Posted on: Feb 6, 2018, | By Steve, WayKen Project Manager
Many industries always face the tough situation of relatively low-volume needs and high tooling costs.
New medical device development is one typical example which small initial quantities are needed for validation procedures. In a situation which often calls for low volume of parts, conventional, long-life tooling is expensive, if without an innovative thinking of low volume manufacturing solutions, high tooling costs can render even the best products uncompetitive, new designs might not even get to market.
Even automotive companies often need small quantities of molded and formed parts for interim production and prototype and niche vehicles, where the quantities are typically low but appearance are required highly aesthetic and parts functionality cannot be compromised, quick response for design modification is also a necessity. This critical demand is no doubt great challenges for parts manufacturers. When a client comes to order a few dozen pieces, it’s often hard to respond, which is why auto suppliers frequently have to turn to low-volume manufacturing solutions.
Low-Volume manufacturing solutions and strategies
With the development of rapid manufacturing technology, RT(Rapid Tooling) which characterized as short cycle and low cost are now widely used in low volume production, this makes it possible for customers to bring small quantities of customized products to the market. Currently, there are three kinds of rapid tooling strategies for low volume manufacturing.
Silicone mold for vacuum casting process;
Silicone mold is widely used in rapid tooling process, the mold has a good toughness, there is no draft consideration for silicone mold as it is one of the simplest ways in the rapid tools, with good flexibility and replication performance. It is suitable for low volume trial system which meets certain function requirements during product development.
Aluminum alloy, ABS mold or epoxy mold used for reaction injection molding
Reaction Injection Molding (RIM), also known as low pressure or high-pressure perfusion. It’s a technology utilizing chemical reactions (Two-component polyurethane material) to produce stronger, tougher, more lightweight, more complex and more customizable parts in a significantly more cost-efficient manner than standard injection molding. It has the advantages of high efficiency, short production cycle, simple process and low cost. It’s suitable for low volume production in product development phase, as well as in producing simple structured covering parts in small batches and large products with a thick wall or uneven wall thickness.
Aluminum tooling and simple steel tooling for injection molding parts
Rapid injection mold materials are mainly soft steel (for example, P-20) and aluminum (such as 7075 T-6 Aerospace grade aluminum). Compared to hard steel, it can increase the processing speed by 15% to 30%, and the polishing time can be 3 to10 times faster with lighter weight, so as to reduce the cost of making the mold and shortening the cycle. In addition, the rapid aluminum tool facilitates temperature control, allowing faster cycle times and eliminating plastic stress. These materials can be milled to final shape rather than being ground, which cuts time and saves money as a result. Aluminum has different thermal properties than steel, which must be taken into consideration, but this feature can also cut costs by eliminating the need for cooling galleries.
Compared with ordinary steel mold, the two materials made almost the same surface quality. The life of aluminum mold is related to the complexity of the product, although far lower than the steel mold, but also can achieve no less than 1000 times of service life, which is more than enough for the initial loading test.
The application of low volume production in auto industry.
Prototyping design and low-volume production are interrelated steps in bringing a new product to market. The small batch demand of parts in the research and development cycle is mainly applied to reliability test to verify the strength and durability of the car, such as field test, road test, wind tunnel test, collision test, etc. Through the development phase of verification and testing, early detection of product structure to solve the unreasonable or mold defects caused by other problems can easily take preventive measures to avoid loss and reduce the risk for mold manufacturing.