Monthly Archives: August 2016

Five Things You Should Never Do With Your Batch Powder Coating Oven

Whether yoBatch Powder Curing Oven Control Panelu’ve just started coating or have been operating a batch powder coating system for years, you know that the coating oven is an expensive appliance and a vital part of your coating operation. Keeping your batch oven in good working order is critical to long-term success. A well-maintained powder coating oven can last for over a decade, produce thousands of high-quality parts for your customers and be a considerable source of income for your business.

However, a batch oven that is operated incorrectly can be a serious safety hazard that’s unreliable and can cause you nothing but problems and headaches. To help you avoid making a costly – and potentially dangerous – mistake, here are five things you should NEVER do when operating a powder coating oven.

1) Don’t Run The Oven Above The Recommended Temperature

Most batch powder coating ovens are rated for sustained operation at temperatures of up to 450° F, while some more expensive models are rated up to 500° F or higher. If you own a conventional 450° batch oven, jumping up from 380° to 480° in an attempt to save a few minutes of cure time will harm the equipment, possibly trip the safety devices (leading to downtime) and potentially damage the finish on your parts. Every powder is rated for a specific temperature range. Going above this range will make the finish brittle and less durable, and can cause discoloration issues. This is especially true with glossy white finishes. Also, the few extra minutes you might save aren’t worth voiding your warranty or damaging costly components, especially on a critical piece of equipment like a batch curing oven.

2) Don’t Reduce The Exhaust Airflow In An Attempt To Save On Heating Costs

All professional-grade gas fueled ovens are built to exhaust a certain amount of air whenever the oven is in operation. The exhaust causes the air to move in a particular pattern within the oven cabin, keeping the cabin a stable temperature throughout. If you reduce or eliminate the exhaust airflow, you can create hot and cold spots that weren’t there before. These temperature changes will cause the powder to overbake or underbake, resulting in poor finishes and lots of reworks.

You’ll also have problems with safety devices. If you disable the safeties to keep them from tripping, you are violating important safety codes and you’ll void your warranty, no matter who built your oven. Another problem is that if there isn’t enough air being exhausted from the oven, you can have significant heat loss at the doors or oven panel seams. You may also have problems getting the doors to latch properly.

3) Don’t Overload The Oven Trying To Increase Throughput

If too many objects and racks are added to the oven, there’s a high probability you will accidentally block the oven exhaust or airflow ducts inside the cabin. If the exhaust is blocked, it adds stress to the exhaust fan and can shorten the service life of both the fan and the drive motor. It can also promote hot spots inside the oven that can damage parts, rolling racks or the oven cabin itself. If the supply ducts from the heater are obstructed, the powder can get blown off the parts. A bigger problem arises if the airflow through the heat unit gets reduced. This not only kills fuel efficiency but it also causes the temperature inside the heat unit to skyrocket. This can result in the heat unit’s fan failing, reduced service life from the motor, erratic operation due to safety circuits being tripped and even structural damage to the heat unit.

4) Don’t Skip Maintenance

Remove-BoltNo matter how busy the coating line is, skipping scheduled maintenance will shorten the service life of important oven components and can lead to critical failures. The majority of service calls we receive regarding older ovens are linked to poor maintenance practices. Most of these calls come from successful powder coating shops that use their equipment daily and stay busy–but they learn the hard way that “we’ve been busy” is no excuse for avoiding routine maintenance procedures. Keep your oven clean. Service the burner regularly. Lubricate bearings as directed. Check ductwork for obstructions. Don’t let a nuisance issue, like a noisy exhaust fan or a worn-out door latch, result in costly downtime because you were too busy to deal with it when you first noticed it.

5) Don’t Install The Oven Too Close To Other Equipment Just To Save Shop Space

Batch Powder Coating Oven Maintenance Walkway

Make sure to allow for enough space around your coating oven to meet safety codes and allow for easy maintenance access.

From time to time we encounter a situation where a customer has installed his oven too close to his powder booth, his welding operation, a clean-up station, his blasting operation or some type of chemical pretreatment wash station. Not only does this violate safety codes, but debris, fumes or even powder from other appliances can cause problems with your oven or your finishes.

