Abstract: This article introduces the P-500 painting robot launched by FANUC Robotics. This robot is a suspended track type and has higher painting efficiency, lower cost, smaller installation space and size compared with traditional painting robots. It is currently the ideal equipment for the exterior painting of vehicles.
Keywords: External painting of suspended track robot
In recent years, the development of robot applications in painting workshops has yielded significant improvements in painting efficiency, quality, reduced operating costs, and lower investment. FANUC Robotics' FANUC P-500 external painting robot system, a suspended track-mounted painting robot, achieves lower costs, smaller installation dimensions, and shorter installation time, and can handle a wide range of vehicle models.
Figure 1: P-500 External Swirl Cup Coating System
Research in the field of painting robots in recent years
1.1 The paint color-changing module group of the integrated process equipment installed in the robot arm is as close as possible to the spray cup (see Figure 2). This can minimize paint waste. Such improvements are reflected in operating costs and the entire operating cycle, greatly improving the spraying efficiency of the equipment, shortening the system uptime, and reducing equipment investment.
Figure 2-1: Inside of a typical robot arm
Figure 2-2: Process equipment of P-500 robot
1.2 Optimization of Spray Coating
From the late 20th century to the first five years of this century, researchers primarily focused on optimizing two areas of coating: robotic application of 100% electrostatic atomizers (or rotary cups) for exterior vehicle coating and robotic application of robots for interior vehicle coating on moving conveyor chains (such as door interiors, engine compartments, underbody panels, etc.). The development of robotic 100% exterior rotary cup coating applications emphasized rotary cup design and paint mixing ratios to achieve acceptable color and appearance standards for metallic paint using rotary cups. Previously, to achieve good surface finishes, at least one of the two coats of metallic paint on the exterior surface of a vehicle was applied using an air atomizing spray gun. This cup+cup process significantly reduces paint usage (20%-40%) compared to the previous air gun coating process.
The research on the "cup + cup" process has been fully applied. From the mid-1990s to the early 21st century, in automotive painting, the ratio of robot spray cups using spray guns and rotary cups has changed from approximately 85% spray guns and 15% rotary cups in 1995 to 85% rotary cups and 15% spray guns in recent years.
Since rotary cup spraying has become the most common application for exterior vehicle coating in the industry recently, exterior coating using rotary cups is a key focus of research for the FANUC P-500 coating system's end products. The FANUC Robotics P-500 coating system is designed for exterior vehicle coating applications.
The FANUC P-500 robotic exterior painting system has been a great success, having a profound impact on the automotive industry by using a robot suspended on a track to paint car body exteriors. Since its initial launch in 2003, more than 2,000 P-500 systems have been installed worldwide.
The FANUC P-500 design methodology has sparked innovative thinking across several areas, resulting in numerous patents and patent applications in areas such as robot design, process equipment design, production maintenance, programming methodologies, and installation. The P-500 system delivers the highest levels of uniformity and coating process efficiency. Patented process methods and optimized coating equipment design minimize overspray during production.
exterior painting of the vehicle body
2.1 Painting requirements for the exterior of the vehicle body:
◇Coating quality: Mainly, the thickness and appearance should be improved to reduce dust and dirt;
◇Control the spraying trajectory;
◇Flexibility: Adaptable to varying production volumes; adaptable to future models (complex models; distinctive models);
◇Low investment cost;
◇Low operating costs;
◇This can shorten the debugging cycle and thus shorten the time to launch new models;
◇Easy to maintain and convenient to operate.
2.2 Solution ◇Use flexible and easy-to-use robots;
◇Introducing the concept of "cleaning wall (suspended robot)";
◇Improve investment and operating costs;
◇Simplify robot trajectory programming, reduce the time required for robot programming, and ensure consistency between simulation and programming throughout the workshop.
Features of the suspended track-type rotary cup painting robot system:
Suspended track-mounted painting robot systems offer superior painting performance for vehicle exterior surfaces compared to traditional robots, reducing user costs and production expenses. They can also be installed and commissioned faster than fixed-installation robots. Key advantages of suspended track-mounted painting robots include:
3.1 The robot is smaller, more flexible, and easier to use.
A two-axis wrist
Researchers analyzed a wide range of existing production systems by developing robotic kinematic designs for robotic mechanical units, and then redesigned them. This design includes a suspended robot, eliminates the axis at the robot's waist, and uses a two-axis wrist, simplifying the entire system.
