As I am starting to think about a plastic accessory for my line of stuffed animal toys, trying to wrap my head around plastic and plastic manufacturing. Had a quick conversation with Fathom today – a 3D printing and plastic manufacturing facility with locations in Seattle and San Francisco. They were super friendly.
Some tid-bits they shared:
1. 3D Printing
– 3D printing is great during the initial design phase to quickly and cheaply print rough drafts of concepts
– You can find 3D printers often at your local library, or you can use online 3D printers like Shapeways, Sculpteo, or even Fathom
2. RTV Molding
– Great for low volume batch runs of 50-100 units
– The 3D printing facility, like a Fathom, will make 1 room-temperature silicon mold. Then, they can do individual castings by injecting poly urethane or a hard plastic. However, each mold cast will cost approx. $20. Not sure how much the initial silicon mold would cost. (Also called urethane casting?)
3. Injection Molding
– This is a common plastics manufacturing method that is used for large runs. It is the most cost effective manufacturing method for mass production. Legos are made by injection molding.
– All plastic injection molding requires the initial creation molds made out of either (a) soft steel or (b) hard steel.
– Soft steel molds are quicker to manufacture (2-3 weeks), are less expensive to manufacture, but will corrode more quickly and thus allow a lower number of “molds” to be made over the course of its lifetime. In industry parlance, this is referred to as a mold’s “shot allowance”. As a rule of thumb, I have been told, is to use a soft steel mold, if less than 100,000 shots (again, think of shots as units) are needed.
– Hard steel molds are more time-consuming to manufacture (8-12 weeks), are more expensive to manufacture (8-12K), but have a longer lifespan (think 1,000,000 shots).
Random question I asked: How does someone manufacture a toy truck, if, the toy truck is made up of separate non-continuous plastic pieces that are only later assembled?
I saw a plastic firetruck toy for sale in my local Whole Foods supermarket, and I wondered: “Does this toy require the separate manufacture for molds for each truck part? A mold for the wheels, a mold for the chassis, etc.? With 4 separate non-continuous pieces compromising this toy truck, does this mean that a company would have sunk some 10Kx4 or $40,000 into just the development of moldings?” Answer: You CAN create a more complicated plastics mold that is compromised of separate mini-molds. This is called a FAMILY TOOL. But, family tools are complicated to make and therefore much more expensive. Usually, they see companies avoid these complexities by simply making a separate mold for each separate toy piece. These separate pieces get assembled later.