Black-oxide Process Uses Almost No Rinse Water

Birchwood Technologies offers a new option for its black-oxide process. Now it is possible to operate the in-house TRU TEMP® black-oxide system while using almost no rinse water. The Near-Zero^TM water recycler allows for reusing the rinse water in the process line. For black-oxide users in water-restricted areas, this means they can continue critical metal finishing operations while observing tight water usage guidelines.

Where water use is under scrutiny, the water recycling system can be installed on a new line or on an existing line as a retrofit. According to the company, its normal 100-gal. black-oxide process line uses three flowing rinse tanks, each of which uses about 2 gal. of water/min. When operated for one shift per day for a month, the total water consumption is about 63,000 gal., all going to the city sewer as nonhazardous discharge.

The water recycling system allows the user to recycle and reuse the rinse water in the process tanks for about a month. When the recycling system filter is changed, all three rinse tanks are purged and refilled with fresh water. A 100-gal. tank line would require about 600 gal. of water each time the system is purged, which the company says is a 99 percent reduction in water usage.

The water recycling system is designed for process lines up to 200 gal. in tank size and is pre-engineered for fast setup.

The in-house process produces Mil Spec-/RoHS-compliant black-oxide finishes, with a 30-min. turnaround time. The bath operates at 200 degrees F and forms a nondimensional, black magnetite finish on all types of tooling and machine components. According to the company, because the process uses a short cycle time, it streamlines part movement, provides better control of finished part inventory, and enhances ISO accountability, giving the user a same-day turnaround capability.

Birchwood Technologies * 952-937-7931 * www.birchwoodtechnologies.com