Control Systems For Finishing Lines Improve Profits

For most companies, the ultimate goal is to increase profits. (I say most because some Internet companies are still about making the "big score" in the IPO game. But, that's another story.) And, there are lots of ways to reach that goal, including selling more product, reducing costs, improving product quality and increasing customer satisfaction. The first two methods have an obvious impact on the bottom line. While the impact of the last two methods is not as obvious and much more difficult to measure, they still have a significant effect on profits in the long run.

Simultaneously pursuing each of these methods to increase profits can be quite an undertaking for many companies in the finishing industry due to their smaller size. But, UpRight, Inc. (Selma, CA), a manufacturer of what is generically called aerial work platforms and telescopic handlers, found a way to do it by exercising control of its pretreatment system and powder coating and painting lines.

The Need for Control

While many of UpRight's scissor lifts and other products are designed for indoor use, the company introduced a rough terrain scissor lift several years ago. Such outdoor use, as well as the company's expanding sales in Europe, makes corrosion resistance a top priority at UpRight.

The need for excellent corrosion resistance was not due to greater demands from the European market. Rather, it was to combat the corrosive salt environment the products would encounter during their transportation across the Atlantic Ocean. In order to meet the need for improved corrosion resistance, UpRight felt it was necessary to improve the control of its pretreatment and finishing systems.

Another reason UpRight wanted to install a control system on its finishing lines was to improve its monitoring capabilities, allowing the company to better understand the nuances of its finishing processes. According to Mark Askew, planning engineer at UpRight, "We wanted to improve the monitoring as well as to immediately know when there is a change. Before we got the controllers, if a problem came up, we never knew until a week later when we started assembling parts that had been painted and the adhesion wasn't good." Finding out there was a problem with the pretreatment a week after the part was painted meant that it was likely there were more parts with the same problem. So, if UpRight could identify a problem immediately, it could limit the number of parts with adhesion problems or eliminate those problems altogether.

Real-Time, Automated Control

In order to meet its goals of increased corrosion resistance and adhesion and improved monitoring, UpRight installed the GL Controller from Coral Technologies on its pretreatment system and powder coating and liquid painting lines. The system provides real-time, automated control of UpRight's pretreatment system, conveyor, ovens, waste treatment and spray booths. The system provides UpRight with more than just control over its processes through alarms, trend analysis and real-time communication functions.

Pretreatment. UpRight uses a five-stage pretreatment for its powder coating line and a three-stage pretreatment for its liquid painting line in Selma and a five-stage pretreatment system on its line in Madera. While each system is different, the controller monitors and controls the same parameters for all three lines. For each process stage, the concentration, pH and conductivity is automatically monitored and controlled. The controller also automatically monitors and/or adjusts a variety of mechanical variables, including spray pressure, temperature, tank levels, nozzle blockages and part detection.

Conveyors. Monitoring the conveyors on all three lines is extremely important for UpRight. Why? Well, some of its parts are so large that they might be in more than one pretreatment stage at any given time. If the line stops but the pretreatment system continues to run because parts are in the system, chemicals can be sprayed in one stage, run the length of the part and deposit in the next stage, causing serious cross contamination.

The controller monitors the conveyors' stoppages, speed, status and drives. Not only does the system monitor each of these parameters, but it maintains a log that can be called up by the paint line manager at any time so he can determine why a line was stopped and how long it was stopped.

Ovens. As every finisher knows, maintaining the proper oven temperature and curing time is critical to achieving a quality finish. Therefore, UpRight uses the controller to monitor and adjust oven temperature.

Spray Booths. In Selma, the outside air temperature can be quite cool in the morning and extremely hot in the afternoon. (Trust me, I was there.) Consequently, it is necessary for UpRight to precisely monitor and control the powder coating and painting booths' temperature, humidity and airflow. And, the system allows it to do just that.

Alarms. While the controller automatically monitors and adjusts a variety of finishing line parameters, it is still necessary to have people in ultimate control of the line. Therefore, alarms are used to notify UpRight's personnel when a parameter is outside of its setpoint. (Coral helped UpRight establish its setpoints. It's important to not make them too tight, causing nuisance alarms, or too loose, causing finishing problems.) Once an alarm has gone off, an employee must enter his password and the corrective action he took. This information is stored in a database so that UpRight can know exactly what is happening on the line.

Trend Analysis. The controller stores all the information that it gathers from its monitoring and adjustments in a database. This information can be used to provide trend analysis, which is an effective tool for paint line managers to identify opportunities to improve their finishing systems. The controller can present this information in graph or report form, allowing the paint line managers to quickly see the trend of any parameter for any period of time.

