How to Develop an Eco-Friendly Metal Parts Cleaning System

How to Select an Eco-Friendly Ultrasonic Parts Cleaner

Challenges relating to cleaning new or refurbished parts, many of which require subsequent processing such as painting and plating, are increasing due to environmental regulations.  This post shows you why an ultrasonic parts cleaner using eco-friendly biodegradable parts cleaning solutions is a favored alternate to washing and spraying with harsh solvents along with their associated disposal concerns.   

Why Choose an Ultrasonic Parts Cleaner?

Let’s start with why you should consider an ultrasonic parts cleaner.

Cleaning is faster, safer and easier when using an ultrasonic parts cleaner.  Machining oils, grease, residues left from molding or handling, soot and other contamination are difficult and can be dangerous to remove by soaking in harsh and sometimes flammable solvents, manually scrubbing or power washing in solvent parts washers. 

Moreover these methods do not reach difficult-to-access surfaces such as cracks, crevices, small diameter and blind holes where contaminants remain and can cause future problems.

Why Ultrasonic Parts Cleaners are Effective

Cleaning is accomplished by what is called ultrasonic cavitation.  Quickly explained, it is the violent implosion of billions of microscopic vacuum bubbles that implode on contact.  This blasts loose and carries away contaminants on parts immersed in an ultrasonic parts cleaner solution (described below).

The bubbles access and work on all surfaces of the parts – cracks, crevices, small diameter and blind holes as mentioned above.  The process is fast and safe for any part that can be wetted in an aqueous cleaning solution – metals, plastics, rubber, glass……

Specification Tips for an Ultrasonic Parts Cleaner

Ultrasonic cleaners are available in various cleaning tank capacities and dimensions.  You’ll need to accommodate the largest parts you’ll be cleaning.  Keep in mind that your parts must be completely immersed in the ultrasonic cleaning solution.

Also remember that cleaning is usually accomplished in baskets, the dimensions of which are slightly smaller than tank dimensions. Large parts may be suspended in the cleaning solution – in which case care is taken to keep them from contacting tank sides and bottoms.

Useful Features

While all ultrasonic cleaners come with an on-off switch there are other features that may prove useful when you shop for your ultrasonic parts cleaner.

  • Timers let you “set and forget” the cleaning cycle, turning off the ultrasonic energy at the end of the cycle.
  • Heaters let you set the cleaning temperature recommended by the cleaning solution manufacturer.   Some units will start the cleaning when the set temperature is reached.
  • A sweep mode provides a slight ± variation in ultrasonic frequency to avoid areas of too intense and no cavitation.
  • A pulse mode provides bursts of higher energy to blast away more stubborn contaminants.
  • A degas mode drives off cavitation-inhibiting trapped air from fresh cleaning solutions and is especially useful for large-capacity tanks.  Pulse can also accomplish this.
  • Dual-frequency cleaners allow you to select between a higher frequency for more delicate cleaning or cleaning highly finished surfaces, and a lower frequency for more intense cleaning.
  • Adjustable power likewise lets you customize parts cleaning cycles to the tasks at hand.

Benchtop and Floor Model Ultrasonic Parts Cleaners

Elmasonic Select 60
Select 60

Benchtop ultrasonic cleaners come in various models. 

A good choice is the Elma Select series from 0.7 to 24 gallons.  For long-term parts cleaning, contact us for options

Tovatech also offers a wide selection of floor mounted ultrasonic cleaners for cleaning larger parts. These units, some of which are wheel mounted for portability, offer multiple features such as dual frequencies and agitation for faster cleaning cycles.  The industrial ultrasonic cleaner line is also offered in several cleaning solution capacities.     

How to Select an Industrial Ultrasonic Cleaner
See Our Full Line of Industrial Ultrasonic Parts Cleaners

Industrial-sized parts cleaners can be equipped with skimmers and filters to prolong cleaning solution life.  Contact our professionals for information on these processes.

An Economical Ultrasonic Parts Cleaning Solution

As suggested above aerosol sprays and parts washer solvents generally are used full strength and are environmentally unattractive. 

Use elma tec clean A4

An attractive alternative is biodegradable Elma tec clean A4 concentrate available in 2.5, 10 and 25 liter containers.  It is diluted to 2% to 5% with water, depending on the condition of the parts you are cleaning.  With proper bath maintenance it can provide a long service life before replacement is necessary.

Note that while this cleaning solution is biodegradable, always consult local authorities regarding proper disposal.

Setting Up an Ultrasonic Parts Cleaning Procedure

As an example, we’ll use the 37 kHz Elmasonic S series noted above and Elma tec clean A4.  The S series has features that contribute to the efficiency of the cleaning operation.  These include a heater, a timer, a degas mode, and a sweep mode.

Presented here is a typical procedure for using the A4 biodegradable ultrasonic parts cleaning concentrate.  With experience you can modify it to suit your requirements.

  1. Fill the ultrasonic cleaner tank half way with water then add the proper amount of A4 cleaning solution concentrate for a full tank.  Continue adding water to the fill line.
  2. Activate the unit and degas mode to mix and degas the solution.  These steps must be taken each time a new batch is prepared.  In about 15 minutes you are ready to clean.
  3. Place your parts in the basket in such a way that they do not contact each other.  Lower the basket into the cleaning solution.  Set the thermostat for 50⁰ to 80⁰C, the timer for 10 minutes, activate the sweep mode to evenly distribute cavitation throughout the bath, and start the unit. 
  4. Remove the basket and inspect the parts (caution – they may be hot).  If satisfied let them flash dry; otherwise rearrange them and repeat the cycle.

If parts being cleaned must be spot free rinse them to remove cleaning residue from the surfaces. Depending on the degree of cleanliness you may want to use distilled or DI water for rinsing.

If rusting is a concern add 0.1% elma KS rust inhibitor to the cleaning solution for temporary corrosion protection.  This inhibitor can also be used with a rinsing bath.

Maintaining the Ultrasonic Parts Cleaner System

Cleaning solution life can be prolonged by removing gross contaminants before the ultrasonic cleaning operation.  During ultrasonic cleaning skim off and set aside material that floats to the surface. 

When cleaning efficiency drops it is time to replace the solution.  Drain it and dispose of it along with the skimmed off material in a locally approved manner.  Following the owner’s manual clean the tank to remove films and potentially damaging particles that fall to the bottom.   Prepare and degas a new batch and you’re ready to resume cleaning.

Chat or call Tovatech for more details on equipment and formulas for your metal parts cleaning requirements.

About Rachel Kohn

So how did an MIT Ph.D. end up selling refrigerators? When I figured out that a lot more scientists buy lab refrigerators than innovative leading-edge instruments. I hope that my many years of lab experience will help you find the right equipment for your work. Before co-founding Tovatech I worked in business development and project management at Smiths Detection, Photon-X, Cardinal Health, and Hoechst Celanese. And before that I spent 12 years as an R&D chemist at Hoechst Celanese and Aventis working on advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Some day, eventually, I’ll make enough money to develop an innovative technology that will change the world. Read More