Mechanical Design, Spring Semester
Building A Real Model
One of the major hang-ups the mechanicals faced during the Fall Semester was coming up with actual dimensions for the table. We knew we'd be limited by our budget to materials at hand, and had to limit our design to those materials. But we weren't sure how to pick out those materials until we had a decent design.
Thankfully, Phil Jasperse in the Machine Shop helped us past this hurdle. Phil has been a tremendous resource for us. Not only has he given us a lot of advice on how to build our project, he's been responsible for a lot of the machining that's been beyond our skill level.
The model above shows our new design. Every part is based on real materials, and every part is drawn and dimenioned in our design notebook. (A .pdf of our design notebook is under construction!)
The Mechanical construction consists of four main stages:
- Base with X-axis
- Slider with Y-axis
- Z-axis support and dremel
The Base with X-axis:
The base has to be as rigid as possible, but still light-weight. We're using 16-inch long aluminum L-beams for our main support. Custom-machined aluminum blocks will support the rails and power screw to drive the Slider. The rails have to be in perfect alignment, or the Slider will bind up and stop moving.
Slider with Y-axis:
The Slider will move along the X-axis rails on ball bearings. The Slider has a lot of the same design issues as the base. It needs to be light-weight, but strong. Its rails also need to be in perfect alignment to prevent the table from binding up.
The Table will ride along the Y-axis rails on ball bearings. The main structure of the table will be aluminum, but the top layer will be plywood. This layer allows for the drilling of through-holes, since we don't want to run our high-precision mill bits against aluminum.
The Z-axis has two defining characteristics: it has to hold and position the Dremel tool accurately, and it has to be strong enough to support the weight of the entire machine, should someone pick the Mill up by the Z-axis arm.
To provide the necessary strength, we're using two-inch square aluminum tubing. To support the Dremel, we've purchase a Dremel workstation, and we are modifying the Dremel cradle and motion control to fit our purposes. Rather than a lever arm controling the Z motion, we're inserting a stepper motor into the drive mechanism
Here's what the mill looks like now!
For more pictures how the mill was put together, check out our photo gallery!