Industrial Paint and Coating Robots

Industrial Paints and Coatings Robots

Introduction

In the dynamic environment of modern production in the 21st century, breakthrough technological developments—parallel to Industry 4.0, namely digital transformation technologies—continue to reshape high-technology sectors such as automotive, aerospace and aviation, and other heavy industries, optimizing processes and increasing efficiency. Among these technological developments, the innovation attracting the greatest interest without doubt is the integration of industrial robots into production automation, also known as robotics, which offers significant benefits—that is, the integration of robots with automation processes in order to operate efficiently and stably. These robotic systems are transforming the way products are finished by offering unique precision, speed, and quality in surface processing applications. This article aims to describe industrial paint and coating robots and to shed light on their important roles in the manufacturing sector. Industrial painting applications are advancing rapidly.

A Brief History

Although the word "robot" first appeared in Czech author Karel Čapek's 1921 play "R.U.R.: Rossum's Universal Robots," the beginning of the industrial robot sector in our modern world is credited to American inventor George Devol filing the first mechanical arm patent in 1954. (He is known as the Grandfather of Robotics.) However, people have imagined robots since ancient times, and various civilizations even used them for different purposes (for example, a servant statue capable of mixing and pouring water and wine). Since the 1970s, although early examples of robotic painting and coating technology are known in global industry, the first notable example is marked at the time General Motors began using it in production at its Michigan plant in 1985. These initial painting/coating robots operated on hydraulic principles and offered lower levels of safety and quality standards compared to today's electronic/digital versions (2).

Sectors Using Robots and the Paint and Coating Types They Can Apply

Painting and coating robots have been widely adopted in manufacturing and automotive industries because they offer many advantages compared to manual, hand-applied painting and coating applications.

Some of the sectors where robots are in use:

• Automotive, • Glass, • Aerospace and aviation, • Defence, • Smartphones, • Railway, • Shipyards, • Office equipment, • White goods, • Other high-volume or high-quality manufacturing sectors.

Various Types of Industrial Paints and Coatings

In the sectors mentioned above, there are painting/coating robots using a wide variety of painting and coating types. These are: • Thermal Spray Coating Robots, • Electrostatic/Powder Coating Robots, • Automotive Paint/Varnish/Sealer Application Robots, • Pipe Paint/Coating Application Robots, • Field Seam Coating Application Robots.

These paints and coatings can also fall into the following categories:

• Anti-corrosion/Rust prevention, • Anti-bacterial/Bacteria prevention, • Anti-fingerprint/Fingerprint prevention, • Anti-fog/Anti-fogging, • Water-repellent (especially for glass), • Sound-absorbing, • Vibration-absorbing.

Industrial Benefits and Advantages

Some of the benefits and advantages that can be cited as reasons these sectors prefer painting and coating are as follows:

Paint/Coating Homogeneity: Robots can move at a constant speed far better than a person, thus providing an even paint/coating film. Application Precision: The robotic painting arm moves with great accuracy. The robot's position, each time, is far more precise and repeatable than a human painter. Painting and Coating Hard-to-Reach Areas: Because they can reach areas that are difficult to access more easily, they are perfect for careful painting/coating applications on complex objects. They are extremely useful for painting highly sloped surfaces that would be difficult to paint by hand, as is the case with some automotive and aircraft parts. Application Speed: Can be much faster (30 times faster) than manual, hand-only painting/coating applications (1). Environmentally Friendly: These robotic systems, set up with necessary occupational safety and environmental precautions, protect both workers and the environment from various harmful chemicals (such as HAPs) and gases (such as VOC, NOX). Cost Savings: At first glance, if only the robot and auxiliary systems are considered, purchase costs may appear deceptively high. However, both the technical and administrative advantages mentioned above and the increase in efficiency and reduction in wasted paint/coating amounts will offset the initial investment cost in a relatively short timeframe. While there are numerous studies on this subject, you can examine the IERA award-winning ABB Pixelpaint technology study and find both cost and other benefits supported with numerical data. Providing Extra Time for Other Work: Painting surfaces by hand is usually a laborious process requiring standing in the same position for long periods and performing repetitive movements. However, a painting robot can give people more time to focus on tasks they find more enjoyable.

