How Robot Calibration Systems Support High-Precision Robotic Applications
Modern manufacturing relies more and more on robotics for their impressive speed, uniformity and accuracy. Automotive, aerospace, electronics, medical manufacturing, and more find fast and accurate robotics assembly imperative. Even the slightest misplacement can create defects, delays and cause loss to the manufacturer. Robot Calibration Systems allow for better accuracy and less variances for reliability in high and tough demand manufacturing areas.
This blog discusses Robot Calibration Systems and how they support robotic quality control in diverse industries.
What are Robot Calibration Systems?
Robot Calibration Systems are advanced tools for measuring and correcting issues to enhance the accuracy of industrial robots. All robots have variances in small amounts due to tolerances in manufacturing, installation differences, so-called wear, and even environmental differences. Calibration aids in identifying variances, correcting, and updating control parameters for the robots.
Robot programming deficiencies are often improved when calibration focuses on the positioning of the robotics versus the repeated programmed moves.
Manufacturers are now capable of robotics having greater accuracy for less monetary investment and not requiring all new robotic systems.
Why Does Precision Matter for Robotics Applications?
Robots are used for assembly and other manufacturing tasks that require greater accuracy and precision like:
Welding
Laser Cutting
Dispensing
CNC Tending
Inspection
Pick-and-Place
Machining
There are even more robotic applications that require high precision. A small variance of even a millimeter can impact quality. Ensuring a robot retains accuracy is critical for a manufacturer in achieving a goal of reduced waste and optimized production.
Calibration also provides assurance of design specifications for each and every movement of the robotics system.
How Can Calibration Systems Help Improve the Accuracy of Robots?
Correcting Mechanical Deviations
In order to improve the accuracy of robots, we must first understand that there are many deviations that may cause robots to not be as accurate as they could be.
Manufacturing tolerances
Joint alignment
Link length differences
Gear backlash
Encoder offsets
Deviations may come in all of these forms and more. Robot Calibration Systems are able to measure all of these deviations by using laser trackers and advanced optical measurement systems.
Increasing Absolute Position Accuracy
Robot accuracy, and robot repeatability, are often misunderstood.
While it may be true that a robot can return to the same position repetitively, this does not mean that the robot is accurate in return to that position.
Absolute positioning
Path accuracy
Tool center point accuracy
Robotics system calibration can expand accuracy in all these areas as well as many others, including multi-robot coordination, and is especially beneficial in areas of robotics such as aerospace and automotive manufacturing.
Supporting Multi-Robot Production Lines
Most production facilities utilize multiple robots that work on the same component.
When systems are left uncalibrated:
Alignment errors build
Parts will not fit
Consistency in production declines
When calibrating systems, all of the robots are set to utilize the same coordinate system, and as a result, fulfill the same reference coordinates, which improves the coordination of all of the robots in the production cell.
The Role of Robot Calibration in Robotic Quality Control
Quality control of robotics systems relies heavily on the measurement of accurate systems.
Robots that are used to inspect products and measure them in order to find faults and determine if a product meets specifications typically employ cameras and laser scanners.
When an inspection robot is not calibrated, the results of the inspection are in question.
How Calibration Automation Enhances Robotic Quality Control
Calibration automation helps improve robotic quality control in the following ways:
- Increases measurement accuracy
- Decreases inspection errors
- Provides more robust defect detection
- Assists with automated quality verification
- Improves traceability in production.
All these factors improve inspection, which drives higher customer satisfaction and reduces warranty claims.
Improving Offline Robot Programming
Most manufacturers offer offline programming that allows users to create robotic paths before actual production.
Offline programming assumes the robotic unit matches the digital model exactly.
To keep the robotic unit and the digital model in sync, the following happens:
- Robotic paths are corrected manually.
- The time spent on such tasks is increased.
- The commissioning time is extended.
Robot Calibration Systems allow digital robotic models to match and behave like physical robotic units. Benefits of such systems include:
- Reduced time for programming
- Reduced time in production
- Better accuracy in simulation
- Faster deployment
Better use of these systems aligns with technology strategies for digital manufacturing and Industry 4.0.
Improving Tool Center Point Accuracy
The Tool Center Point (TCP) is the exact location of where the robotic tool uses and requires precision.
Small errors in the TCP may affect:
- Welding
- Drilling
- Cutting paths
- Placement of adhesives
- Accuracy of inspections
Calibration maintains the Tool Center Point (TCP) for the duration of production. This is critical for high-precision operations.
