September 2009- Lean manufacturing is all about getting the waste out of production, and parts cleaning is one area that's ripe for eliminating waste.

Cleaning parts has inefficiencies, such as using toxic chemicals that are costly to buy, dispose of and handle. Others include the use of cleaning equipment such as rags, wire brushes or compressed air, which aren't efficient for high-production work.

Even with the best methods, labor is often wasted and cleaning is ineffective, meaning critical part features might not be reached.

Often, to gain productivity, the parts-cleaning process is outsourced. But this can also add waste to the system, as many parts are often needed for a bulk discount before shipment. More waste is added when personnel must prepare the paperwork, gather the parts, have the space available for the shipment and sometimes even package the parts to prevent damage--and then pay for the shipping costs.

Once returned, the parts might not be properly cleaned or they could be damaged, which entails additional labor for inspection and in-house cleaning.

Comprehensive cleaning
So what's the most efficient way to clean parts? For lean manufacturing, ultrasonic cleaning offers significant benefits. This process cleans parts in a chamber or tank with an environmentally friendly, water-based cleaning soap. Within the tank, an energy-converting electronic transducer produces sonic frequencies approaching 40,000 cycles per second.

As these ultrasonic frequencies release energy, microscopic bubbles are created and collapsed, sending out shock waves which, when the proper cleaning agents are added, clean the parts. Ultrasonic systems can remove dirt, oil or grease residues and other contaminants.

Benefits of this process include substantially reduced labor both in hours and personnel, lower cleaning agent costs and thoroughly cleansed parts. In addition, the entire process of shipping parts for vendor cleaning is eliminated.

"Instead of building up a large inventory and then sending the parts out for cleaning so that they can then go into plating, anodizing or other processes, parts can be cleaned in-line in smaller batches as needed," Frank Pedeflous, president of Omegasonics, an ultrasonic cleaning tank manufacturer in Simi Valley, Calif., said in a press release.

In lean manufacturing, an important process is getting production lines to flow where there's no wasted motion or secondary processes. For cleaning, ultrasonic tanks are available as small single-batch tanks to large multi-batch ones, allowing them to be placed where needed for efficient parts cleaning.

Saving money
Hal Weatherly, an engineering consultant, was hired to improve the parts-cleaning process of a medical oxygen application for a manufacturer of portable air separation equipment.

"The previous cleaning method [involved] hand scrubbing, was labor-intensive and not entirely consistent," he said in a company article. "By nature, people have difficulty doing something exactly the same way every time. We aimed to streamline the parts-cleaning process while proactively improving quality control."

By installing ultrasonic cleaning equipment, his results went beyond his expectations.

"Before, each cylinder took about 45 minutes to clean by hand," he said. "Now it takes just five minutes to clean each ultrasonically. We're seeing similar benefits in a range of parts."

With saved labor and process efficiencies, Weatherly forecasted that the ultrasonic machines will have a return on investment in about three months.

"The ultrasonic process is better, faster and more efficient at getting the contaminants out, which ultimately enhances product safety, quality and cost for the end user," he said. FFJ