How Does an Industrial Paint and Coating Robot Work? Basic Components

The most basic components of an industrial painting and coating robot are as follows:

Manipulator: This is the main body of the robot; it consists of links, joints, and other structural elements. End Effector: The end effector is the device at the end of a robot manipulator; it is designed to interact with the environment. This tool is used to perform the application programmed according to the required task. Actuators: Actuators are like the muscle of the manipulator. They are controlled using a robot controller. They convert stored energy into motion. Sensor, Controller, Processor, Software and Painting Device and Part to Be Painted: Sensors are used to gather information about the robot's internal state or to communicate with the external environment. Sensors integrated into the robot send information to the controller about each joint or link, determining the robot's configuration. - The robot's controller controls the motion. It receives its data from a computer; controls the movement of the actuators and the coordinates of the movement with sensory feedback information. - The processor is the robot's brain. It calculates the movements of the robot's joints, determines how much and how fast each joint should move to reach the desired positions and speeds, and supervises the coordinated movements of the controller and sensors. The processor is a computer that operates like any other computer but is dedicated to a single function. It requires an operating system, programs, and monitors, and has the capability of a computer processor. Spray Gun. Automatic paint guns play a decisive role especially in the automation of painting and coating operations. For mass production, low downtime and maintenance times, efficiency, and highest quality are particularly important. Additionally, a wide range of nozzles provides individual customization and scaling. A robot becomes a painting/coating robot only through the integration of a painting/coating device. "Painting/Coating Robot" is an industry term used for a robot with two major differences from all other standard industrial robots: 1) Explosion-Proof Arms: Painting/coating robots are manufactured with explosion-proof robot arms, meaning they are designed so they can safely spray paints/coatings that create flammable gases. These coatings typically create an environment that must be monitored for fire safety when applied. Coatings are usually solvent-based paints that can trigger fire. Coating robots must operate safely in a volatile environment and can control all aspects of spray parameters such as fan air, atomization air, liquid flow, and voltage. 2) Self-Contained Painting/Coating Systems: When painting/coating robots were first designed, they had a single function—to operate safely in a volatile environment. As acceptance and use expanded, painting robots became not just a conventional robot with only explosion-proof options, but a unique subset of industrial robots. Painting robots now have the ability to control all aspects of spray parameters. Fan air, atomization air, liquid flow, voltage, etc., can all be controlled by the robot control system. The above two points are essential for safe and reliable application, that is, for painting and coating the desired surface in question! A robot's primary task is to bring the coating device to the appropriate position. The required movements are performed with robot control. The coating technology with all its parameters and programs is controlled by a separate gun control unit. Therefore, an interface between the controls is required to synchronize movement and spraying. Painting/coating robots use different methods to convert paint or coating into a thin film. This is important for uniform application.

The most common paint/coating application technologies used:

Air Spray: An air stream is mixed into the coating to break the liquid into fine droplets. It is the most common for paints. Ultrasonic Spray: An atomization surface vibrates at ultrasonic frequency. The coating hits the vibrating surface and transforms into a fine mist. Used for applying isolation and conductive films to small products. Other uses include gloss-prevention coatings, photoresist, and various coatings with special properties. Electrostatic: The coating liquid is charged with thousands of volts of static electricity at the nozzle. Electrostatic repulsion converts the liquid into a mist. The mist is drawn to the surface to be coated with an opposite electrical charge. With this method, uniform coating can be applied to non-flat surfaces. Efficiency is quite high with very little paint waste. In addition to these components, painting/coating robots can have the desired application in spray painting/coating programs automatically generated from computer-aided design (CAD) models and subsequently modified with minimal effort for: • Changing the spray pattern, • Nozzle diameter, • Distance from nozzle to part, • Number of passes, • Number of coats, • Entry/exit can be automatically managed to extend beyond the CAD model. • Can automatically manage and change the distance between steps without reprogramming the part. • Equal step distances ensure spray consistency. • Tool orientations can be automatically managed to optimize the program for minimal wrist rotation and maximize robot reach. Today's common painting/coating robots consist of 6 axes to reach material surfaces as flexibly as possible. With a seventh axis, the entire robot moves along a linear axis close to the ground. Meanwhile, all recognized robot manufacturers offer models specially developed for the coating industry. For the user, these differ in programming methods, coverage ranges, and the load capacity of the robot arm. As mentioned above, multi-axis robots specially developed for the painting and coating sector, equipped with modern wet, powder/electrostatic application technology, can efficiently paint and coat parts at the highest quality, as if by magic, once the robots have been programmed. If examples of painting and coating robots commonly used in global industry today are to be given, brands and models such as Fanuc Paint Mate 200iA/5L, Fanuc P-50iA, Motoman P8, and KUKA KR 100HA can be cited.

