Complexity and Cost

The next generation of design is going to be something remarkable.  Consider the impact of part fabrication in which complexity has no impact on cost.  In fact, the more complex part the part construction the less it will cost.

Why? Because the cost of a 3D printed part is almost exclusively based on the weight of the material required to make the part.  ABS and chopped fiber mixtures are all quoted based on cost per pound, so that should tell you something.

The major point of 3D printing is that machines are relatively low in cost.  A “personal” CNC like the Tormach starts at less than$10,000 and a good quality 5 axis machining center will cost around $55,000.  In contrast 3D printers are selling for $300-2,300.  A small fraction of the cost of machine tools.

This makes machine amortization costs extremely low.  Labor to load and unload the machine is equally low in cost.  Speed to process the part in 3D tends to be somewhat slow, but if the market you are selling to is a certain volume, the net part cost may make it possible to purchase multiple machines to meet demand.  A printer “farm” as they are called, is very low labor per part and does not require highly skilled labor.

Machine tools are used for machining metals like steel and aluminum.  Part strength in ABS and chopped fiber reinforced materials is excellent, but not easily engineered to meet load requirements comparable to metals.  3D printers for exotic alloys are available that print Inconel and Titanium where the high cost for parts in aerospace and down hole oilwell drilling applications is acceptable. In addition, high strength carbon fiber and kevlar parts are being printed by machines from Mark Forged.  These parts are tested to perform well beyond the limits of T6061-T6 Aluminum.

So if a part design is weight-reduced by using complex reinforcement structures, who cares?  The net cost of the finished part will be lower because the fundamental material cost is directly reduced.  Conventional processes like machining operate by removing material from a solid block, so machining time to weight reduce a part increases process cost and does not impact material cost at all.  Injection molding processes can potentially benefit from reduced material requirements, but mold complexity and cost goes up significantly.

As 3D print process experimentation continues, unique process and materials science improvements will continue to drive improved performance and lower costs.  So if it costs the same to make parts that are more complex with more integrated features, who cares?  Keep innovating.