Coaster Project

The MECH200B Coaster Project involved the fabrication of an aluminum coaster, using the HAAS CNC machine to produce the final part. The associated oral exam tested knowledge of machine anatomy, tooling, metrology, safety procedures, and proficiency running the machine in general.

Aluminum Coaster

The aluminum coaster required the use of the HAAS CNC machine to cut the bar stock into shape.

What I Learned

Although it's called the "coaster project", the main purpose is to learn your way around the CNC machine, and pass the oral examination while it does the work for you. My exam happened to be at the very end of the semester, which I didn't mind, because I had seen pretty much everything the class had to offer by that point. Obviously, studying the material beforehand was what led to my grade, but I really enjoyed the exam because you get a chance to use your common sense on the things that you maybe didn't prepare for. It's a great opportunity to use your social and problem solving skills to figure something out, versus just not knowing like a typical exam.

My Advice For Future Students
- Study for the exam by explaining what you know to your study partner, not by waiting for questions.
- As I mentioned earlier, you can use common sense for a lot of the problems, but not the specific names of things like the Jacob's chuck or CAT-40 taper. Make sure you go over everything at least once beforehand.
- In the metrology portion, it's helpful to expand upon your measurement by guessing what you think the value should really be, it doesn't have to be the exact reading you get.

Cost of a Single Coaster

As of December 2024, the cost for one coaster is about $59.49.

Materials
- 3/4" x 4" Aluminum Rectangular Bar Stock (1ft)
  - $33.53
Labor
- The average pay for a machinist in Colorado
  - $25.96/hour
- Hours Required
  - 1 hour

Modernizing the Process

To streamline the production of the coaster, one might consider different alternatives to the machining process.

Casting
- Because of the coaster's complex shape, casting would be a great way to bring down the cost of the product. CNC machining is also much more wasteful when it comes to excess material compared to casting.
Stamping
- Stamping is a great way to lower the cost of material, as sheet metal is easy to purchase in bulk. It's also likely the fastest way to produce a coaster in an assembly line.

Mass Production - 10,000 Units

A worthwhile comparison would be to see how the costs and time of mass production compare to custom production in the CSU EMECH.

Machining Process - Casting
- Cost
  - If one pound of casting aluminum costs about $2.50, and a coaster weighs about 0.2 pounds, the total cost to produce 10,000 would be $5,000.
- Time
  - With a batch size of 20 coaster and an estimated production time of one hour per batch, the total time would be about 63 workdays.
Machining Process - CSU EMECH
- Cost
  - Assuming one coaster at a time, the final cost would be $335,300.
- Time
  - With coasters taking roughly one hour each, it would take 1,250 workdays to produce 10,000.

Coaster Project

Aluminum Coaster

What I Learned

Max Coulter