Robot Factory Inspection (FAT): Standards, Testing Items, and Procedures for Outgoing Quality Contro

Robot factory inspection is the systematic outgoing quality control and factory acceptance testing process that verifies every industrial robot, collaborative robot, or mobile robot meets design specifications, performance criteria, and safety requirements before shipment. This article explains the applicable international standards such as ISO 9283, ISO 10218-1, and IEC 60204-1, along with typical test samples, testing items, testing methods, and common questions to help manufacturers and buyers ensure consistent product quality and regulatory compliance.

Technical Overview

Robot factory inspection, also referred to as outgoing quality control (OQC) or factory acceptance testing (FAT), is the final verification stage in robot manufacturing. It confirms that each finished robot, together with its controller, teach pendant, cables, and accessories, conforms to the approved design documents, declared technical specifications, and relevant safety and performance standards before leaving the production facility. The process typically combines a 100% routine test performed on every unit with sampling-based type tests performed on a statistical basis or after major design changes.

The inspection framework is built upon internationally recognized standards published by organizations such as ISO, IEC, UL, EN, and GB. Core references include ISO 9283 for manipulator performance criteria, ISO 10218-1 for safety requirements of industrial robots, ISO/TS 15066 for collaborative robot applications, ISO 3691-4 for driverless industrial trucks, IEC 60204-1 for electrical equipment of machinery, and the IEC 61000 series for electromagnetic compatibility. In China, corresponding national standards such as GB/T 12642 and GB 11291.1 are aligned with these ISO documents and are frequently applied in domestic factory inspection procedures.

From a quality management perspective, robot factory inspection is an essential element of an ISO 9001-certified production system. It generates objective evidence, including test records, inspection reports, and traceable serial number data, which supports product certification schemes such as CE marking under the Machinery Regulation, UL listing, and customer-specific approval protocols. Effective factory inspection reduces field failure rates, minimizes warranty costs, and protects brand reputation in highly automated industries.

Testing Samples

Articulated Industrial Robots

Six-axis and seven-axis articulated robots constitute the largest inspection volume. Samples include the complete robot unit with mechanical structure, servo motors, harmonic or cycloidal gear reducers, encoders, and integrated cabling. Each unit is inspected after final assembly and calibration, normally in the configuration specified for delivery.

Collaborative Robots (Cobots)

Collaborative robots require additional verification of power- and force-limiting functions, safety-rated monitored stops, and speed and separation monitoring parameters. Inspection samples cover the complete cobot arm, controller, and safety configuration files declared in the technical documentation.

SCARA, Delta, and Cartesian Robots

High-speed picking and assembly robots such as SCARA, delta (parallel kinematic), and gantry (Cartesian) robots are inspected for cycle time, positioning repeatability, and structural rigidity under rated payload and maximum acceleration conditions.

Mobile Robots (AGV/AMR)

Automated guided vehicles and autonomous mobile robots are inspected for navigation accuracy, obstacle detection performance, personnel detection fields, braking distance, battery safety, and charging system integrity, with reference to ISO 3691-4 and applicable battery transport and safety standards such as IEC 62133 and UN 38.3 for lithium-ion packs.

Controllers, Teach Pendants, and Subassemblies

In addition to complete robots, outgoing inspection covers robot controllers, teach pendants, safety boards, servo drives, and end-of-arm tooling interfaces. These subassemblies are verified against their own specification sheets, firmware versions, and interface protocols before integration or separate shipment.

Testing Items

A comprehensive robot factory inspection program typically includes the following categories of test items, tailored to the robot type and applicable standards.

