3D Printer Project: Fabrication #2

Once I completed cutting the outer shapes of the plates, I went ahead and started putting together the outer tube frame so that I could test fit the overall structure. This gave me some encouragement, since it began to look like an actual printer (albeit briefly):

So having milled the outer shape of the core plates, the next step was to cut the precision mating points for the plates and to drill the numerous holes in the plates. Because of the number of hole sizes, combined with the alignment pin holes (which required drilling, boring and reaming), I ended up with quite a number of tools just for this step:

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As with the outer shape of the plate, I had to rotate the plate four times to cut the overall shape.  The most critical step in this task was being very careful about the tool height for the mill I used to cut the ways, since variation between runs would cause steps in the milled paths.  I did have to run one section twice due to a shallow cut caused by a bit of flex.  I repositioned the supports, ran it again and it all worked perfectly:

I decided at this point to go ahead and assemble the full X/Y assembly next before finishing the other plate. To fabricate the blocks and mounting brackets I chose to 3D print these first prototypes.  I'm able to print the entire set of X/Y assembly blocks overnight, try it out, make adjustments and then print it again.  I estimate each piece cost less than $1 to print.  I had to work a few alignment bugs out with each piece, but most of them were OK by the second print.  At this point I have the overall structure of the X/Y assembly completely fabricated and mounted:

My initial sense moving it around is that as expected it is an extremely rigid, smooth design. I still strongly believe that providing a continuous support of the side rails will have a huge positive impact on the dynamic behavior of the system. 

This weekend I will be mounting the pulleys and belts and adjusting the overall belt path. I've already determined a slight error in the belt path due to a change in the pulley diameters.  I can correct that by slightly modifying the Y axis end blocks. I am also going to start working on the Z axis assembly.

More to come!



Posted on February 6, 2015 and filed under CNC Machining, 3D Printers, Projects.