Lessons Learned: Advice
One of the biggest tips I can give to future students is to take initiative to learn outside of scheduled lab times. Something that helped me tremendously was going into the EMEC on my own time and finding someone who was about to start machining one of their clock components. I would ask if i could watch, and then I'd take detailed notes, just like during our weekly lab demos. Watching someone else go step by step gave me a clearer understanding of the processes and often turned into a collaborative discussion where we'd talk through the steps together. This not only made me feel confident enough to tackle the machining myself, but when all the machines were being used it served as a good use of my time.
Project 1 | Clock Project
Clock Project Components and Processes
Cost Estimate
Brass Pen Holder:
Considerations
For the brass nut we have the 9/16" hex brass bar, and the lengths we were provided during manufacturing were typically 1"-3". The brass pen holder used 5/8" round brass rod and the raw stock which we will assume is approximately 12" is cut down to 2.5". For the steel pen holder, we are also assuming that we have 12", this raw stock was cut down to approximately 2.18". The aluminum base we are also assuming 12", this needed to be cut down to approximately 8.12 plus or minus 0.1" length. Finally, for the clock face we are assuming we have a 6" by 5" PMMA acrylic. In Colorado, the average hourly rate for a machinist is $25.92. I took very long to machine my pieces, so I will be taking approximate times for each of the pieces. Approximately 35 minutes for the brass nut, both the steel and brass pen holder approximately 4 hours each, aluminum base approximately 5 hours, and the acrylic clock face about 45 minutes.
Material: 5/8" round brass rod (Stoner Metals on Amazon)Cost for 12": $23.39Cost: 23.39* 2.5/12 = 4.87Labor Cost-->Machining Time: 4 hours4*25.92 = 103.68Total Cost: 4.87 + 103.68 = $108.55
Aluminum Base
Material: 6061 aluminum flat bar (Metals Depot) Cost for 12": estimated to be $9.00 Cost: 9.00* 8.12/12 = 6.09 Labor --> Machining Time: 5 hours 5 * 25.92 = 129.60 Total Cost: 6.09 + 129.60 = 135.69
Steel Pen Holder:
PMMA Clock Face
Total Clock Cost:
Material: 5/8" cold-rolled steel rod (All Metal Inc.) Cost for 12": $8.04 Length Used: 2.18" Cost: 8.04 * (2.18/12) = $1.46. Labor Cost --> Machining time: 4 hours Machinist Rate: $25.92/hr Labor Cost: 4 * 25.92 = 103.68 Total Cost: 1.46 + 103.68 = $105.14
Material: PMMA acrylic sheet (Interstate Plastics) Cost for 48"x96" sheet: $126.36 Our 6"x5": 126.36 * 30/4608 = 0.82 Labor --> Machining Time: 45 minutes Cost: 0.75(45min.) * 25.92 = 19.44 Total Cost: 0.82 + 19.44 = 20.26
Adding up every component: $18.04 + $108.55 + $105.14 + $135.69 + $20.26 = $387.68!
Efficiency Improvement Proposal
Improving the production process for the clock project can be done in several ways. For example, although the brass nut is made more efficient by using a turret lathe adding an automatic bar feeder could save time by eliminating the need to have an operator load the material. Not only that, but it would also reduce labor costs. The brass and steel pen holders, which are currently machined on manual lathes could be improved by switching over to CNC lathes instead of performing tasks manually. The CNC lathe would automate most of the operations like turning, threading, and drilling. By automating these processes, we are able to reduce the chances of errors and save time. For the aluminum base, using a CNC mill would allow us to be more precise in our cuts and make the process much smoother. The acrylic clock face process could be made more efficient with a laser cutter as opposed to the vertical bandsaw where it is difficult to get a super clean cut.
Mass Production Cost: 10,000 units
Producing 10,000 units really highlights the difference between switching to automation compared to the manual methods we used in the EMEC. For material costs, I calculated $170,700 by scaling up the raw materials required for each unit. The real difference comes with the labor costs. With the manual methods that we utilize at the EMEC I calculated that one unit takes approximately 14.5 hours to a machine. In Colorado the machinist hourly rate is $25.92, the labor cost therefore adds up to an astounding $3.7 million. On top of that, with five machinists working full-time, it would take around 13.8 years to complete 10,000 units.
Now if we compare it to automated processes where we can use machines like the CNC lathes and mills the labor cost and time productions significantly decrease. These machines can run non-stop, they don't get tired, and they reduce error that is introduced when there is an operator. By automating everything the production time can be cut down to 30 days, as well as cutting out labor costs for production. This drops the cost per unit from $388.44 to just $17.07!
