New technology and new trends in injection mold manufacturing

In order to be able to produce injection molds that can save investment and time costs, as well as improve the efficiency of injection molding, mold manufacturers continue to use new materials and new technologies, and these new materials and technologies represent to some extent New trends in injection mold manufacturing.

New materials promote the development of mold inserts

There is a new material that can reduce the investment cost and time cost of injection mold manufacturers. The new alloy, called Cobalt Chromium MP1, was developed for use in Rapid Prototyping (RP) equipment using the Metal Laser Direct Sintering (DMLS) process. The material is produced by German rapid prototyping equipment and materials supplier EOS (Electro Optical Systems) GmbH. Users in North America can now purchase this material through EOS North America and Morris Technologies.

Morris Technologies is an injection mold development company that first applied the material to commercial manufacturing. This cobalt-chromium alloy has been proven to have high strength, high temperature resistance and corrosion resistance during the company's use. Morris Technologies was the first company in the US to introduce EOS's Eosint M-class rapid prototyping machine because it had foreseen a huge market for rapid prototyping based on DMLS. However, it was found through experiments that there was no material on the market that could meet the application needs of many of its customers.

“There are many projects that require rapid prototyping solutions, but the customer's experimental conditions require materials with better high temperature and corrosion resistance and higher mechanical properties,” said Greg Morris, president of Morris Technologies. “Even if it costs more Time and money, stainless steel or other alloys still can't meet their requirements."

To solve the above problem, Morris Technologies chose EOS's cobalt-chromium MP1 material. According to Morris, the alloy's Rockwell hardness is between 30 and 40. It can produce small and complex mold products, which are usually manufactured by EDM or machining.

Since the structural layer of this material is very thin, only 20 μm, the product can be completely sintered. Morris believes that this material and metal laser direct sintering technology can help the injection mold manufacturing industry produce fine core and cavity inserts at lower cost. “The reason why many mold makers are not adopting this technology is, in my opinion, because many people think that they only have the best way to make cores and cavities in the previous way,” explains Morris.

Clear conservative

John Tenbusch, president of mold maker Linear Mold & Engineering, did not hesitate to adopt the above technology. Because Tenbusch found that EOS's new customers of metal laser direct sintering rapid prototyping equipment have even extended to Mexico and South America.
In the manufacturing process of injection molds, it is popular to use typical electric sparking equipment (EDM) for welding, and the use of wire cutting in the manufacture of rapid prototyping molds is also growing. In this regard, Tenbusch explained: “The use of wire cutting can help us save time, that is, we use wire cutting to cut out the cavity, while fine parts like inserts are processed using the DMLS process.”

According to Tenbusch, this method is highly accurate and does not require many points to be measured, while the ribs can be separated as an exhaust port. Some stainless steel inserts can also be machined using wire cutting and placed in a mold. If the material used is hard enough and the life is long enough, the processor does not have to perform EDM machining on the part details, as is the case with the commonly used pre-hardened high tensile nitriding die steel. Molding can be done in 4 to 5 weeks using wire cutting, and the root cause of this speed increase is the replacement of the EDM device with EOS DMLS equipment.

Cobalt Chromium MP1 is a series of EOS's new stainless steel 17-4 family, which is scheduled to be introduced this year by MaragingSteel MS1, an 18 martensite 300 steel (model: 1.2709), which is at least equivalent in performance. Even better than traditional die steel, it is very suitable for making mold inserts using DMLS process.

Less polishing, more coating

Bales Molding Services, Inc. is a company that provides polishing and plating services for injection molds. In order to reduce costs for customers, the company has seldom adopted the special EDM polishing technology, instead using electroplating technology to form a coating on the mold surface. Steve Bales, president of Bales Tooling Services, said: "Now not every mold needs polishing, and the use of coatings is growing. We use electroplating instead of EDM live polishing to save customers time and money."

It is well known that fillers can shorten the life of injection molds. As the amount of filler in injection molding increases, the problem of corrosion and wear caused by the filler on the mold is increasingly prominent. Adding coatings to the mold, such as Nicklon (a nickel-PTFE coating) and Nibore (nickel boron nitride), provides excellent protection. At the same time, these coatings are very cheap compared to expensive plastic lubricant additives.

Use Ritemp to get the right temperature

Ritemp's mold cooling technology was introduced in 2005 by Ritemp, Australia (a division of Comtec IPE, an Australian processing and auxiliary equipment supplier). The technology is currently exclusively represented by SWM & Associates in North America.

With Ritemp mold cooling technology, higher cooling efficiencies and shorter molding cycles can be achieved. For example, a 15g electrical enclosure is injection molded, using GE Plastics' Noryl PA/PPE, the mold is 2 chambers, and the molding cycle is 18s. With Ritemp cooling technology, a 4-cavity mold can be used and the molding cycle can be reduced to 13 s, resulting in an annual production of over 7 million. SWM & Associates believes that if downstream equipment can handle more products, the molding cycle can be shortened to 10s.

Ritemp works as follows: Ritemp uses a sink instead of a water gun to cool the mold surface. By removing the vacuum caused by the air, the water can boil at a low temperature in the cooling chamber. The water evaporates to the surface of the mold for heat exchange and is then discharged through the water tank. During the evaporation process, the water molecules absorb the heat and regulate the heat level through the mold temperature control system, thus ensuring the mold temperature.

Eliminate visible gate marks with submerged gate inserts

This submerged gate insert comes from the i-mold company in Germany, where the injection point is designed at the end of the product and the flow path is open from the front end, so that the gate surface is positioned inconspicuous on the product. For example, in the side gates at the bottom of the ribs on the outside of the product, people cannot see obvious gate marks.

A dye is a colored substance which has an affinity for the substrate it is applied. Dyes and other materials to make fiber coloring substances, natural and synthetic sub-two categories. Dyes are colored substance. But not necessarily colored substance is a dye. Because they absorb certain wavelengths of light more than others. In contrast to dyes, pigments are insoluble, and has no affinity for the substrate. Some dyes can be precipitated with an inert salt to produce a lake Pigment, and based on the use of which may be aluminum lake, calcium lake or barium lake pigments of salt.

Dye was able to make sure the color attached to the fiber material, and easy to fall off, change color. Typically dye dissolved in water, a part of the dye Mordant dye can require adhesion to the fibers. Archaeological data show that staining technique in India and the Middle East for over five thousand years of history. Then dyes or minerals come from plants and animals, rarely treated.
Dyes are usually applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber.

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