After more than 20 years of experience and study in the molding industry, I have summarized and proposed the "Eight Key Factors" for injection molding: "Man, Machine, Material, Method (Process), Environment, Mold, Measurement (Inspection), and Design (Product Design)." This is very similar to the five elements proposed by Mr. Suhas Kulkarni, except that Suhas overlooked the three elements of man, environment, and measurement.
However, it is quite meaningful that Suhas included "component design" as one of the key factors, and placed it first.
These eight factors determine the success or failure of new product and new mold development, determine the cost of injection molding production, and ultimately determine the boss's profits. They are a main technical thread and core framework in the molding industry. The eight factors complement and interact with each other; they cannot be considered in isolation.
Among the eight key factors, the mold is the most critical; 70% of injection molding defects are caused by mold problems.
Within the mold factor, the gate is the most critical; 70% of mold problems are related to the gate. This, of course, does not mean that other factors are unimportant; it is merely a general proportion derived from extensive practical experience.
Following the sequence of product development, let's start with product design. Speaking of product design, a term that must be mentioned is DFM: Design for Manufacturing / Design for Manufacturability.
A good design must fully consider factors such as ease of manufacturing, low manufacturing cost, high efficiency, and a low cost proportion. Product design is the source. Not every designer is highly proficient in molds and injection molding. Those who are detached from the manufacturing site and work behind closed doors may design products that are unsuitable for mold and injection molding production. When we discover such situations, we must provide timely feedback to the client. With an attitude of considering the client's best interests, we should persuade the client to achieve a win-win situation.
Similarly, mold designers may also lack understanding of injection molding, resulting in numerous problems in the designed mold, which ultimately cannot achieve mass production. This brings endless troubles to subsequent injection molding production. Therefore, injection molding engineers must participate in mold design evaluations during the early mold design stage. Potential issues from mold design that could trouble subsequent injection molding production should be reviewed and discussed in advance with the mold designers.
Strive to resolve mold design issues during the design stage, eliminating problems at the sprout stage. True masters take measures before problems reach injection molding production to avoid them altogether. Instead of waiting until the mold is transferred to production for so-called "improvement while production," which not only leads to low molding yield rates and high production costs but may even cause failure to deliver on time. This seriously affects the boss's profits and may even result in losing important clients due to delayed delivery, damaging the company's reputation.
The same principle applies to mold problems:
First, the mold design stage is the best period to prevent difficult and complicated problems in later injection molding production. 70% of product problems are caused by unreasonable mold design. Optimizing mold design to prevent future product problems is "treating an illness before it occurs." At this point, the illness is in the skin, the treatment cost is lowest (simply modifying design drawings on a computer), and the harm to the patient is minimal.
Second, the trial and sampling stage is the second-best window for treating difficult problems. At this point, the mold has already been made. Modifying the mold is much more difficult and costly than modifying the design. Some design problems may even be impossible to change, leading ultimately to concessions or production with issues. At this stage, the illness is in the muscles. Fortunately, the client has given us time for mold trials and modifications, so we still have time to correct the mold.
Finally, if mold problems are not resolved in the design stage, nor in the trial and sampling stage, and are instead covered up and dragged into the production stage, that becomes troublesome. At this point, the mold is made, the trial and modification stages are missed, and production delivery deadlines are tight. It can be said that the only two treatment windows have been missed. This ultimately leads to delayed product delivery due to mold problems, lowering the company's credibility and potentially losing future orders. At this point, the design and R&D departments, fearing exposure of their faults, may shift blame to production. Not only do the problems never get solved, but internal company conflicts are also intensified. At this stage, the illness is in the bone marrow.
Today, I mainly introduced the DFM concept for product design and mold design. Everyone must first have this concept in mind. As for the specific problems in product and mold design that cause which injection molding defects, I will provide a detailed analysis in later chapters on common injection molding defects and countermeasures, based on specific defects.
