| As the information industry develops,computer aided selective assembly becomes a hot spot of new technics.More and more research workers make every efforts to clear up the mystery. Adopting the economical technics,developing a new software,we can improve the assembly quality of the products by it.In reality,when manufacturing products,we always meet some difficulties.Take the type of bearing as we called NO.6308 for example,we meet the problem that how to make a good selection for the bearings. In this paper,the revised Taguchi quality loss function which guided the manufacturing process was put forward .After that,a new computer aided selective assembly method came out.It is effective and convinient with high efficiency for the assembly workers.(1)In order to combine the thoery with the manufacturing together,a selective assembly model was built based on the ant colony optimized algorithm.It will assure the assembly ratio.(2) According to the national standard and the bearing quality documents which are set down by Luo Yang Bearing Research Institute(CSBTS TC98.56-1999,GB/T273.3-1999, eqvISO15:1998 , GB/T4199-2003, GB/T308-2002,ZYB2-89 .etc),the quality requirements of the bearing's each parts were stated. They contained the types of the bearings(such as C-Grade,D-Grade bearings),the optimal design theory now we used,the outer race,the inner race,the selection of the steel balls,the bearings we processed,the tolerance of the assembly parts,the manufacturing processes,the measuring processes and the assembly checking technics.(3) Under the common producing patterns,the paper put forward that the upgrade of the products.If any of the parts which were of high qualities,we should select them out,then we could assemble some superior products.So the common parts would not take the chance to assemble with the superior parts.Also we could improve the products'qualities,it would bring more profits to the enterprises.(4) When we assemble the products,we should face the fact.On one hand,if wewant to improve the assembling precision,it would decline the assembled ratio.On the other hand,if we want to raise the the assembled ratio,we should broaden the machining tolerances.In order to take the factors into consideration,we put forward the new optimized function.(5) In the area of selective assembly,compared with the other products,the bearings have their unique characteristics,the assembly precision should be obeyed by the national standard.According to the requirements of the factories,each group of the tolerance is suitable for the oppionted working conditions.Indeed,the fitting windage is only a small portion of the sealing ring dimension which is received by the method of extremum calculation,so the assembly precision is very rigid.Luckily,we nowadays use the optimized designing method.When we fit the parts,we use the disengaged size which are the branches from the main dimensions of the parts.In this way,it is really convenient,you should only choose the different groups of the balls when you fitting the parts.(6) How to use different groups of the balls when we fitting parts without any calculations,and how to assure the assembly qualities?Now we could use the ant colony optimized algorithm, you need input computer the parts'data,the computer would tell you the fitting results immediately.Ant colony optimized algorithm is a"natural"algorithm,it came out from the study of ant colony behaviors.Each ant of the colony interconnects with others by the medium"pheromone".Its speciality is that when the ant search for the food,it would leave a sort of chemical,we called it"pheromone".If the route was shorter,the trail pheromone is better,the behavior of the ant colony would put up a positive feedback phenomena,this would tend to the best route as the time goes by.The ant colony optimized algorithm has several characteristics as follows:(1)Let each ant construct a path separately,then improve the paths by local search algorithm.By the updating pheromone,we get the excellent solution in the end.(2)The algorithm has human intelligence and studying characteristic,it does not only simulate the course that ants search for the excellent paths.(3)It can carry on the string calculation and on the proceeding calculation.(4)It is a kind of overall type excellent algorithm.The optimization of the one or several parameters could be settled by it.(5)It is a kind of heuristic methods,the complexity of the calculation could beO(NC·m·n~2) .In it,NC refers iterated times,m refers ants'number,n refers nodes'number.Based on the ant colony optimized algorithm,we got the process of the computer aided selective assembly:(1)Constuct the ant solutions'diagram which is based on ant colony optimized algorithm.(2)Set up the improved selective assembly model.(3)Updating the pheromone"τij".(4)Choose the bionics pheromone"ηi j".The paper investigated NO.6308 bearing in the areas of manufacturing, measuring, selective assembly and quality control.It put forward the concept of upgrade.In it,firstly,we should select the superior parts from all the parts.Although the courses of the measuring and the selection were cost a lot,the products'upgrade is valuable,especially for the products which were restricted by few parameters.If the parts were restricted by a few of parameters, the superior parts would be less.When checking each parts,all of the machining equipments and the checking instruments would be in good working conditions.Moreover,research and develop the automatic chencking and automatic classification equipments do have great significance,it would bring more profits to the enterprises.On the way of the optimized selection for the parts of the bearings,based on the ant colony optimized algorithm,we could use computer aided selective assembly.It is very convinient and it will assure the assembly qualities.This is proved by the experimental results.For assembling the bearings which do have different windages,the software is also effective.The windages are very close to the ideal value,this will improve the products'qualities.The enterprise will enhance its competition and the selling price,this will bring more profits to the enterprise.
|
PDF Full Text Request