Assisting Automated Inspection Systems
Robotic inspection systems perform a variety of inspections including:
- Surface
- Dimensional
- Visual
- Laser scans
- Quality verifications.
Calibration helps these systems automate inspections when the inspection devices capture measurement paths.
Manufacturers gain more trust in the inspection data provided and experience fewer rejected products. Accurate inspection data also aids in predictive maintenance of systems by showing gradual changes in systems that may lead to failure.
Lowering Production Costs
While the initial cost of automation and calibration systems may be perceived as costly, the systems quickly pay for themselves.
Manufacturers observe a variety of advantages to robotic precision, calibrated to increased factory productivity, such as:
- Less scrap
- Less material waste
- Quicker set-up
- Quicker production cycles
- Higher first-pass yields
- Less manual rework
- Less downtime
Robotic precision improved accuracy of production result and productivity.
**High Precision Industries**
The following descriptions show various uses of robots in high precision manufacturing along with a few examples of robotic tasks.
**Automotive Manufacturing**
Robots perform:
- Spot welding
- Adhesive dispensing
- Body assembly
- Precision inspection
Calibration allows robots to maintain consistent accuracy at each station along the automotive assembly line.
**Aerospace Manufacturing**
Many aerospace components are subject to extremely tight tolerances.
Calibration facilitates robotic automation of tasks such as:
- Precision drilling
- Composite trimming
- Laser processing
- Assembly verification
**Electronics Manufacturing**
Modern electronics have very small components.
Robotics automation of:
- PCB assembly
- Component placement
- Automated soldering
- Optical inspection
is improved with precision calibration.
**Medical Device Manufacturing**
Many medical products must be dimensionally precise.
Robotic calibration aids:
- Compliance with regulation
- Product consistency
- Quality assurance of high manufacturing standards and tolerances
**Robot Calibration and Its Importance**
Robot accuracy changes over time due to a variety of factors. Some of these factors include:
- Mechanical abrasion
- Temperature changes
- Heavy work loads
- Relocation of robots
- Maintenance of robots
- Replacement of tools
For accuracy and precision robotic manufacturers implement periodic calibration.
**Integrating Calibration with Industry 4.0**
Factories of the future utilize connected manufacturing systems. Modern Robotic Calibration Systems have the following systems integrated:
- Manufacturing Execution Systems (MES)
- Digital twins
- Predictive maintenance
- Production analytics
- Industrial IoT systems
Manufacturers are able to work with robots that have rationalized their performance and calibrated their accuracy.
Data-based calibration enables rapid troubleshooting and encourages continuous improvement of all processes.
**Robot Accuracy**
To optimize performance of each robot, accuracy must be assessed and corrected.
- Routine calibration must be completed.
- Each Tool Center Point(TCP) must be verified.
- Assessment of robot wear must be completed during routine maintenance.
- Measurements must be strict.
- Robot programs must be validated post calibration.
Train Operators for Calibration Procedures
- Training operators ensure correct implementation of calibration procedures.
Ensure Calibration Results are Recorded
- Recording calibration results is essential for quality assurance.
Benefits of Following These Procedures
- Following these procedures provides manufacturers an edge to maintain reliability in the performance of production operations.
Future Trends in Robot Calibration Systems
- Automation is causing rapid developments in calibration technologies. Trends include:
- Artificial Intelligence (AI) will be used to facilitate analysis of calibration procedures.
- Automation will enable systems to calibrate themselves.
- Accuracy will be monitored in real-time.
- Calibration management will utilize the cloud.
- Digital twins will be used.
- Predictive adjustments to accuracy will be based on machine learning.
Continued developments in these technologies will allow manufacturing operation with greater precision with the least amount of manual work.
Conclusion
- Superior precision in manufacturing is a requirement for robots to be able to perform tasks with high levels of accuracy. Robot Calibration Systems correct mechanical deviations and bring enhancements in Positional Accuracy, Offline Programming, and Robotic Quality Assurance.
- In all manufacturing sectors (automotive, aerospace, electronics, medical), routinely calibrating robotic systems results in improved product quality, decreased waste, downtime, and increased operational performance. As factories adopt more technologies related to smart manufacturing, robotic system calibration will remain a key feature of dependable high-performance robotic systems used in factory automation.