We were recently asked to troubleshoot problems with a high-end oven from another manufacturer. We discovered that the oven worked fine, but the parts were being exposed to WD-40 fumes during both the coating and cool-down stages—resulting in unacceptable finishes. Although this wasn’t damaging to the oven, similar exposure to airborne grit from blasting or pretreatment chemistry from a washer could have been.

Another common problem is when the “guts” of a powder coating oven get coated with a layer of powder over and over again during operation because of powder overspray from a nearby booth (usually one that needs a filter service). The burner safeties can cause the oven to shut down, the fan can come out of balance due to an uneven layer of melted powder and ductwork can become restricted. All of this can be prevented with proper planning and equipment placement.

Routine Maintenance and Scheduled Service Can Keep You In Operation For Years To Come

At Reliant Finishing Systems, we pride ourselves on providing some of the best and most efficient batch coating equipment on the market. By following these tips, making sure you’re following a set maintenance schedule and contacting us for service visits when you have problems, you can help increase the lifespan of your equipment and maximize your ROI.

Have any questions about powder coating equipment or need to schedule a service visit? Give us a call today.

Improving The Performance Of Your Batch Powder Curing Oven

Batch Powder Curing Oven From Reliant Finishing Systems If you use a walk-in sized batch powder curing oven for your powder coating operation, you may have questions about how to consistently get the best results from your equipment. The oven’s performance–particularly the air temperature and airflow inside the oven–can make or break the quality of your finished products.

These important tips can help you get the best finish possible from your curing oven:

Make Sure The Oven Is Sized Correctly For The Project

Powder coating ovens can be built to nearly any height, width or depth. The ideal size for your project is dependent upon what you are going to be coating. No matter what you want to coat, the entire object needs to fit inside the oven with room to spare. For more information on oven sizing guidelines, click here.

Keep Parts Away From Walls, Doors, Ductwork And Ceiling

Powder Coating Oven VentsDepending on which brand of oven you have, heated air is usually blown into the oven via ducts in the ceiling or wall, or sometimes both. When curing, make sure you have enough space between the ductwork and the parts. If the parts get too close to the ducts, the powder can get blown off and you will have to rework the part.

Likewise, if a part touches the oven’s interior, the powder is likely to either rub off completely or flake away during curing. In order to get a proper finish, the parts can’t touch the ceiling, ductwork or walls, and they can’t impede the operation of the doors or rub against them.

Also consider how the parts will be carried in and out of the batch powder curing oven. Most parts are hung on rolling racks (also called parts carts), so there has to be enough room for the rack to fit into the oven once the parts have been hung. If your rack bumps into the walls of the oven, the powder you applied can get knocked off.

Keep Parts Off The Ground

Just like you will need to allow for room near the walls, ceiling, doors and ductwork, you also need to avoid hanging parts so that they nearly drag the ground. If possible, the lowest part of the biggest parts should be 10” or more off the floor. This makes the temperature of the parts more uniform and allows the powder to cure more evenly. It also helps prevent dust contamination if the oven’s heat system blows dust and dirt from the floor onto the parts.

Routinely Check Your Batch Powder Curing Oven’s Temperature

Some ovens have better temperature uniformity than others, but none are perfectly uniform. Ovens with ceiling ducts are usually cooler at the floor than elsewhere. Ovens with wall ducts may be cooler in the corners, and possibly near the floor. It is recommended that you routinely check your oven’s temperature with an oven data recorder (a Datapaq or similar) and keep a log of the results. Get professional help fine tuning your oven and adjust your curing practices as needed.

Check Your Shop For Airflow Issues

Batch Powder Curing Oven - Doors OpenAlthough it might not be obvious, drafts and air currents in the shop influence the way an oven operates. Some days there may be giant wall-mounted vent fans in operation to help keep the shop cool or get rid of welding fumes. Other days there may be one or more heaters in operation to keep office or shop space warm. Many shops have roll-up doors that are constantly being opened and closed. Wind can blow into the building or move across openings and create an imperceptible vacuum or pressurize a shop in ways that can easily overcome a powerful fan system. All of these things can impact your oven’s performance.

