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bravach repstrap

Posted by bravach 
bravach repstrap
January 20, 2013 04:24AM
Hello everyone,

I'm fairly new to the 3D printing community but I started one month ago to develop my own repstrap inspired by the eventorbot and other printer from the wiki.
It is now complete in its 1.0 version and able to print at slow speed (30 mm/s).
I've some more ideas and material to upgrade it in a better, more rigid version (with precision linear axis) which would allow faster printing speed.

In the meantime, here are some pictures of the printer in its current form :

And also a test part made before (on the right) and after (on the left) tuning parameters in kisslicer :

Re: bravach repstrap
February 16, 2013 10:51AM
Nice work!

I was thinking of building an Eventorbot, but some emergency expenses blew the budget for it. I also have tons of dead printer parts and I think that after looking at what you did it is going to be the best route to follow. This way I won't deprive myself from a 3D printer and the only expense will be in the form of time and work (and learn more about them in the process). The unit built will always be useful and help make the parts for future units.

I see your frame uses some custom parts I assume you cut/machined yourself. Is it correct to think that those dimensions were taken from the size of rods you had available for your build? I can't tell from the angle of the pictures (perhaps a dumb question but I'm new at this)
Re: bravach repstrap
February 20, 2013 03:00AM
I've done some improvements since I made this first version like reinforcing the Z carriage with 4 linear bearing instead of 2 (to reduce wobble and add rigidity ) and also I changed the shitty steel rod with some precision ground stainless steel rod.
I printed a new part for the extruder with a filament guide to keep the filament centered (and so, keep a steady feeding).

All parts are custom made with my milling machine apart from the J-head and the printed extruder I buyed on e-bay (and also the "vitamins" like bearings, belts and aluminium pulley). I dimensionned them from the parts selection I made and from the steel/aluminium raw material stock I could find at my local dealer. I could have done a better job by going to a professionnal raw material vendor but they only sell in big quantities.

The current big mistake is on the X axis where the hollow profile doesn't put enough constraint on the steel rod. But hey, with my first prototype being now functionnal, I can print better parts to improve it.
Re: bravach repstrap
March 26, 2013 10:18PM
i was designing a printer on a similar concept of the cantilevered y axis... i would like to know is how much does the y axis flex during its movement? is it better of worse than a standard prusa?
Re: bravach repstrap
March 27, 2013 04:00AM
Do you mean on the X-axis ? (My Y-axis is the one with the extruder so it is not cantilevered and so rigid that even by pushing on it like hell it would not show deformation to the naked eye. This, because it is made of plain steel.)

The X-axis (the one with the bed) flexes some tenth of millimeters from the side to the center of the beam but only because the rod aren't constrained enough by the hollow aluminium profiles on the side. To overcome this, I adjust the bed level around the center so the error is really low but it means that my parts can't be too large right now to keep the linearization.
To improve this, I will switch to plain steel or aluminium fittings.

I can't tell you if it is better or worse than a prusa since I have never seen one.
Re: bravach repstrap
March 31, 2013 03:27PM
Here are some new pics of my repstrap with its improvements.

I changed the fixation of the belt on the Y axis and the idler of the extruder (the new piece has a guide for the filament)

Here is the reinforcement of the Z-axis carriage with 4 linear bearings to add rigidity.

I changed the elastic aluminium coupler for a "cardan" printed one which is giving me better results in suppressing the wobble.

Re: bravach repstrap
September 01, 2013 02:38PM
I'm back with some improvements on the printer :

As the new bed is heavier, I had to design and machine an upgrade to ensure a relieve of the deformation under load :

I also bought an electronic level for machining complex part on another project but it is great to ensure the leveling of the bed :

And the first part after the modifications, a wade main gear :

Edited 1 time(s). Last edit at 09/01/2013 02:42PM by bravach.
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