What Is a Coping Saw?

The quality of high-planning universal saw chains involves many factors and their connections. Therefore, it is important to decompose the factors from the overall product quality and determine the relationship between them.

As a cutting tool for chainsaws and chainsaws, saw chains are widely used and indispensable in forestry. With the development of forestry to high efficiency, the technical performance of saw chain has improved. Small-pitch planer saw chains (universal chains) with a chain speed 22m / s have been finalized in foreign countries and are still in the research and trial production stage in China. Compared with the famous brand products, the quality of the trial products is very different. In the past ten years, relevant personnel have made unremitting efforts, and have achieved significant results in theoretical and experimental equipment and methods such as saw chain structure, cutting principle, working conditions, cutting performance, etc., and have made research on the quality of saw chains and the improvement of performance. Many jobs. However, there are still many problems to be solved in the shaping and production of high-speed planing universal saw chains.The poor quality of its prototype products has led to the use of small-pitch high-speed planing universal saw chains in forestry for a long time. Form the status quo of "Chinese tiger, foreign teeth".

Technically complex products, quality is a comprehensive concept, factors have systemic and multi-dimensional characteristics, each factor affects and restricts each other, making the problem complicated. Therefore, the research on the quality of the saw chain should not only have an in-depth discussion in various aspects, but also analyze and optimize the quality system. This article is based on the user's comprehensive requirements for the technical performance of high-speed planing universal saw chains, the theoretical research results of domestic experts, and the factors involved in the development of saw chains in recent years. Based on the theory of system theory and quality multidimensional characteristics, the saw chain quality system is designed to reveal Factors related to quality, determine the relationship between them, and provide methods and ways to solve and analyze problems for improving the quality of saw chains. ^[1]

1.Design of saw chain quality system

The multidimensional quality of quality refers to the multi-level and multi-objective interrelationships among various quality elements in a complex product quality system. Study the saw quality from the perspective of system theory and quality multidimensionality, and decompose it into a quality characteristic system and a factor system involving quality characteristics. In each subsystem, factors are decomposed into a three-layer multi-object structure, and the factors are decomposed layer by layer in sequence. Until it breaks down to basic elements that can be quantified using a variety of standards.

2. System Structure Analysis

(1) Structural analysis of quality characteristics

The quality characteristic system is composed of three levels of user characteristic layer, technical specification layer and quality characteristic technical parameter layer and the elements contained in each layer. The system structure belongs to the sequence multi-item structure.

The first layer: user characteristics layer. It is designed according to the user's evaluation of the quality of the saw chain. In China, the use of small-pitch high-speed planer type universal saw chains has been used for many years before its development, and the user has strong identification experience and quality perception ability. The five factors in this layer are obtained after investigation and analysis, and invited experts to verify, which reflects the user's quality requirements more comprehensively.

The second layer: the technical specification layer. It is composed of elements that have a affiliation relationship with the relevant professional technical specifications and the upper-level elements. It clarifies the relationship between the quality characteristics and the relevant elements of the technical specifications. The elements of this level need to be further decomposed.

The third layer: the element layer of technical parameters of quality characteristics. They are composed of second-order elements of quality characteristics, which are the deepening of first-order elements. The elements of this layer are relatively independent and can be quantified directly or indirectly. It is the basis for implementation in production, and it is the information for judging the quality characteristics (the elements of this layer are not listed).

(2) Structural analysis of factors related to quality characteristic elements

The quality characteristic element related factor system is composed of factors corresponding to the elements of each layer of the quality characteristic system, and the system structure belongs to a sequential multi-item structure. According to the quality loop analysis, product quality is guaranteed by the quality of the parts and the quality of the assembly process, while the parts and assembly process involve part structure, part angle, size and tolerance accuracy, dimension and tolerance process stability, materials and strengthening processes, parts Factors in five aspects of processing technology. The system decomposes and composes according to various levels of factors in these aspects.

The first layer: factors related to user quality characteristics. It is mainly composed of five factors of each part and assembly of the saw chain.

The second layer: the technical specification involves the factor layer. It is composed of first-order factors that affect the quality of parts and assemblies. Each factor needs to be deepened and further decomposed.

The third layer: the quality characteristic technical parameter involves the factor layer. It is a second-order factor decomposed from the first-order factor and the basic factor that affects the quality of parts and assembly.

The significance of the establishment of the above two subsystems is to arrange the various types of factors in a hierarchical manner according to the membership relationship, reflect the local research and the overall situation, and make the system elements form a logically connected whole, taking into account both the local and the Overall, it can prevent forgetting and confusing factors. ^[1]

Analysis of the quality and related factors of the durability of the saw chainThe durability of the domestic prototype is only 1/4 of the famous brand saw chain. If it is improved to improve its quality, what factors should be considered?

Durability is one of the quality characteristics of user evaluation, and it is also a relatively important performance, which cannot be ignored or evaded.

Durability characteristics relate to the structure of incisors, small shafts, transmission plates and connecting plates, the relative angle, size and tolerance accuracy of incisors, small shafts and connecting plates, and their mass production stability, incisor materials and strengthening processes, work Load and wear resistance of the saw chain as a whole.

The above factors affect other quality characteristics elements. For example: the structural changes of the incisor parts affect the cutting efficiency, cutting power, comprehensive mechanical properties of the material, filing characteristics, failure rate, repairable parts service life, process costs and equipment costs. ^[1]