A leading American powertrain remanufacturer for light vehicles and medium- and heavy-duty trucks turned to PROCECO for help with their new heavy duty truck transmission remanufacturing program. The goal of the program is for each transmission they process to be expertly remanufactured to provide truck dealers and the aftermarket with a reliable product for fleets or owner/operators facing a truck down situation. In addition to remanufacturing transmissions and engines, the company is known for providing a wide range of services including engineering design, core management, and logistics services to automotive original equipment manufacturers and the independent aftermarket.
The heartbeat of any remanufacturing operation is to have an adequate supply of usable cores on hand to be remanufactured. When cores arrive at this company’s core receiving area they are inspected and tagged for storage. The company typically has 3,000 to 3,500 cores in storage at any one time.
Once demand arises for a specific transmission core, it is removed from storage to begin the process of preparing it to be cleaned and remanufactured. Transmission cores that arrive at the company’s remanufacturing facility have been put through severe service by Class 8 trucks under a variety of highway and road conditions. The cores arrive at the facility, “as is,” coated with grease, oil and other oxides due to road salt and rust.
“Most cores have half a million miles of sludge and crud on them,” explained John, the product engineer responsible for the heavy duty transmission remanufacturing line.
To help accelerate the cleaning process, the company installed a PROCECO Spinner Hanger Slurry Blaster which is designed to degrease, blast clean, aqueous clean and inhibit rust in one operation.
No complementary process equipment is required making it a simple, yet effective metal component blast cleaning process.
Because the PROCECO Spinner Hanger Slurry Blaster combines multiple processes into one, a smaller machinery “footprint” is required. This saves factory floor space for other remanufacturing activities to take place.
PROCECO’s patented slurry blasting technology, also known as “wet blasting,” provides the ultimate parts cleaning performance within minutes.
For this leading remanufacturer, the first step in restoring a transmission core to useful life is to process it through their disassembly or teardown area. Here transmissions are carefully disassembled and prepared for cleaning.
“All the materials we process here are heavy, cast iron,” said John. “Although the clutch housings are aluminum, the majority of the parts are heavy steel.” Because of the material composition, John says his company can be a little bit more aggressive in its cleaning methods.
A typical transmission is normally made of a front and back case. “The front box is the main case of the transmission that houses the main shaft and the counter shafts,” explained John. “The back case is another piece of cast iron that goes on the back of the transmission where gear multipliers are located.” The main shaft has four gears, while the gears on the back case vary depending on the gear ratio desired.
John says the transmission is disassembled to split out the “gray iron,” or the steel parts of the transmission that can be more aggressively cleaned.
“The cases and clutch housings typically have half a million miles of oil and dirt accumulation that a regular washer isn’t going to take off,” said John. “The PROCECO slurry blasting machine is perfect for pulling off the grime that won’t necessarily come off by traditional means.”
After leaving the disassembly area where the shafts are disassembled and the gears are pressed off, all parts are first cleaned using an inline washer. Then they are ready for more aggressive cleaning with the slurry blast machine.
All the parts for one transmission core come back together after disassembly and cleaning, “because we are working with experienced parts, we like to keep them together as a unit.”
Parts are all tagged and placed into a tote. While the housing parts are not critical to keep together, the gear sets are. “If you keep the gear sets together, you’ll have more success when the remanufactured units are sent to the test stand for inspection,” said John.
Cores go from storage to be disassembled, cleaned, reassembled (including the replacement of worn parts), inspected, tested (using a dynamometer), painted and shipped. “Our goal is to process 30 to 40% more units a day by the end of the year,” said John.
Michael serves as the production supervisor for the remanufactured transmission line. “The objective of the slurry blasting technology is primarily to help remove baked on gaskets and old paint,” said Michael. “Removing the old paint helps with adhesion when it comes to painting a newly remanufactured transmission.”
Micheal says a single part (front case) spends a minute and a half inside the slurry blasting machine. When two or more parts (clutch housings, shift bar housings and back cases) are hung inside the machine, the cycle lasts two minutes.
Slurry blasting is basically a shot blasting process that uses abrasive media combined with a water-based detergent. The slurry is fed to a rotary blast wheel that mechanically accelerates and discharges the slurry at high velocity, towards the objects being treated. After this primary cleaning cycle, the supply of abrasive shot is interrupted and only clean detergent is fed to the blast wheel. This secondary washing cycle removes abrasive residue from the parts. The combination of the mechanical cleaning of the abrasive and the aqueous detergent, provides a cleaned, de-oiled, finished product with a white metal surface free of scale and contaminants.
The slurry is composed of abrasive media combined with a hot-water alkali cleaning solution to provide a very clean and smooth finished surface that is ready for the remanufacturing process. The heart of the cleaning process is the rotary slurry blast wheel, which accelerates and discharges the abrasive slurry at high velocity in a controlled pattern.
The blast wheel is equipped with a patented slurry projection nozzle that directs the slurry onto the rotary wheel.
Michael said by using the wet blast process with the PROCECO slurry blast machine, it has probably saved them from hiring two people and contributed toward speeding up the process. “Plus, we clean out places inside the transmission housing that a wire wheel can’t get to.”
“If we did not have the slurry blast machine, we would have had to hire someone with a wire wheel and a grinder,” said Michael. “They would need to spend a considerable amount of time attempting to eliminate worn gaskets, loose paint and baked on mud or grease. With the slurry machine, we don’t have to spend as much time doing that.”
While dust and debris are accumulated using a dry blast process, the PROCECO slurry blast machine does not produce dust so no dust collector is needed or required. Having no dust released into the air inside the factory is a unique advantage of the slurry blast method. Plus, there’s no risk of fire using the slurry blast system since flammable dust particles, common to dry blasting, are not released into the shop air. With dust and debris eliminated, this leading remanufacturer can assure workers that they have a safe work environment with clean air for remanufacturing transmissions.
Machine maintenance is minimal using the slurry blastmachine. “You clean the solution out of it, once a
week,” explained Michael. “With the media hopper, we clean it out after processing every 200 units. We are basically trying to get any loose gaskets or material that is stuck in there. It’s a fairly simple process.”
While the company has never used a dry blast process to clean transmissions, Michael says his previous employer used a dry blast process prior to purchasing a PROCECO slurry blasting machine. “It was a horrendous process and very messy,” related Michael of the dry blasting. “There was a lot maintenance using the dry blast process and the slurry blast is much cleaner and more self-contained.”
Michael says the setup process for the PROCECO slurry blast machine is fairly easy and changing settings on the machine takes no time at all.
Environmental and Safety Achievements
Because the PROCECO slurry blaster uses a closed loop process, both detergent and material are recycled. “The sludge out of the machines is recycled just like we would with materials from any of our other machines,” said Michael. The sludge is recycled following state and local ordinances, which ensures a safe working environment for employees.
Michael says there is one additional benefit of using the slurry blast process. Because the surface is cleaner than what would have been achieved using a dry blast process, they are able to use a premium quality paint to finish the remanufactured transmissions. He says this is possible because a cleaner surface helps the paint better adhere to the metal. Both John and Michael are pleased with the progress they’ve made in less than a year of overseeing the transmission remanufacturing process and from utilizing the wet blast process.
“The greatest benefit from using this technology is having a happy customer,” said Michael, “and ultimately that’s the biggest benefit from using the slurry blasting machine.”