With today’s economic trends hampered by escalating costs in all areas of manufacturing, continual liaison and communication with total utilization of resources must be established to ensure timely project completion with maximum costs savings.

The necessity for control and maintenance of different engineering transactions required for cost-efficient operations is obvious; however, to achieve success a program of knowledge and experience in all phases of plastics manufacturing must be available.

Mold design/mold building is not only one of the important engineering transactions, but moreover the keystone to success within the injection molding industry. First-rate Mold has been working with its customers to better align the incentives of moldmaking with the performance requirements of the molder. The proposal offered is based on the customer’s part design and further investigation into the desired product manufacturing cost models.

When we can determine desired cycle time and acceptable scrap rates we can craft a proposal, which consists of a mold cost and a penalty for a mold delivered outside the agreed upon performance specifications. In order to be successful we need to be knowledgeable and in control of two key areas: (1) scientific molding and (2) mold manufacturing.

The injection molding process is comprised of four elements: (1) the mold, (2) the molding machine, (3) raw material (resin) and (4) manpower.

The mold is easily 70 to 75 percent of the process. It is the most important, yet the most overlooked as a truly optimized factor to the injection molding process. Throughout the plastics industry the mold is called a tool. The dictionary defines a tool as Any instrument or apparatus necessary to the efficient prosecution of ones profession or trade.The key word is efficient. Some antonyms are ineffective, inoperative, negligent and useless.

Upon delivery to the customer, an efficient mold should not only have the mechanical functions optimized (proper steel/shrinkage dimensions, slides, unscrewing mechanisms, ejection systems, manifolds, etc.), but moreover the process values optimized as well.
A series of studies has to be conducted, which includes but is not limited to:

Viscosity shear rate curves to determine optimum filling velocity;

Segmented pressure loss analysis to determine areas that will narrow the process window;

Cavity-to-cavity balance within 5 percent weight;

Gate seal study to achieve consistent final part weight and dimensions;

Melt temperature versus packing pres-sure/time to achieve widest process win-dow and venting requirements to provide maximum filling velocity and time.

These studies will enable the mold to produce quality parts with minimum acceptable scrap rate at reduced cycle time. A robust process! These requirements are the responsibility of mold builder not the end user.

The time and expense to conduct these process studies are minimal compared to the indirect costs associated with debugging the mold once it has been delivered—such as travel expenses and time for the tooling/process engineers, multiple setup and process times on the injection molding machine, loss of market share for product launch, training, etc.

Since the 1990s, indirect costs have soared while labor costs have dramatically decreased as a percent of total cost associated with design and manufacturing as noted by the Institute for Competitive Design. In addition, according to Forrester Research, indirect costs could amount to seven times more than direct costs themselves.

These indirect costs have to be built into the overall cost of the mold even if these expenses are separate budgets. Once these indirect costs are included, the low-cost mold can become very expensive. Being able to determine both (indirect and direct costs) is what separates a wise investment from a crapshoot.