How Industrial Robots Are Classified
Industrial robots are grouped by mechanical configuration — the number and arrangement of joints that define their reachable workspace. ISO 8373:2021 defines an industrial robot as an automatically controlled, reprogrammable, multipurpose manipulator, and the International Federation of Robotics tracks six configurations in its annual World Robotics report: articulated, SCARA, cartesian/linear, parallel (delta), cylindrical, and collaborative.
Configuration is the first specification to lock in because it determines workspace shape, top speed, achievable precision, and — importantly — what end-of-arm tooling and safeguarding you will need around it. A change from a 6-axis articulated arm to a SCARA halfway through a project is not a swap, it is a redesign.
The names buyers hear on the floor — FANUC LR Mate, ABB IRB, KUKA KR AGILUS, Yaskawa MotoMini, Universal Robots UR series, Epson G-series, ABB IRB 360 FlexPicker — all map back to one of these six configurations. Once you can name the configuration, you can compare vendors on the same axis.
| Configuration | Axes / DOF | Workspace shape | Typical payload | Typical reach | Best-fit work |
|---|---|---|---|---|---|
| Articulated (6-axis) | 6 rotary | Spherical | 3–2,300 kg | 0.5–4.7 m | Welding, assembly, machine tending, material handling |
| SCARA | 4 (3 rotary + 1 linear Z) | Cylindrical, planar | 1–20 kg | 100–1,200 mm | High-speed pick-and-place, PCB assembly, screwdriving |
| Delta (parallel) | 3–4 parallel arms | Dome / hemisphere | 0.1–8 kg | 800–1,600 mm dia. | High-rate packaging, sorting, primary food handling |
| Cartesian / Gantry | 3+ linear (X-Y-Z) | Rectangular box | 1 kg to multi-ton | Any (frame-defined) | Palletizing, dispensing, 3D printing, CNC-style motion |
| Cylindrical | 1 rotary base + linear axes | Cylindrical | 1–100 kg | 0.3–3 m | Assembly around a spindle, machine loading, welding |
| Collaborative (cobot) | 6–7 rotary | Spherical (limited force) | 3–35 kg | 0.5–1.8 m | Fenceless machine tending, light assembly, inspection |
Articulated Robots: The Six-Axis Workhorse
Articulated robots use six rotary joints to reach any position and orientation within a roughly spherical workspace. They are the most common industrial configuration by installed base — IFR World Robotics 2024 reports that articulated arms account for the majority of the 4.28 million operational stock worldwide.
Payload and reach span two orders of magnitude within this single configuration. The FANUC LR Mate 200iD/4S handles 4 kg at 550 mm reach for benchtop assembly, while the ABB IRB 8700 lifts 800 kg at 4.2 m for automotive body-in-white. The KUKA KR QUANTEC and Yaskawa Motoman GP-series cover the middle ground where most plants shop.
Articulated arms win when the task needs orientation freedom — welding a joint from multiple angles, spraying a compound-curved surface, or reaching into a machine tool through a side door. They lose to SCARA and delta on raw pick rate for flat-plane, top-down work.
SCARA, Delta, and Cartesian: Speed and Precision Specialists
SCARA (Selective Compliance Assembly Robot Arm) robots are stiff vertically and compliant horizontally, which makes them fast and accurate for insertion tasks. The Epson G-series and Stäubli TS2 line hit sub-second cycle times on PCB assembly, screwdriving, and small-part pick-and-place with ±0.01 mm repeatability.
Delta robots — three or four lightweight arms driven by base-mounted motors — deliver the highest pick rates in the industry. The ABB IRB 360 FlexPicker is rated up to about 300 picks per minute on light payloads and is the default for high-speed packaging and primary food handling. Trade-off: workspace is a shallow dome, and payload rarely exceeds 8 kg.