• Appearance and workmanship inspection: surface finish, coating quality, labeling, nameplate data, serial number traceability, and absence of mechanical damage or corrosion.
• Dimensional and interface verification: mounting dimensions, bolt hole patterns, base and flange tolerances, cable connector pinouts, and payload capacity markings.
• Documentation completeness check: instruction manuals, declaration of conformity, test certificates, spare parts lists, and software license documents.
• Electrical safety tests: protective bonding continuity, insulation resistance, dielectric strength (high-potential test), and residual voltage measurement after disconnection.
• Functional tests: power-on self-diagnostics, master and slave communication checks, jogging of every axis across the full travel range, homing and calibration routines, brake function, limit switch operation, and teach pendant controls.
• Performance tests per ISO 9283: pose repeatability, pose accuracy, distance accuracy, path accuracy, path repeatability, overshoot, settling time, and cycle time at rated load and speed.
• Safety function tests per ISO 10218-1 and ISO 13849-1: emergency stop function, protective stop, reduced speed mode (250 mm/s at the TCP in the collaborative case), safety-rated soft axis and space limiting, and behavior upon sensor fault injection.
• Electromagnetic compatibility (EMC): conducted and radiated emissions, electrostatic discharge immunity, radio-frequency electromagnetic field immunity, electrical fast transient burst, and surge immunity, referencing the IEC 61000-4 series and IEC 61000-6 standards.
• Noise measurement: sound pressure level at defined positions around the robot under rated operating conditions, using methods consistent with ISO 3744 and declaration methods per ISO 4871.
• Environmental adaptability: operating temperature range verification, humidity resistance, vibration and shock resistance during transport simulation, and ingress protection (IP code) verification per IEC 60529 where declared.
• Endurance and burn-in testing: continuous operation for a defined soak period at rated payload and duty cycle to expose early-life failures in motors, reducers, and drive electronics.
• Software and firmware verification: version control, parameter backup and restoration, communication protocol conformance (for example industrial Ethernet protocols), and checksum validation.
• Packaging and shipping inspection: protective packaging integrity, desiccant placement, shock indicators, and correctness of shipping marks and packing lists.

Testing Methods

Testing methods used in robot factory inspection combine metrology-grade measurement instrumentation with standardized test procedures so that results are reproducible and comparable across production batches and test facilities.

Performance Measurement Using Laser Tracking

Pose repeatability and accuracy are measured with a laser tracker or high-precision measurement system following the test pose arrangement defined in ISO 9283. The standard cube located within the working space is used, with the robot commanded to a series of points (typically the cube center and four corner points on the diagonal plane) repeated for at least 30 cycles. The scatter of attained positions is statistically evaluated to determine the repeatability value, which must not exceed the manufacturer's published specification.

Electrical Safety Test Methods

Protective bonding continuity is verified by injecting a test current (commonly at least 10 A per relevant electrical safety standards) and measuring impedance between the protective earth terminal and accessible conductive parts. Insulation resistance is measured between power circuits and protective earth using a DC insulation tester, typically at 500 V or 1000 V depending on the rated voltage. Dielectric strength testing applies a specified AC or DC high voltage for a defined duration, with leakage current monitored against the acceptance limit.

Safety Function Validation

Safety-related functions are validated by exercising each safety input and observing the robot response. Emergency stop and protective stop tests confirm category 0 or category 1 stopping behavior and stop time measurement. Collaborative robots undergo power- and force-limiting verification using calibrated force-pressure measurement devices applied to contact zones, comparing quasi-static and transient contact values against the allowable limits described in ISO/TS 15066. Safety function performance is documented with reference to the required Performance Level and Category defined under ISO 13849-1.

EMC and Environmental Test Methods

EMC tests are performed in accredited third-party laboratories or shielded on-site chambers using receivers, antennas, coupling networks, and transient generators conforming to the IEC 61000-4 series. Environmental tests use climate chambers for temperature and humidity cycling, electrodynamic shakers for vibration and shock simulation per IEC 60068-2 standards, and dust and water enclosures for IP code verification per IEC 60529. For type tests, sampling plans and severity levels are defined by the manufacturer's quality plan and, where applicable, by product family standards.

