What an industrial robot is
An industrial robot is a reprogrammable, multi-jointed machine that moves a tool or workpiece through a series of positions. The best-known form is the robot arm bolted to a floor, pedestal or ceiling. It repeats motions with consistent accuracy and does not tire, which is why robots are widely used for work that is repetitive, heavy, hot, dirty or hazardous to people.
A robot is more than the arm. A typical workcell includes a controller, a teach pendant or programming interface, an end effector (the “hand,” such as a gripper, welding torch or vacuum cup), safeguarding, and often conveyors, fixtures or vision. Much of the engineering effort in a robot project goes into these surroundings rather than the arm itself.
Common types of robot arms
Articulated arms. These have several rotating joints, commonly six, resembling a human arm. They reach around objects and orient tools in many directions, so they are used for welding, painting, machine tending, palletizing and a wide range of handling jobs. They come in a broad range of sizes, from light benchtop units to very large models that move heavy loads.
SCARA robots. SCARA arms are stiff vertically and flexible horizontally, suited to fast pick-and-place and assembly in a plane, such as inserting parts into a board or fitting small components.
Delta (parallel) robots. Several light arms joined at a common platform hang above the work area and move very quickly. They are common in packaging and food lines for picking small, light items from a moving conveyor.
Cartesian (gantry) robots. These move along straight axes, like an overhead crane or a printer. They are simple, rigid and good for large work areas, loading machines and palletizing.
Collaborative robots. Designed to work near people with additional safety features, often limited in force and speed, they are discussed under collaborative robots. Their suitability depends on the application and a proper risk assessment.
Choosing among them depends on payload, reach, speed, accuracy, environment and cost. Some of the factors in picking one are covered in the discussion of robot types and robot selection factors.
Typical tasks
Welding. Arms carry spot-welding guns or arc-welding torches along repeatable paths, which supports consistent weld placement. Fixtures hold parts in the same position every time, and the setup must be right for good results.
Material handling. Robots load and unload machines, move parts between stations, stack boxes on pallets and transfer items from one conveyor to another. Handling is among the most common applications.
Assembly. Robots place and fasten components, press parts together, apply adhesive or tighten screws. Part variation and fixturing often decide how well this works, which is why robotic assembly projects commonly rely on vision or force sensing for small corrections.
Painting and coating. Arms apply finishes evenly and keep people out of fume-filled spaces.
Inspection and testing. A robot can present a part to a camera or gauge, or carry a sensor over a surface.
Machine tending. An arm feeds raw parts to a machine tool and removes finished ones, allowing longer unattended running.
How robots are programmed
Traditionally, a programmer uses a teach pendant to jog the arm to each point and record it, then builds sequences with speeds and logic. Offline programming and simulation allow the work to be prepared on a computer before touching the real cell. Newer tools simplify programming further, as noted in the overview of robotics advances. The robot controller usually exchanges signals with a plant controller, which coordinates the robot with conveyors, safety systems and the rest of the line.
Safety and safeguarding
Robots can cause serious injury because they are strong, fast and may move unexpectedly. Cells are typically protected by fences, light curtains, safety-rated interlocks and emergency stops, chosen after a risk assessment. Requirements vary by country and application, so designers follow the relevant standards, machine safety features and local regulations, and only trained, authorized people should enter a cell. Maintenance should follow lockout/tagout style procedures described by the manufacturer and the site.
Practical considerations
- Total cost includes tooling, fixtures, safeguarding, integration, training and maintenance, not just the arm.
- Part presentation is often the hardest problem. If parts arrive in unpredictable positions, vision or better feeding is needed.
- Maintenance includes checking cables, lubricating as the manufacturer specifies, replacing wear items, and keeping backups of programs.
- Skills matter: operators, technicians and programmers need training.
Robots are a strong fit for stable, high-volume tasks and can also serve smaller shops when changeovers are manageable. Results depend heavily on planning. This article is general information, not engineering advice.