Inspection on Investment casting
To supply qualified investment castings to customers, inspection is a very important process after the castings completed. This will help to avoid costs that might be caused by scraps after castings received by customers.
Before delivery, we usually do the below inspections on the investment castings.
1.Material Inspection
a.Chemical components inspection
We will test the material to analyze the chemical components of the cast materials. Thus, to ensure the percentages of all elements are within the required range. The material inspection will be done before casting and after casting. Two processes are mainly used to test the chemical components of materials.
*One is testing the chemical components by spectrum.
 |
*The other is inspecting the chemical components by physical test.
 |
b.Mechanical property inspection
*Tensile test
*Impact test
*Elongation test
2.Dimensional Inspection
Dimensions are very important for customed investment castings. To guarantee the final assembly, the dimensions cast should be as accurate as possible. Before delivery of castings, we will inspect all dimensions. There're also two ways to test the dimensions.
*One is testing the dimensions by instruments, such as callipers, inside micrometers, depthometers, height gauges, dial indicator, etc. For complex or important components, CMM is used to test the dimensions of the castings. It's much more accurate.
 |
 |
*The other is testing the dimensions by gauges. Sometimes, it's difficult to measure the dimensions by instruments. Or it's not convenient to measure each part during mass production. In such situation, we usually make gauges to test the castings, just to ensure the assembly of the components.
 |
3.Surface inspection
*Surface defects
To check whether there're surface defects such as, sand holes, porosities, dents, fins, trimmings, etc. Such defects have to be repaired by certain reparing methods. These defects can be tested by visual inspection or by magnetic test(MT).
*Surface roughness
*Surface coating layers
4.Inner structure inspection
*NDT, such as UT, X-ray test.
In such way, we can know whether the inside of the castings are with defects or not. And no need to destroy the castings.
*Section test.
Sometime, we need to section the investment castings to check whether there're any defects inside the castings. We can see the defects visually in this way. But the products are not usable any longer.