What Is the Difference Between Quality Assurance and Quality Control?

The techniques and activities adopted to achieve quality requirements are called quality control. That is to say, quality control is to eliminate factors that cause substandard or unsatisfactory effects at all stages of the quality cycle by monitoring the quality formation process. In order to meet the quality requirements and obtain economic benefits, various quality operation techniques and activities are adopted.

QC

To achieve

To survive and develop in the fierce market competition, directional strategic choices alone are not enough. The competition between any enterprise is inseparable from the competition of "product quality". Without perfect product quality, enterprises will eventually disappear in the wave of market economy. Product quality, as the most difficult to control and most prone problem, often makes suppliers miserable.

In the corporate sector, quality control activities are primarily internal

(1) The construction unit shall notify in writing a certain time before reaching a witness point

The stop point is a quality control point that is more important than the witness point. It is usually for "special processes" or "special processes". For any control object listed as a stopping point, the supervisor must be notified to send someone to implement the control point before the prescribed control point arrives.

1. The position of quality control in production process in product quality control. Since the 1990s, the quality control doctrine has undergone major changes. Modern quality engineering technology divides quality control into several stages.

SPC is a kind of quality control analysis software. When SPC is used to monitor the quality of the product processing process, the last step is to analyze the statistical process and analyze the abnormal quality problems through statistics. The following mainly explains the contents of SPC statistical analysis.

SPC statistical analysis

Through the SPC system, process analysis, control chart analysis, histogram analysis, trend chart analysis, and process capability analysis can be performed on mechanically processed product parts. And can analyze the quality indicators (standard deviation, CPK) of the batch according to different latitudes such as products, workshops, processes, etc., such as: trend graph analysis, comparative analysis by year, month and week. You can intuitively see the fluctuations between the batches of product parts. In the heat treatment, forming and processing workshop, the process data is obtained by automatic collection, and statistical analysis can be used to draw the actual process parameter graphics. By comparing with the process required parameter graphics, it is used to analyze the implementation of key parameters of heat treatment, forming and processing. Level of compliance. These analysis tools are applied at different stages in the SPC system, focusing on different aspects, ensuring the realization of the goals of the SPC system, and at the same time, it can form and export analysis reports by analyzing the data.

1. Application in process analysis

By analyzing the process, the system automatically calculates the mean value, standard deviation, process capability index Cp, and non-conforming product rate p of the quality characteristics, and draws the analysis conclusions. The sampling analysis report of the quality characteristics can be derived.

2. Analysis and application of control charts

Through the control chart, you can analyze and judge whether the production process is stable, timely detect abnormal conditions in the production process and prevent the occurrence of non-conformities.

Before discussing the specific preparations for the implementation of SPC software, let's clarify the general idea of implementing SPC. SPC literally means statistical process control, in other words, it uses statistical techniques to control the process. The core theory is to use the upper and lower 3-sigma boundaries around the center line in the control chart to identify economically whether there are fluctuations caused by abnormal causes. Donald J. Wheeler described in Understanding Statistical Process Control, the thinking logic of the control chart is as follows:

In the TS16949 SPC manual, the specific steps of SPC implementation are very clear, divided into the following three steps:

Step 1: Collect the data and plot it.

Step 2: Set control limits, identify special causes and take action.

The third step: analysis and improvement, determine the magnitude of the common cause variation, and take measures to reduce the variation.

Aiming at the above SPC theoretical thinking logic and implementation steps, let's think about what preparations should be done to implement SPC.

SPC uses statistical methods to control the process. Before implementing SPC, companies need to review whether the various quality management systems are complete and whether they have a good habit of acting according to chapters. This is required by the management environment of the SPC implementation.

Quality technical level:

1. Staff training, all personnel related to quality have SPC concept and awareness.

2. Identification of critical control points, what quality characteristics or process parameters need to be controlled, and which parameters are targeted at which product or process.

3. Develop measurement methods and select appropriate measurement instruments, and evaluate the measurement system correctly.

4. Develop a reasonable sampling plan and standardize relevant information into the inspection plan.

5. Develop a preliminary response plan.

Quality management level:

1. A standardized quality management system is a powerful guarantee for the implementation of SPC.

2. Emphasize full participation.

3. Appropriate human and material resources.

The problems mentioned above highlight the importance of process control, and also explain that effective process control is a necessary means to ensure product quality. The following sections discuss how to implement effective process quality control.

1. Comprehensively carry out quality education and training. The production and operation personnel of small and medium-sized enterprises generally have a low quality phenomenon. The workers recruited by enterprises are more "migrant workers" than real technical "workers", and their minds of "quality" are weak. Therefore, to improve the product quality of an enterprise,

1. Supervise the factory to establish and improve the post responsibility system, formulate or revise and strictly implement various operating procedures in time, and observe production discipline.

