Coaster Project

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This aluminum coaster was completed as part of the final evaluation for the Haas CNC Basic Mill Operator Certificate [40]. All work was done using CNC equipment in the Engineering Manufacturing Education Center (EMEC). Aluminum was selected for its machinability and excellent surface finish. The project involved key processes such as toolpath generation, CNC milling, chamfering, and an integrated oral exam, requiring candidates to explain each machining step in real time. This exam format combined technical performance with verbal communication skills, making the experience a real-world simulation of shop floor expectations.

This was one of the most gratifying projects I have done. The high standards pushed me to prepare thoroughly, and when it came time to perform under pressure, I felt ready. The HAAS training videos paid off; everything I had studied became second nature. I passed the certification and walked away with a clean, functional part that proves I can operate CNC machinery professionally. Not all students in my class earned the certification, so achieving the Haas CNC Basic Mill Operator Certificate was a major milestone that demonstrates my technical competency and ability to perform under pressure [40].

The HAAS CNC Basic Mill Operator exam is unique because it includes a real-time oral exam during active machining. One key lesson was how useful the HAAS video training modules really are. They are not just background info; they are directly aligned with what you need to do and say during the certification. Because I studied those closely, I was able to explain each step naturally while performing it.

Advice for Future Students:

• Treat the training videos like your blueprint. They cover both the machine operations and the types of questions you will be asked.

• Do not just memorize the steps; understand them.

• Talk with the EMEC staff ahead of time. They can help you narrow your focus to what is most important.

• Ask questions and study with intention.

• Treat the project like a professional job. The more active you are in your learning, the more confident you will feel when it counts.

This coaster project already shows how efficient CNC machining can be when it’s done right. Every step, including material removal, engraving, edge finishing, and detailing, was completed on a single CNC mill in one setup. Once the aluminum blank was clamped into place, the machine ran a preprogrammed toolpath that handled the entire process with very little operator input.

One of the biggest strengths of this method is repeatability. The G-code can be reused whenever needed. Tool offsets are already stored, and the machine delivers consistent results from one part to the next. That level of consistency makes this part easy to scale up. Here is how I would work toward optimizing each part of the CNC machining process to improve efficiency. 

To make the cycle time estimate more accurate, I used a standard machining formula:

Feed rate (inches per minute) = RPM × number of flutes × feed per tooth

For this project, I chose a moderate cutting setup:

Feed rate = 4000 × 2 × 0.004 = 32 IPM

This feed rate falls well within the recommended range for machining 6061 aluminum with a standard end mill [41].

1. Facing

• Surface area: 3.5-inch diameter, roughly 9.6 square inches
   
• About 18 passes at 0.2-inch stepover
   
• Each pass is around 3.5 inches long
   
• Total cutting distance: 63 inches
   
• Time = 63 ÷ 32 = about 1.97 minutes
   

2. Pocketing and Engraving

• Estimated toolpath: 60 inches
   
• Depth of cut: 0.1 inch, done in 3 passes
   
• Total travel: 180 inches
   
• Time = 180 ÷ 32 = about 5.63 minutes
   

3. Chamfering

• Outer edge: roughly 11 inches
   
• Feed rate: 25 IPM
   
• Time = 11 ÷ 25 = about 0.44 minutes
   

4. Tool Changes and Rapid Movement

• Extra time for repositioning and tool swaps = about 1.5 minutes
   

• Facing: ~1.97 minutes
   
• Pocketing and engraving: ~5.63 minutes
   
• Chamfering: ~0.44 minutes
   
• Tool changes and machine movement: ~1.5 minutes
   
• Total: approximately 8.5 minutes per part
   

In a production environment, the same part could be made much faster by improving the process. Some key upgrades would include:

• Increasing feed per tooth using better tooling
   
• Using high-efficiency roughing strategies that remove material faster
   
• Setting up multi-part fixtures to run several coasters at once
   
• Reducing time between operations by overlapping toolpaths and minimizing pauses
   

With those improvements, the pocketing operation alone could be cut down to 2 or 3 minutes. Combined with reduced tool changes and faster feeds, the total cycle time would realistically drop to about 5 minutes per part, even with the thicker 0.5-inch material.

That means this project is more than just a class requirement; it’s a real example of a design that is ready for scalable, professional production.

The difference between making one coaster at EMEC and mass-producing it at scale is dramatic, both in cost and time.

• One coaster produced at EMEC costs $23.48 in materials
   
• One mass-produced coaster costs just $6.68, nearly three and a half times cheaper
   
• For 10,000 units, the material cost through EMEC adds up to $234,800.00
   
• The same 10,000 units using mass production materials would cost only $66,800.00
   

This massive drop in material cost is possible because bulk purchasing, simplified setups, and optimized raw stock use all drive down waste and improve efficiency.

• One coaster made at EMEC takes 0.5 hours (30 minutes) to complete
   
• One mass-produced coaster can be finished in 0.083 hours, or about 5 minutes
   
• At scale, producing 10,000 coasters manually would take 5,000 hours
   
• With mass production methods, that same output takes just 830 hours
   

That’s a 6x reduction in time. The time savings are especially important in large orders, where faster turnaround can make the difference between a prototype and a market-ready product.

And although labor was excluded from this estimate, it brings up a new curiosity. What would the full cost of a mass-produced coaster look like if labor were included, and how would that compare to the one I built by hand? That feels like a question worth exploring.

At the end of this project, the numbers speak for themselves.

• The total estimated cost to produce one coaster at EMEC, including materials and labor, came out to $36.21.
   
• The total cost to produce one coaster through mass production was only $8.80.
   

That’s more than a 75 percent reduction in cost per unit when moving from small-scale, hands-on production to an automated manufacturing process. The shift in scale not only saves time and materials, but also unlocks real financial efficiency.

This comparison makes something clear. What I built in the shop was valuable as a learning experience, but the mass-produced version is what makes the design viable in the real world. It’s the difference between practicing engineering and applying it.