Study On Injection Molding Process Of Automotive Light Guide With Thick And Transparent Wall

With the development of light weight in automobile and engineering materials rapid,

plastics is widely used to automotive engineering as parts which are from ornaments to

structural components and functional components due to its dominant properties, and the

weight of plastic components in automotive light exceeds 90% of the total weight of the light.

It is known that plastic components in light not only have heat aging resistance but also have

impact resistance, and visual quality and optical property are required for lens and light guide.

Therefore it is vital significant for improving quality, shortening production cycle and

reducing cost to study optimal parameters of injection molding process rapidly.

An automotive light guide is studied in this paper, optimal injection molding process is

achieved through experimental design combined with optimization, and then shrink marks

and warpage in light guide are reduced and its quality and performance are improved. The

research is as follows:

1. To an automotive light guide with thick and transparent wall, its product structure,

main injection molding defects and their formation mechanism as well as relative solutions

are analyzed. The cooling, filling, packing and warpage in injection molding process are

simulated by Moldflow and then the shrink marks and warpage deformation are determined as

optimization objectives.

2. Utilizing an amount of experiment datum obtained by fractional factorial experiment

and mold flow analysis, the effects of the injection molding parameters and their interactions

on shrink mark and warpage are studied by means of variance analysis, and then the packing

pressure, packing time and injection time which are remarkable effecting factors are screen

out..

3. The response surface is designed under the factors having remarkable effects assigned

as variables and shrink mark and warpage deformation as optimal objective, a functional

relationship between the factors and the objective is established through fitting response

surface model and variance analysis of experiment data, and then injection molding process is

optimized regionally.

4. Based on simulation and analysis an light guide is tested proceed, the problems

appeared in experiment are analyzed and figure out, and then the light guide which is satisfied

the requirement of automotive light is produced.