Multi-color injection molding mold assembly

In-mold labeling, decorating and fabric lamination film is becoming familiar with the technology. So, in the mold to complete these processes without the need for secondary operations, followed by the next technology trends will be what is it? Now can think of is mold assembly.
With molders, mold makers and machinery manufacturers to discuss this topic in the process, reporters found that the "in-mold assembly (IMA)" the term, they have very different definitions. This article also conducted in-depth discussion of this, hope to mold assembly with multi-color injection molding or overmolding (overmolding) to distinguish between the concepts. Although the mold assembly is usually required for multi-color injection molding, but the essence of the concept in the mold of the various separate parts into one whole, and not outside of the various components in the mold by fastening, welding or glue stick combined approach for assembly. Ferromatik Milacron Europe's U.S. general manager Bob Hare said: "If the molding process, the next step of the process also need to operate, the easiest way is to consider using in-mold assembly."
Abstract...Articles section In-mold laminated fabric technology seem very consistent with this definition. But, in fact, it can be seen as a form of embedded shape. Because of this technology is quite enough, this will not rehearse them here. From the examples discussed below can be seen, in-mold assembly is not just overmolding or insert molding, but their combined technologies.
The many advantages of in-mold assembly
Compared with other machining processes, in-mold assembly is not only economic, but also to produce high quality parts. Molders and mold manufacturers Electroform, president of Wade Clark said: "The mold assembly can be more stable quality and performance products, often without a secondary operation warpage or shrinkage."
"You can use a machine, and a smaller die, lower the cost of processing the assembly of each single product, but if you take into account the one-piece assembled into the assembly line assembly line parts and the use of additional Total up all the costs, then, to complete a single piece in the mold assembly of the cost savings are very impressive. "Engel's processing technology manager Joachim Kragl added," to assemble a three component product, for example, choose in-mold assembly, the processors only use one production line. By contrast, the mold assembly will need to use outside the 3 automatic production lines, potentially also increase the likelihood of interruption of production. "mold assembly also eliminates the need for transportation, hoppers, jigs, and ultrasonic welding machine, thereby eliminating errors due to processing, misalignment, abnormal processing or pollution caused by waste and other reasons.Tooling and equipment manufacturers generally believe that mold assembly also has the following advantages: directly from the mold to produce the final injection molded parts, to avoid the generation of semi-finished products; reduce the number of press and die, reducing the demand for manpower and floor space ; to ensure that the injection molded parts to be assembled, in particular, pieces of decorative molding the right mix or combination; can significantly reduce the production of the various components separately and then assembled the total time spent. In addition, the mold assembly can also produce those due to cost or technical constraints can not produce parts using conventional methods.
 General, in-mold assembly production of injection molded parts have certain requirements, because the mold cavity with the same number of cost than the standard die and 30% to 70%. Professionals believe that about 250,000 more demand for in-mold assembly. They also believe that the mold assembly in Europe, North America faster than the speed of development, and mainly for the automotive and consumer goods, a small injection molded parts for medical.
Development to date, in-mold assembly many unique technologies and applications in the mold in more innovative applications, instead of molding equipment improvements. Arburg, Engel's, Krauss-Maffei and Milacron equipment manufacturers that the mold assembly used equipment and other multi-component molding equipment is not much different, the main difference is that the former will be automated operation and subsequent steps integrated together. Krauss-Maffei injection molding business, said general manager Peter Lipp: "As long as the machine has to ensure repeatability and accuracy of the closed-loop process control system, then it can be used for in-mold assembly."
In some cases, in-mold assembly molds suppliers and specific injection molding machine manufacturers to cooperate. An example is the Ferromatik and Foboha companies (German mold maker) co-operation, the molds have one or more of the rotating center of the template, each template has four faces, showing the "cube" configuration. Denmark Gram Technology, Inc. provides multi-faceted "rotating stack" mold, and Demag Plastics Group has a number of cooperation projects. Engel companies choose their own multi-faceted manufacturing laminated mold, or the partners and the North American manufacturing methods. Kragl said, "Now that we have created for multi-component molding equipment, and has a powerful automation capabilities, in-mold assembly will undoubtedly be our focus areas of technology."
