Each company has a unique set of requirements for tooling and molding. The tooling and molded part cost is always a significant consideration for most companies. When dealing with budgetary issues that limit tooling costs, I for one will always present a simple spreadsheet which identifies various tool options (like cavitation) along with capacity (hourly, weekly…..) and part price. Once these numbers are expressed and understood by the decision makers, it becomes obvious which option is most advantageous to the program at hand.
I would also add that many toolmakers/ mold makers that I partnered with over the years were quite open to amortization schedules on part prices, whereas the base tooling cost was reduced based on a slightly higher part cost for a time limit and/or part quantity. I have been involved with many companies of this type and it has numerous benefits for all parties involved. When high volume part output is a must to support JIT product manufacturing, any interruption of the part supply (due to tool failure) can be catastrophic to a business plan. Any risk that might upset production must also be a part of the tooling decisions. Perhaps Two 2 Cavity tools would serve the company better than One 4 Cavity tool—-just an example for thought.
There are many variables involved in the determination of cavitation, grade of tooling, and related part price. However, there is the assumption that the decision makers just have to pick from the breakdown proposed and the project is a done deal. That is not always the case since in many situations, we could be quoting against 4 or 5 other tooling and molding companies, all doing the same breakdown, and quality is sometimes assumed, so it still comes down to price (and wish I had a dollar for every lost opportunity with that scenario).
I do appreciate the aspect of multiple tooling with less cavitation, especially in JIT manufacturing environments, which allows for lower overall tooling cost (building two identical small molds can be less expensive than one large mold), smaller injection molding machine usage (better process & cycle control, and no downtime), and improved production and mold maintenance opportunities which again comes down to price of quality. I wish that would be considered more often.