3D printing versus injection molding: balancing quantity, quality and cost


The emergence of 3D printing as a viable means of mass production has prompted some observers, albeit with vested interests, to ponder over the potential demise of injection molding. With current 3D printing technologies and even factoring in improvements likely to emerge moving forward, however, that possibility appears remote.

A paper presented by David Kazmer, Professor of Plastics Engineering at the University of Massachusetts Lowell at the recent ANTEC conference estimates that 3D printing currently makes sense for the most rapid "procurement time to quantity" for a production run of just 50 units, whereas tooling with aluminum inserts is the quickest means of getting to product to market for anything beyond this up to 1 million parts, and Class 101 tool steel takes over for larger production runs.

The study carried out at Lowell considered a medium-sized chassis measuring 35 cm x 13.5 cm by 3 cm with wall thickness of 3 mm and part weight of 131 g. It found that the cost of direct printing 300 such chassis worked out at $20 per piece, compared with $1.56/piece for 500,000 chassis molded using tooling with aluminum inserts and $1.13/piece using a steel mold and turning out 1 million units.

Read more