Students may be expected to engage with course content online during the published course dates. Dao, Tuan M, Sr. Consultant, Polymer Engineering Group, Inc. Tuan M. Dao is a senior consultant at the Polymer Engineering Group, Inc. He has over 25 years of experience in plastic engineering, with applications in the automotive, medical, electrical, electronics, irrigation and consumer industries.
His expertise includes product design, mold design, runnerless technology and optimum molding. Due to COVID and the new guidelines, enrollment for this course will close 3 weeks prior to start date.
There are no sections of this course currently scheduled. Plastic Part Design for Injection Molding. Tolerance Analysis.
Mold shrinkage, Effects of molding and tooling and environment on part performance Assembly Techniques Snap-fit, Press-fit, Threaded inserts, Sonic Welding Failure Analysis Techniques used to analyze part failure Emerging Technologies Over-molding, Mold Flow flow simulation , 3D Printing Prototyping Course Benefits: Working knowledge in plastic part design that can be applied to improve product quality as well as productivity.
Understanding of plastic behavior over time creep, relaxation and environmental effects on plastics humidity, temperature, chemicals, etc. Establish end-use product specifications. Harder steel is also required for molding glass-filled material, which can prematurely wear down tooling; wear can also be heavy on runner systems and gates.
Because of its rapid cooling characteristics, aluminum is sometimes used for tooling. It can also reduce the time required for building the mold because it is easier to machine than steel, providing faster turnaround and production cycles. However, because it is softer than steel, even hardened aluminum is harder to weld, difficult to maintain, and wears more rapidly—making it most suitable for prototypes and short runs. Depending on the product and mold design, hybrid molds can sometimes be built that are mostly steel but use aluminum in low-wear areas to transfer heat.
Aluminum is not a good choice for complex parts or harder, glass-filled plastics because of premature wear. Copper alloys are sometimes used as an aluminum replacement when rapid heat dissipation is required. Both steel and aluminum molds can be coated with special materials to improve wear resistance and reduce friction, especially when molding fiber glass-reinforced plastics, making tooling last longer.
Common coatings are nickel-boron and nickel-teflon the 0. Gates are the openings at the end of the runners that direct the flow of molten plastic into the mold cavity. Gates vary in size and shape depending on the part design and resin material. One aspect of mold design that cannot be overlooked is the easy removal of the final product from the mold, with no damage to the surface of the part.
This is accomplished by applying a draft angle, or taper, to the walls of the mold. The amount or degree of draft angle depends on several factors, including design of the part, material, depth of the mold cavity, surface finish, texture, and amount of shrinkage.
Typically an angle of only a few degrees is applied to the side walls of the mold and creates enough space that the part can be easily removed when the mold is opened. Generally, the deeper the cavity, the more draft is required. Draft angles typically vary from about 1 to 5 degrees. Mold cooling and part cooling are critical for determining surface finish. For example, a smooth surface finish on a percent glass-filled resin depends on proper temperature control.
The surface must be resin-rich with the fiber glass slightly deeper in the part, which requires a hotter mold—this also means it takes about ten percent longer to cool.
Molds can also be designed to apply a texture or pattern to the mold surface—this can actually eliminate assembly steps by creating the company logo in the plastic, for example. Texture can also provide better product function, such as enhanced grip or reduced wear from friction. Types of textures include matte, gloss, graphics, grains, logos, and geometric patterns.
Depending on the type, depth, and location of texture, draft may need to be adjusted to facilitate part ejection, which is determined during the mold design process. The main goal of mold design and tooling is to create a product with high manufacturability—a high-quality process that is simple and efficient, long-lasting, easy to operate and maintain, and that meets all customer specifications at the lowest possible cost.
To accomplish this, tooling decisions must be made in the earliest design stages. The tool-maker must be involved as early as possible to provide a realistic machining perspective on product design, requested tolerances, tool design, selected materials, and associated costs. Taking this step up front is the best way to eliminate wasted effort and rework, which adds significant cost to the tooling budget. Part design and tool design are dependent on each other and thus should be done concurrently whenever possible.
For good reason, customers are always concerned about cost. After all, tool-making is one of the highest expenses in the production process. Properly designing, building, and using tooling for each part requires a highly skilled team of engineers and technicians utilizing the latest in sophisticated design and manufacturing technologies. Labor cost can be optimized, however, by working closely with an experienced, efficient tooling team that makes wise decisions on material selection and design tradeoffs, early in the design process.
In an effort to save costs up front, some companies shop tooling according to price, looking for the lowest bid. The best way to get maximum value for your tooling budget is to consider lifecycle costs, not up-front costs. The ultimate goal is quality and repeatability.
Up-front costs for quality tooling may be higher compared to cheaper vendors or offshore suppliers, but the payback come quickly in higher quality, fewer defects, greater throughput, longer-lasting equipment, and over better return on your tooling investment—leading, ultimately, to higher customer satisfaction and loyalty.
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