The most efficient 3D printer can manufacture tria

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Use a three-dimensional printer to manufacture trial moulds quickly and cheaply. The figure shows the trial products of a product and the trial moulds used (Figure 1). This product is a foot health care product called "moisturizing gel socks", which is developed by Akaishi company (headquartered in Shizuoka city)

moisturizing gel socks are made of elastic materials with a thickness of 2.5mm. Although the appearance looks very simple, the internal design creates small protrusions. In the injection molding of elastic materials, not only the high temperature above 200 ℃ is required, but also the injection speed should be very fast. Therefore, the mold is required to have high heat resistance and high strength

resin mold with high heat resistance

when Akaishi company developed moisturizing gel socks, the reason why it used a three-dimensional printer (three-dimensional laminated shape) to make the trial mold is that "it is hoped that the trial product and the finished product have the same material" (the head of the functional design group and mold manufacturing group of the company's commodity development department, murakaka Zhen). Because the product needs a very soft feeling, it is necessary to evaluate not only the static shape and size, but also how the user will deform when actually wearing it and whether it will produce a sense of contraction. However, the trial products made directly with 3D printers cannot achieve this feature, and if the mold needs to be made repeatedly, it means that the cost cannot be reduced and the work period is short

Fig. 1 trial mold for injection molding made of 3D printer

top mold, bottom mold and internal mold are all made of polysulfone (ppsf/ppsu) material 3D printer. The test product is made of elastic material with a thickness of 2.5mm, which has the same thickness and material as the finished product. The resin temperature during injection molding is above 200 ℃

therefore, the company decided to try to use three-dimensional printers to make trial moulds. Therefore, a three-dimensional printer that can melt thermoplastic resin and form laminations at the same time is introduced, so that the required molds can be made quickly and cheaply

however, as mentioned above, in order to form moisturizing gel socks, the mold requires high heat resistance and high strength. Therefore, the company chose polysulfone (ppsf/p) among a variety of resins that can be used in 3D printers, so it needs to develop a special experimental fixture PSU. The heat-resistant temperature of this material is as high as about 200 ℃, which is the highest among all available materials

nevertheless, the company has made some improvements when using ppsf/ppsu materials for trial production molds. The first is demoulding. According to the principle of use, the use of a three-dimensional printer will produce fine segment differences on the surface of the mold, which will reduce the demoulding property. Although the mold surface was slightly polished, the segment difference could not be completely eliminated. Therefore, the company coated a certain powder (interfacial active agent) on the surface of the mold, thereby improving the demoulding property

followed by intensity. When the injection molding machine pours resin at the maximum speed, can the mold bear it? "To tell the truth, we have no bottom in our hearts" (murakaka Zhen). Compared with ordinary molds, although the trial moulds are made faster and cheaper, if they are damaged every time they are formed, their advantages will disappear. Therefore, the company also made the injection port part that needs to bear the maximum strength during forming. In this way, even in case of damage, the loss can be controlled to a minimum

when the ppsf/ppsu material trial mold made by three-dimensional printer was installed on the injection molding machine for forming, the trial product was successfully manufactured. "Although the temperature was raised to 300 ℃, the injection port was still not damaged, but because it was the first attempt, we adhered to the principle of safety first." (murakaokazhen). Although the mold used as a trial product can withstand 20 ~ 30 pours is enough, it is estimated that the mold can withstand more than 100 pours

as a result, the manufacturing time of trial mold is shortened from the previous one week to one night. In order to save costs, the mold is not made solid as a whole, but improved. When viewed from the back, the structure of strengthening the formed surface with stiffeners is adopted, which minimizes the material cost and reduces it to about 1/10 of the previous one

use it differently according to the material of the product

the three-dimensional printer originally introduced by Akaishi company is different from the above, and the available material is one of ABS resins. At first, we used ABS resin to make trial products * 1 with health appliances as the core

* 1 the three-dimensional printer was introduced as a supplementary output machine for machining during the trial production process using three-dimensional data

however, soft materials like elastic materials cannot be replaced by ABS resin test products. Although it is not impossible to use just to confirm the shape, the hardness of the human contact part directly affects the feeling of use on health appliances. "Therefore, we consider that if we can't use a three-dimensional printer to directly shape, can we make an injection molding mold for molding?" (murakaokazhen)

based on the above considerations, the company introduces a three-dimensional printer that can use not only ABS resin, but also polycarbonate (PC) and ppsf. First of all, ppsf material with excellent heat resistance and strength was used to make the trial mold. However, it is not easy to remove the test product of elastic material from the mold when developing the product mold similar to fine brush. The reason is that the die surface segment difference within the minimum lamination thickness (0.254mm) that can be achieved with ppsf material will cause great friction on the surface of the formed products

therefore, the company made the mold with PC material this time. Because PC material can achieve 0.127mm thinner layer thickness than ppsf. As a result, the test product of the elastic material was successfully removed from the abrasive tool (Fig. 2). At the same time, PC materials are impeccable in both heat resistance and strength

