Laser Transmission Welding (LTW) is a well-known technique for joining conventionally manufactured high-volume thermoplastic parts, such as automotive injection molded parts. When LTW is used for additively manufactured parts (typically prototypes, low-volume production, or one-offs), the technology must be developed to overcome the difficulties in welding the parts, that result from the additive manufacturing process itself. Compared to injection molding, additive manufacturing results in an inhomogeneous structure with entrapped air within the volume. Therefore, there is a change in the transmissivity behavior in the weld area due to the additive manufacturing process. In order to make LTW available for additively manufactured thermoplastic components, a process chain was developed to support manufacturing. This process chain ranges from the optimization of the additive manufacturing process to the welding process and is supported by an expert system. For the evaluation of the manufacturing process chain, welding experiments with additively manufactured samples were performed. The transparent samples were welded to black samples with varying process parameters in overlap configuration and tensile shear tests were performed. The additive manufacturing process parameters were used to predict the transmittance of the transparent sample and the weld seam strength of welded parts using the expert system.
Laser transmission welding (LTW) is a known technique to join conventionally produced high volume thermoplastic parts, e.g. injected molded parts for the automotive sector. For using LTW for additively manufactured parts (usually prototypes, small series, or one-off products), this technique has to be evolved to overcome the difficulties in the part composition resulted in the additive manufacturing process itself. In comparison to the injection molding process, the additive manufacturing process leads to an inhomogeneous structure with trapped air inside the volume. Therefore, a change in the transmissivity results due to the additive manufacturing process. In this paper, a method is presented to enhance the weld seam quality of laser welded additively manufactured parts assisted by a neural network-based expert system. The designed expert system supports the user setting up the additive manufacturing process. With the results of a preliminary work, a neural network is trained to predict the transmissivity values of the transparent samples. To validate the expert system, specimen of transparent polylactide are additively manufactured with various manufacturing parameters in order to change the transmissivity. The transmissivity of the parts are measured with a spectroscope. The parameters of the additive manufacturing process are used to predict the transmissivity with the neural network and are compared to the measurements. The transparent samples are welded to black polylactide samples with different laser power in overlap configuration and shear tensile tests are performed. With these experiments, the prediction of additive manufacturing parameters with the expert system in order to use the parts for a LTW process is demonstrated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.