Parts Washing

In selecting an immersion parts washing system it is important to consider the size, shape, and configuration of the parts themselves. Massive weights, large surface areas, acute angles, occluded sections, and blind holes pose special problems, independent of the contaminant(s) to be removed or the chemical cleaner to be used. Proper cleaning of all parts can only result when consideration has been given to these physical variables.

To replace vapor/solvent degreasing we must change old habits and procedures. Traditional vapor/solvent degreasing is primarily a dipping process using aggressive chemicals to do all of the work. Modern detergent cleaning is a washing process using mild chemicals that rely on the performance and flexibility of the washing systems. The equipment must provide enough mechanical agitation to accelerate the process and detergent conditioning to maintain consistent solution quality.

There are several methods of mechanical agitation used for immersion washing:

Platform oscillation

• moving the parts through solution
• moving the parts in and out of solution

Solution turbulation

• moving the solution over and through the parts

Cavitation

• precision cleaning using sonic wave energy

Each method has unique characteristics which can be used to solve specific cleaning problems.

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Platform oscillation is the most common method of batch immersion parts washing. It is the simplest way of covering irregular surfaces and reaching intricacies and the inside of hollow forms with a cleaning solution. Oscillation of the work is an easy way of accelerating the cleaning action. With each oscillation the mechanical force of the moving solution keeps washing newly formed emulsions and soaps away from surfaces while applying fresh chemical cleaning agents to the newly exposed layers of dirt, thereby speeding the entire action.

Cleaning Characteristics

• complete immersion, recessed areas in contact with solution.
• parts moved up and down
• parts break in and out of solution
• filling and draining of blind holes.
• up/down motion swirls solution over surfaces dispersing contaminants.

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Solution Turbulation (aka – “spray” under immersion) moves solution over, under, around and through part(s). In this case pump agitation is used to turbulate the solution. The turbulent flow is then directed over the working zone using manifolds with jets or eductors. Specific problem areas can be addressed by positioning of the manifold(s). This method produces higher impingement than straight platform oscillation. As such, it is most effectively used together with platform oscillation to produce constantly changing flow patterns. This further accelerates the process by reducing shielding.

Cleaning Characteristics

• complete immersion, recessed areas in contact with solution.
• high velocity agitation of solution around and through the parts.
• shearing action strips away contaminants from the surfaces.

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Cavitation or ultrasonic cleaning is a special tool used mainly for precision cleaning. It is most effective used in conjunction with other methods of immersion washing (i.e. part oscillation and solution turbulation) to handle stubborn contaminants.

Cleaning Characteristics

• complete immersion, recessed areas in contact with solution.
• high frequency sound waves produce an intense microscopic scrubbing action at the surface of the substrate.
• The energy released (produced by millions of microscopic bubbles imploding in the cleaning solution) heightens chemical activity and strips away contaminants from the surface of the substrate.