Customers today demand higher quality and durability from the products they buy. Not only do they expect these products to perform well, but they want the finish to look good and resist corrosion for a much longer period of time. The finishing processes offered by Honestjoy are designed to do just that. One of those finishing processes is electrocoating (e-coating).
E-coating is a method of painting which uses electrical current to deposit the paint. The process works on the principal of "Opposites Attract". This process is also known as electrodeposition.
The e-coat process can be divided into these four distinct zones:
The pretreatment zone cleans and phosphates the metal to prepare the surface for e-coating. Cleaning and phosphating are essential to achieving the performance requirements desired by today's end user of the product. Honestjoy analyzes the metals to be processed and chooses the most appropriate chemicals. A high quality zinc phosphate system using the immersion method is primarily used in Honestjoy systems where steel and iron parts are to be coated.
The electrocoat bath and ancillary equipment zone is where the coating is applied and the process control equipment operates. The e-coat bath consists of 80-90% deionized water and 10-20% paint solids. The deionized water acts as the carrier for the paint solids which are under constant agitation. The solids consist of resin and pigment. Resin is the backbone of the final paint film and provides corrosion protection, durability and toughness. Pigments are used to provide color and gloss.
The post rinses provide both quality and conservation. During the e-coat process, paint is applied to a part at a certain film thickness, regulated by the amount of voltage applied. Once the coating reaches the desired film thickness, the part insulates and the coating process slows down. As the part exits the bath, paint solids cling to the surface and have to be rinsed off to maintain efficiency and aesthetics. The excess paint solids are called "drag out" or "cream coat." These excess paint solids are returned to the tank to create a coating application efficiency above 95%.
The bake oven receives the parts after they exit the post rinses. The bake oven cross links and cures the paint film to assure maximum performance properties. The minimum bake schedule is 20 minutes with the part temperature at 375°F for most e-coat technologies. However, Honestjoy also applies a "low temperature cure" e-coat material. This material has a minimum cure of 20 minutes at a part temperature of 180°F so that many assemblies containing seals, bushings, bearings, or oil can use the e-coat process.
At Honestjoy we categorize e-coat technology by the way they are primarily used. Certain technologies tend to be most commonly used as a primer or as a topcoat.
As a primer:
Cathodic epoxy electrocoat is the most popular technology at Honestjoy because of its superior adhesion and corrosion protection properties. It is designed to be compatible with a wide range of liquid and powder topcoat materials. Since this technology has good appearance properties it can also be a single coat where resistance to the ultraviolet rays from sunlight is not needed. Cathodic epoxy e-coat materials available today are very environmentally friendly. These materials are used on piece parts where a cure temperature above 380°F is possible.
Anodic epoxy electrocoat materials are used in the same way as the cathodic epoxy e-coat. Adhesion and corrosion resistance properties are generally better than commonly used liquid paint primer materials. Anodic epoxy e-coat materials are used where components must be coated as assemblies that contain heat sensitive parts such as bearings and seals. The part temperature for curing can be as low as 180°F.
As a topcoat:
Cathodic acrylic electrocoat materials lend themselves to topcoat applications because of their very good resistance to the ultraviolet rays from sunlight. A big advantage is that only one coat is necessary. The overall adhesion and corrosion resistance properties are good when compared to popular liquid primer plus topcoat paint systems. Electrocoat technologies are generally restricted to a given color, however, in some applications additional color options are required. A good solution is to use cathodic acrylic as a one coat system for the primary product color. It can also be used as a primer to be topcoated with a liquid or powder topcoat material for multiple color options.
An e-coating system with the appropriate supporting equipment such as the treatment system for process fluids represents a significant capital and staffing investment. For low to moderate production volumes, outsourcing is an easy decision. It is the cost effective way to obtain the advantages of e-coating for a product. However, when production volumes reach the levels where it would seem to be justified to install a system in-house, the outsource decision for e-coating becomes more than a normal "make or buy" decision. It is also a "strategic" decision. It means, "becoming a coater." Considering an in-house coating system brings new meaning to the strategic question, "What is our business?"
Here are a few of the advantages of outsourcing with Honestjoy:
Honestjoy offers e-coating services in several different locations. Other technologies such as powder coating and liquid painting are available at certain locations as additional coating service options. Call the Honestjoy Corporate Marketing Office (+86-133-168-62761) for a brochure showing a map of plant locations and a chart of services offered.
Regardless of the size of the coating program, Honestjoy services should be considered. Honestjoy is known for the capabilities of its internal Technology Group, Equipment Division and experienced operating teams. These capabilities have earned Honestjoy a reputation for providing a total, integrated, cost-effective coating solution.