Precision casting process in the production

Precision casting process, Manufacturing cycle

A drive support structure is complex, manufactured by welding, the first processed separately for four parts, and then the respective parts assembled into a whole and then the vacuum furnace brazing, not only a long manufacturing cycle, and after welding the drive carriage deformationlarge, poor quality assurance. After transmission bearing structure, materials, geometry and other design elements, as well as the bulk of production analysis, decision to adopt the forming of precision casting process, then certain important dimensions machining, and finally meet product quality requirements.
By comparison of the above two processes on the gear holder, from the manufacturing costs, cycles, etc., can be found both in the mass-production of different effects:
1, the manufacturing cost is relatively
By comparison of the cost of machine plus welding and precision casting two processes, one-piece cost than for 1:1.3,10 parts cost than for 1.5:1,100 pieces cost ratio of 2.7:1. Manufacturing costs of the two methods, the biggest difference is that a single piece of material and working hours, fees, and mass production, the cost of precision casting machine plus welding is much lower, which is a different process methods are determined.
2, Manufacturing cycle
Machine plus welding drive bearing is a combination of four parts welded together, a part of the manufacturing process up to 10, and the process involves time and labor forging, heat treatment, the number of milling, EDM wire cutting. Then again when processing portfolio also needs 16 steps to complete the final manufacturing, including vacuum brazing, the number of milling, EDM wire cutting, and the two modular fixture clamping process more time-consuming. In general, a batch of 10 transmission bearing manufacturing cycle takes 3 to 4 months.
Precision casting parts production processes of the main model manufacturing, mixing, vacuum grouting as casting, drying roasting, vacuum casting, under the pressure of crystallization, clean-up and correction of 9.
If it is the first production, due to the processing of mold manufacturing model, manufacturing cycle takes 1 to 2 months. If production again, a batch of 20 transmission bearing manufacturing cycle takes 3 to 4 weeks (including casting further precision rough machining).
Two process methods, precision casting volume manufacturing costs and cycle machine and welding have a great advantage, and more importantly, the use of precision casting is specialized social resources, and is conducive to the better use of the resources of the unit manufacturing .What process in the production is constrained by part structure, geometry, material, quality, cycle, costs as well as the people of the concept of many factors, the practical application of precision casting process is the same, in the decision-makingbefore to pay attention to the following two aspects:
1, dimensional tolerances and surface roughness
Casting process, casting size tolerances specified in GB, the value of the minimum level of 3, a far cry from this specified tolerances and machining GB level. The same basic dimensions casting tolerances 3 equivalent to only 11 to 12 of the machining tolerances, the same as in level m without individual tolerance, the dimensional accuracy of the castings is very low. The tolerance grade aluminum alloy precision casting, casting generally achieved CT4 ~ 6 level.
Similarly, precision casting aluminum alloy castings generally can reach the surface roughness value Ral.6 ~ 3.2, more demanding requirements on a high level of casting technology, but it can only improve the twelve grades and duplication of efforts.
Therefore, the aluminum alloy precision casting is generally applied to dimensional tolerances less demanding structural parts, supports, pipe pieces, parts of dimensional accuracy and surface roughness have higher expectations,but also necessary precision mechanical cutting of rough castings processing to arrive.
2, surface coating and protective properties
Generally, the surface treatment of the castings will be greatly limited, and the processing quality is poor. However, for casting aluminum alloy, through testing, the material for the precision casting parts of ZL101A can also be subjected to an anodic oxidation, and the material itself, the corrosion resistance can be quite high, after 10 cycles of the cross becomes hot and humid, and 48h of the salt spray test after casting did not show any adverse reactions, which is better than the corrosion resistance of aluminum alloy the LY12 material of.
In summary, the precision casting process has its own advantages, and can improve the utilization of metallic materials, and shorten the product manufacturing cycle and reduce product costs, improve product quality, process method in the research and production should be a good in the research and production of certain conditions, can be extended to applications.