Recent Technological Developments in Industrial Painting and Coating Robots

A recent example in this field is an automatic painting and finishing machine built by an Italian company that can mount two spray guns on a robot arm. This setup doubles the coverage rate that a person can achieve. This system can also apply paint or coating to any component shorter than 6 inches (approximately 15 cm). Alternatively, the machine can spray adhesive onto medium-density fiberboard cabinet doors and prepare them for membrane presses. It has a 3D visual scanner that sends details about a part to a robot inside the spray booth. Another example of technological innovation is PixelPaint technology, which consists of a pair of 6-axis robots equipped with inkjet painting heads instead of traditional spray valves. This robotic system addresses customers concerned with automotive paint automation. This robotic system, addressing customers concerned with automotive paint automation, not only eliminates the need for masking and unmasking each car but also allows the application of bi-color or customized paint designs in a single pass instead of two. Another technological development comes from the DÜRR EcoRP 10 R1100 six-axis robotic system, an automated painting solution with the latest application technology including two-component paints (2C), paint distribution systems, and mixing and metering technology for the controller. With this system, the coating layers of chrome-effect paint can be applied uniformly in extremely thin layers of only 2 to 3 μm in some cases with maximum repetition accuracy. This is made possible with the continuous mixing metering system. Finally, the technological development to be mentioned is the development of a self-programming robot painting cell by Fraunhofer IPA in 2020, which can be used to paint very small production batches and individual parts. The cell uses a vision system to identify the object to be painted and then programs the robot to paint it accordingly. In today's era of widespread Industry 4.0, in addition to these, there are continuous improvements in both hardware and software of painting/coating robots, which increases efficiency while reducing waste rates, thus bringing down unit costs even further.

Conclusion

Some of the benefits of using industrial painting and coating robots in manufacturing have been presented above. It is well-known industrial and commercial reality that the use of painting/coating robots will increase in the existing automation field in the future. This is because robots provide a definitive solution when maximum flexibility, productivity, efficiency, and excellent painting/coating quality are required. The most important role in robotic painting/coating will continue to be played by the reliability and efficiency of painting/coating equipment. A flexible and automatic (even autonomous) production system is an essential matter for many manufacturers who want to overcome the challenges posed by increasing product complexity and greater customization at the same time. The ability to quickly switch production from one product to another will be a defining characteristic of companies on the path to batch size and tomorrow's highly customizable products. Finally; investing in a painting/coating robot is not a guarantee of future success. The relevant parties should first clarify their expectations; they should evaluate which processes or stages are causing the most problems. They can then determine whether robotic technologies can solve these challenges. Robotic painting/coating systems or painting/coating robots are undoubtedly a technological marvel that has revolutionized the painting and coating industries. Industrial painting and coating robots have become increasingly popular in recent years due to their numerous advantages over traditional manual painting/coating methods. In addition to being more efficient, consistent, and accurate, they can be used to paint/coat a wide variety of surfaces more promptly. Additionally, they can help increase workplace safety by reducing the risk of exposure to hazardous chemicals and fumes. As a result, industrial paint coating robots are a valuable tool for businesses that need to paint large or complex objects safely and efficiently. These robots are relentless perfectionists and can perform nearly flawless paint coating applications with superhuman consistency and work volume. Robotic paint coating technology is as much an art as a science. It is no longer just about volume and quantity; there are also aspects of quality and consistency. It will continue to become more suitable not only for top-tier supplier bases in all the industrial sectors mentioned above, particularly automotive, but also for smaller, more general industrial applications.   References: • 1) Painting Robots: Benefits, Applications and How to Source Them - Mark FairChild - https://howtorobot.com/expert-insight/painting-robots • 2) Paint Robot - Wikipedia https://en.wikipedia.org/wiki/Paint_robot • 3) Robot Nano Spray Painting - A Review https://iopscience.iop.org/article/10.1088/1757-899X/912/3/032044 • 4) Five Amazing Ways Robots Are Disrupting the Painting Industry - By Emily Newton, Editor-in-Chief, Revolutionized Magazine • 5) How robotics can save a business time and money - Junair - https://www.junairspraybooths.co.uk/how-robotics-can-save-abusiness-time-and-money/ • 6) Robotic Spray Painting - https://www.arion.asia/robotic-spraypainting/ • 7) Using Robot Application in Powder Coatings for Flexibility, Perfect Coating - https://finishingandcoating.com/index.php/powder-coat/972-using-robot-application-in-powdercoatings-forflexibility-perfect-coating • 8) 13 Milestones in the History of Robotics - https://www.aventine.org/robotics/history-ofrobotics • 9) Types of Robotic Coatings - Robots.com https://www.robots.com/articles/types-ofrobotic-coatings   Eng. Tolga Dıraz Chemical Engineer/Project Manager Corrosion, Protective Paints and Coatings Specialist