◇The track-based system improves the flexibility and operability of the spraying path and reduces the spraying equipment's dependence on the conveyor system.
◇By eliminating unnecessary axes in external spraying applications, this five-axis robot integrates the advantages of a seven-axis robot and achieves 100% utilization of the working range with fewer axes.
◇The track-based design is easier to program online than the fixed design, and the programming design of five-axis robots is much simpler than that of six-axis or seven-axis robots.
PaintPRO software is a graphical offline programming solution that simplifies robot trajectory programming and reduces programming time. All path programming can be completed during installation and modeling, saving time on subsequent installation and debugging.
◇Since most application devices are embedded in the FANUC P-500, the number of outdoor-installed devices is generally lower than that of the pedestal-mounted system.
◇Plug-and-play design – easily installs and connects paint lines, air lines, and power. Many parts of the system are pre-installed and calibrated before arriving on site, making it a standard production design. The location of the pneumatic control cabinet takes into account the need to eliminate delays in pneumatic calibration and to accommodate on-site updates. The pneumatic control panel, mounted on the robot body, allows for more sensitive gun switching and spray pattern changes.
3.2 Easy Control of Painting Quality ◇ The FANUC P-500 with its track configuration offers the longest painting time and the fewest non-painting actions. In contrast, pedestal-type robots require frequent repositioning after the path is programmed or the color is changed.
◇Track-based systems are easier to program online than fixed systems. This approach offers the longest firing time, minimum flow rate, and highest paint utilization, which is crucial when considering degradation and the effectiveness of the spray window. In contrast, fixed systems require faster robot movement, resulting in a correspondingly higher flow rate, which in turn leads to lower paint utilization and reduced quality.
◇The FANUC P-500 system's track axis ensures that the robot can repeat the same robot movements at any conveying speed, without unexpected movement errors or abnormal robot movements.
◇The FANUC P-500 robot design incorporates fully integrated process control. During the painting process, it can respond very quickly and repeatably to changes in fluid and pneumatic processes.
◇The airflow from the spray booth has a smaller impact on suspended robots compared to fixed or ground-based track robots.
◇The pneumatic control panel is mounted on the robot body, making the switching on and off of the gun and the conversion of the spray pattern more sensitive.
3.3 Customer Direct Costs Reducing customer direct costs significantly decreases in two ways:
(1) The price of the robot system itself is reduced; (2) The design of the robot system allows for a smaller installation area, reducing the required space by about 40%. This significantly reduces the engineering costs of the spray booth.
3.3.1 Reduced cost of the robot system itself ; reduced number of control systems.
Each robot controller controls two robots.
* The system’s steel structure is used as cable trays and hose paths, which reduces the number of connections to a single robot.
* A shared air control cabinet is used to supply multiple robots.
* Since most application devices are embedded in the P-500 system, the number of outdoor-installed devices is generally lower than that of the pedestal-mounted system.
The number of interconnections in the control system has been significantly reduced.
Figure 4: Comparison of FANUC P-500 control system with previous systems
3.3.2 The design of the robotic system allows for a smaller installation area, reducing the required space by approximately 40%. This significantly reduces the engineering costs of the spray booth.
◇The length and width of the spray booth are reduced.
* Because the FANUC P-500 robot lacks a large axis of rotation, the robotic arm's movement cannot extend beyond the rear of the spray booth, thus shortening the safety zone at the rear of the booth and consequently reducing the overall length of the booth. There is no need to reserve 1-2 meters of space indoors to meet operator safety requirements.
* Compared to many pedestal robots, the FANUC P-500 robot, designed according to the latest kinematics, features features that reduce the width of the spray booth.
* The robot is designed to handle a wide range of vehicles while reducing the width of the spray booth by 10-20% and the length of the spray booth by 40%.
Figure 4: Comparison of FANUC P-500 spray booth and automatic spray booth
(1) Suspended track painting robot: The spray booth is 13m long, 4.3m wide, and has an area of 55.9m2.
(2) Fixed painting robot: The spray booth is 14.5m long and 5.5m wide, with an area of 77.5m2.
Figure 5: Comparison of FANUC P-500 spray booth and fixed spray booth
The suspension method eliminates the need for installation on a steel frame inside the spray booth, thus reducing the need for a robot foundation and minimizing the steel profiles and base frame required to support the robot.
