Case Study 004 - Ford

FORD MOTOR CO. increased the requirements for spur gear assemblies to include special assembly grease for the proper mating of the gears.

ABSTRACT

Cutting fluids and oils used during the gear facing operations left a residue which included the grinding compound and was being found to score the precision gears during run-in. It was essential that these parts be free of any grinding contamination prior to the application of the grease as well as during the critical start up of the transmission in the “hot-test” area. FORD had also made a firm commitment to reduce the volumes of flammable solvents typically employed for the level of cleanliness required of the part. A newer concept as well as a cleaning solution was required.
PROBLEM
Gears which are employed in the internal drive of the transmission must mate against each other to a high level of precision to minimize noise as well as assure the reliability and longevity of the transmission itself. The precision machining of these gears requires a final stage of grinding for surface finish and precision. Due to the volume of the parts required, they were being placed in open faced racks and passed through traditional parts washers with only marginal success. Grinding compounds in many cases were not fully removed and were being carried forward with the part, into the final clutch assembly. These compounds would then contaminate the gears and cause scoring to occur which led to defects and eventual rejects on the line. Other units affected could enter the final customer carand lead to eventual warranty issues as well and had to be addressed. Within the area of the plant where these gears were installed was quite congested and allowed very little room for any type of a cleaning process to occur. Also as workers were in the area, a safe type cleaning solution was mandated as well. Gears were received in trays which stacked within each other which also minimized the fluid delivery to all the internal areas of the gears and recessed cut areas.
SOLUTION
TECH-TRANS worked closely with the FORD Toxicology Dept. and was instrumental in gaining the approval (tox# 132-612) for a water-based cleaning product capable of removing the grease and grinding compound from the cut gears. Lab tests conducted by TECH-TRANS verified the expected results utilizing this material and generated the flow rates / temperatures / as well as agitation required to meet the systems demands. From these tests, a process became defined and the subsequent design and build of the washing system around these parameters occurred. The entire system was manufactured of 304 /6 stainless steel and included a lift elevator capable of raising the covered lid of the system and at the same time, raising an internal rack upon which the parts could be stacked in their shipping trays. Shipping trays containing the parts are manually loaded and may be stacked up to four levels high. The internal rack can accommodate up to four of these stacks as well. The total lift capacity of the system is in excess of 1,200 lbs. When the rack is lowered, the stacked shipping trays / parts become submerged in the heated chemicals. These chemicals are re-circulated and filtered upon each pass through a stainless steel impeller driven pump. The cylinders engaged for the lifting process are also employed in a short stroke lift and lower cycle which provides a vertical motion to the parts as well. The entire system therefore provided a safe cleaning chemical which is heated, circulating as well parts which are mechanically agitated for optimized cleaning efficiency. TECH-TRANS provided a full 3-D CAD simulation of the entire process and design of the lift and other components to confirm optimized capability and process cycle. Dual fluid filtration is also provided to allow for filter change out while the system is operational.
ADDENDUM
Based upon the success and reliability of this process, a second unit was ordered by FORD Livonia for another area of the plant and is used for cleaning valve body assemblies which are repaired after testing.
BENEFITS
REDUCED RE-WORK OF ASSEMBLIES INCREASED PART / PART RELIABILITY AND IMPROVED THROUGH-PUT REDUCED: POSSIBLE WARRENTY ISSUES – INCREASED OWNER LOYALTY IMPROVED ENVIRONMENT – ENHANCED WORKER SAFETY -
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