Aluminum Motor Housing for E-Automobile

Aluminum motor housing has following features
  • non-uniform wall thickness
  • relatively thin wall in the middle
  • thick wall in the corner
  • complex shape
  • quite a few of holes and ribs

The weight of motor housing is about 8.89kg and the casting material is A356.The overall size is 290mmx220mmx180mm.The main thickness is 6-10mm and the thickest area is about 20mm and the thinnest area is about 5mm.There are complicate water line inside housing.It is difficult for casting and easy to have some defects such shrinkage porosity,cold shut etc.It is very hard to control the quality.

We are professional aluminum casting factory and good at producing all kinds of motor housing.

Aluminum motor housing has to reach requirement as following
  • Airtightness:there will be no leakage for 130 seconds at 510kPa pressure.
  • Mechanical properties:Tensile strength more than 260MPa.Yield strength more than 190MPa.Elongation more than 3.5%.The hardness more than 85HB.Any kind of crack,cold shut,shrinkage porosity is not allowed.

By low pressure die casting,the pouring speed can be controlled.The castings are formed under certain pressure,which can improve the density and mechanical strength of castings.The feeding capacity can be done via pouring system so the extra sprue is not required.Therefore,low pressure die casting is best option for production of this kind of motor housing.

The tooling is equipped with double pouring system,which can avoid quick cooling of molten alloy.The cavity and core use H13 steel.The casting parameters are temperature of pre-heat for mold is 350℃,the pouring temperature is 710℃,the pressure is 0.022-0.004MPa.

By simulation,there is shrinkage porosity in castings as picture.It happen to pouring gate and sand core.The reason why there is shrinkage porosity is that the wall is relatively thick in these areas and sand core affect cooling time and feeding capacity badly.


Mold optimization

Reduce upper core diameter and increase pouring gate dimension,which can avoid feeding path to stop too earlier and improve feeding capacity to some extent.

Add cooling coil into upper core in order to improve the cooling ability around sand core.

coil cooling
coil cooling

After optimization,there will be no more shrinkage porosity in the area where it used to be.

No Shrinkage Porosity
No Shrinkage Porosity

By x-ray,there is not any kind of defects.

X-ray test
X-ray test

By airtightness test,there is not leakage for 130 seconds at 510KPa.

Airtightness Test
Airtightness Test
  • By professional simulation,there is shrinkage porosity during solidification.
  • After optimization,the feeding capacity is improved.The shrinkage porosity is totally avoided.
  • Optimization is proved.The production can be proceed accordingly.

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