As an advanced quality management concept and model, Six Sigma has been widely developed and applied in the world. In 2005, with the technical support of Zhang Chi Consulting Company, China Aerospace Industry first began to explore the management mode and method of Six Sigma, and carried out some research on Six Sigma projects. However, a large number of projects still adopt six sigma improvement process, which rarely involves the pre-design and development stage of products. Therefore, how to effectively carry out the product research of pre-research projects and form targeted design processes and models is of great significance to aerospace pre-research projects.

According to the characteristics of product development of aerospace pre-research project, through the in-depth study of Six Sigma process design, the Six Sigma process and model design of aerospace pre-research project products are put forward, so as to promote the application of design for six sigma in aerospace industrial system and improve the quality level of products and projects.

Second, the analysis of the development stages of aerospace pre-research projects

According to the final technical maturity and exhibition results, the aerospace pre-research project can be divided into three stages: concept demonstration, prototype development and integration demonstration.

For the concept demonstration stage, the main task is to complete the feasibility demonstration of the expected product technical scheme. The specific work mainly includes:

1. The validity of the basic principle is verified by theoretical analysis, modeling and simulation.

2. According to the basic principles, put forward clear technical concepts and application ideas;

3. Put forward key technologies, key features and technical approaches;

4. Put forward the basic composition and functional characteristics of the expected product;

5. Technical feasibility analysis of expected products.

For the prototype research stage, the main task is to carry out prototype development and principle test on the basis of scheme demonstration. The specific work includes:

1. According to the application background, define the target and overall demand of the expected product.

2. Put forward the technical scheme and approach of the expected product;

3. Complete the research on key technologies;

4. Complete the integration of laboratory samples, components and functional modules into the principle experimental prototype, and verify the functional characteristics of technology application;

5. The feasibility of the technical scheme and method is verified by the prototype test of the principle experiment;

6. Put forward the overall design requirements of the integrated demonstration prototype.

For the integration demonstration stage, the main task is to carry out the integration demonstration experiment on the basis of the development of the principle prototype. The specific work mainly includes:

1. Complete the overall design of the demonstration prototype;

2. Verified by typical simulation environments such as samples, components and functional modules, the functions and main performances meet the overall requirements;

3. Complete the design of demonstration prototype, and all indicators meet the overall requirements;

4. The key production process specifications are basically determined, and the process stability basically meets the requirements; Basically determine the selection range of key materials and components, and analyze the feasibility of engineering application;

5. Complete the processing of the demonstration prototype, and pass the typical environmental test, the function and performance meet the design requirements;

6. Put forward suggestions on engineering development, etc.

The development of aerospace pre-research projects is restricted by many factors such as progress, cycle and technical maturity, which determines its unique development law. Traditional quality control and management measures can no longer fully meet the development needs of pre-research projects. It is necessary to introduce advanced quality management concepts and methods of Six Sigma to manage and improve the quality of aerospace pre-research projects.

Three. Research on Six-sigma Model of Aerospace Pre-research Project

(I) Six Sigma basic design processes and tools

Design for six sigma, based on the idea of concurrent engineering and optimization design (DFX), is a method to realize defect-free product and process design, which can shorten the delivery time, reduce the development cost, effectively improve the comprehensive quality of products or services, and further improve customer satisfaction. Facing the whole life cycle of a system or a product, design for six sigma adopts a systematic problem-solving method, and integrates the customer demand of the tube puller into the product and process design, thus ensuring the development speed and quality of the product, reducing the product life cycle cost and providing effective solutions for enterprises to solve the product and process design problems.

Like the Six Sigma improvement process, design for six sigma has its own process, but there is no unified model at present. Up to now, the design for Six Sigma processes mainly includes: DMADV process (definition, measurement, analysis, design and verification), DMADOV process (definition, measurement, analysis, design, optimization and verification), IDDOV process (identification, definition, development, optimization and verification) and DCCDI process (definition, identification, conceptual design, product and process design). The main tools and methods used in these design processes can usually be divided into three categories:

(1) Tools and methods for obtaining and analyzing customer requirements. There are mainly QFD, benchmarking, Kano analysis, general matrix, brainstorming and so on.

(2) Tools and methods related to system conceptual design. There are mainly invention problem solving theory (TRIZ), failure mode and impact analysis (FMEA), axiomatic design, reliability design, design scorecard, risk matrix and so on.

(3) Robust and optimized design and simulation and prediction tools. There are mainly experimental design (DOE), Taguchi robust design, response surface method, optimization operation (EVOP), statistical process control (SPC), Monte Carlo simulation and so on.

4. Research on Six Sigma Process Design of Aerospace Pre-research Project

According to the characteristics of strong innovation and low technical maturity of aerospace pre-research project, combined with the division of concept demonstration stage, prototype development stage and integration demonstration stage of pre-research project, through in-depth research on Six Sigma process design, and organically combining each stage and its development work with Six Sigma process design, design tools and methods, a Six Sigma IDADOV process design based on the development outline of aerospace pre-research project is put forward, and the six Sigma tools and methods that should be used in each stage are clarified.

1. Identification stage.

The appraisal stage is to define the needs of customers and determine the development goals of the project, which belongs to the research content of the concept demonstration stage in the aerospace pre-research project.