◇No grille is required.
◇In the design and improvement of new methods for spraying equipment and automatic rotary cup cleaning equipment, the need for an air heater in the system was eliminated. This improves maintenance and reduces system complexity. It also saves electricity and reduces operating costs.
3.4 Reduced operating costs for customers ◇ The smaller installation area reduces the energy consumption required, resulting in savings of more than 20% in most cases compared to previous robot systems.
◇The FANUC P-500 robot features a non-conductive arm and wrist, allowing for indoor suspension and maximizing transfer efficiency while minimizing paint buildup, thus reducing cleaning frequency and vehicle contamination. The robot's protective sleeve also doesn't require frequent replacement like that of conventional robots, reducing operating costs.
◇Ensuring the cleanliness of the ground is reflected in four aspects:
(1) The number of control cabinets required by the system is reduced, and the floor space is smaller.
(2) It provides a simple passageway space, which reduces the use of panels, connection boxes and other components.
(3) The system design places the unnecessary and conventional control cabinets in the middle layer, away from the floor.
(4) The high-altitude suspended type does not need to be installed on the steel frame supporting the ground of the spray booth, which reduces the spraying pollution on the ground caused by the vibration of the spray booth and the cleaning cost is low.
(5) "Cleaning Operation" The photo shows the condition of the spray booth after a month of production without cleaning.
3.5 The equipment is easy to edit.
PaintPRO offline programmable software uses the same motion planner as the actual robot, simplifying the programming path and enabling rapid generation of robot programs.
Figure 5: PaintPro offline programming software
◇With a computer, all path arrangement can be completed during installation and modeling, saving time for future installation and debugging.
Programming a five-axis robot is much simpler than programming a six- or seven-axis robot, and the FANUC P-500's design integrates all the advantages of a seven-axis robot.
3.6 Easy equipment installation ◇ Due to the standard process and system composition, integrated pneumatic control panel, and standard cable bundle, installation time is reduced.
◇Compared to other robots, it has fewer parts and is easier to install.
◇The pneumatic devices, forming air control, and cup speed control components have all been pre-calibrated according to a well-known coating calibration standard.
◇The FANUC P-500 painting system is fully assembled and thoroughly tested at the factory, significantly reducing the time and cost of on-site installation compared to traditional benchtop systems. This also reduces the chance of problems occurring during installation.
◇ Successfully installed and debugged within one week.
3.7 Easy operation and maintenance of equipment ◇ The operation interface and PLC are installed on one panel, which can easily and quickly handle faults.
◇ Reduced maintenance and simplified and improved layout of paint and air piping. ◇ Easy installation of color change valves and piping. Due to the simplified design and maintenance of the P-500 system, a large number of vulnerable parts have been reduced.
◇A unique, well-known coating solvent-air valve saves 50-70% of solvent compared to other systems during the cleaning process.
While some tools are required to ensure the correct installation of some spraying equipment, the robot's design offers significant improvements, surpassing previous systems in reducing mean time to repair.
3.8 The suspension method of the FANUC P-500 robot fully embodies the "clean wall" design. ◇ The FANUC P-500 robot is an elevated device, placed below the robot. Compared with ground-mounted robots, the visibility of the indoor spraying process is improved;
◇And allows the placement of inspection doors under the robot track;
Figure 5: Actual FANUC P-500 installation shows process visibility.
3.9 The FANUC P-500 system can be used for water-based electrostatic rotary cup spraying.
One of the biggest breakthroughs in spraying equipment is its applicability to water-based electrostatic rotary cup spraying. FANUC Spraying Systems has developed a highly efficient direct-fill spraying system that eliminates the need for external docking stations or container exchange systems. This new approach not only significantly increases the efficiency of water-based systems but also significantly reduces the associated complexity and maintenance costs.
Summarize:
The FANUC P-500 suspended track painting robot is an ideal robot for painting the exterior surfaces of automobiles. Its design offers a perfect combination of high performance, high durability, flexibility, ease of operation, and low maintenance. This system has successfully improved operational efficiency and the quality of paint application on workpiece exteriors. Compared to its predecessor, it also significantly reduces investment costs and production operating expenses for external coating systems. Currently, it is being widely adopted in newly built large-scale automotive painting lines in China.
References:
Lu Tonglin's Multifunctional Spray Painting Robot, Automotive Manufacturing Industry, 2005/6