If you notice a change in your oven’s performance, check for changes in the way air moves through your building. Is air blowing in from outside that wasn’t a few days ago? Were the building exhaust fans turned off but the vents left open? Have you started using an AC system or have you cranked up heaters that weren’t in use until recently? Does the oven only have problems when a roll-up door is opened or closed? Examining the airflow within the shop can often help you pinpoint oven operation issues.

Check Your Fuel Source When Local Usage Changes

Another factor that can make a huge difference in the way an oven runs is fuel supply. Whether your oven is burning LP or natural gas, changes in the fuel supply can cause problems that are almost impossible to trace. These issues can be due to weather changes, new construction near your shop, changes within your building, or changes to your style of use.

If an oven is calibrated during the summer, the gas supply may decrease during the winter because of increased demand. This may be due to your neighbors (especially if located near a hospital, apartments or a large office complex) or may be because you’re using more fuel to run heaters or gas-fueled appliances within your own building that are tied in to the same line feeding your batch powder curing oven.

A similar problem can occur if new apartments or other types of high-demand buildings are constructed near your building. Once occupied, they may cause changes to the fuel supply coming into your building. Along the same lines, if you add shop heaters, steam units, or additional ovens, it may reduce the amount of available LP or natural gas fuel.

Remember, gas pressure and gas volume are not the same thing. It is possible to have a situation where the pressure gauge shows plenty of pressure when the oven is at idle or turned off, but then have performance issues once the oven goes to high fire. This usually happens when the supply line or regulator is too small. The oven can also have problems if the supply has enough volume, but the pressure is too high (dangerous and can cause the safeties to trip) or too low (can cause the oven to fail to ignite or to take too long to get to curing temperature). For best results, the oven needs an adequate volume of gas delivered at just the right pressure.

Always Follow Safety Procedures

IMPORTANT: If your shop’s work schedule becomes busier or you change operators, it is possible to have oven issues crop up because of the way the oven is being used. One common problem is caused by operators opening the oven doors for loading/unloading while the oven is running. This is unsafe and can lead to property damage, serious injury or death. It also causes the heat system to burn a large amount of fuel as it tries to maintain curing temperature while heat is rapidly escaping from the oven through the open doors. Not only does this waste fuel, it can reduce the service life of expensive oven components because of the burner’s extremely high output. When you’re ready to open the oven doors, shut down the burner but leave the fans running. Turning off the fans while the oven is at curing temperature can cause them to warp or can cause related parts to fail prematurely.

Follow Factory Maintenance Recommendations And Usage Guidelines

Batch Powder Curing Oven Control PanelEvery powder coating oven manufacturer provides a maintenance schedule which outlines the safest and most effective ways to operate their equipment. These factory-recommended “best practices” describe the style of use that is safest, most efficient in terms of manpower, least expensive in terms of fuel use, least likely to result in down-time due to equipment repair, and most likely to prevent unusable powder coated parts that are rejected due to poor finish quality.

There’s a reason why successful shops that are noted for premium quality work or incredibly high throughput keep their equipment in top shape and operate it properly. Having a set schedule for cleaning, maintenance and lubrication of your batch powder curing oven and related equipment will help you get consistent, high-quality finishes. Similarly, only running the oven within recommended temperature ranges is not only more fuel-efficient, it is safer for your operators and less likely to damage parts. Oven providers typically offer strict guidelines designed to assure that you get the best results from your equipment and the highest level of efficiency. Following those guidelines will help save you from expensive equipment repairs and costly parts reworks due to bad finishes.

Need An Equipment Check-up?

Reliant Finishing Systems batch powder curing ovens are always set up by our factory-authorized technicians to provide performance that is well balanced. We want our ovens to reach operating temperature quickly, while burning as little fuel as possible, and we are committed to helping shop owners keep our equipment in the best operating condition possible.

If you have any service or maintenance issues, please give us a call today. Scheduling a visit from one of our factory-authorized technicians can help solve curing issues, improve your efficiency and increase the lifespan of your equipment. Available services include troubleshooting, Datapaq recording and line audits, preventative maintenance, and both routine and emergency repairs. Call today for more information or to schedule an appointment.