I finally have a arrived at a part that I’m content with in its precision. All of the recesses are at an equal depth, and will hopefully be consistent enough to run a multi-part milling process.
I really wish that this could have all been done automated. However, after two attempts using a higher speed milling process that returned atrocious results (still working on the reasons why), I reduced the speed to arrive at a part that wasn’t all that bad. From there, I milled the rest in the manual function of the machine. In this mode, the machine operates like a normal 3-axis mill would, accept it uses a digital, ultra-precise stepper motors instead of hand cranked, analog dials. I started with the not to bad, but still uneven part, set a z axis zero at the lowest slot, and equalized all of the slots. I measured x and y set points, and the distances of each slot, and each wall. What I got back was a really nice, but time consuming result.
The last step was to cut the part in half to sandwich the pieces of stock together. To do this in the most accurate way, I attempted to cut it fully down the middle with an 1/8 inch endmill. I realized that the could would travel perpendicular to the clamping forces of the vice, and as the tool cut a slot down the center of the part, compromising it’s structural integrity, there was definitely a possibility that the two halves would cave in into each other, squishing the endmill. This is exactly what happened, despite loosening the vice to next to no squeeze. Even worse, the sudden change in material for the mill to cut sheered the endmill right of the shank (the thick metal it that the cutter is made from).
So, with a broken endmill, and a lot of time sunken into this piece, I hope that it will be a smooth transition to mass production milling.
In other news, me being a senior and all, I head off to senior projects this Friday. By “heading off to,” I mean going home, and learning how to weld the following Monday in Downingtown, with the Challenge program. It’s a skill that I’ve always wanted to learn, and i think it will definitely have applications for the Grazer.