New E-Coat ThinCell Ramps Up Power

Highly-efficient anolyte cell provides 10 amps for every square foot of anode area.

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Anolyte Cell Resources’ (ACR, Crossville, Tennessee) new ThinCell is a highly-efficient anolyte cell for electrocoating designed to provide up to 10 amps of power for every square foot of anode area.

ACR sales representative Dave Garrett says the amps supplied to the painted product are almost double the amps supplied when using cylindrical—or tubular—style anode cells.

“Since e-coat is applied to the product on a per amp basis, this is a great benefit for the e-coater. It greatly reduces the number of cells needed to maintain a paint bath,” Garrett says.

In an e-coat tank, the product to be painted has paint electrically applied by the operations of the anolyte cells, typically located on two sides of the tank.

During this process, two important function are required of these anolyte cells. First, the anolyte cell is providing power through the anode area. This polarizes the paint pigments and resin molecules, which are suspended in the paint bath by solvents (typically low-VOC, organic acids). This process is dependent on the anolyte cells’ ability to provide the power to the e-coat paint bath.

“If the geometry of the cell is cylindrical or tubular, power is mainly transferred from the closest peak of the radius, toward the painted product,” Garrett says. “This area is usually about one-third to one-half of the calculated anode area from the OEM. This limits the current density to 5 amps per square foot of anode area.”

More Power

However, Garrett says the flat design of the ThinCell operates at 10 amps per square foot. It takes up the same space as a cylindrical cell, but more power is available due to the balancing of the amps, so that the proper current density is achieved over the entire anode area of the ThinCell.

The second action required is to remove the released solvents (acids) freed during the application of the pigments and resins to the product being painted. If the solvents are not removed, the pH of the paint bath will decline, which creates issues with the paint finish. Garrett says the anolyte cell must remove the acid from the paint bath to keep the pH within the specific range set by the paint manufacturer. A highly efficient cell will provide exceptional pH control.

Garrett says an anolyte cell also needs to run cool so that the paint does not crosslink prematurely. He adds that the ThinCell design provides excellent amp distribution over the entire face of the anode. This— along with the anolyte’s efficient and effective flow pattern over the anode effective area—allows for a lower thermal exchange footprint in an e-coat process.

Garrett says the ThinCell design is also maintenance free. The design allows 10 amps per square foot of power, evenly distributed over 100 percent of the calculated anode and membrane area. Field data shows the lifespan of a ThinCell, under normal operations, is 3–6 years without any maintenance, while other geometries require rotating, monitoring and other OEM-required procedures to stay operational.

Slim Design

While other cells on the market are 3 or more inches in thickness, Garrett says the slim design of the ThinCell being under 2" thick greatly reduces damage caused by swinging or dropped products that have come loose during production, saving the e-coater valuable money, time and labor.

The ThinCell is produced in vertical and horizontal configurations, and the company says installation is simple on existing strut channel and trough systems. The LD8 model features up to 90" effective length × 8" effective anode width, and is the standard replacement model for most applications. The HPLD8 model features dual 1/2" return ports, and anolyte flow modifications, for high current densities, with prolonged deposition power curves. It runs cool at high loads, and provides 90" effective length × 8" effective width. The HLD10 is a horizontal cell used in many specialized tanks that paint long parts, as well as barrel systems, and tanks with a lot of short tube cells. It provides effective lengths up to 90" × 10" effective width.

Originally published in the August 2015 issue.