Optimization Of Window Heat Curing Parameters For IPad2Assembly

In2010, Foxconn built factory in ChengDu city, then set up20assembly linesfor iPad2production in the MacIII assembly plant. In the iPad2assembly process,window curing station needs the most equipment, which occupied the largest space.During the mass production at the early stage, production yield rate is not high andthe production tasks is heavy, so this station needs more equipment, and accordinglymore production operators and QC persons are necessary. The production scene isjumbled. In order to complete the tasks, operators often need to work overtime. Afterthe mass production of iPad2in Chengdu city, company requires improvement ofproduction efficiency and cost-down. Therefore, it is necessary to optimize thewindow heat curing machine. Under the circumstance of ensuring the product quality,reduce the curing time of each machine to improve the production efficiency. Afterthen, the less number of equipments and operators are required on the same capacityto achieve cost-down.Firstly, this study introduced some basic theories about central compositecircumscribed design methods and then introduced its practical application by meansof a case about automobile factory bearing life optimization.Secondly, this study introduced the heat curing theory and heat curing machinein the window heat curing station of iPad2assembly process. In the initial design,window heat curing machines only designed upper-mould heating plate and nolower-mold heating plate. In order to increase the curing effect, engineers addlower-mold heating plate in this curing machine, and then reset the machineparameters for production.The next is to optimize the parameters of window heat curing machine. By fullfactor experiment, we find out the key factors are upper-mold temperature,lower-mold temperature and curing time. The experimental data shows the index doesnot reach the target value. The second is to reduce the curing time and continue to dothe experiment to find the best experimental area. The inflexion parameters ofexperiental area are190℃for upper-mold temperature70℃for lower-mold temperature and120seconds for the curing time. The third is based on the sequentialexperient; add6star points and3center points to experiment. Then under theconstrainted condition of push-force is not less than250N and at the minimum curingtime and cost, using the optimizer to get the optimal factors. After optimization, theoptimal parameter is that the upper-mold temperature is190℃, lower-moldtemperature is70℃and curing time is111seconds. The number of machines isreduced from16to12, cost is reduced from5952000yuan to4464000yuan, reducecost of1488000yuan.Finally, after no other production abnormity for two continual weeks of smallbatch test, we introduce these parameters into production.