R&ID

March 2017

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ESTG

Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Leiria
(School of Technology and Management, Polytechnic Institute of Leiria - PORTUGAL)

Mechanical Engineering Department

“Applicability of Additive Manufacturing in the Injection Molds Industry”

Autor

Nilza Catarina Rodrigues Reis

Dimlaser

Dimlaser as co-participant in the project

Abstract

The injection molding industry for plastics is nowadays one of the most solid sectors of activity at the national level, recognized worldwide for its quality. However, in the aggressive and competitive global economy of today, innovation and consequent rapid response are the most important factors of competitiveness in today's market. Allying the production of injection molds to the new technologies of manufacturing additive appears as an alternative for the reduction of cycle times and production costs. 


In order to better study the feasibility of additive technology in injection molds, three case studies were selected using the selective laser melting technology (SLM). This process was chosen because its products present similar characteristics to the ones obtained by conventional methods, concerning to materials, hardness, surface finish, possibility of machining, among others. 


In the present project, the additive technology, SLM, was used to create molding areas with conformal cooling channels, the result of which was evaluated through numerical simulations and later with practical / real results. 


There are three case studies presented, the geometries belong to two types of industry, medical and automobile, the project intends to show not only the versatility of geometry, but also the possibility of minimizing the costs of additive technology, for example, one part is made in the conventional process and the other in the additive process. 


In order to quantify the impact of additive manufacturing on this industrial sector, an evaluation was made of the costs and times associated with the additive technology and the added value that the process could bring to the injection mold industry. 


The results show that selective laser fusion technology (SLM) not only makes it possible the reduction of cycle times and warpage of plastic parts, but also shows that it is a technology with a significant cost, to be improved in some aspects, such as, roughness and geometric limitations. The SLM process, in most cases, is not an end-user technology, but rather requires adequate integration into the manufacturing process to respond to the limitations presented.

Analysis of the Case 2

Sensor HousingIn case study 2, Sensor housing, the additive mold sample shows better results when compared to the conventional mold sample. The MFA sample is presented without sucks, without burrs, compacted and the cycle time is shorter than that requested by the customer (the customer indicates 15 seconds, while the cycle time obtained to inject the sample was 12 seconds). The mass of the plastic part is homogeneous between moldings, for different processing conditions. These results indicate that for a cycle time of 12 seconds the part is compacted.


Conventional and additive


Real Results of the Convencional Manufacturing (MFC) and Additive Manufacturing (MFA)


Break-even for Case 2: Sensor Housing