Benefits of New Application Equipment

Q. We have been powder coating for around 20 years. We coat many different parts and reclaim our higher-volume powders. Overall, we are efficient and operate better than some other powder coating systems I have seen or heard about. Our equipment is old, and we have not updated anything in many years. Although we think our current system is quite efficient, we have heard of the benefits of digital controls and other features that can reduce cost. Is there really any benefit from these new controls, and what kind of cost savings can be expected?

A. Digital spray system controls have been on the market for almost 20 years now, and they do offer some unique functions that can often produce material savings and quality improvements. They are particularly useful if you can run somewhat larger batches of different products. 

Some of the benefits of digital control are the ability to minimize the number of variables in the system, provide more control over the application parameters, and make the system less susceptible to operator error or the effects of outside variables. The high level of control and flexibility of these new systems often results in coating and quality cost savings.

There are three specific areas in which cost savings can be achieved with digital controls. First, if you are using a cartridge-based powder recovery system and reclaiming higher-volume powders, savings can be realized from controlling the applied coating cost and making sure that the film-build control is as good as it can be and film thickness is within a tight range. If your reclaim system uses a cyclone that is somewhat lower in efficiency than the module system, the potential savings could be greater from improvements in powder application efficiency. And of course, spray-to-waste operations are even more dependent on application system efficiency for high material utilization. It is also important to understand that tangible savings can result from quality improvements.

Consider the capabilities offered by the newer generation equipment. If your equipment is more than 15 years old, these features definitely can benefit your application and save you money:

• They are able to store multiple application system settings in memory. The different settings (commonly called presets or recipes) can be programmed for different product types and quickly retrieved when changing from coating one product to another. With a digital spray system, control of the recipe can be changed, and the overall coverage can be much better controlled for more uniform film build and reduced overspray. Another example of savings is adjustment for different powders and colors. Different powders may reach full opacity (complete hiding) at different coating thickness. For example, white powder may require 2 or 3 mils of applied coating for full opacity, while black powder may only need 1.0 to 1.5 mils and yellow may need 2.5 to 3.5 mils. If the system is not adjusted for the different colors, it may apply too much or too little thickness for a specific powder, resulting in a waste of money or possibly a rejected part. 
• With a digital control system, different settings can be programmed for different powders. Flow rates and gun positions with digital controls can minimize areas of the part that need manual touch-up. Regardless of training and experience, manual touch-up operators are major contributors to excessive applied coating cost. They work hard to make sure parts are fully coated and often (inadvertently) apply an extra mil or two. Thus, minimizing touch-up often results in applied coating savings. 
• Automatic gun triggering can produce tangible operating cost savings and is often integrated into the new digital control systems. If you have more than three to four seconds worth of line gaps between your parts, turning the guns off during the gaps can not only minimize the overspray but also reduce the picture-framing on the edges of the parts. When coating parts of different heights, the use of “vertical zoning” will turn on only those guns that have parts in their spray area. The increase in the application efficiency of the spray system and reduction in picture-framing on the parts lowers your operating costs.
• It is not unusual to find that operators on different shifts do not agree on system settings. Different workers on the line may have different ideas about how the system should be operated. Of course, you should attempt to optimize system performance and encourage uniform settings, but chances are that changes in system settings from shift to shift or operator to operator will occur, and the variances to the applied coating will add cost and reduce overall finish quality. Many digital control systems feature password protection for system settings. Thus, to avoid variances and have better control over system performance, different levels of password protection can be established so that only supervisors can be authorized to change certain system parameters. 
• Digital control systems can also incorporate a closed-loop control of the airflow to the powder pumps. Powder output of a conventional powder feed system is prone to variations resulting from upstream pressure changes in the compressed air system and other variables. A digital system with closed-loop airflow control continuously monitors itself and provides 100 percent repeatable airflow output to the pump. The high degree of repeatability of the system outputs can significantly reduce the variations in applied coating cost.

Many of these adjustments can be made by capable and well-trained operators, but we all appreciate the difference between reliance on a manual operator and an automated system.
In addition to the benefits of digital controls, some excellent gains in performance can be gained from newer pumps, more precise flow controls, more advanced electrostatic controls (especially current controls) and other features that will justify the cost.

If you are getting the most out of your existing system, great! However, what if your system capabilities were to expand? Would you be doing even better? Examine your system, talk to your equipment vendor, and see if some of the digital system capabilities mentioned above can produce tangible savings in your operation. Try some testing if you can and see what newer equipment has to offer.