Industrial Robotics: Arms That Never Tire
What Are Industrial Robots?
Imagine running a car body welding line. You need 4000 spot welds per body, accurate to +/-0.5 mm, at 60 bodies per hour, 24 hours a day. No human worker can achieve this. This is where the industrial robot works: a programmable, multi-axis mechanical arm designed to move tools, parts, and materials with speed, accuracy, and repeatability that humans cannot match.
The first industrial robot — Unimate — began operating in 1961 at a General Motors plant, handling hot die-cast parts. Today, over 4 million industrial robots operate in factories worldwide.
Types of Industrial Robots
Articulated Robot
The most common type. It resembles a human arm: a fixed base, shoulder, elbow, and wrist. Typically 6 rotational axes. It can reach any point within its workspace from any orientation.
Applications: spot and arc welding, painting, assembly, heavy material handling.
Examples: KUKA KR series, FANUC R-2000, ABB IRB 6700.
SCARA Robot
SCARA (Selective Compliance Assembly Robot Arm) — a horizontal arm that is rigid vertically and compliant horizontally. It moves very quickly in the horizontal plane (X-Y) with limited vertical (Z) travel.
Applications: electronics assembly, inserting components into PCBs, fast packaging.
Examples: Epson T6, FANUC SR-3iA.
Delta Robot
Three parallel arms connected to a central platform, suspended from above. Lightweight and extremely fast — up to 300 picks per minute.
Applications: pick-and-place on packaging lines, sorting food and pharmaceutical products.
Examples: ABB IRB 360 FlexPicker, FANUC M-1iA.
Cartesian/Gantry Robot
Moves in straight lines along three orthogonal axes (X, Y, Z), similar to a CNC machine. Simple design, easy to program, very accurate.
Applications: laser cutting, industrial 3D printing, automated welding over large areas, CNC machine loading/unloading.
Examples: Gudel, Macron Dynamics.
Robot Type Comparison
| Type | Axes | Speed | Accuracy | Payload | Primary Use |
|---|---|---|---|---|---|
| Articulated | 4-7 | Medium-High | +/-0.02-0.1 mm | 3-2300 kg | Welding, painting, heavy assembly |
| SCARA | 4 | Very High | +/-0.01-0.02 mm | 1-20 kg | Electronics assembly, insertion |
| Delta | 3-4 | Highest | +/-0.05-0.1 mm | 0.5-8 kg | Fast picking, packaging |
| Cartesian | 3-4 | Medium | +/-0.01-0.05 mm | 5-500 kg | Cutting, printing, handling |
Degrees of Freedom
A degree of freedom (DOF) is a joint's ability to move independently in one direction. A human arm has approximately 7 DOF (shoulder 3 + elbow 1 + wrist 3). A standard articulated robot has 6 degrees of freedom:
J1: Base rotation (left-right)
J2: Shoulder (forward-back)
J3: Elbow (up-down)
J4: Wrist rotation 1
J5: Wrist bend
J6: Wrist rotation 2 (tool flange)
Why 6? Because any position in 3D space is defined by 6 variables: 3 for position (X, Y, Z) and 3 for orientation (rotation around each axis). Six DOF allow the tool to reach any point at any angle.
Some robots have 7 DOF (such as KUKA LBR iiwa), providing additional flexibility — like rotating your arm around an obstacle.
End Effectors
The end effector is the robot's "hand" — the tool mounted at the end of the wrist. It changes based on the task:
| End Effector | Mechanism | Application |
|---|---|---|
| Mechanical Gripper | Fingers open/close | Handling solid parts |
| Vacuum Cups | Pneumatic suction | Lifting sheets, glass, cardboard |
| Spot Welding Gun | High electrical current | Automotive body welding |
| Arc Welding Torch | Electric arc + filler wire | Pipe and structural welding |
| Paint Gun | Electrostatic spray | Automotive and furniture painting |
| Spindle/Router | High-speed rotary motor | Trimming, polishing, cutting |
| Force/Torque Sensor | Measures applied forces | Precision assembly, adaptive polishing |
In modern factories, a robot may automatically swap its end effector using a Quick Change System — similar to CNC tool changes.
Teach Pendant
The teach pendant is the handheld device used by the programmer to manually jog the robot and record positions. It includes:
- Touchscreen displaying the program and coordinates
- Buttons for independent axis movement
- Joystick for free movement
- Deadman Switch: must be held continuously during manual movement — if the programmer releases it (due to fear or an incident), the robot stops immediately
- Emergency Stop (E-Stop) button
Teaching procedure:
- Manually jog the robot to the desired position
- Record the point (Teach Point)
- Define the motion type (linear, circular, joint)
- Set speed and acceleration
- Repeat for all points
- Run the program at low speed for verification
Modern programming also includes Offline Programming: simulating the robot in software such as RoboDK or KUKA.Sim, then transferring the program to the robot — without stopping production.
Collaborative Robots (Cobots)
A cobot (Collaborative Robot) is designed to work alongside humans without safety fences. It differs from traditional robots:
| Comparison | Traditional Robot | Cobot |
|---|---|---|
| Speed | Very high (2+ m/s) | Limited (~1 m/s) |
| Payload | Up to 2300 kg | Typically 3-25 kg |
| Safety | Fences + restricted zones | Force sensors + stop on contact |
| Programming | Specialized | Easy — hand guiding |
| Cost | High + infrastructure | Lower + quick deployment |
| Use Case | High-volume production | Variable tasks, small batches |
Leading cobots: Universal Robots (UR3/5/10/16/20/30) — programmed by physically moving the arm and recording the path.
Consider an assembly line: a traditional robot welds the body frame inside a fenced cell, while a UR10 cobot works beside a human operator who hands it parts — no barrier between them.
Safety Standards: ISO 10218
Safety is not optional in industrial robotics. The ISO 10218 standard (two parts) specifies:
ISO 10218-1 (the robot itself):
- Every robot must have an independent emergency stop
- Speed in teach mode must not exceed 250 mm/s
- Force and torque limits for human contact situations
ISO 10218-2 (robot system and integration):
- Risk assessment is mandatory before commissioning
- Work zones are divided: restricted zone, monitored zone, collaborative zone
- Protection systems: physical fences, light curtains, laser area scanners
The technical specification ISO/TS 15066 complements ISO 10218 specifically for cobots and defines:
- Force and pressure limits for each region of the human body (the head is more sensitive than the arm)
- Four safe collaboration methods: safety-rated monitored stop, hand guiding, speed and separation monitoring, power and force limiting
Real-World Industrial Applications
Automotive: 50-70% of operations are robot-automated — body-in-white welding, painting, engine assembly.
Electronics: SCARA robots place thousands of components on printed circuit boards at remarkable speed.
Food and Beverage: Delta robots sort and package products — 120 cycles per minute in cleanroom conditions.
Logistics and Warehousing: Autonomous Mobile Robots (AMRs) transport goods between shelves; robotic arms unload containers.
The Future of Industrial Robotics
- Computer Vision + AI: robots see, recognize parts, and adapt to their position
- Sim-to-Real Learning: training robots in virtual environments, then transferring skills to the real world
- Robot Swarms: multiple robots cooperating on a single task
- Soft Robotics: flexible materials replacing metals — for handling food and fragile objects