Selecting a Parts Washer

Thanks to advances in technology and its declining price, parts washing equipment has continued to become more sophisticated. Higher levels of automation, more advanced electronics, and processes such as ultrasonics have become widespread in recent years. Though basic, entry-level machinery is still common, other products have advanced to adopt formerly optional or high-end features, such as PLC controls in place of previous manual, rotary-type switches. Parts washers have evolved without sacrificing the dependability crucial to users.

However, the selection process for choosing a piece of cleaning equipment has not changed much through the years. The same questions need to be answered, and understanding how they might change over the life of the equipment is equally important:
1) What is the type of contaminant?
2) How clean is clean enough?
3) What are the environmental regulations or goals?
4) What size and shape are the parts?
5) What is the necessary capacity (e.g., parts per hour)?

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These questions are not independent of each other. But by answering them in conjunction with input from the local parts washer representative can help establish the “three legs” of the parts washer stool—system style; size, quality and automation level; and fluid type.

System Style

The first leg of the stool is defined by the type of system needed. Various cleaning methods are available, each with pluses and minuses.

Soak. Soaking in an aqueous or solvent cleaner is the simplest, least aggressive cleaning action. It is more effective with longer immersion time. These cleaners are applicable where soils are readily removed, cleaning time and throughput are secondary concerns and low equipment cost is important.

Directed Stream. A flushing stream of low pressure solvent or heated aqueous cleaning fluid is applied directly at the soiled part via a flexible hose. The cleaning action is particularly effective for flushing parts when brushing. For enhanced results, the directed stream can be used in combination with other cleaning actions. While effective, throughput is limited in a system like this.

Brush. Manual brushing is used in conjunction with soaking as a supplement to other cleaning actions. This method is helpful in removing stubborn soils in small batches but involves manual labor. Some companies offer “flow-through” brushes that work with a directed stream unit to deliver cleaning solution right to the brush to flush away the removed contaminant.

High Pressure Spray. A quicker and more effective cleaning is accomplished by powerful spray, typically of water-based detergents. A high pressure directed stream of up to 600 psi can be focused on different areas of the parts, allowing the user to tailor the cleaning approach to the individual part. Configuration types include front- and top-loading systems with rotating platforms for semi-automatic cleaning; enclosed manual cabinet systems for precision cleaning applications; and conveyorized “tunnel” systems for high throughput, automated cleaning.

Total Immersion Cleaning. Similar to soaking, this cleaning action is a result of parts being totally immersed in the cleaning solution so that all areas are in contact with the fluid. This process provides much improved cleaning of external surfaces, internal passages and blind holes when combined with various methods of in-tank agitation:
• Pump agitation creates constant movement of fluid through the use of a pump. This provides faster cleaning than in a stagnant tank.
• Platform agitation creates a flushing action through the up and down motion of the pneumatically-operated lift platform within the tank. The vertical motion causes the solution to reach difficult to clean areas. Additionally, agitating platforms can typically be raised for easier loading and unloading of parts.
• Ultrasonics creates a scouring action within the tank via sound waves that create imploding cavitation bubbles within the cleaning fluid. These are effective in cleaning even the most difficult application. Since the sound waves can pass through the part itself, the cleaning action is not limited only to outside surfaces but can tackle even hard-to-reach surfaces and narrow, blind holes.

Size, Quality and Automation

The second leg of the stool is determined by the size of the parts washer, its quality and its automation level.

Size. The size of parts washer to buy depends on a few variables. Obviously, the washer needs to be physically large enough to handle the parts that are to be cleaned. Beyond that, a decision must be made regarding the tradeoff of higher capacity and throughput from a larger machine versus lower initial and operating costs and a smaller footprint with a smaller machine. A detailed analysis of cleaning needs, both current and anticipated, is crucial here. Generally it is easier and faster to load parts in a washer that has a little extra capacity than one where space is at a premium.

Quality. A quality product is essential. People often try to economize, but this can end up costing more in the long run. A parts washer that only lasts for a year, or can’t cope with a stepped-up workload, is not a bargain. The individual components of the washer should be examined, such as construction quality, pump capacity and even the quality of simple components such as fasteners, hoses and fittings. These components provide a good indication of how long the unit will last.

Automation Level. As mentioned previously, parts washers have become more advanced. Manufacturers offer a variety of automation levels, from non-existent to completely hands-off. Automation saves labor in areas such as cleaning, loading and unloading but costs more money up front (sometimes substantially more). Some systems can even automatically move parts from the wash cycle to a rinse cycle and a drying cycle, providing hands-off parts cleaning. Automation makes more sense in high-throughput, manufacturing operations than it does in more ad-hoc maintenance operations.

Fluid Type

The final leg of the stool is sized up by fluid type. A wide variety of fluids are available for parts washers today, and choosing the proper one is essential. It is also worth checking on any specific environmental regulations in the area. The parts washer representative can walk through the benefits of each type for a specific application. Not every washer can handle every fluid type.

Solvent. Petroleum-based solvents are the most widely used cleaning fluids and are considered by many users to be the most effective. Solvent removes a wide variety of soils and typically does not need a separate drying step. Useful in soaking, brush, directed stream and total immersion cleaners, solvents should not be heated or sprayed. Solvents become saturated with grease and oils and therefore have an effective life, after which they need to be recycled or properly disposed of. Several companies offer filters that can extend this life.

Aqueous. Aqueous (or water-based) parts cleaning has been making steady inroads over the past few decades. Historically viewed as cheaper but less effective than solvent, aqueous detergents have advanced in recent years, with a variety of targeted chemicals available for most part materials and soil types. Aqueous detergents are typically heated, increasing their efficacy. In addition to soaking, brush, directed stream and total immersion cleaning, these solutions can typically be sprayed under pressure, creating a wider variety of cleaning system solutions. Aqueous detergents should be checked prior to use for compatibility with the parts being cleaned and with the washer. Anti-rusting agents may be needed, use of a stainless steel or plastic parts washer is usually recommended. Aqueous detergents also have an effective life, after which they need to be recycled or properly disposed of.

Bioremediation. Bioremediation parts cleaning is an offshoot of aqueous systems. However, these detergents add microbes that “eat” the carbon-based waste produced in the cleaning process, turning it into water and carbon dioxide. This process extends the life of the cleaning solution dramatically, reducing the waste stream and disposal costs. The one caveat is that these systems need to have constant heat and be properly aerated to keep the microbes working at peak performance levels.

Custom Units. Finally, some customers have specialized needs that may require a custom unit. A parts washer representative or distributor can determine what is needed and then discuss those needs with the manufacturer. It helps to deal with a vendor that has some experience in building custom units, as they can recommend options that have been implemented for other applications.

Do Your Homework

With the options available under each leg of the stool, there is rarely a “one size fits all” solution to parts cleaning applications. That is why it is important for buyers to do their homework and partner with a reputable company that offers more than one type of parts washer. If they do this—and answer the five key questions up front—they will receive the right advice and buy the parts washer that is proper for their particular application.