Lubricating Powder Coating Systems

Article From: Products Finishing, , from Digilube Systems Inc.

Posted on: 12/1/1998

Ideas to consider in selecting a lubrication system for a powder coating operation . . .

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Lubrication System

Lubrication System for powder coating line.

Powder Coating system

Powder Coating system uses dry-film lubrication on the conveyor.

If you powder coat in high volumes or continuously, automatic conveyor lubrication equipment is or will become nearly essential. A lubricating system that is well engineered and properly installed benefits powder coaters in numerous ways.

Precise, programmed dispensing of the lubricant is one of the most important things you can do to protect the integrity of the final product. Over-lubricating is wasteful and costly and attracts airborne dusts, heightening the risk that lubricant will contaminate the product. By avoiding under-lubrication of the conveyor, its service life and many of its critical components are maximized.

Automatic lubrication is the best tool available for eliminating sliding friction and preventing seizing, two factors that save energy and minimize overall system wear. Automatic lubrication also allows each point to be lubricated to its individual best advantages. A good system allows this type of flexibility. It also assures that hidden and inaccessible points are lubricated as efficiently as those that are more visible.

Programmed lubrication is obviously an excellent rust-preventive for the conveyor. Some lubricant formulas used in automated systems will also perform a cleaning function, penetrating recesses and evicting dirt and other contaminants from bearings.

Finally, predictable lubrication directly reduces labor costs by eliminating the manual applications process and minimizing wear-related maintenance and repair.

So, how do you decide what equipment will serve your powder coating system best? It is wise to start with the lubricant itself. Many choices as well as market and environmental factors are changing the comparative dynamics of these choices.

1. Determine the best conveyor lubricant for your facility. Given your powder coating system, product line and throughput, is it a conventional petroleum-based product? A true synthetic? Semi-synthetic? Dry film? New moly-free formula? The optimum choice will be heavily influenced by the amount of heat and load the lubricant is exposed to, the time the conveyor spends in cure and dry ovens, conveyor speed and waste management considerations.

 
Powder Coating system uses dry-film lubrication on the conveyor.

Presently, dry films are the prevailing choice. Dry films clean and penetrate simultaneously. They are easy to dispense; can be applied in small, precise amounts; and will not attract dust. They are heat stable to about 450F. Also, when exposed to heat, they tend to dry rather than drip, offering significant advantage over conventional lubricants that become dangerously prone to dripping when heat lowers their viscosity.

Within the dry-film category, the newest development is molybdenum-free formulas that satisfy some of the new EPA regulations.

2. Consider the "other" chemical in the system: the specific powder used. Lubricants and lubricators are compatible with some coatings and not others. Electrocoating systems, for example, are highly subject to contamination. If a drop of the non-compatible lubricant lands on the part, instant fish eyes can result. No other factor makes such a strong case for precisely metered amounts of appropriate lubricant than the issue of compatibility.

3. Calculate your conveyor load. This number affects the choice of both lubricant and equipment. External load factors, such as dust and contamination from adjacent processes, will also impact your load factor. It is common to see a shot blasting or similar dust-producing operation close to a conveyor that is manually lubricated using a tacky lube—a virtual dust magnet.

It is also common that this will substantially boost the conveyor load, making each cycle more costly. Therefore, you need to determine your conveyor load and realize that there may be simple steps you can take to lighten it.

4. Consider the level of outside service that will be needed. Lubrication system buyers generally plan to maintain them with their own personnel. Whether you prefer this route or use a contractor, buy a system that has a proven track record.

If you powder coat, talk with operators of lubrication systems for powder coating rather than suppliers whose systems serve non-finishing applications. If possible, talk with the individuals at those facilities that actually do the maintenance. Understand the service level needed as well as how and why it can vary. Make sure that whatever you choose, it works for you.

5. Automated lubricators should dispense low-viscosity fluid in precise, metered amounts and lubricate by conveyor cycle. This is not a universal feature among the various equipment possibilities. Some use clock-like devices. It is important that cycles, not hours, be tracked. Power outages and semi-annual daylight savings time changes cause enough difficulties. Do not add one more by disrupting your lubrication cycle.

Also, if you change production rates or add shifts, you will want your conveyor to accommodate the change without re-calculating and resetting. Microprocessor-based systems offer cycle counting capability and automatically accommodate increases and decreases in production schedules, one-time variances and other breaks in production.

 
Lubrication System for powder coating line.

6. Buy a system that has a brain so it can help control costs as well as the process. A system with a microprocessor can count cycles, vary the lubricant dispensed and monitor conveyor speed. It is also valuable in its ability to tell you, in terms you can use, how much lubricant was used for job costing purposes.

If you link several conveyors and use a single tank, a microprocessor-based system can also calculate the amount of lubricant used for each conveyor.

7. Location, location, location. If possible, install the lubricator where there is no product. The best position is as far away from the washer as possible so that the lubricant dispensed has the chance to thoroughly penetrate the wear points before it reaches the washer. An alternative spot is after the parts loading station. Then, if there is an equipment failure or misalignment of dispensing tubes and lubricant falls on a part, the washer will clean it off.

If the conveyor has sanitary hooks, another consideration regarding placement is to install the lubricator at a site where the chain has cooled from the oven, preferably on a flat stretch that is free of inclines/declines. Then, one can install a pan directly under the lubricator.

8. Select a lubrication system that accommodates the new formulas. The new chemistries and wider viscosity ranges of the new lubricants will demand great flexibility in lubrication equipment. An all-electronic system is recommended. Quite simply, there is a lot less that can go wrong compared to air-assisted units that use pistons, seals and similar maintenance loving components. The solenoid dispensing offered by electronic units also provides the greatest reliability in dispensing accuracy over long periods.

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