Investment Casting Quality Control
Quality is the core of all products or production. Quality control will be in each step of production. Same in the investment casting industry. Since we founded in 1997, we are proud of our investment in casting quality control and standard. we sure that each product exported is strictly tested and qualified. Every client gives us a high evaluation.
In our foundry company, We strictly implement our quality control system and measures according to ISO quality management system.The departme structure is clear in our company, and each department has the responsibilities and workflow of each department. Especially in quality control, there are three people in each process. They are on-site inspections, random inspections, and final inspections.
Each order has a strict set of QC flow charts and procedures. From product design, mold making, sample production, bulk production, inspection, packaging, delivery. Every process is well documented. Every customer, every order, we will create a set of files record and save. Our earliest file was made in 1997.From that time,we have started recording each order quality control in our factory.
Investment Casting Quality Control testing tools and Inspection items
In terms of testing tools, we have different types and specifications of inspection tools and advanced testing equipment.
- Vernier caliper
- Coordinate Measuring Machine (CMM)
- Height gage
- Thread Gage, Homemade or customer And so on.
In inspection items:
- Quality Control & Inspection of Equipment
- Wax inspection as well as final inspections.
- Accurate physical and chemical testing (Non-destructive testing) performed
- Spectrographic analysis
- Analysical processes such as statistical process control and inspection.
- Mechanical and Physical testing equipment
- Corrosion Testing
- Mechanical Testing – tensile, impact, hardness testing.
- Process Control of Waxes and Slurring
Raw Materials Quality control
From wax, steel materials. wax, and glue, and additional materials. It will be shown the Quality certificate when we get it from our suppliers. AND we will make the second inspection when raw materials arrived. Each material has its own quality inspection record.
Investment Casting appearance Quality control.
Common surface defects of investment castings are scales, air holes, sand holes, cracks, shrinkage cavities, etc. it is a harmful defect. It can be checked by eyes. In our investment casting foundry, it is 100% carried out, and need to make sure there will be no defects on the surface of investment castings.
Our casting quality control expert. any castings with such defects must be picked out and can not be delivered to our customers.
During the final phase of inspection, parts are inspected and compared to the casting quality control plan and written process instructions. Lastly, the casting quality results are documented and stored .to record all the products made from our foundry.
Chemical Composition investment Casting Quality control
We have a spectrometer in our investment casting foundry. Each pouring, we will take a part of. Before the melting liquid is poured from the pot, we will take a sample of molten metal. the casting quality is evaluated in the spectrometer. If the sample is qualified, the pouring will be continuing. If not or needed, the pouring materials will be added to other alloying elements to meet the alloy melt into the required specification. Then make the second test again. Then another coupon is tested and certified to ensure proper chemical composition.
Every alloy melt chemical composition will be tested and recorded. Our Casting alloys standard is from ASTM, AMS alloy specifications. The alloy composition is analyzed by spectrographic atomic absorption (spectrometer), or x-ray fluorescence analysis.
Investment casting Mechanical Properties Quality Inspection
To confirm the properties of the investment cast part are correct, mechanical testing is performed to approve the casting. We will make mechanical properties testing from next aspects:
|Hardness testing||A non-destructive procedure that demonstrates the alloy’s machinability and wears resistance.|
|Tensile testing||A destructive casting quality test that provides ultimate tensile strength, yield strength, elongation, and reduction of the material test specimen.|
|Load testing||This test is performed on the entire casting lot to evaluate its casting quality and to verify that the cast part can carry (deflect) the required or specified structural load when applied. Pressure-containing parts can be hydraulically tested to a proof load or destruction maximum limit.|
Investment casting Quality Control in Dimension
Investment casting is an OEM casting process for various components.Since Variance in cast dimension is an inherent part of the manufacturing process, different products have different dimensions and tolerances requirements. Due to these differences, it can be difficult to expect exacting dimensions throughout the production lot. In order to obtain precision products with ideal sizes and dimensions for their high accuracy. We have to get the result by further machining. In this case, dimensional inspection is vital to guarantee. Below is the common dimensional inspection methods used in our foundry:
|Measuring tools||it is the most direct and simple way to test the dimensions and tolerances by hand. Common used measuring tools for investment castings include vernier caliper, depth indicator, dial indicator, etc. To ensure qualified products, we need to test the product by measuring tools one by one according to the drawing.|
|Testing guage||It is made according to the sizes which will probably affect the assembly or use of products. For threaded holes, we can buy go and not go gauge according to the thread specification directly from the market. Testing guage is mostly used when the dimensions can not be tested by measuring tools directly thread and plug gauges,|
|CMM||It is the most accurate way to test the dimensions of products. But it will add the cost of manufacturers for the high cost of CMM equipment and only few foundries have such instruments. We have our own CMM machine which is made of German.|
Non-Destructive Casting Quality Testing and Inspection
NDT (Non-Destructive Testing) allows us the capability of testing the quality of an investment casting part without any destroying. The most common methods available are listed below:
Dye Penetrant Inspection: Sometimes it is difficult to find the surface defects by the naked eyes, such as tiny cracks, pores, or other surface defects.DPI is a testing method used for surface defects of all alloy investment castings. In this inspection process, a dye solution with color is applied to the surface of the castings. The dye, which is suspended in penetrating oil, finds its way into the surface defects. When a special developer is applied, the defects are clearly indicated under a special “blue” light. The solution is to detect any cracks or other surface defects due to porosity or gas produced on the surface.
No matter what is your final application, every precision investment cast component will be examined, inspected, and approved before sending. We wish we are your first source choosing for precision investment cast parts. Through the above description, you have great confidence in our quality control. Contact us and tell us what you need.