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Application of inner lamination of automobile plastic decorative parts

2021-09-03 14:51

In the automobile plastic decoration products, the lamination technology of the mold occupies a place. Molding manufacturers can choose from a wide range of process technologies to achieve labor and other cost savings.


Among several methods of laminating a fabric or blanket onto a plastic base in a mold, low pressure molding is the basis. These in-die lamination techniques utilize molding pressures of no more than 1,000 psi, which gently compresses the outer material. Various processing techniques utilize a wide variety of equipment, including horizontal and vertical injection molding machines with different die types, as well as vertical punching machines, and mobile extruders for depositing melt


Why is lamination technology increasingly used in automotive interiors? Adding a thin layer on top of plastic, which is usually a solid form, enhances the appearance and enhances softness and texture. Advantages of one-step in-die lamination (or "pad forming") over conventional post-die lamination include the elimination of multiple process steps and dirty adhesives, reduced labor and part handling, and a stronger melt bond than adhesives can provide. The ability to reduce mold closing tonnage requirements allows the use of smaller presses and savings in machine construction costs compared to conventional injection molding. The lower pressure eliminates the need for thick plates. (All in all, machine suppliers predict that their in-die laminating systems can reduce production costs by 15-30% compared to traditional methods.


Inner lamination usually does not require preforming the outer material before bonding it to the hard base. Preforming is still feasible for deep drawing.


Molding manufacturers should expect a slightly longer laminating cycle in the mold. But moulded finished products can compensate for this. The new in-mold cutting tool eliminates the need for secondary finishing of laminates, says Helmut Teckardt, head of low-pressure molding technology at Battenfeld Injection Molding Technology.


One exception is felt bonding, which is a thicker material that is difficult to cut in the die and still requires post-die trimming in most cases.


Indie lamination is well established in Europe, where auto parts manufacturers use it to produce door panels, steering wheels, glove box knee pads, rear frames, roof covers and trunk liners. Ralf Liese, managing director of Krauss-Mafia in the US, says these advantages are already recognised in Europe. But things are different in the United States. Door trim is a decisive application of die inner lamination in automotive field. Apps are popping up in dashboards, seats and back shelves.


Closed or open?


Lamination technology is spreading around the world. At least eight machine manufacturers offer improved in-die laminators in various styles: Battenfeld, Dieffenbache, Engel, Husky, FerromatikMilacron, Hettinga, Krauss-Maffei and Ube. Some new technologies can use the traditional press, so molding manufacturers do not need to buy special machines. Milacron, for example, provides non-specialized components that allow users to operate at low pressure on conventional presses.


Die lamination technology can be divided into two categories: closed or open die. They can be injected, injected, or molded. "A lot comes down to the size of the piece, the outer material and the thickness of the base," said Jeanine Nettinga, president of Hettinga Technologies, the first U.S. company to commercialize the low-pressure molding process. High temperatures and pressures can create "flare spots" on the outer material facing the gate, so some type of loose cloth or barrier material may be required for the outer material.


This barrier will make the parts more expensive, but it will also give the molding manufacturer more options in the laminating methods they wish to use. First and foremost, the use of foam liner outer material without barrier material requires injection/die casting or die opening processes. This double layer foam (TPO outer layer and foam liner) disintegrates if resin is injected. If three layers of construction (outer material, foam and protective PP liner) are used, then the inner lamination of any open or closed die can be utilized.