then I designed an endless belt with 76 teeth - 380 mm length. The best of all: This is not even a quarter of what is printable!
I tested the printed endless belt with a few mendel parts fixed to my desk. I tensioned it with force to test, to see if you can tense it like the belt on the reprap machine.
With this 380 mm belt the gears worked perfect. It was as intended, it was strong.



When testing the limits of the belt it broke with brute force - but it was hard to break it!

The belts in the reprap machines are with steel wire inside to prevent them from stretching. The soft PLA belt is not comparable to these belts. But I was deeply impressed by the stability of the printed belt.

The possibilities are nearly unlimited. I think about printing tires for RC cars or chains for a RC tanks, button covers for electronics, belts for transmissions, springs, etc.

After little initial problems with soft PLA I'm now convinced. Soft PLA brings a lot of fun!

The objects can be downloaded here as usual.

If anybody want's to try this soft PLA - here you can order: www.2printbeta.de

Greetings from the lake of constance

BonsaiBrain


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