ENGEL, the injection molding machine manufacturer and system solutions provider, announced that it will show a model part of a door module produced using the organomelt process at K 2019. The production unit of this part is the first system in the world that uses infrared heating technology to form three different thickness organic plates and can form high-quality visible surfaces in the same injection processing stage. The system is equipped with three ENGEL easix articulated robots that can run simultaneously.
"In terms of lightweight applications in the automotive industry, thermoplastic composites are becoming increasingly important," said Dr. Norbert Müller, head of the ENGEL lightweight composites technology center. On the one hand, thermoplastic composites can integrate the formability and functionality of prepregs, thereby effectively reducing unit costs; on the other hand, the use of thermoplastic polymers alone makes it easier to formulate recycling strategies.
"At the end of its useful life, returning composite parts to the material cycle is one of the top priorities for the continued development of the electric vehicle industry," Müller said. "Thermoplastic composite solutions are becoming more and more widely used, even in aircraft manufacturing.
ENGEL uses the organomelt process to meet the development needs of sustainable transportation. In the organomelt process, a fiber-reinforced prepreg made of thermoplastics, such as organic sheets and strips, is first heated, then placed in a mold to form it, and then it is overmolded with a thermoplastic. This mature process has been used in high-volume production, enabling fully automated production of products such as front-end brackets.
With the development of this process, ENGEL further cooperates with its customers and partners to try to produce "composite parts with target load distribution".
"In the future, several different prepregs will be used in combination for each component to develop structural components custom-made based on the shape of the relevant component and different stresses in various areas inside the component," explained Müller. "The production units to be exhibited at the K show will clearly show the great potential of this application."
This process was developed by ENGEL in cooperation with automotive supplier Brose, and is currently the only system in the world that integrates an infrared heating furnace. It can simultaneously process 3 different shapes and thicknesses of organic sheets in an automated process. According to the results of various simulations conducted by Brose in the early stage, based on the load distribution, the selective selection of organic sheet materials can meet the stress requirements of different parts of the component.
Ultra-compact integrated infrared heating furnace
One of the challenges in processing organic sheets is the heating of prepregs, and the time it takes to heat and cool them depends on their thickness. Because the heated prepreg needs to be fed quickly and directly into the mold, it is important to heat the material quickly without damaging it.
The organomelt production unit is based on a duo 3660/800 injection molding machine and has two additional integrated infrared heating furnaces.
A vertical infrared heating furnace is located directly above the clamping unit and is used to heat organic sheets with a thickness of only 0.6 mm. In this way, the thin organic sheet reaches the mold in almost no time, ensuring that the material still maintains a sufficiently high temperature during the molding process.
A standard horizontal infrared heating furnace on the square base of the movable template will be used to heat 1mm and 2.5mm organic plates. This arrangement shortens the distance between the heating furnace and the mold and saves space.
Both infrared heating furnaces are developed and manufactured by ENGEL. They and 3 easix robots are fully integrated into the CC300 control unit of the injection molding machine, which can be uniformly controlled through the touch screen.
Three organic plates are heated at the same time, and then two of the three easix robots are used to handle the organic plates. They are located next to each other above the clamping unit. When the first robot handles two thicker organic plates, the second robot carefully handles the thinnest plate. The third robot is located next to the clamping unit, and its task is to take out the molded parts and simultaneously place one of the three organic plates into the mold for injection molding.
These organic sheets are glass-fiber-reinforced polypropylene composites provided by Chinese raw material producer Jin Huan.
When the mold is closed, the organic sheet is formed.
Next, glass fiber reinforced polypropylene was used for secondary molding in the same pair of molds, so that the ribs were formed on the back of the part, and the appearance of the leather texture was formed on the visible side.
"When directly overmolding the organic board, we can get an excellent leather texture appearance, which was not possible with organic boards before," Müller emphasized. "This work laid the foundation for the future production of large structural thermoplastic doors using the organomelt process."