Research On Key Technologies Of Digital Manufacturing For Special-shape Spring

With the development of industry, the increasing interest in quality control andproduction efficiency is also having impact in the spring production field. Copingwith this situation, the CNC spring coiler that suited for coiling special-shape spring isplaying more and more important role in the spring manufacturing process. Butbecause of various restricting factors, there is big gap between China and otherdeveloped countries in the spring manufacturing technologies. Therefore, the researchon spring coiler will have important significance for promoting the development ofour country's spring manufacturing industry.On the other hand, as a kind of common mechanical product, the research ofadvanced manufacture method for spring is often neglected. But in fact, there aresome problems of spring coiler, such as lower automation and inconvenient operation.So, it has important theory significance and application value to deeply study thespring coiling process.For the reasons mentioned above, the main problems and restriction factors ofspring coiling process are analyzed and the spring digital manufacturing system isestablished in this dissertation. The main contents and achievements of thedissertation are as follows:1. The spring coiling process and principle are illuminated, some parameterswhich influence the coiling are analyzed, the coiling step of spring with typical shapefeature are decomposed, the corresponding relations between the spring spatial shapeand coiling method are established, the knowledge and rule about spring coiling areconstructed. All these works provide the important foundation for the digitalmanufacturing of spring.2. Based on the problems of the spring coiling, the concept of spring digitalmanufacturing which in core of CAD/CAPP/CAM is put forward. Several mainsupporting technologies of the spring digital coiling system are defined and studied.According to the viewpoint of object-oriented, the requirement and function of thesystem are analyzed. Using UML, the detailed static and dynamic model of the systemare established. The general frame and function structure for spring digitalmanufacturing is also constructed. The digital manufacture system help implement theintegration of design and manufacture of spring and provide the new realization method for the spring CNC coiling.3. The shapes of spring is quite different, thus there are various special-shapespring with complex spatial shape. It is difficult to use simple and commonparameters to generalize and express various special-shape spring comprehensively,especially for their complicated and diverse end structure. Using the feature-basedtechnology, four kinds of elementary shape features are extracted and their datastructures also are defined respectively in this dissertation. Many different elementaryshape features are linked and formed the whole spring. Through classifying differentfeatures, the whole part information of spring is created. This representation methodprovide entire information source for spring digital manufacturing.4. The 3D solid modeling of spring can facility the operator to watch the springshape earlier and reduce the production time. So, the 3D modeling technology ofspecial-shape spring using OpenGL is studied in this dissertation. The emphasis is onhow to disperse the spring solid surface and store the coordinates of these discreetpoints. In order to avoid the gap between the helix and spring end, a solution tosubstitute this transition part with cylinder and torus is presented. The high realitysolid modeling is created using this method.5. In most present-day coiling machines, all the setup jobs, including toolselection, cam layout, program, are achieved by manual work using a trial-and-errormethod. This method seriously affects the spring production efficiency. It is obviousthat the machine adjustment is the toughest part of the production process and themost time-consuming phase. In order to solve this problem, the artificial intelligenceis applied to the spring coiling process and the knowledge-based computer-aidedprocess planning for spring coiling is proposed. According to the formingcharacteristic of the special-shape spring, the hybrid reasoning techniques whichintegrating case-based and rule-based reasoning are proposed and used to plan thesetup of the coiler.6. The integrated system for spring digital manufacturing is developed andapplied in practice on the foundation of study work above. The information sharing ofspring coiling process is realized in system, including spring spatial shaperepresentation, 3D modeling, coiling process planning and automatic programming.