Types, not brands
“Top 5” here means five main kinds of industrial robot, not a ranking of products. No single type is best. Each one is a different way of arranging joints and motors, and each is good at certain tasks. Picking the right type for the work usually matters more than anything else about the machine.
1. Articulated robots
The articulated robot is the familiar jointed arm, much like a human arm with a shoulder, elbow and wrist. Most have four to seven rotating joints, and six is very common. This layout gives a large working volume and lets the tool approach a part from many angles.
Typical uses include welding, painting, machine tending, material handling, palletizing and assembly. They are widely used because they are flexible, and the same basic arm can be fitted with a welding torch, a gripper or a dispensing nozzle. Their drawbacks are that they need guarding and floor space, and that their accuracy at the tool tip depends on the whole chain of joints.
2. SCARA robots
SCARA stands for selective compliance assembly robot arm. It has joints that rotate around vertical axes, so the arm is stiff when pushing down and flexible sideways. A short vertical axis moves the tool up and down.
This makes SCARA robots well suited to fast, light work in a horizontal plane: placing small components, inserting pins, screwing small fasteners, and packing or loading items onto a tray. They are common in electronics and small-parts assembly. They are less suited to reaching around obstacles or approaching parts from the side.
3. Delta robots
A delta robot hangs from above. Three light arms join at a small platform, and the motors sit on the fixed frame rather than moving with the arm. Since the moving parts are so light, delta robots can accelerate very quickly.
They are typically used for high-speed picking and placing of lightweight items, especially on a moving conveyor, with a camera locating each item. Food, pharmaceutical and consumer-goods packaging lines are common examples. They carry little weight and have a limited working area, so they are not a choice for heavy parts.
4. Cartesian (gantry) robots
A Cartesian robot moves along straight axes at right angles, usually called X, Y and Z. Think of a crane over a workspace, or the motion of a 3D printer or a CNC machine. These axes are often built from linear actuators or ball screws and linear guides driven by motors.
The layout is simple to understand and program, and positions are easy to calculate. Because the structure can be extended, gantry versions can cover large areas and carry heavy loads, which suits loading machines, pick-and-place over large trays, and palletizing. The trade-off is that the structure takes up space and offers less freedom of motion than a jointed arm.
5. Collaborative robots
Collaborative robots, often called cobots, are designed to work near people, usually without a full safety fence, provided a risk assessment supports it. They typically have lower speeds and forces, rounded shapes and sensors that detect contact. They are often easy to move from task to task and to program by guiding the arm by hand.
They tend to suit lighter, lower-volume work such as machine tending, simple assembly, testing, and packing, particularly in smaller shops where setups change often. The speed and payload of many collaborative arms is lower than that of a traditional arm, and safety still depends on the whole application. A sharp tool or a heavy part held by a cobot can still be hazardous, so the whole cell must be assessed, not just the robot.
Quick comparison
| Type | Motion style | Usually suited to |
|---|---|---|
| Articulated | Rotating joints, large reach | Welding, handling, painting, palletizing |
| SCARA | Horizontal swing with short vertical stroke | Small-part assembly and placement |
| Delta | Light arms hanging from above | Fast picking of light items |
| Cartesian | Straight-line axes | Loading, large-area placement, heavy loads |
| Collaborative | Lower force, shared workspace | Light tasks near people |
What these robots have in common
Under the skin, most share the same building blocks. Electric servo motors drive the joints, and position encoders report where each joint is. A controller coordinates all the motion, and a gripper or tool does the work at the end. Some simple machines use pneumatic actuators for open-and-close movements, though full robots mostly rely on electric drives. Every robot cell also needs protective measures, including guarding or sensing, and emergency stop circuits that bring motion to a safe condition. Safety requirements depend on the application and on local rules, and installation should be done by trained personnel following the manufacturer’s manuals.
Choosing between them
Start with the task. Is the motion mostly in a plane, or does it need many angles? Are the items light and fast-moving, or heavy and slow? Will people work close by? The answers usually point towards one or two types. The finer questions of payload, reach and cycle time come next, and those are a separate decision from picking the basic type.