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ABSTRACT:
This paper details the failure analysis of deformed passenger car door lock case and presents a solution to avoid the part deformation during caulking process. This failure was observed during the assembly of case and its cover by caulking process. Mechanical properties and chemical composition of case (Zn Al4 material) has been checked by universal testing machine and spectra material analyser. The material composition having less aluminium content leads to the casting strength and cast ability losses. In order to get the exact load requirement for caulking process, analysis has been carried out by using finite element method. In finite element method, the case and its cover model has created by AUTODESK INVENTOR & stress analysis was carried using same software. The induced stress and deflection are obtained for various load conditions. The experimental measurement was taken from the machine by using load cells. By comparing the experimental data with FEM data we found that the problem happened due to the overload. From this result data the machine design was optimized by changing booster and cylinder which is used to generate the load. The hydro pneumatic circuit of the caulking machine has been optimized and redesigned to avoid future problems.
KEYWORDS:
Caulking process; Failure analysis; Finite element method; Stress analysis
1. Introduction
In the present manufacturing process, there are many types of failure occurs during the operation. The failure can happen due to fatigue, creep, wear and tear, corrosion, chemical composition issues and over load during the pressing. Passenger door lock assembly process contains several stages [1-3]. In that caulking is one of the stages to assemble the case and its cover parts. Caulking is one of the press fit process which is used to assembly the two parts permanently. Here the high force is applied at any one part to deform the material to get the required shape to make both the parts in as assembled condition. Another part should not get any deformation or shape change due to the high force [4-7]. In our case both the parts got deformation during the caulking process. Reason for the failure can be material, machine, method, and man. If the problem is happening frequently, it is difficult to achieve the product quality and functional...