Gear processing machine tool quality appraisal

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gear processing machine tool takes precision forming principles as its core and achieves high-precision processing of gear tooth shapes through hobbing, gear shaping, gear grinding and other processes. It is widely used in automotive transmission, aerospace engines, wind power equipment and other fields. In automobile manufacturing, it completes micron-level processing of transmission gears; in the aerospace field, it ensures the high reliability of aircraft landing gear gears; in the energy industry, it realizes low-noise operation of wind power gearboxes. Compared with ordinary machine tools, gear processing machine tools have the characteristics of high dynamic response, high-precision control, and complex surface processing capabilities, and are key equipment for high-end equipment manufacturing.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide quality appraisal services for gear processing machine tools. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for the quality appraisal of gear processing machine tools.

As the technical complexity of gear processing machine tools increases, quality dispute cases are gradually increasing. The judicial dispute focuses on:

1. Dispute over performance indicators: whether the tooth profile error of the processed gear meets the standard and whether the surface roughness meets the design value;

2. Material and process defects: insufficient wear resistance of the tool material and heat treatment process Improper control leads to uneven tooth surface hardness;

3. Control system failure: the repeat positioning accuracy of the feed axis is out of tolerance, and the interpolation algorithm error of the CNC system leads to tooth pitch deviation;

4. Contract performance issues: the delivered machine tool does not comply with the technical agreement.

0In such cases, the quality appraisal of gear processing machine tools needs to combine geometric accuracy testing, material composition analysis and machine tool dynamic characteristics testing to provide technical support for the court to determine the attribution of liability.

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Gear processing machine tool quality appraisal technical methods include:

1. Appearance inspection: Check whether there are defects or damage in the appearance of the equipment, such as shell deformation, paint peeling, etc.

2. Accuracy inspection: Use precision measuring instruments to detect the accuracy indicators of the equipment, such as positioning accuracy, repeated positioning accuracy, straightness, flatness, etc.

3. Functional test: According to the purpose of the equipment, simulated processing or actual processing tests are conducted to examine its processing capabilities, stability, efficiency and other performance indicators.

4. Material analysis: Conduct composition analysis and mechanical property testing on the materials of key components of the equipment to check whether they meet the design requirements.

05. Electrical inspection: Check whether the electrical system of the equipment meets safety standards and whether there are leakage, short circuit and other problems.

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The applicant, an auto parts company, signed a "CNC Gear Hobbing Machine Purchase Contract" with a machine tool factory, the respondent, agreeing to purchase three gear hobbing machines of model YK3120. After being put into production, the tooth profile error of the processed gearbox gear exceeded 10 μm, causing abnormal noise in the entire vehicle. The parts company believed that the machine tool had quality defects and demanded compensation for losses. The machine tool factory argued that the problem was caused by improper tool selection, and both parties took the case to court.

Identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "gear processing machine tool", contract technical agreement, on-site investigation case materials and other data, and made the following quality analysis opinions:

The hob material of the gear processing machine tool involved is ordinary high-speed steel (contract requirement HSS-Co8), and the Co content is only 2%, the wear resistance is insufficient; the workbench worm gear pair is made of cast iron (the contract requires tin bronze), and the hardness is insufficient, resulting in excessive wear; the hobbing feed fluctuates by more than ±15%, and the tooth surface roughness Ra reaches 1.6 μm (standard ≤ 0.8 μm); the heat treatment process is not performed according to the standard, and the tooth surface hardness is unevenly distributed (HRC50-60).

The machine tool factory failed to provide the specified material cutters and worm gear pairs according to the contract, and the process parameter control was not up to standard, which was the main reason for the equipment problems.

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Gear processing machine tool quality appraisal report should include the following content:

1. The purpose and basis of the appraisal.

2. Model, specification, manufacturer and other information of the equipment being identified.

3. Identification method.

4. Identification results (including whether there are quality problems, causes of problems, etc.).

05. Identification conclusion.

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26. Signature and seal of the appraiser, and official seal of the appraisal institution.

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