Development Of The Rolling Plastic Precise Machine

Plastic process forming is an important branch of forming and manufacturing technology which is an important developing aspect in advanced manufacturing technology. As reported ,there would be 75 percents performs and 50 percents precise process products would be manufactured by plastic process forming in twenty-first century. Plastic process technology developed from the earlier forging to plastic process forming is the result of market need and technique's progress. And now it has developed to precision and intelligentize . Recently, many paper often use the following words such as near net-shape, net-shape and precise forming which shows that the research point has been put in little even no cutting. The precise forming not only means shape and size's changes, but also microstructure and performance's evolution after deformed. Saving material, less dissipation, lower cost, improving surface quality and getting better microstructures and performance have been the trends of plastic process forming. Successive partial plastic forming is an important aspect in material forming and processing and is used maturely in rolling which results from its advantages of less pollution like hydrostatic pressure, taking fuller advantage of energy, stable productive quality, implementing mechanization and automation easily, higher productivity and being able to making full use of the plasticity of metal materials etc.. However, there are some problems in successive partial plastic forming that we should solve to form accurately. Roll forging is a kind of forging technic that imports the rolling to forging and its feature is to make the blank to produce successive local deformation by a couple of reverse rotating dies. Because of the successive and local forming way, roll forging has obvious advantages in improving the using efficiency of the metal materials ,productivity and product quality in the manufacturing of rod drawing and board blank grinding ect.. But there is a natural limitation in the process, forward and backward slides. Which are important factors affecting the length precision of part. So we must calculate the value of forward slide in roll forging process and take into account that value when we design dies. Many experts had made a lot of research in lubrication, temperature and feed value to calculate the amount of forward slide. But these research could not get accurate value, because there are many factors affecting forward and backward slides such as roller diameter, deforming temperature, speed, contact attrition condition, lubrication, relative deformation degree ect.. In production, these factors'changes will cause the changes of the forward slide value and then cause the part change in length direction further. So roll forging process is not suit to produce precise part which need high accurate in length . My tutor, professor Song Yuquan, integrated the virtues of roll forging with closed die forging and invested the new process of rolling plastic precise forming, further contrived the rolling plastic precise machine, which has been accepted as the national patent(patent No.ZL95109871.3). The rolling plastic precise machine takes advantage of feature of successive local plastic forming of roll forging and has the same excellence of closed die forging. Thus, the new rolling plastic precise forming process has high usage efficiency of energy and low forging force of successive local plastic forging and high precision of closed die rolling. The rolling plastic precise machine made the new process come true This paper according to my tutor professor Song Yuquan's patent of the rolling plastic precise machine(patent No. ZL95109871.3) puts up several key problems in the design process of the equipment and solves them. According to the patent of rolling plastic precise machine, the closed section between the rotating concave die and convex die should match up to the cross section of deformed part, which could eliminate the forward and backward slides during roll forging. So it must be sure that outskirt's linear speed of the convex die equals to the moving speed of the concave die in order to shape pieces correctly, Furthermore, the moving speed of the concave should be equal to the linear speed of the gear's reference circle, so the reference circleof the gear and the outskirt of the convex die should be on the same cylinder surface, and the outskirt of the concave die should be tangent to the convex die, to make a successive closed die zone. We described the relationship as geometry relationship of the rolling plastic precise machine. Rolling plastic precise machine is a kind of facility for mass production. However there may be different thickness parts in produce. For the sake of meeting with the changes of the concave thickness, the paper present a project to adjust the machine. that is the center distance is adjusted to satisfy the geometry relationship. Facility serves process, the possible problems during implementing should be analysized. For example, dislocation along axial direction or the die dislocation error along axial direction caused by axial force. which requests that the dies align along axial direction. the error along the width direction of forging part caused by elasticity of the frame, which will cause the die be blocked. In this case, the distance between the two rollers should be increased, So designing a protecting equipment to avoid over-load and prevent from destroying dies even the machine also is an important problem; Part is placed in the concave die whose upper and lower parts is open, So it must be solved how to support the workpiece before it is bite into the dies; Rolling process integrates roll forging with successive closed die forging process, part would be blocked in cancave die. In order to withdraw the part from cancave die, an ejectior machanism is needed. Owning to the large inertia of the moduling board, the moduling board cann't stop immediately when needed. so safe break is needed to stop the moduling board at preset position and then the piece cane be ejected accurately by ejection machinism. The above-mentioned problems are solved during the research and development process of roll forging plastic precision machine. This paper model parts of roll forging plastic precision machine by the UG software. and assemble the parts to a whole equipment. Through the calculation and design of the parts'structures, account the main technology parameters of the machine and analyze the factors affecting the rigidity of the machine. Frame and rollers are key parts of the machine and could not be replaced, so they must satisfy strength requirement. Furthermore, rigidity affects the...