Polypropylene Copolymer Material for Automotive Thin Wall Front Bumper with Integrated Grill Application 2018-01-0153

This paper describes modified polypropylene copolymer (PPCP) material for thin wall front bumper development (2.5 mm) with integrated grill in automotive application. This compounded PPCP material has optimized flow behavior, tensile strength, modulus, impact strength, and thermal properties to meet the functional requirements. This is a ready to mold material used in injection molding process. Front bumper and grill are functional components with slow speed impact requirement to absorb impact in real world. These parts have precise fitment requirement under sun load condition. Front bumper is also having other critical criteria with respect to vehicle variants such as aesthetic mold-in-color finish as well as painted finish. Grill has air entry performance criteria to ensure cooling efficiency in intercooler compartment.

In this paper, PPCP material filled with talc filler has been explored for thin wall front bumper part with a wall thickness of 2.5 mm and with an integration of functional grill part. Structural durability of the design was validated by virtual engineering. Part design and material combinations with better tooling design iterations were analyzed by using mold flow analysis. Complete product performances were validated for predefined key test metrics such as slow speed impact, structural durability, thermal aging, cold impact, scratch resistance and weathering criteria. This part met required specification. This PPCP material based thin wall front bumper integrated grill part has various benefits such as potential weight reduction (400 g) leading to low emission, good surface quality, dimensional stability under sun load, NVH improvement due to grill integration and considerable cost reduction on part, tool and process as compared to conventional way of doing front bumper.