Why Are Paint Booths Automated?

Automation is a fast-moving train that shows no signs of stopping, nor does it even slow down. Production processes are increasingly included worldwide. Let us look at the performance demonstrated in the North American automation market during the first nine months of 2017. This region is a good indicator of the global state of the industry. According to the Robotic Industries Association, growth in robots, computer vision, and motion control segments is at the highest level to date. In the field of robotics, approximately USD 1.5 billion in orders were sold in North America. This corresponds to 14% growth in units compared to the same period last year. The hottest industries were metals (54%), automotive parts (42%), and food and consumer products (21%). Record order levels were also recorded in motion control and motors (up to 10%) and in vision and imaging (up to 14%). This year marks the eighth consecutive year of growth in global industrial robot sales; forecasts for 2018 and beyond are also promising. Automation is a fundamental supporter in industrial development. It provides improvements in work quality. It allows hazardous, unpleasant, or difficult work to be transferred from human labor to machines. It reduces labor costs and improves productivity; it offers flexible production and strong product customization solutions tailored to customer demand.

Is it expensive?

Questions must be asked about the investment cost for automation. Does it create an obstacle? For example, what is the cost for a paint booth operator to transition from manual to automatic spray application? The most advanced examples of automatic paint spray applications are found in the automotive industry. Here, ATEX paint robots integrate all paint process variables into a single process. Robot controllers, metering and mixing equipment, color change and spray equipment are all controlled centrally by the Paint Robot's PLC. The PLC is fully integrated, programmable down to fine details; however, this comes at a cost. The investment cost required for such a system can easily exceed EUR 200,000. In general industry, there is an increasingly growing need for fully automatic paint applications. However, the return on investment obtained when purchasing such an automotive-class paint robot is not always optimal. Moreover, these automotive-class paint robots require programmers, maintenance personnel, and users to have a certain level of training. Once programmed, the paint application will run without problems; however, when ad-hoc changes need to be programmed and implemented, this task must be carried out by qualified, specialist personnel. Alternatively, in general industry, many automatic paint spray processes are set up around a central PLC, and thus applicator parameters, proportioner parameters, robot, reciprocator, and other equipment, sensors, etc. are controlled separately. This also requires comprehensive PLC programming knowledge. Additionally, the programmer must have a very good understanding of the entire paint spray process. However, the total cost of an automatic paint spray process in general industry is less than that of a fully equipped automotive paint robot.

Graco's Approach to Paint Booth Automation

A third approach is also possible; this is the approach preferred by Graco. This approach involves creating a fully automatic paint application system at a reasonable price that can be easily and completely integrated with metering, mixing, color change, and applicator. In this concept, a single system controls all paint process variables of fluid management equipment and applicators. Communication with the robot or reciprocator is simplified and standardized; this also reduces the level of PLC programming required. At its core are pre-programmed logic routines within the equipment: Graco Control Architecture (GCA). Many integration options are possible in a similar system. Regardless of the brand of reciprocator, robot, or other equipment working with a PLC, Graco Control Architecture software can be easily integrated. Whether using Profinet, Profibus, Ethernet, or Devicenet, the external PLC will be loaded with a standardized configuration file (GSD, GSDML, etc.). With this configuration file, system integrators can define simple data such as communication options, I/O configuration, and available diagnostic data from Graco Control Architecture. Because this standardized I/O configuration is ready for use, the workload on the PLC programmer is greatly reduced. Connection is made through a single Ethernet IP cable with the Graco GCA Network Gateway. The GCA contains the mapping that provides seamless communication between the communication protocol used by the PLC and the Modbus protocol used within Graco Control Architecture.

A single system controls all paint process variables:

Mixing and metering: • Flow control, • Recipe: Color change, mix ratio. Distribution: • Fan or atomization air control, electrostatic kV and μA • Gun trigger or trigger input signals, • Brush files. Thanks to this unique and innovative concept, you can automate your entire paint spray process. It is controlled with an easily programmable PLC. Fluid supply, metering, mixing, flow and pressure control, atomization and spray parameters, robot or reciprocator: All are controlled with a single PLC.

Integrated System Offering Numerous Advantages

This unique integration concept offers numerous advantages. First, it is easy to use. All paint variables are brought together in one place for improved integration. Mix ratio, flow, fan air, atomization air, electrostatic, and gun trigger are all found in a single, simple system. The communication structure is simple and consistent. All that is needed is a single Graco network gateway and a single Ethernet cable to connect the system to the PLC or robot control unit. The mapping structure is standardized for repeatable operation and consistency; robot presets (brush files) are available for group control of spray variables. Additionally, it offers a user interface that is familiar to anyone who has worked with Graco. It is a safe system with built-in logic to disable electrostatics in certain situations and low-voltage wired guns that reduce user risk. Furthermore, it is intelligent. Internal logic to link spray gun operation with fluid control reduces PLC programming. Logic routines exist to enable/disable specific features when certain conditions such as PD2K Mixing, Idle Mixing, or Color Change occur. Moreover, the gun selection tool enables features based on gun type.

Good Return on Investment

The equipment investment for such a system is approximately EUR 90,000. Cost-benefit break-even is expected within one year. All factors affecting return on investment must be included in the calculation: • Labor cost • Process improvement (more parts per year) • Reduction in process materials, solvent, and consumables • Higher quality, fewer rejected parts, scrap, warranty costs. Lower total cost per part. Beyond return on investment, there is another advantage; the automatic paint spray process minimizes total cost per part. A well-known practice for reducing total cost per part in paint booths is remote color change and mixing. By mixing near the applicator and increasing the number of color changes during wash cycles, wash waste can be reduced by up to 80%. The situation is very clear since only the area between the color change block and the metering pumps needs to be washed. However, since energy consumption and VOC emissions can also be reduced, automation in the paint shop reduces costs by a much greater margin. Graco Control Architecture Paint Kitchen Manager controls different paint kitchen system components such as an electric paint circulation pump, back pressure regulator, electric mixer, pressure transducers, and tank level monitor. With an intelligent paint kitchen, you can remotely monitor and control basic circulation parameters such as pressure, flow, tank level, and mixer speed. Especially when compared with traditional custom systems, it is a less complex and less costly alternative for improving remote monitoring and control throughout the paint shop. All components are standard products; thus, they can be easily configured and installed. Both initial investment and installation costs are low. Graco's easily integrated automation technology can significantly increase efficiency, profitability, and quality in the paint shop. It is no surprise that smart manufacturers are making the transition.   Bart Clerx Finishing Products Marketing Specialist Graco