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How to manage the quality for CNC machining parts?

The realization of customer requirements is finally achieved through internal transformation of requirements by the technology and quality department. Usually, customer requirements will be fully reflected through specific process and technical documents. Therefore, technical and quality department personnel are required to have high ability, which should be clearly defined in post responsibilities

Take the CNC machining part as an example, the technical department often has the following jobs:
1) Compile raw material procurement specifications and acceptance standards.
2) Make process flow chart.
3) Work out the machining specification (operation instruction) for each work step, which includes the size and requirements of processing, the equipment used, fixture number (when needed), tool model and specification, cutting parameter including feed rate, cutting thickness, rotation (R /min), numerical control program number and so on.
4) Calculation of processing hours.

5) Formulate product packaging specifications, etc.

A) Frequently asked questions at this stage
1) Product requirements were omitted in the transformation process.
2) Product requirements are misunderstood and transformed.

3) The process documents prepared are simple, and on-site operators have a large space for interpretation and understanding.

B) Solutions
1) Strengthen the training and assessment of technical personnel.
2) Set KPI(Key Process Indicator) indicators and ensure that the results are linked to employees' income.
3) Other technical personnel shall conduct parallel audit and sampling inspection and approval system for senior personnel.
4) Refine process documents and carry out standardization to ensure that the free operating space of on-site staff is within the controlled scope.
5) Number the customer's requirements to ensure that there is no omission. Prepare the number in the internal process documents.

5. Planning the realization of customer requirements

The technical department converts customer requirements into manufacturing requirements through process documents. The quality department needs to plan quality assurance for the realization of requirements.
A) Take the CNC machining partas an example, the quality department often needs the following work
1) According to the process flow chart, risk identification is carried out for each step and corresponding measures are formulated to reduce the risk. Product failure mode and consequence analysis (PFMEA) of the automobile industry can be considered.
2) Create a Process Control Plan for the product that fully describes the customer's requirements in the control plan and defines its control and documentation methods.
3) According to the key dimensions and requirements, the measurement system analysis plan (MSA) shall be established and implemented.
4) Prepare the inspection and testing instruction of raw materials.
5) Formulate the inspection specifications for the first piece of product inspection process and the last piece of product inspection.
6) Make training plan for inspection and testing personnel.

7) Set product quality objectives.

B) Frequently asked questions at this stage
1) There is no analysis plan for the measurement system.
2) There is no training plan for inspectors and testers.
3) No product process control plan has been prepared.
4) Poor communication with the technical department, and the quality documents formulated are inconsistent with the requirements of the process documents.

5) No product quality target is set

C) Solutions
1) In the process of new product development, work activities of each functional department are refined according to the process and relevant document requirements are clarified.
2) Establish a project team (including at least technical, production and quality departments) to review and summarize the development of new products on a regular basis.
3) Assess the project team according to the realization of product quality objectives.

4) The quality system maintenance department shall regularly check the new product development process and ensure that the nonconformance terms are closed in time.

6. Implementation of customer requirements

The realization of customer requirements is finally reflected through the realization of product requirements. In order to ensure the accurate implementation of the process and quality documents formulated by the technical department and the quality department, technical and quality personnel shall participate in the manufacturing of new products together with on-site operation staff during the development stage of new products.

A) During the implementation of the product, the following activities must be carried out
1) The trial production of new products shall be completely recorded and the modifications made in the trial production shall be confirmed in time.
2) The formulated personnel training plan shall be carried out in a timely manner and the capability analysis of the measurement system shall be completed in the trial production stage of the new product.
3) In the mass production stage, the technical department and the quality department shall randomly inspect the implementation of the process documents.
4) All requirements of the product must be checked, verified and confirmed as planned. In order to ensure the accuracy of measurement results, production personnel and inspection department personnel should try not to use the same instrument and equipment.
5) Special inspection tools used for product inspection should be checked before use to ensure that they meet the design and product requirements.

6) The drawings and specifications provided by the customer are recommended for the detection of products before warehousing to avoid problems caused by errors in internal requirements conversion.

B) Frequently asked questions at this stage
1) In the manufacturing stage of new products, the process document makers did not participate in the trial production of new products, resulting in the waste of time.
2) The trial production process of new products is not recorded and retained.
3) In the mass production stage, the operator did not comply with the process documents;The tester changes the test method without permission.
4) In the mass production stage, relevant product quality data (such as qualified rate, first pass rate, circulating qualified rate, quality target completion, etc.) are not collected to ensure the follow-up data analysis for continuous improvement.

5) Trial production and mass production adopt different processes. For example, conventional general processing methods are adopted in trial production due to time and investment constraints, and special fixtures and gauges for special equipment are put into batch production due to economy of scale. This conversion brings quality fluctuation.

JIUYUAN has two floors for CNC machining workshop cover 3000 square meters and built our own anodized factory for aluminum CNC machined parts. We has advantages on aluminum CNC machining parts,anodized CNC machining parts,CNC steel machining parts, precision CNC turning parts,precision CNC milling parts, plastic CNC machining parts etc.
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