To achieve a variety of ways to mold assembly
Mold maker mold assembly has been developed for a variety of application methods, and some use a slide template or template-sided rotating mold, and some are using the traditional linear design or use the updated design of the rotating plate multisection type of stack molds.In many cases, single-sided mold by rotating or sliding movement of the template to change the configuration of the cavity between the injection point. Center of rotation with one or more translocation Tower (turning center turrets), availability of single and stacked die applications more functionality, because the rotation center of each tower has four faces, each face a different executable function. In these applications, may also be used robot or similar device to the cavity, forming a good pass between machines and even injection molded parts.
For example, the mold maker StackTeck will "transfer molding" concept applied to single mold-mold assembly. The company's sales, general manager of Jordan Robertson, said mold load handling device on the mechanical motion through the role of the mold, the injection molded parts from one cavity to another cavity.
Gram Technology, Inc. has this mechanical transmission applied to the product production. Two transparent polycarbonate case in a machine in the two "rotating stack" shape from the mold, and then pass from the other device in a silicone membrane, and embedded in one of case on. When the rotating stack mold the center of the template rotated to a position, two shell contact with each other, then heated again on the engagement surface to be welded together.
Engel companies in this technology to be improved, for the production of liquid silicone rubber and the faucet filter PBT material. The parts assembled by two plastic components, injection molded parts, respectively, each with an eccentric rotating plate in the non-rod device shape. Then, in the mold, injection molded parts using the robot to exert force, to form a fastening structure, thus completing the assembly of parts.
JSW is the first use of single-mold assembly molds one of several companies. The company and Japan's Sakamoto Tool and Die companies developed a snug fit the mold injection molding (DSI) process. The process can be used for molding hollow parts.
The specific method is the first in the mold in the shape of two semi-independent type, by sliding the template they are put together, then overmolded to seal the two parts together. JSW's Chicago Technical Center, said general manager Robert Columbus, in Asia there are two such systems are in use.
Rotating stack mold
Ferromatik Milacron Inc. and Foboha jointly developed a model for the assembly of two components within the assembly system. Foboha sales engineer Lisa Mauro said, TwinCube four surface mold can be printing, labeling and back button (unscrewing) and other functions.
U.S. Stull Technologies is the Milacron / Foboha the system's first users. The company used to produce it with a label insert and fastening components of the storage box. The company's senior director of marketing, said Jason Stull, the system has been installed in the rotation with a 48-cavity stack mold TwinCube the K-Tec device (clamping force of 275t), with a circular cover for the production of fastening the dome of PP.
Stull said the system capacity can be increased to an annual level of production of hundreds of millions of caps, and single product prices enough to compete with foreign competitors. The system can also be shared with the conventional production line used to produce the same parts. But the company hopes the system can use only half of the labor and 70% of floor space, while higher productivity and more stable quality.
Gram's Spin Stack Technology (Spin Stack) mold with up to four side next to the edge of the small center stack structure, each laminated structure, each has four faces and each face of the rotation angle of 90 °. Jes Gram, President of the company, said the company used to test the mold assembly of the first project is the production of costumes, apply deodorant roll-type spherical container. He said: "Most of this product is produced as spherical, and usually the first type of shell forming a two and a half, then welded together." This vessel wall is very thick, can withstand harsh processing conditions of the welding process, and requires the shape of the final shape must be spherical in order to disperse in the deodorant on the smooth rolling. The type of the two and a half together in the mold the mold is Gram mold.
KTW Austria is a manufacturer of high number of rotating stack mold cavity mold manufacturer, may apply to the personal care and consumer market cap mold. The company uses a Gram's Spin Stack technology to produce edible oil dressed container cap assembly. KTW managing director Claus Ziegler said, by the time of the injection molded pull tab, bottle cap and screw-shaped oral composition. "Can not be completed using the injection-molding parts assembly, in-mold assembly is the only feasible way." If the mold were forming a separate individual components, you may need 8 ~ 9s time forming the matrix, 4 ~ 5s time cap molding, and use KTW has provided a test mold cavity 16 can be 8 ~ 9s in forming the entire structure. Currently, the company produced a number of mold cavities can be as high as 48 or 64 cavities.
Molders and mold makers MGS Manufacturing Group has produced a number of in-mold assembly of plastic parts, including a fastening structure of the accommodation zone, on which there is a fixed non-removable locking nut. The entire molding process eliminates the need for 4 to 5 devices, and multiple downstream devices.
