Sunday, 26 May 2013

MGS update

The link on the main reprap forum page http://reprap.org/wiki/Prusa_i3_Build_Manual clearly point to https://github.com/alexrj/Prusa3/tree/i3-unterwelt for MGS plastic parts.

This is in error!

It should be https://github.com/Joaz/machine_parts/tree/master/mgs_prusa

This also has the source and is for 30mm holes, perfect for I3

I have updated the link on the wiki

I now need to reprint... 

Tuesday, 14 May 2013

I3 Metal Gear System Extruder

I've been wondering for a while what extruder to put on my I3

I decided to try the Metal Gear System Extruder

I ordered a kit online from http://www.reprapsource.com/en/show/6770 

The web site put a scary amount of shipping cost to New Zealand, so I contacted the site owner on #reprap and he was happy to send it via normal post (3.45 EUR) , with the understanding there was no insurance or tracking. I went with this option.

This arrived!






Here are all the parts, as pictured on the site.


Plus some plastics I prepared earlier

And assembled.

It is reasonably easy to assemble but also the main shaft is a bit fiddly

Now the issues:

The mount is for a X carriage with 24mm hole spacing, the standard Prusa I3 has hole spacings of 30mm. They do provide stl files for their own X carriage, but the two lm8uu's and single lm8uu where swapped over. I didn't want to completely rebuild my X axis just to move one lm8uu.

So I made a bigger mount.  http://www.thingiverse.com/thing:84228
This is still listed as experimental, as I haven’t actually mounted it on the I3 yet.
The new hole isn't on the extruder, I used the mount as a drill guide and drilled a new hole. 

If I have assembled it correctly. I am one m3 nut short and one m3 bolt short.

I'm also left with four left over parts, which I can't find a use for.


This is probably for a different extruder mounting system

I'm fairly sure I have it assembled correctly, now I'm going to pull it apart again,
The main drive gear on the stepper only over laps the large gear by about 1 mm, I think it should have more contact, so I am going to move it a fraction.



Saturday, 4 May 2013

4pi mount for I3

I've been slowly building up my own Prusa I3 Single Sheet Frame

The first challenge for me was that I wished to use my 4pi controller. This is not one of boards that there are mount holes for. In fact its to wide to mount flat on the X axis on the Aluminium directly without large overhangs.

The first step I needed the measurements from the 4pi board.  I started by just measuring the main PCB, While doing this I noticed that the various connectors are somewhat unevenly spaced, so I was going to have to measure this too. I quickly came to the conclusion that this was going to be a lot of work to measure everything.

I then had an Idea. The Eagle brd file is available, and the X and Y position data should be in the file somewhere.  I took a look at the .brd file, it seems to be well structured XML I have no experience with programming and XML, but a friend "Finch" Showed me how to process XML files in Python. The resulting components file was edited by hand to add Z axis data. The resulting Board file was modified slightly to move one component and remove a 6pin connector that isn't on he board.

The result is the following, very accurate 4pi model




This can be found here

So now I have a nice model to work from. I started to work on a way to mount this on my I3.  I wanted a protective box, but not enclosed so I can watch the LED's. With the model it was very easy to make a box for the 4pi and cut out all the required connecter holes.



I added a small Lip to the box so the box wouldn’t rotate when mounted on the mount arms.

The mount proved to be trickery to make that the box, mostly because I was being fancy and added rounded corners.



The mount is "RAMPS" sized, as it is attached to the ramps holes in the plate.

The final parts mounted on the machine


Files are available here
Currently its still "Experimental" as I need to tweak the sizes of the m2 nut traps.