Electrocoating(pelapisan dengan arus listrik)

The Basics of Electrocoating

Electrocoating is a process critical to every segment of metalworking industries. Advanced electrocoating systems allow product designers greater latitude in the choice of materials, improve the performance and wear properties of critical components, and give metals a high quality, nonporous, high-adhering surface for the subsequent application of liquid or powder topcoats, where desirable.

A Definition:

Electrocoating uses electrical energy to apply organic finishes. The part is grounded and immersed in paint that has been charged with the opposite polarity. Resin and pigment migrate to the part, and a uniform film is irreversibly deposited. The part is rinsed, then cured.

4 Critical Processes:

Successful film depo sition depends on four simultaneous processes:

• Electr o ph oresis - the mo vement of colloidal materials dispersed in liquid under the influence of a potential gradient.
• Electrolysis - the dissociation and movement of ions.
• Electro-osmosis - (the reverse of electrophoresis) the extraction of water from the deposited film.
• Polarization - the ability of the deposited film to exhibit electricity resistance, thereby insuring even coverage.

E-Coat Advantages:

Properly engineered systems offer precise control over film thickness, highest film integrity and an unblemished appearance. The process offers extremely high repeatability of results, and is a practical alternative for metal parts of virtually all sizes and shapes, gauges and grades.

The most common applications of electrocoating include underhood/underbody components, recreational goods, cooking and laundry appliances, HVAC products, and aerospace products. Recently, manufacturers of upscale consumer products have popularized electrocoating as a primer for powder-coated goods.

E-Coat and the Environment:

Electrocoating benefits the user in several important ways. Closed loop rinsing, ultrafiltration, and the applications process itself allow material utilization of virtually 100%. Many electrocoat paint formulas are now available which are free of heavy metals; many are also near-zero in VOCs and HAPs.

Electrocoating may not require a dry-off oven, thus exhaust air and makeup needs are minimized. Finally, because the paint is 80-90% water, the risk of fire - the “ultimate” environmental disaster - is vastly reduced.

The Anodic/Cathodic Debate:

Anodic systems deposit a negatively charged polymer onto a positively charged part; in a cathodic system, the reverse is true. KOCH can demonstrate, and help you compare these options in terms relevant to your plant, your product, your production, and your future requirements. Today, acrylic, epoxy and hybrid electrocoating are the alternatives. Of these, cathodic epoxy systems are widely regarded as the “ultimate” in terms of delivering high hardness, excellent salt spray and other performance properties.