Figure 2 the trial mold made of polycarbonate (PC)

in the trial production of brushes with slender protrusions (about 1.5mm in diameter) densely arranged, it is required to have high demoulding property. Because PC can carry out high-precision (small segment difference) shaping, it is suitable for the trial mold of this shape

as a result, the company concluded that "almost all the test products of elastic materials can be realized by using PC material molds" (Murakami Kazuo) (Figure 3). However, as introduced at the beginning of this article, even if elastic materials are used, the test products will still be damaged when higher heat resistance and strength are required. Therefore, ppsf/ppsu molds are used instead of PC materials (Fig. 4)

Figure 3 massage appliance made by roller forming with PC trial mold

in order to test the use feeling of this product (massage appliance), the part contacting the user's skin should use the same material as the finished product. Therefore, the trial mold made by the three-dimensional printer is used for roller forming. In addition, the parts are directly trial produced by the three-dimensional printer

Fig. 4 damaged trial mold

when the injection pressure is high, forming may lead to mold damage. Akaishi retained the damaged trial mold to prevent forgetting such a failure lesson

in addition, during the formation of PA and polypropylene (PP) materials, the company adjusted the manufacturing method and material of the test products according to the material of the products (Fig. 5). For example, moulds made of ppsf materials are used due to heat resistance problems. As mentioned above, even if the product material is elastic material, the material of the mold is basically PC material, and sometimes ppsf is used as needed. When the product material is PA, PC material can be used for direct molding of the trial product to play a substitute role. Therefore, according to the situation, injection molding and direct molding will be adopted respectively

Figure 5 differences in trial production methods when using

products made of ABS and PC, we will consider whether to use trial products directly shaped by 3D printers. When PA, PP and elastic material test products are needed, ppsf or PC molds are manufactured with a three-dimensional printer for injection molding. When the material is PA, the direct shaping of PC will also become one of the options

in order to give further play to the advantages of 3D printers, the company is currently trying to electroplate the surface of the produced mold. This measure is also introduced to solve the eternal problem of accumulative formation - segment difference * 2. If the demoulding property is improved by electroplating, the variety of available materials is expected to increase significantly

* 2 although the surface has been simply polished, polyurethane has strong adhesion to the poor mold section and cannot be formed

the company not only carries out the trial production of its own products, but also starts to contract the design and trial production business from the outside * 3. Therefore, the company hopes to make full use of the advantages of 3D printers and continue to increase the number of orders for trial moulds and other businesses

* 3akaishi company once established a new Department called modeling group when it carried out this business. Besides the official website, the company also launched a website to introduce the modeling business (URL:)

resin mold is also used in stamping processing.

the trial mold used for injection molding is made through three-dimensional printer, which can improve the efficiency of the trial production process. Wang Zhonghui, a former three-dimensional printer, believes that first of all, we must create an innovation ecosystem of graphene. There are many ways to do this, and the available materials are also extremely rich. In addition to using 3D printers for direct modeling of test products, if the mold made by 3D printers is considered, the test products that can be obtained quickly and cheaply will be expanded to a larger range

as a way of using the mold, it can not only be used for injection molding, but also for stamping processing. In the takasha Manufacturing Institute of Mitsubishi Heavy Industries, in order to carry out the trial production of components of gas turbine burners, resin molds made by three-dimensional printers are being studied (Fig. 6)

Figure 6 resin mold for stamping processing manufactured by three-dimensional printer

in the burner test, although metal stamping parts are essential, if the mold is made in the trial production stage and tested repeatedly, it will lead to a waste of cost and time. If the resin mold can be used for metal stamping, this topic can be easily solved. Mitsubishi Heavy Industries concluded that for nickel alloy flat plates with a thickness of more than 5mm, resin molds made by three-dimensional printers can be used for stamping

as a way of using the mold, it can not only be used for injection molding, but also for stamping processing. In the takasha Manufacturing Institute of Mitsubishi Heavy Industries, in order to carry out the trial production of components of gas turbine burners, resin molds made by three-dimensional printers are being studied (Fig. 6)

resin mold can be used to bend nickel alloy plates with a thickness of more than 5mm by stamping. At present, it is in the stage of "installing the resin mold on the stamping machine to confirm whether the metal plate can be bent" (Yinggang Haraguchi, head of the production technology section of the blade and burner Manufacturing Department of Mitsubishi Heavy Industries prime mover business headquarters)

in addition, Gaosha Manufacturing Institute is using 3D printers for some molds used in dewaxing casting (lost wax) in the field of precision casting. Although the main body of the mold is metal, when the shape needs to be changed due to design changes, a part of the mold is made with a three-dimensional printer, and then matched with the ordinary mold

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