Monday, March 22, 2010

MDF Secured

Made a little more progress this weekend on the RepStrap. Attached most of the MDF that will be on the frame, and i think the proof of concept build surface is going to work just fine.

This is the underside of my y-axis/build surface. It is basically just bearing supporting the carriage like a normal 4 wheeled cart. I am using 2 bearings per corner, but this could probably be reduced to 1.

The bearings i used are smaller than the fixit blocks so they were easy to mount. the support for side-to-side tray motion is provided by the slight lip of the fixit block pressed against the square rail, which you can make out in the 1st picture. So far this seems to work, there is very little wiggle in the bed, and it moved freely forward and backward. My hope is once the herringbone rack is printed and installed the tray will be further stabilized, and the tight tolerances will be less important.

Lastly, I managed to install the bottom tray that will mount the z-axis and potentially the stepper for the y-axis. I notched the MDF to allow the gear/pulley drive to clear the threaded rod on the bottom of the machine.

Thursday, March 18, 2010

Initial Assembly

Assembled the base frame last night. The PVC ends seem to be more than up to the task, and everything squared up nicely.

I am playing with square rails on the bottom axis. It should allow for floating trays, and when I have a functional printer I will upgrade to a rack and pinion configuration. My goal is to produce a repstrap that has removable trays that can be fed into and out of the machine automatically.

Auto feed trays open many possible avenues for production. Secondary machines can be added to perform subsequent steps in manufacturing as we produce more complicated designs. Simple examples would be a pick and place, or tray sorter.

This would allow for many different build surfaces quickly interchanged or longer rails clipped onto the ends to allow for longer build surfaces.

Thoughts? I am not very far along yet, so if anyone has concerns please raise them now.

Tuesday, March 16, 2010

Improvised Corner Bracket

I wanted to share my method for creating the corner brackets on my repstrap. It is not anything as clean looking as others have done, but so far it seems to have worked for me. My only concern is potential deformation of the PVC under strain, but so far it seems like it is rigid enough for the job.

It is just a piece of PVC pipe from a local hardware store ~$1.25. I cut it into 1" rings and marked where 3 intersected to create the desired holes for the triangular sides.

Monday, March 15, 2010

First Post

So, i have made some progress on my RepStrap and figured it was time to start a blog to share my progress.

It is based on the Reprap Mendel, but since I lack a functional 3d printer or the funds to purchase everything I have been cutting corners to get something working for as little money as possible.

The construction is based on the same corner blocks that BodgeIt is using on the Bertha, but I am not trying to as faithfully reproduce the Mendel. I hope to make some improvements to the existing Mendel design. Primarily, a y axis tray that is longer and can be fed into and out of the machine.

For electronics I am using an Arduino Mega and the Pololu Stepper Carriers.

I'll post pictures of my progress as appropriate.