Abstract:
In the present world with the increasing use of Aluminium alloy wheels in automotive industry
the Aluminium foundry industry had to focus on the quality of the products. The quality of a
foundry industry can be increased by minimizing the casting defects during production.
Aim of the current study is to study the production line of an aluminum alloy wheel
manufacturing industry and to improve the quality of production using quality control tools.
This study shows the systematic approach to find the root cause of a major defects in
aluminium castings using defect diagnostic approach as well as cause and effect diagram.
Casting defect analysis is carried out using techniques like historical data analysis, causeeffect
diagrams, design of experiments and root cause analysis. Data from X-ray inspection
(Radiographic Inspection) have been collected along with the production parameter data.
Using check sheets data has been collected and all the defects have been studied. Using
Pareto chart major defects in the aluminium castings were noted. The major defects for the
rejections during production were identified as shrinkages, inclusions, porosity/gas holes and
cracks. Each defect is studied thoroughly and the possible causes for the defects are shown in
Fishbone Diagrams (Cause Effect Diagrams). As the shrinkages mainly occur due to lack of
feedability during the fluid flow the stalk changing frequency is noted along with the
shrinkages defects and a relation is drawn between them. As hydrogen forms gas holes and
porosity in the aluminium castings the amount of hydrogen present in the molten metal is
studied by finding specific gravity of the samples collected. The molten metal temperature
effects the amount of the hydrogen absorbed by it. .So the effect of molten metal temperature
on the specific gravity of the sample collected have been shown in a graph and the optimum
value for molten metal temperature was found out.