This stage is mainly to collect and determine the customer needs of the products to be developed, and use evaluation tools to identify and prioritize the customer needs to ensure that the designed products meet the customer needs. It is necessary to systematically consider external and internal factors to determine the feasibility of the project. The main work contents include: communication, investigation and report with customers (military and superior units); Sort out the express or potential needs of customers; Discuss the technology and requirements to meet customer needs; Conduct project demand analysis; Determine the project objectives and form the preliminary design requirements of the project.

The tools and methods used in Six Sigma are: brainstorming, customer demand analysis, QFD, tree diagram, etc.

2. Define the stage.

The definition stage is to determine the key needs of customers and specify the specific technical index requirements, which belongs to the research content of the concept demonstration stage of aerospace pre-research projects.

At this stage, we should visit users, develop and tap the needs of potential customers, and the main task is to further refine VOC, and use fuzzy information processing technology to convert massive and fuzzy VOC into accurate VOC; Then use QFD to expand VOC layer by layer into design requirements, process requirements and production requirements, and extract the key requirements of customers; Accurately identify and quantify customers' needs and expectations, carry out targeted product design, and finally produce product design scheme and process requirement specification. Main work contents: determine the project requirements and characteristics; Conduct competition gap analysis; Clarify the technical index requirements of the project.

The six suitable tools and methods used include: customer demand analysis, market survey, affinity diagram, Karnaugh map, QFD, horizontal comparison method, feasibility analysis, etc.

3. Analysis stage.

The analysis stage is to determine the factors affecting the key characteristics of products and processes and their relationships, which belongs to the research content of the concept demonstration stage of aerospace pre-research projects.

At this stage, the function of the product should be analyzed to provide support for the design stage. If there is a conflict in functional analysis, use TRIZ's inventive principle to solve the conflict problem and determine the feasible scheme; The feasible scheme is selected and analyzed by using the goodness matrix to determine the best design scheme; Analyze and design the reliability of products, and use FMEA and risk matrix to analyze and evaluate risks, and establish a risk avoidance plan. The main work includes: determining the key minority and choosing X; Identify key technologies.

The six tools and methods used include: brainstorming, causality diagram, FMEA, level comparison, experimental design, regression analysis, process analysis, hypothesis testing and so on.

4. Development stage.

The development stage is to design products or processes, which belongs to both the conceptual demonstration stage and the prototype development stage of aerospace pre-research projects.

This stage is to design the new product in detail, and design the new product within the scale of key quality characteristics (CTQ) and key process characteristics (CTP) within the framework of the solution given in the previous work. The main work includes: forming a pair of alternative design schemes; Compare multiple schemes and choose the best scheme; Put forward the realization way of key technology research and form the design requirements.

The six suitable tools and methods used include TRIZ, simulation technology, reverse engineering, kilometer design and so on.

5. Optimization stage.

The optimization stage is to optimize the design parameters, which belongs to the research content of the prototype development stage in the aerospace pre-research project.

This stage is to optimize product and process design parameters to maximize the benefits between quality, cost and schedule. By looking for controllable design factors to realize parameter design, the key factors affecting output are designed and optimized to find the best parameter combination. In addition, it is necessary to optimize robustness and analyze potential failure modes and functional variability through FMEA, so as to minimize the possibility of product and process failure in the design stage. The main work includes: robust design, tolerance design, error-proof design, FMEA design, verification and recalculation; Simulation (simulation, molding) and performance measurement; Coordination and confirmation of interfaces; In the development process, deal with quality problems.

The six suitable tools and methods used include: experimental design, Taguchi method, robust design, FMEA, double check and calculation, IDS, "double return to zero" and so on.

6. Verification stage.

The verification stage is to verify the effectiveness of the product and process design scheme, which belongs to the prototype development stage and integration demonstration stage of the aerospace pre-research project.

This stage is the confirmation process of whether the product design meets the customer requirements and reaches the expected quality level. According to the results of design and optimization, confirm and verify whether the technical indicators of the product meet the requirements of customers, whether the uncertain factors and risks meet the requirements of customers, and whether the uncertain factors and risks are reduced to an acceptable level. The main work includes: writing test outline, test scheme and test details; Confirm the status of test products; Carry out experimental verification.

The tools and methods used by Six Sigma include: simulation technology, process capability analysis, hypothesis testing, experimental verification, etc.

Verb (abbreviation of verb) abstract

Six kinds of Magma design processes, tools and methods are studied. Combined with the characteristics of aerospace pre-research project, the Six Sigma process and mode design suitable for product development of aerospace pre-research project are put forward. The product development is divided into six stages of IDADOV (identification, definition, analysis, development, optimization and verification), and the key points of each stage are analyzed, which provides a theoretical basis for the application of Six Sigma in aerospace industry system design. Design for six sigma based on IDADOV process can effectively improve product quality, ensure success and effectively enhance the core competitiveness of enterprises.

Zhang Chi Consulting/KLOC-has been focusing on providing Six Sigma, Lean Six Sigma and Six Sigma dfss design training and project counseling for 0/6 years (Zhang Chi Company has been providing six Sigma DFSS design training consulting services for China Aerospace since 2005, and the DFSS Project Excellent Improvement Award has won the first prize for many times).