Real-Time Communication. Because the controller is continuously monitoring and adjusting a variety of parameters, UpRight's paint line managers have access to a variety of real-time data. But, that is not the controller's only real-time communication function. The controller is connected to the Internet as well. This allows UpRight's personnel to monitor and control the finishing lines from another plant, home or even a hotel room, as long as they have access to the Internet. It also allows Coral's employees to monitor the system from its home office anytime UpRight has questions or concerns about the system's operation. Also, the controller is tied into UpRight's Ethernet, connecting the plants in Selma and Madera.

Profiting from Control

So, how did a decision to add real-time, automated control affect profits at UpRight? To answer that question, one must understand the benefits the system provided: increased corrosion resistance and adhesion; decreased chemical costs; improved monitoring; and an Internet connection.

Increased Corrosion Resistance and Adhesion. UpRight manufactures large parts with unusual geometries that, when combined with small process spaces, can cause large deviations in pretreatment chemistry due to dragout. Before it added the controller, UpRight performed manual checks on its pretreatment system every couple of hours. Since it was so easy for the pretreatment chemistry to get out of balance in that short time, it was forced to make very large additions to the process tanks.

But, with the controller in place, UpRight can automatically make small chemical additions on a regular basis, ensuring that the pretreatment tanks always meet the required specs. "With the controller, the lines are set up so that if a chemical gets out of balance, an alarm goes off. And, we can take care of the problem before it even gets to the assembly line," stated Mr. Askew. According to UpRight, this has been one of the most significant reasons for the increased corrosion resistance and adhesion of its parts.

And, because the controller has increased paint adhesion, UpRight has virtually eliminated the rework it used to perform. "We're using less paint because there's less rework now. When there was a bad paint job where the paint didn't stick, it had to be stripped and recoated. But, rework is basically gone now," said Bob York, paint system supervisor at UpRight.

Decreased Chemical Costs. Now that UpRight is making small additions on a regular basis with the controller instead of large, less frequent additions, the company has been able to decrease its chemical use and costs. "It's definitely helped with our chemical consumption. We are able to track our use. We can go back to the system and find out why," explained Mr. Askew. "If the nozzles are out of adjustment it will tell us. That was one thing that Coral kept going over with us. When we were still working the bugs out of the system, we were using quite a bit more chemical than we should have. But, the controller has definitely helped us with that now."

Improved Monitoring. One of the great benefits of the controller is that it archives all of the data it collects and the corrective steps taken to bring the system back into spec. Why is this so important? Suppose a customer calls UpRight and says it has four scissor lifts where the paint isn't adhering properly. Because UpRight uses serial numbers to know exactly when each part was produced, it can go back to the archive on the pretreatment system and see what the conditions were that day. The ability to monitor its process in this fashion gives UpRight enhanced knowledge of its system. This knowledge allows UpRight to make changes to its system to prevent those conditions from occurring again.

Internet Connection. This is a feature that might seem unnecessary to those that think the Internet is simply going to sell more product for them. The real value in the Internet is not selling something faster or cheaper, but the ability to transfer or share information quickly and more efficiently. "One good thing about the Internet connection was that during the startup, it was easy for Coral to monitor our progress and find out our weaknesses and where we needed a little more training with the operators. Also, not only does it allow us to monitor remotely, but we can literally turn paint guns on and off from a remote location," said Mr. Askew.

Future Benefits. Even with all of these benefits, there are features of the controller that UpRight is not using. The company is looking into monitoring and adjusting paint parameters, such as gun-to-part distance, mix ratio and paint viscosity, with the controller. "What's nice about the controller is if you want to monitor something, you can buy a block of memory, plug it in, get a program, run your wires and you're ready to go," stated Mr. Askew.

The combination of these benefits has allowed UpRight to increase its profits in the four methods mentioned earlier. By increasing its corrosion resistance, UpRight was able to enter a new market, allowing the company to sell more product. With improved monitoring, UpRight was able to cut down on its chemical use and, consequently, its chemical costs. The improved monitoring also has improved paint adhesion, which has improved product quality. And, the company was able to increase customer satisfaction because it can solve any customer's problem by examining its monitoring records. Best of all, the payback on UpRight's investment was less than a year.

Employees respond to alarms and take corrective action at this computer. It is password protected so that employees can only make changes to those areas that they are responsible for. Also, UpRight has installed the computer close to the finishing line so employees can respond more quickly.

UpRight uses the controller to monitor and adjust the spray booth's temperature, humidity and airflow. It is considering adding functionality that will also allow it to control the paint's mix ratio and viscosity.

The overview screen gives the operator and supervisor current information on all aspects of the finishing line as well as current alarms. A point-and-click interface allows the user to go to any area for detailed information.

All current sensor information as well as manually inputted data can be seen on this detailed screen of the first stage of the five-stage powder coating pretreatment system.

It is critical that the last stage of the powder coating pretreatment system run within the pH specifications. This graph provided a detailed look at the pH level of the non-chrome seal tank for the last 31 days.

To learn more visit Coral Chemical Co..