2. Urge factories to earnestly carry out civilized production, especially to maintain a good production order, reasonably equip station equipment, and ensure that production channels are unobstructed. Greening the environment to prevent pollution and dust. strengthen

Quality control can be roughly divided into 7 steps:

(1) Select the control object;

(2) Select the quality characteristic value to be monitored;

(3) Determine the specifications and specifications, and specify the quality characteristics in detail;

(4) Select a monitoring instrument or self-made test method that can accurately measure the characteristic value or the corresponding process parameter;

(5) Conduct actual tests and make data records;

(6) Analyze the reasons for the differences between the actual and the specifications;

(7) Take appropriate corrective actions. When taking the corresponding

I. Overall Planning

Matrix diagram

Third, the balanced scorecard

Fourth, the process decision process diagram

V. cause and effect diagram

Arrangement

Scatter diagram

Histogram

Nine, system diagram

(1) Contract documents

The contract contract documents and the commissioned supervision contract documents stipulate the rights and obligations of the parties involved in quality control, and the parties concerned must fulfill their commitments in the contract. As for the supervision unit, it is necessary to perform the terms of the entrusted supervision contract, as well as urge the construction unit, the supervision contractor and the design unit to implement the relevant quality control clauses. Therefore, the supervising engineer should be familiar with these terms, so as to carry out quality supervision and control.

(Two) design documents

"Construction according to drawings" is an important principle of quality control during the construction phase. Therefore, design documents such as approved design drawings and technical specifications are undoubtedly an important basis for quality control. However, from the perspective of strict quality management and quality control, the supervision unit should also participate in the design submission and drawing review of the design unit and contractor organized by the construction unit before construction in order to understand the design intent and quality requirements, and find the drawings The purpose of errors and reducing quality risks.

(3) Laws and regulations on quality management issued by the state and relevant government departments

(1) Building Law of the People's Republic of China [Promulgated by Order No. 91 of the President of the People's Republic of China on November 1, 1997];

(2) "Regulations on the Quality Management of Construction Projects" [Promulgated by Order No. 279 of the State Council of the People's Republic of China on January 30, 2000];

(3) "Regulations on Construction Enterprise Qualification Management" issued by the Ministry of Construction in April 2001.

(4) Other government departments in charge of transportation, energy, water conservancy, metallurgy, chemical industry, etc. and relevant authorities in provinces, municipalities, and autonomous regions have also formulated and issued relevant regulations based on the characteristics of the industry and locality file.

(IV) Special technical regulations related to quality inspection and control

Such documents are generally technical and regulatory documents formulated for different industries and different quality control objects, including various related standards, norms, rules or regulations. The quality control of engineering construction mainly includes the following categories:

1. Construction project quality acceptance criteria

This type of standard is mainly developed by the state or the ministry and is used as the technical and regulatory document for the inspection and acceptance of the quality level of the project. For example, the "Uniform Standard for Construction Engineering Quality Acceptance" for assessing the quality of construction projects [GB 50300-2013], "Construction Quality Acceptance Specifications for Concrete Structure Engineering" [GB 50204-2002>, "Quality Acceptance Specifications for Building Decoration Engineering" GB 50210-2001> and so on. For other industries such as water conservancy, electric power, transportation and other engineering quality acceptance, there are similar quality acceptance standards.

2. Special technical and regulatory basis for quality control of engineering materials, semi-finished products and structural parts

(1) Technical standards concerning the quality of materials and their products. Such as cement, wood and its products, steel, bricks, blocks, stone, lime, sand, glass, ceramics and their products; coatings, insulation and sound-absorbing materials, waterproof materials, plastic products; construction hardware, cables and wires, insulation Quality standards for materials and other materials or articles.

(2) Technical standards or regulations related to the sampling and testing of materials or semi-finished products. For example: general principles of physical and mechanical test methods for wood, sampling methods for mechanical and technological test of steel materials, and stability test methods for cement.

(3) Technical standards and regulations on materials acceptance, packaging, and marking. For example, the general requirements for the acceptance, packaging, marking, and quality certification of section steel; the general requirements for the acceptance, packaging, marking, and quality certification of steel pipes. Technical procedures to control the quality of construction activities such as welding procedures, bricklaying procedures, concrete construction procedures, etc. They are to ensure that the quality of construction activities should follow the technical procedures performed during the operation.

(4) All projects using new processes, new technologies and new materials shall be tested in advance, and shall have a technical appraisal from an authoritative technical department and relevant quality data and indicators. Based on this, relevant quality standards and Construction process regulations, as a basis for judging and controlling quality.