Complex overmolding
MGS director of marketing John Berg said: "The greatest advantage of mold assembly is assembled by the process of injection molding the parts are connected together, as a whole will not separate, but some components can be free." More and more companies started using different materials bonded to each other without forming a mechanical interlock with the hinge connection, and all accessories can freely open and close without the risk of separation. This traditional overmolding are very different, because the traditional craft to the different materials bonded together with each other for the purpose. Here, the mold assembly will be a material injected into another material, rather than to glue them.
Use this method for in-mold assembly idea originally came from Fickenscher company. Mold supplier Multiject IMA's president and Jack Elder said the company started from the 1980s, the use of different types of polymer forming the assembly with activity features injection molded parts.
Elder won in 1995, the company's North American region Fickenscher exclusive technology licensing, technology transfer IMA the first time the United States. The company manufactured and sold for Fickenscher process dies, and began to use the technology on their equipment (and other multi-component injection molding technique).
The process uses a special "L - switch to the" core system, has been widely used in European automotive, toy and electronics manufacturing. The application of two best-known case is that with the active arms, legs and head of the toy monkey (manufactured by the PlayMobil) and consists of three components assembled automotive HVAC systems hopper windows. This hopper windows Innatech company consists of a blade, a connecting rod and a framework, which leaves the use of PBT material, connecting rod of ABS material, the plastic frame is made of PP materials. Elder said: "This is a very complex injection molded parts, but still using the mold assembly technology than the traditional way of assembling the same injection molding parts that cost is lower."
MGS companies use this method of forming a multi-component molding with a rotating central structure of a medical valve. The injection molded parts assembled by the three components, namely the PC, PP and TPV materials.
Engel is making a four yuan car electric switch components. Three of injection molded parts made from different resins, and each other to the relative motion. All four injection molded parts are molded in a mold at the same time, the materials used are nylon, and two grades of POM. Single mold cavity has three rows, were arranged in the structure of 4,4 and 8. Kragl recalled: "Do not use the three molds and the corresponding downstream assembly line equipment, and more, we have a 120t clamping force injection molding machine will be able to complete the four injection molded parts production, the entire cycle time of only 38s . "
Another example is electrical with a screw lid. Lid using glass-filled polypropylene, nylon 6 and screw system. Kragl explained: "screw is locked into the box, so that they can only be rotated, and will not fall off and be lost." Engel in a 2 +2 cavity mold in the shape of the injection molded parts, the whole forming period of 25s.
Engel's first use of in-mold assembly technology to produce a baby pacifier. The product with the use of nylon and polypropylene materials obtained rings and masks. Due to security regulations require these structures can not be separated, so the company chose Engel mold assembly. Kragl said: "We can not be used to bond different materials to produce this product, so if you want to separate them, and would have broken them."
In-mold assembly can also use the same material forming the different components, and to ensure the free movement between components. Such a benefit is injection molded in a single barrel with standard injection molding machine out. The process by Ferromatik Milacron introduced in 1995, and was called "Ice Cold Trick". As its name through the quenching of ways to avoid second injection of the same material at the interface occurred due to infiltration and adhesion molecules together, thus obtained by the same kinds of materials assembled with functional activity of the injection molded parts.
Ferromatik's Hare said: "The first injection the temperature is much lower than the conventional injection molding temperatures." In the mold using a small refrigeration unit and cooling inserts, the temperature of the mold can be reduced to around freezing point of water, even lower (-5 ℃). Hare added: "This is the material of a very high demands, we must be the same as the crystallization of nylon, but also can be a lot of filling, to ensure that the material does not occur when the first injection of contraction." At present, the process has been be used to produce an interlocking hinge device.
This "Ice Cold Trick" is also used by other manufacturers of in-mold assembly used. Gram Technology, Inc. and Foboha's multi-faceted rotating stack mold to allow additional cooling time for the molding time for the cooling process components, molded products to ensure their adhesion does not occur. Valve is a two-component medical success story. The injection molded interior with a sliding insert, by Gram's Spin Stack molds from forming. In addition, Gram has also introduced a mold cavity with 24 +24, juice boxes for the production of the triangle and the dumping of mouth screw cap, LDPE material obtained by the thread dump port formed within the lid of PP copolymer . As the lid for extra cooling processing cycle, and LDPE materials, low melting temperature than polypropylene, so set aside plenty of time out for "very cold" treatment, the entire production cycle of only 8s.
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Peter Huang