Cartesian and gantry robots move on linear X-Y-Z axes over a rectangular volume defined by their frame. They scale from desktop dispensers to multi-ton palletizing gantries and are the natural choice when the work envelope is long and rectangular — see FANUC M-410iC palletizers or the Cartesian frames documented by Bosch Rexroth linear systems.
| Configuration | Typical cycle / speed | Repeatability | Representative model | Common misuse |
|---|---|---|---|---|
| SCARA | 0.3–0.5 s pick cycle | ±0.01–0.025 mm | Epson G6, Stäubli TS2-60 | Buying it for out-of-plane orientation work |
| Delta | Up to ~300 picks/min | ±0.05–0.1 mm | ABB IRB 360, FANUC M-3iA | Trying to run heavy payloads or side-loading |
| Cartesian / Gantry | Frame-dependent | ±0.05–0.1 mm | FANUC M-410iC, custom gantry | Underspecifying frame stiffness for the payload |
Cylindrical and Collaborative Robots
Cylindrical robots pair a rotating base with one or more linear axes, sweeping a cylindrical workspace. They were dominant in the 1980s for machine loading and are still specified where the process is organized around a vertical spindle or a single workstation. Modern installations are relatively niche compared with articulated arms, but the geometry remains efficient for spot welding and simple assembly around a fixture.
Collaborative robots — cobots — are typically articulated arms designed to operate near people without a fixed guard, subject to a task-specific risk assessment under ISO 10218-1:2025 and ISO/TS 15066:2016. The Universal Robots UR series, FANUC CRX line, Techman TM-series, and ABB GoFa and YuMi are the buyer-visible names.
Cobot payloads have climbed — the Universal Robots UR30 lifts 30 kg — but cobot does not mean safe by default. OSHA reports that most robot incidents happen during programming, setup, and maintenance rather than production, and a cobot carrying a knife, hot torch, or sharp gripper still needs guarding, light curtains, or scanners.
Choosing a Configuration: The Buyer Checklist
Configuration selection should follow the task, not the other way around. Buyers who start with a brand preference tend to force-fit an arm onto a job it was not designed for, which is how a 6-axis articulated robot ends up doing a pick-and-place a SCARA would finish in half the cycle time.
Work through payload including the end-of-arm tool, worst-case reach, orientation requirements, cycle time, workspace footprint, and safeguarding class before you shortlist vendors. Every configuration in the table above has a well-defined sweet spot and a set of tasks where it is the wrong tool.
- Payload: sum the part, the gripper, and any dynamic load — not just the part.
- Reach: measure to the farthest point the tool center must touch, in the worst orientation.
- Orientation: does the tool need to approach from multiple angles, or only straight down?
- Speed: quote pick rate or cycle time from the manufacturer at the actual payload.
- Workspace: match the shape (spherical, cylindrical, rectangular, dome) to the floor plan.
- Safeguarding: risk-assess the cell per ISO 10218 before choosing cobot vs. fenced arm.
Bottom Line
The six industrial robot configurations are not interchangeable. Articulated arms flex across most tasks, SCARA and delta win on speed, cartesian scales the envelope, cylindrical suits spindle-centered work, and cobots trade payload and speed for a fenceless footprint. Name the configuration first, then the vendor.
List payload, reach, orientation, cycle time, and safeguarding class before you request a single robot quote.
FAQs
What are the main types of industrial robots?
Industrial robots are classified into six configurations: articulated (6-axis rotary), SCARA (rotary plus vertical linear), delta (parallel-arm), cartesian or gantry (linear X-Y-Z), cylindrical (rotary base plus linear axes), and collaborative cobots. Each has a distinct workspace shape and best-fit task profile.
Which industrial robot type is most common?
Articulated 6-axis robots are the most widely installed configuration worldwide. IFR World Robotics data shows they dominate the operational stock because their spherical workspace and orientation freedom cover welding, assembly, machine tending, and material handling with the same base machine.
What is the difference between a SCARA and a delta robot?
A SCARA has a rigid vertical axis and a compliant horizontal plane, making it ideal for precise top-down insertion at high speed. A delta uses three parallel arms driven from a fixed base to move a light end effector across a dome-shaped workspace at very high pick rates, but with lower payload and no vertical stiffness.
Are collaborative robots a separate industrial robot type?
Cobots are usually articulated arms engineered and rated for operation near people under a task-specific risk assessment per ISO 10218-1 and ISO/TS 15066. Mechanically they overlap with articulated robots; the classification reflects their safety design, force limits, and typical deployment pattern rather than a new kinematic family.
How do I choose the right industrial robot configuration?
Match the configuration to the task. Define payload including tooling, worst-case reach, orientation requirements, cycle time, workspace shape, and the safeguarding class the cell will need. Once those are fixed, most jobs narrow to one or two configurations before any vendor is contacted.