The cost analysis of most 3D printing processes is based on the direct material cost, usually in dollars per pound. By making machine costs low and eliminating tooling costs the barrier to entry in many markets is reduced to a tiny fraction of other processes. Which is entirely intentional and why 3D printing gets so much attention.
The less obvious aspect is that 3D printing is completely linear in cost with regard to material usage, the less material the lower the cost. At the same time, less material being processed means greater throughput. Half the material, half the process time. Need more throughput? Buy another machine! Because the cost analysis is also linear. If you have to supply more market, you need more machines.
So if you could build a car in 55 hours with, say, a team of 4 people, for 8760 hours per year the printer could make around 160 cars. 8760 hours is 24/7/365, so you need crews to work 3 shifts and weekends just because of the chronological time. Probably at least 4 crews or 20 people. If the labor required is fairly constant, then 4 crews could keep up with 4 printers, more like 640 cars a year.
So the name of the game is really paralleling a lot of printers and increasing throughput. The print process scales directly, so a plant with 100 lines and 400 people might produce 16,000 vehicles a year. And 100 plants around the country would produce 1.6 million cars and employ 40,000 people. Which does suggest that a printed approach could supply 10% of the market assuming comparable prices and performance.
The other major aspect of 3D printing is that parts do not suffer from increasing cost with increasing complexity. In fact, the opposite is true. More complex parts that integrate structural reinforcement are cheaper to make because they use less material and are faster to produce. This process is called “lightweighting” and it is a key strategy for the industry.
The light weight aspect is extremely significant particularly since a printing car will most likely be an electric car. The Shelby Cobra printed by Oak Ridge National Labs is reported to weigh half of the original, around 1100 pounds. The Tesla Model S sedan has a curb weight of approximately 4400 pounds. This means that to get the same performance and drive range, the 3D printed Shelby Cobra would only need 1/4th of the battery pack to achieve the same drive range.
At today’s cost of $300/kWhr of storage, a 60kW battery for the Tesla Sedan is $18,000, a major factor in the vehicle selling price. The same price point for 15kWhr for a Shelby Cobra 2 seater would be $4,500. This is where 3D printing and electric cars intersect, making a $20,000 car a practical solution in the near future.
If the government can make a car in 6 weeks, maybe they can reduce the time to get the car to pass regulatory approval.