Endurance Burn-In Procedure

Each robot undergoes a burn-in or soak test in which the arm executes a representative duty-cycle program at rated load for a defined period, often ranging from several hours to 48 hours or more depending on the product class. Axis temperatures, current draw, vibration signatures, and fault logs are recorded continuously, and any abnormality triggers corrective action and retesting before release.

Records and Judgment Criteria

All measurements are compared against documented acceptance criteria derived from the product specification and applicable standards. Results are recorded in outgoing inspection reports linked to the robot serial number. Units that pass receive a release label; nonconforming units are quarantined, reworked, and re-inspected under the nonconformity control procedure of the quality management system.

Applications

Robot factory inspection applies across the full spectrum of robotics manufacturing and deployment scenarios, serving both producers and end users.

• Automotive manufacturing: welding, handling, painting, and assembly robots shipped to car plants and tier suppliers are released only after verified repeatability, safety stop performance, and documentation checks.
• Electronics and semiconductor production: high-precision SCARA and delta robots for placement, dispensing, and inspection are validated for micron-level repeatability and ESD-safe configuration.
• Logistics and warehousing: AGV and AMR fleets are inspected for navigation accuracy, personnel safety fields, and battery compliance before deployment in distribution centers.
• Medical, laboratory, and pharmaceutical automation: robots destined for controlled environments require verified cleanliness, low particle emission, and validated safety functions supporting regulatory submission files.
• Food and beverage processing: washdown-rated robots are inspected for IP protection level, hygienic materials, and chemical resistance consistent with declared specifications.
• Export compliance: factory inspection results form the technical evidence file supporting CE marking, UKCA marking, UL certification follow-up, and import documentation for global markets.
• Customer acceptance: buyers and engineering contractors use factory inspection and FAT protocols as contractual quality gates before shipment, often witnessing tests on-site or through remote video verification in accredited facilities.

FAQ

What is the difference between factory inspection (FAT) and site acceptance testing (SAT)?

Factory acceptance testing is performed at the manufacturer's facility before shipment and verifies the robot against specifications in a controlled environment. Site acceptance testing is performed after installation at the end-user location and verifies the complete integrated system, including tooling, fixtures, and application programs, under real production conditions.

Which standards govern robot factory inspection?

The primary references are ISO 9283 for performance criteria and test methods, ISO 10218-1 for industrial robot safety, ISO/TS 15066 for collaborative applications, ISO 3691-4 for driverless industrial trucks, IEC 60204-1 for electrical equipment of machines, the IEC 61000 series for EMC, and IEC 60529 for ingress protection. Corresponding national standards, such as GB/T 12642 and GB 11291.1 in China, are harmonized with these ISO and IEC documents.

Is 100% inspection required for every robot, or can sampling be used?

Safety-related routine tests, functional tests, and performance verification are generally performed on 100% of units because they verify mandatory requirements and unit-specific assembly quality. Destructive or time-consuming type tests, such as full EMC or environmental testing, are typically performed on a sampling basis or through type certification maintained by accredited third-party laboratories.

What is pose repeatability and why is it a key inspection item?

Pose repeatability, defined in ISO 9283, quantifies the closeness of agreement between repeated attained poses when the robot returns to the same commanded position under the same conditions. It is the most widely cited accuracy indicator in robot datasheets and directly determines process capability in applications such as assembly, welding, and dispensing, which is why it is verified during outgoing inspection.

What documents should accompany a robot that has passed factory inspection?

Typical deliverables include the outgoing inspection or FAT report, electrical safety test records, performance test data, safety function validation records, firmware version documentation, declaration of conformity, operating manuals, calibration certificates, and warranty terms, all traceable to the robot serial number.

How long does a typical factory inspection take?

Routine inspection and burn-in of a standard industrial robot commonly require from several hours up to two or three days depending on the complexity of the robot, the extent of safety validation, and the duration of the endurance soak test. Full type testing programs involving EMC and environmental testing may extend over several weeks and are usually managed separately through accredited third-party laboratories.