By Jesse Garant Metrology Center
For Casting part types, there are 3 primary areas that have had a large amount of success when adopting CT Scanning. These areas include: Failure Investigation For castings, failure investigation using CT scanning has been the primary need for accessing this emerging technology. When a failure is identified, usually the customer is experiencing pressure by their customer to quickly identify the root cause of the failure in additional to mitigating the financial impact the failure could cause. As a non-contact nondestructive testing (NDT) method, X-Ray and CT inspection can identify internal physical geometry failures without destroying the part and preserving its original condition during the forensic investigation. With CAT scan technology, failing parts can be compared to known good parts or the 3D part data to further aid in the identification of a physical geometry defect that could be occurring. In addition to geometry features being out of tolerance material analysis for cracks, pores, voids, and inclusions can be inspected by size where a single or overconcentration of anomalies could affect the overall performance of the casting. Virtually all types of die castings, sand castings, forgings, and investment castings made from both ferrous and non-ferrous materials like aluminum, titanium, stainless steel, Inconel, copper, and brass have paired well with computed tomography. Reducing Costs Typically traditional manufacturing and inspection techniques have proven to be highly effective in verifying production products. However, during the launch of new products (FAI – First Article Inspection) or annual qualifications of production runs (LAI – Last Article Inspection), measurement costs and time frames can really stack up. When utilizing CAT scan inspection, products can be quickly validated without destructive means to save on costly samples being manufactured and allowing additional downstream testing to be performed on the same component. Furthermore, the utilization of surface profiles and wall thickness analysis in the 3D realm allows for a detailed color map aligned by the customers preferred datum scheme for a visual insight paired with key dimensions being measured. As x-ray and radiography specifications have been beneficial when qualifying castings based upon minimum pore sizes and shrinkage, computed tomography is able to leverage existing standards for inputting the radiography parameters into CT analysis and reporting requirements for performing a comparable service in 3D. Benefiting from Service Labs As the technology is rapidly being adopted and standards are evolving all the time, utilizing a CT certified service lab ensures proper compliance to the latest standards. This ensures the project is completed according to a verifiable process and the experienced lab can not only complete the results but communicate the results. As computed tomography data is complex, large in file size, and new for some people; effective communication is key to ensure all parties are properly informed of the results for effective decisions to be made.
