Quality appraisal of sand molding machine

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sand mold forming machine takes the synergy between high-pressure compaction and mold accuracy as its core principle. By optimizing sand injection pressure, mold positioning accuracy and vibration frequency, it achieves synergy between sand mold tightness, surface finish and production efficiency. It is widely used in the field of sand mold preparation in the foundry industry. In the production of automotive castings, it is used for complex cavity molding of engine blocks/cylinder heads; in valve casting, it meets the high strength requirements of thin-walled sand molds; in the field of large steel castings, it ensures the anti-expansion capacity of sand molds. Compared with manual molding, the sand mold molding machine has the characteristics of high process stability, excellent dimensional repeatability, and automated integration (automatic mold change + online detection). It is the core equipment of modern casting technology.

Zhongke Testing is a product quality appraisal service organization registered with the court. It can provide quality appraisal services for sand mold molding machines. It has a professional appraisal team and advanced instruments and equipment to provide fair and accurate appraisal results for the quality appraisal of sand mold molding machines.

With the improvement of casting process precision requirements, related quality dispute cases have increased significantly. The judicial dispute focused on:

1. Dispute over performance indicators: sand mold tightness failed to meet standards and mold repeatability positioning accuracy exceeded standards;

2. Material defects: sand injection valve wear-resistant coating peeling off, vibrating table spring fatigue life

3, process problems: sand shooting pressure fluctuations, hydraulic system temperature rise;

4, contract performance disputes: core modules (such as imported servo drive systems, three-dimensional scanning detection units) are inconsistent with the technical agreement.

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sand mold molding machine litigation quality appraisal technical methods mainly include:

1. On-site investigation

Survey the use site to understand the equipment usage, casting quality problems, and whether there are factors such as improper operation.

2. Equipment inspection

Inspect the appearance, structure and function of the sand mold molding machine, focusing on the accuracy and performance of key components.

03. Sand mold test

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2Conduct performance tests on the strength, air permeability, disintegration and other properties of the sand mold to evaluate the quality of the sand mold.

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44. Casting inspection

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6The appearance, size, performance, etc. of the castings are inspected to determine whether the castings meet the requirements.

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85. Data analysis

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0 analyzes the collected data to find out the root cause of quality problems and determine whether it is related to equipment quality.

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A foundry of the applicant signed a "Purchase Contract for a Fully Automatic Sand Mold Forming Machine" with an equipment manufacturer of the respondent, stipulating that the compactness of the sand mold was ≥88%. After being put into production, the sand-adhering defect rate of castings exceeded 15%. The manufacturer argued that it was caused by improper molding sand ratio.

identification analysis results:

The quality analysis expert group discussed and comprehensively analyzed the relevant information of the "Sand Mold Forming Machine", contract technical agreement, on-site inspection case materials and other data, and made the following quality analysis conclusions See:

The sand injection pressure of the sand mold forming machine involved in the case is only 0.4MPa (agreement ≥0.6MPa), the mold positioning repeatability accuracy is ±0.25mm (agreement ±0.1mm); the vibration table frequency control deviation is ±20Hz (agreement ±5Hz), resulting in a sand mold compactness of only 72%.

The appraisal conclusion determined that defects in the equipment's pressure system and vibration control were the main causes of quality problems.

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sand mold molding machine quality appraisal report should include:

1, appraisal purpose and reference standards;

2, equipment model involved, control system version, production record;

3, testing List of methods and equipment;

4, analysis of correlation between test data and failure;

05, clear conclusion and technical basis for quality responsibility determination;

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26, signature of appraiser, professional qualification certificate and official seal of the organization.

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