Rapid Injection Moulding

Rapid Tooling (is also known as rapid injection moulding) is a tool that shapes a product of a certain shape, size, and surface accuracy in its specific shape. It is mainly used in large-scale production. Although the production and manufacturing costs of moulds are relatively high, the cost per product is greatly reduced due to mass production.
In order to meet the customer's schedule requirements, and the product size and surface have a good consistency, speeding up the development and verification of the product, the rapid mould manufacturing within 100-1000 sets can be satisfied here.

Most people think that 3D printing is a good substitute for injection moulding that requires mould making. Is this really the case? At the moment, 3D printing has already had a huge impact on the manufacturing industry. The prototype that used to cost a few hundred dollars and took weeks to process can now be designed in the morning, printed at night, and delivered to customers the next morning.

Some injection moulding companies are already using the 3D printing process to make injection moulds. It no longer takes a few months to wait for the injection mould that can be used for production, or because of the downstream design changes that result in a large amount of money invested in modifying the mould, or uncertainty in the production layer. Whether it's mould validation or small batch production of injection moulded parts, you can quickly print 3D moulds. If there is a problem with the mould or if you need to modify the design, print one and repeat the verification or production.

These views have some truth. The plastic 3D printed injection mould is a bit like the plastic shed in our backyard. It is cheaper than the metal shed. The plastic shed is built quickly and performs well under low load. But if there is too much snow, they will break into pieces of a house.

3D printing moulds have their own place, and some companies have been successful in the application of 3D printing moulds. Proponents claim that 3D printing moulds are up to 90% faster and 70% cheaper than traditional mould processing. In some cases this may be true, but it is important to understand the advantages/disadvantages of metal moulds compared to 3D printed plastic moulds.

China injection moulding company ACO Mold has been producing fast mould injection parts since 2010. It provides moulds for the manufacture of parts such as engineering plastics, metals, liquid silicone (LSR) and other materials. The mould is mainly machined from aluminum (in some cases with steel), and can process several to 1000 parts, and the delivery time is 1-15 days. Its industrial grade 3D printing services include photo-curing (SLA), selective laser sintering (SLS) and direct metal laser sintering (DMLS). Printable materials include thermoplastics such as polypropylene and ABS, industrial grade nylon and metals such as stainless steel, aluminum alloys and titanium alloys.

Since there is such a large range of processing capabilities, why not directly print the mould, but machine the mould?Injection mould making manufacturers are wary, ACO Mold engineers have been considering printing moulds, but after 16 years of rapid mould business, some reasons have forced them to adhere to a reliable rapid injection moulding process:

1. Surface quality: Plastic parts obtained by processing layer by layer by 3D printing will lead to a staggering effect on the surface of the product. There are similar problems with directly printed moulds, which require machining or sandblasting to eliminate these small, toothed edges. In addition, holes smaller than 1 mm must be drilled, larger holes require reaming or drilling, and thread features require tapping or milling. These secondary treatments greatly reduce the speed advantage of 3D printing mould.
2. Size factor: If you are designing a skateboard or a plastic tool box, the 3D printing mould may be no problem. The part size is limited to 10 cubic inches (164 cubic centimeters), roughly the size of the grapefruit. And despite the high precision of current additive equipment, it is still not comparable to machining centers and EDM equipment. The latter's cavity is typically accurate to ±0.003" (0.076mm) and parts are up to 59 cubic inches in size, roughly six times the volume of 3D printed parts.
3. High temperature environment: In order to ensure good material flow performance, the injection mould needs to be heated to a very high temperature. Aluminum and steel moulds typically experience temperatures of 500 F (260 ° C) or higher, especially in high temperature plastics such as PEEK and PEI (Ultem) materials. It is easy to produce thousands of parts with these metal moulds, and it can also be used as a transition mould before the final mass production mould comes out. Mould materials made using SLA or similar 3D printing processes are typically photosensitive or thermosetting resins that are cured by ultraviolet light or laser light. Although these plastic moulds are relatively hard, they are destroyed very quickly under the thermal cycling conditions of injection moulding. In fact, in a mild environment, 3D printing moulds typically scrap within 100 uses, high temperature plastics such as polyethylene and or styrene. For glass-filled polycarbonate and high-temperature plastics, only a few parts can be produced.
4. Comparison cost: The big original use of 3D printing mould is because of its low cost. The cost of production-grade machining moulds is typically $20,000 or more, which means that the same size as the $1,000 printing mould is comparable. However, this analogy is unfair, and the evaluation of the printing mould cost usually only considers material consumption, and does not consider labor, assembly and installation, injection systems and hardware. For example, aluminum mould costs $1,500 for production. If you need to produce more parts, if you produce with 3D printing mol, you need to reprint and assemble new moulds for every 50-100 products you produce. On the other hand, aluminum moulds are still in good service in the production of 10,000 parts, regardless of the plastic used.
5. Product design: The principles and practices of traditional injection mould manufacturing have been more than a century old, and the industry is relatively thorough in its research. The 3D printing mould is very new. For example, the draft angle must be greater than or equal to 5 degrees to meet most aluminum mould requirements. Plastic moulds are challenging to mould plastic parts, and extra care is required for the number and mounting position of plastic mould thimbles. Plastic moulds (especially high injection temperatures) are somewhat more flexible in terms of increasing cavity wall thickness and reducing pressure. Despite the many advantages of fast aluminum moulds, in some cases 3D printing moulds still play an important role. For manufacturers who have a 3D printer and have enough time to explore how the print mould works on the injection moulding machine, they may think that the mould should be printed directly. Of course, mould designers must understand how to make functional moulds, and it takes a lot of money to redesign and manufacture the moulds. Relevant technicians and equipment are also necessary – mechanical workers for mould blasting, thimble installation, injection moulding machine operators, etc., because the setting of these parameters is very different from traditional moulds.