Quality control remains an essential aspect of the entire die casting process. Ensuring stringent quality control guarantees that the finished products live up to the expected standards set by the manufacturer and the clients as well. In die-casting, quality control is an extensive process and is followed throughout due to the presence of numerous issues that affect the overall process of casting materials. Furthermore, the process of maintaining quality control needs to be specifically focused on the individual products being manufactured.
The die cast process involves many failure modes in generating a quality material. Some of the typical problems in the process like porosity, dimensional incorrectness, appearance issues, casting leakages, etc., will severely affect the output of the process. In quality control, there exist various techniques for detecting and preventing each of the failure modes. Some of the techniques in quality control for each of the failure modes are described below.
Porosity
X-Ray is the main technique used to detect porosity in a material. It is effective in accurately finding out the total porosity amounts in the casted material. However, it is unsuitable for determining the location of smaller voids in the material. The other efficient tool in estimating the porosity levels is destructive machining.
It also suffers from numerous problems, mainly the high cost, and often provides incorrect estimations. Above all, prevention is the best method available in controlling porosity in the die casting process.
Dimensional Issues
In line or off line gaging is the preferred method for detecting any dimensional problems. The number of times the material is subjected to inspection is determined based on the severity of the problems and the stability of the process.
Methods such as poke yoke are also effective in the prevention of any dimensional problems, as issues in the tooling process are the major sources of dimensional problems in die casting.
Appearance Issues
Many of the issue pertaining to the appearance of the casting materials can be detected by a visual inspection. This is a cheap yet unreliable method for detection. To aid in this, vision systems are deployed but are not extensively used for this issue due to its variable nature. Like all cases, preventing them from occurring is still the best method available.
Leaky Castings
An air decay leak tester is utilized for detecting any leaking castings. It has several advantages like a quicker test cycle, but it is not suitable for castings that have zero leak requirements. Preventing these defects is also a part of the process control.