Cleaning Parts in the Remanufacturing Process
With demand for remanufactured parts on the rise, leaders in automotive, agricultural, and heavy equipment remanufacturing are looking for parts cleaning systems that can sustain intense parts cleaning while reducing time and labor for maintenance on the washer. To better understand how remanufacturers can keep their aqueous parts washers performing at top quality with ease of maintenance and less down time, one must consider the system design and key elements of parts cleaning in the remanufacturing environment.
First, it is important to perform regular preventative maintenance on tanks, nozzles, pump housings, and heating devices to ensure high quality performance. Performing the necessary preventative maintenance and monitoring washer performance is much easier and more cost effective than maintaining the washer after a problem occurs. The process of cleaning remanufactured parts involves the removal of an enormous amount of contaminates that can build up in the washer over time. Simply changing the water in the washer is not enough to maintain the equipment. As soil is removed it accumulates in every area of the washer so attention must be paid to all major components of the system. Maintenance can be time consuming and very labor intensive. It should not be overlooked when selecting a washer design to fit your remanufacturing requirements.
Several variables are considered when selecting an appropriate aqueous parts washing system for remanufacturing use. These variables include the type of part, part contaminate, cleanliness specifications, production process, maintenance and service intervals.
Cleaning methods vary depending on the part composition, size, shape, and internal areas to be cleaned. In aqueous systems, contaminates such as oil, dirt, particulate, and grease are removed from items using water and mechanical actions. Types of mechanical actions include high pressure sprays, immersion/agitation, turbulation, motion, and ultrasonic energy. The methodology used in the equipment is based on the cleaning requirements and application. Some of the more common aqueous washer designs are belt, monorail, immersion/agitation, rotary drum, rotary table, rotary basket, and engine block systems. All have unique features and advantages.
Cleanliness specifications vary significantly and play a major role in the washer design. To ensure parts are cleaned to specification, laboratory testing will provide quantifiable results, and determine the appropriate cleaning chemistry and temperature setting. Rinsing procedures compatible with the cleaning method assures sufficient rinse water will remove any remaining soil or detergent. Since rinse water is the last thing to touch the item being cleaned, rinse water that minimizes residue deposits on the item is best. Several rinse cycles may be required depending on the application.
Dryness specifications are determined by the type of part, volume, and where the part will travel next. Choosing the correct drying method is critical to avoid corrosion of metals, particulates sticking to surfaces, and other potential problems. Drying methods may include forced air blow off, vacuum, or centrifugal drying. Not all drying processes are applicable to every situation.
Process considerations are dictated by the volume and throughput of the parts to be washed. Parts may be cleaned in a single piece flow or in a batch system depending on the production requirements and variables mentioned earlier. Small items may require Rotary Basket washers for batch, precision, and ultrasonic cleaning. Parts cleaned with this system include cast aluminum fuel pumps, heavy equipment components, hydraulic valve bodies, engine components and bulk machined parts. Rotary Table washers are best suited for low volume parts, batch cleaning, and parts with multiple sizes and geometries. Examples of items cleaned with Rotary Table washers include remanufacturing cores, machined parts, fuel system components, and hydraulic pump housings. High volume production and in-line cleaning applications may require a belt or monorail washer. These are ideal for cleaning transmission components, fuel system parts, ignition system parts, and industrial equipment components. The physical design of the washer is determined by floor space, utility location, ventilation, and service accessibility.
Cleaning the washer and tank is a tough job, but if it is not cleaned on a regular basis the washer will not have the ability to clean parts to the expected specification. To improve ease of maintenance, consider using a continuous self-cleaning tank that removes remaining debris from inside the tank after components have been processed. Also ensure that tank doors are easy to remove and are accessible. Stainless steel construction provides durability and chemical resistance for longer washer life. High pressure sprays prohibit build up in the spray headers and risers, reducing down time for maintenance.
Given that bath dumps can be expensive, efforts to increase bath life should be a high priority. To extend bath-life it is critical that fresh solutions be used periodically to avoid potential cross contamination and residue build up. The time to dump the bath and start over is usually defined by the number of parts cleaned or the length of time used. Bath life can be extended by physical filtration of particulates and cooling and settling of sludge and skimming of oils.
With the heavy concentration of contaminates found in the remanufacturing industry, options for sludge drag-out tanks, oil coalescers, sludge-towers/clarifiers and hydrocyclonic filtration will improve tank clean out intervals. Sludge drag-out systems can improve quality by keeping rinses and subsequent tanks cleaner. They may also limit chemical usage, save water, and reduce treatment costs and sludge disposal.
A clarifier may be plumbed to the wash tank to remove the particulate sludge from the wash solution. This water separating system will continually pull the contaminated solution from the wash tank and process it through a series of inclined plates to separate the particulate from the solution. The particulate will settle to the bottom of the clarifier and the clean solution will be returned to the wash tank. The sludge at the bottom of the clarifier can be removed by opening a ball valve at the bottom of the unit and draining the sludge into a tote.
An oil coalescing unit may be added to your wash tank as a closed loop oil/water separator. Coalescers are designed to remove oil contaminates from the wash or rinse solution. The contaminated solution is continually pumped into the coalescing tank and then passes through an oleophilic media pack. The pack causes oil to coagulate and quickly rise to the surface of the solution where it is skimmed off to a drain. The cleaned solution then flows into a clean solution reservoir where it is allowed to gravity feed back into the process tank. The oil removal rate will vary with the type of chemicals and oil being used. A Satellite Coalescer requires no additional operator attention after the initial adjustment of the oil decant weir and periodic cleaning of the oleophilic media pack.
Hydrocyclonic filtration are conical shaped and uses centrifugal force to maximize contaminate separation. Rubber inserts are used to enhance performance and minimize wear.
Even with these bath life extensions options, the bath will eventually reach a point where residue or sludge forms and the system will need to be cleaned. If not properly maintained, the equipment may clog making it difficult for the washer to produce a clean product.
To effectively meet production and cleaning requirements with minimal downtime for maintenance, work with a qualified vendor to design the best solution for your remanufacturing needs. Remember to perform regularly scheduled preventative maintenance and monitor washing performance. When purchasing a new parts cleaning system, careful research and planning into the design of the system can save you money and hours of unpleasant labor.