The European Union's "Horizon 2020" plan is implementing the "ComMunion" project research, which aims to develop new technologies for connecting metal and composite materials to manufacture composite parts whose main body is made of steel and partially reinforced with fiber-reinforced plastic to meet the high mechanical requirements of parts Performance, low weight requirements, and further meet the needs of automotive, aerospace, construction and other fields for weight reduction, energy and resource conservation. The project is jointly organized by the two Fraunhofer Institutes in Aachen, Germany, the Production Technology Institute (IPT) and the Laser Technology Institute (ILT), together with 14 partners from industry, research institutions and academia. carry out.
The new hybrid material manufacturing process uses a combination of laser texturing and laser-assisted tape laying. The first step is the laser texturing process. The surface of steel parts is pre-treated with a laser to give it a specially designed, precisely defined texturing structure. The roughened surface allows continuous fiber-reinforced thermoplastic lightweight materials to be bonded directly to steel components. The second step is the laser assisted tape laying process. Firstly, the fiber-reinforced thermoplastic composite material is connected with steel parts by a tape laying process, and then a laser is used to heat a local area of the thermoplastic tape to be connected to the steel surface, and the molten base material flows into the laser texturing area. After the molten material has consolidated, the strip with embedded unidirectional fibers is bonded to the roughened surface of the steel component. This bonding is a mechanical connection and requires no additional pretreatment or additional adhesive.
The combination of these two laser processes becomes apparent when the mechanical properties of the part need to be locally strengthened without significantly increasing the weight of the part. This method is particularly suitable for large-scale production. First, the composite material strip is laid without further post-processing steps to cure the material. Second, the precise local heating can reduce deformation and residue when connecting two materials Stress; third, the laser texturing process can be applied repeatedly and accurately to metal surfaces that need texturing; fourth, the laser is not affected by any tool wear.
The research team has completed the first demonstration prototype made of high-strength steel and unidirectional fiber thermoplastic strips, a lightweight rocker panel, to test the main functions of the combined process.