Grazer – Taking Form — Lukas

A part being milled.

CNC milling.

It’s been a while since I wrote my last blog post, and a lot has happened since then. It’s been a time of relative accomplishment, amidst a trend of thinking, grinding, settling, and redoing.

Many of the ideas I have now for the final Grazer will probably change by the time I’m done with it. That’s one verdict that I’m pretty sure of: that this project will not be finished by the end of this school year. This is certainly a sad conclusion, but also a very necessary one. Rushing the Grazer might lead to a shabby looking hodgepodge of unfilled aluminum, struggling to turn it’s legs. Allowing myself to recognize that I do have another year of high school to complete Grazer (just about the only reason I’m glad that I’m still a junior) will take a lot of stress off of the decisions I make in the future. Motivating this conclusion has been an eye opening experience learning how to use a CNC mill. During this time I’ve worked closely with one my mentors who knows a lot about CNC mills, who taught me some of the basics of how to operate one. I also adopted a more multi facetted design software called Autodesk Fusion 360, one that melds modeling and CAM (computer aided manufacturing) into one platform. Design work and pathing (where the mill moves to remove material) could not be easier, aside from having a slow computer and some cumbersome features in the program.

Autodesk Fusion 360

Autodesk Fusion 360

A typical milling operation.

A typical milling operation. Here, it’s for a round fixture to better stabilize the piece of cylindrical stock.

I began my CNC journey with the same joint components that I had made in Rhino. Simple enough to make it seemed, just a tube with some bits on the end. The shop also had stock that could easily be milled into the part.

an early design used to produce the final model

an early design used to produce the final model

But my, was I mistaken. The main problem stemmed from how the vice of the mill only came into contact with one point on each side of the round piece of stock. When milling started, the force of the bit (known as an end mill) knocked the piece out of line. The end mill continued its operation, unaware of the havoc it created, blindly wiggling back and forth up and down in what it thought was a chunk of aluminum. What followed was a lot of noise and flying aluminum shavings, a moment of amazement, a moment of panic, and then finally lunging at the big red STOP button. The mangled piece of aluminum remained crooked in the vices of the machine.

IMG_2155

To remedy this, I milled round fixtures to increase the clamping surface area, as well as changing the milling operation to be more gentle.

How a fixture interacts with the round piece of stock.  Another fixture would interface on the other side as well and clamp the part.

How a fixture interacts with the round piece of stock. Another fixture would interface on the other side as well and clamp the part.

After another day of tinkering and solving issues, I finally ended up with a real product, exactly what I was looking at on the computer screen…. except in my hand. Screen, hand, screen, hand, screen… hand. I find it pretty exciting to hold something that you were just modifying on the computer, but then chose a specific moment to bring it into the real world.

Final joint component.

Final joint component.

However, this component will never see service on the final Grazer. Instead, I created new designs using square stock. More on that next week. For now, enjoy a cool video on the worlds fastest bike:

http://motherboard.vice.com/read/the-fastest-bicycle-on-earth

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