Strict Quality Control Testing Behind Precision Parts

In key industries like aerospace, medical equipment and automotive industry, small defects in parts can lead to serious consequences.

At QD, we know this well. So quality assurance runs through every step of investment casting. It starts from incoming raw materials to finished products leaving the factory.

We use advanced testing methods. We make sure every part delivered to you is flawless.

Whole Process Quality Control System: Comprehensive Protection from Source to Finished Products

In QD, we have established a quality control system that covers the entire process. We make sure every production step is under strict monitoring.

This system mainly includes three stages:

1. Incoming Material Inspection

All raw materials entering the factory. Such as ceramic powder, alloy ingots, binders and so on. They all must go through preliminary testing. We use high precision balances, humidity meters and rapid chemical composition analyzers. We make sure the materials meet standards like ASTM and ISO. Only qualified materials can move to the next step.

2. In-process Inspection

In key processes of investment casting such as mold making, dewaxing, sintering, pouring and cleaning, we set up multiple inspection points. For example:

• Sampling inspection of wax mold size
• Strength testing of mold shell
• Real time monitoring of pouring temperature
• Preliminary evaluation of surface roughness after cleaning

3. Final Inspection

Finished parts must pass four tests. These tests cover size, internal structure, surface quality and material composition. Only then can they be packaged and leave the factory.We use automated testing equipment. This ensures both efficiency and accuracy.

Stage	Inspection Content	Equipment/Method Used	Standard Basis
Incoming inspection	Composition, humidity, purity	Spectrometer, balance, humidity meter	ASTM, ISO
In-process inspection	Size, strength, temperature	Calipers, strength testing machine, thermocouple	Internal process standards
Final inspection	Size, internal defects, surface, composition	Coordinate measuring machine, X-ray,  penetration testing	Customer drawings/international standards

Tool for Dimensional Inspection: Coordinate Measuring Machine Ensures 100% Compliance with Tolerances

Dimensional accuracy is one of the core requirements for investment casting. At QD, we have introduced multiple high precision Coordinate Measuring Machines (CMM). We achieve fast and accurate measurement of parts with complex geometric shapes.

• Working Principle: The CMM uses a probe to touch the part surface. It collects thousands of data points. It creates a 3D model. Then it compares the model with the CAD drawing.
• Accuracy Guarantee: Our CMM has a repeat positioning accuracy of up to ±1.5μm. It is far higher than the common industry level of ±3μm.
• Application Scenarios: It is especially suitable for high precision parts. These parts include turbine blades and engine components. They have curved surfaces, holes and grooves.

We use Full Dimension Reports. We ensure every part meets the drawing tolerances 100%. We can even detect and correct micro level deviations in time.

Internal Defect Inspection: X Ray and Ultrasonic Testing

Internal defects such as shrinkage porosity, gas holes and inclusions are common challenges in investment casting. We use two mainstream non destructive testing technologies:

X Ray Non Destructive Testing

• Principle: It uses X rays to penetrate parts. It shows the internal structure through an imaging system.
• Advantage: It can directly show the location and size of defects like gas holes and shrinkage cavities.
• Applicable Objects: It is suitable for most metal alloys. It works especially well for aluminum, titanium and steel parts.

Ultrasonic Testing

• Principle: It uses high frequency sound waves to travel through materials. When the waves hit defects, they reflect echoes. The probe receives and analyzes these echoes.
• Advantage: It is sensitive to deep seated defects. It can quantitatively evaluate the depth and size of defects.
• Applicable Objects: It is often used for thick walled parts or castings with complex internal structures.

The two technologies are used together to complement each other. They ensure we can detect internal defects that are invisible to the naked eye. This helps avoid the risk of part failure during service.

Surface Defect Inspection: Liquid Penetrant Testing Reveals Micro Cracks

Even if the internal structure is perfect, defects like surface micro cracks and pinholes may still affect part performance. We use Liquid Penetrant Testing for comprehensive surface screening:

1. Cleaning: The part surface is thoroughly cleaned to remove oil and impurities.
2. Penetration: Spray fluorescent or colored penetrant on the surface, then let it stand for 10-15 minutes.
3. Removal: Use water or solvent to remove excess penetrant on the surface.
4. Development: Spray developer. The penetrant in defects is drawn out and forms clear marks.
5. Inspection: Inspect under ultraviolet light or white light, and record the location of defects.

This method has high sensitivity. It can detect cracks with a width of only 0.5μm. It is widely used in the aerospace and medical device fields.

Material Composition Assurance: Spectrometer Ensures Accurate Alloy Proportioning

The chemical composition of materials directly affects the mechanical properties and corrosion resistance of parts. QD uses an arc spark spectrometer to conduct rapid composition testing on each batch of molten metal:

• Tested Elements: Including key alloying elements such as C, Si, Mn, Cr, Ni, Mo.
• Accuracy Control: The analysis results are compared with the standard composition table. The deviation is controlled within ±0.05%.
• Traceability: Each furnace of molten steel has a unique number. Test data is archived for more than 10 years. This ensures full-process traceability.

This not only ensures material consistency. It also meets the strict requirements of customers for material certification.

Contact Us

QD believes strict testing is the final line of defense to ensure no mistakes. Through full-process quality control and advanced testing technology, we promise to provide you with investment castings with zero defects.

Does your industry have strict quality standards? We can customize testing plans according to your needs. We can also provide complete testing reports.

If you need precision parts, you are welcome to contact us at any time.

FAQ

1. Are your testing standards internationally recognized?

Yes. We follow international standards such as ASTM, ISO and GB. We can also meet special industry certifications like NADCAP.

2. How long does the testing cycle usually take?

Regular testing is completed within 1-3 working days. The expedited service can be shortened to 24 hours. The specific time depends on the complexity of the parts.

3. Is the testing cost included in the quotation?

Basic testing such as dimensional and surface inspection is included in the standard quotation. Special testing such as X ray and ultrasonic testing needs to be quoted separately according to the project.

4. How to ensure the accuracy of test results?

We calibrate equipment regularly. Test personnel work with valid certificates. And we adopt a two person review system.

5. Can you provide material certification reports?

Yes. We provide material certificates that meet EN 10204 3.1 or 3.2 standards for each batch of materials.

6. What to do if parts are unqualified?

We will notify the customer immediately. We will provide a detailed defect analysis report. And we will give priority to arranging rework or recasting without extra charges.