Metal replacement on an automotive door carrier

Metal Replacement on AR Giulietta door carrier

The use of plastic materials allows to find solutions which are in line with two important needs of the automotive market: lightness and integration of functions. A carrier made out of plastics allows to achieve up to 4kg of weight reduction for each car, besides a much easier assembly process.

Target:  

 Same performance of the aluminium carrier

 Optimisation of structure and weight

 Integration of function

 Easy version change

Activity:

  •  Material selection
  •  Mold Flow Analysis to predict warpage
  •  Structural Analysis
  •  Manufacture of a 1+1 cavity mould
  •  Production

Choice of plastic materials

In order to achieve the best weight/performance ratio many different technopolymers have been studied.

Final choice has been a PP + 40% LONG glass fiber, which, thanks to high mechanical performances is able to meet product specs with a limited weight.

 

Use of simulation to prevent critical aspects

For its specific features this material requires a deep attention to rehology, mainly for the potential deformation related to the fiber orientation.

The simoultaneous verification of rehology and structure by our CAE Dept. has individuated the relation between the two aspects and has find the best solution for injection gates and part geometry.

 

Hybrid approach to mouldmaking

The need of having in a very short time samples in final technology for testing, but at the same time to reduce investment has suggested to proceed with an hybrid mouldmaking approach.

Instead of making a dedicated prototype mould, the decision was to make directly the final mould, but with surface inserts made of aluminium.

In this case the outer part of the mould and the injection system (4+4 valve gates) have been used for the serial production.

 

The mould configuration choosen to optimise the use of existing injection machine is a 1+1 cavity (R+L), with interchangeable inserts for the loudspeaker and window lifter versions.

 

Product/process validation and serial production

The aluminium cavities have been used to produce parts which have been tested for the product validation and to verify the process reliability.

After this the final cavity inserts have been manufactured and with them the pre-series have beeen produced for the SOP release.

The AR Giulietta carrier is produced inside the Meccanica Generale plant, following the quality standard of the automotive market.

 

 

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