Is the end-effector included in the robot's payload rating?

No, it eats into it. The payload figure is the total the wrist can carry, so the end-effector's mass plus whatever it's holding both have to fit under that number. A gripper that weighs 6 kg leaves you that much less for the part.

Do I have to re-teach the TCP every time I swap tools?

Yes, or select the tool frame that already has that tool's TCP stored. A different end-effector puts the working point at a different offset from the faceplate, and taught positions are relative to the TCP, so an unmatched TCP means everything lands off target.

Why does a heavy end-effector cause wrist wear even when I'm under the payload limit?

Payload is only one spec. A tool's center of gravity sitting far out from the faceplate multiplies the load on the wrist axes through leverage. Two tools of equal mass can load the wrist very differently depending on how far out their CG sits.

Are gripper and end-effector the same thing?

A gripper is one kind of end-effector, the kind that clamps parts. End-effector is the umbrella term that also covers torches, vacuum cups, dispensers, nutrunners, and anything else that mounts to the faceplate to do work.

EOAT

End-Effector: End-of-Arm Tooling (EOAT)

An end-effector is the tool mounted to a robot's faceplate that does the actual work, such as a gripper, welding torch, vacuum cup, or dispenser.

What it is

The end-effector is whatever bolts to the robot's wrist faceplate to interact with the world. The arm just positions and orients it. Everything the robot is actually for, picking a part, laying a weld, drawing a bead of adhesive, gets done by this piece of tooling.

It goes by a few names. "End-effector" is the textbook term; on the plant floor you'll hear "EOAT" or "end-of-arm tooling" more often. They mean the same thing: the business end. A two-finger gripper, a vacuum cup array, an arc-welding torch, a servo nutrunner, and a glue dispenser are all end-effectors.

How it actually works

The end-effector mounts to the faceplate, usually through a bolt pattern and a locating boss, sometimes through a tool changer so one arm can swap between several tools. Whatever it weighs counts directly against the robot's payload rating, and so does anything it's holding. A robot rated for 25 kg has to carry the gripper plus the part inside that 25 kg, not on top of it.

Mass is only part of the story. The end-effector's center of gravity and its inertia matter just as much. A heavy tool hung far out past the faceplate loads the wrist axes harder than the same mass held close in, which is why you configure the tool's mass and CG into the controller's payload settings. Get that wrong and you'll see overload or collision alarms, or just accelerated wear on the wrist gears.

The end-effector also defines the tool frame through its TCP, the tool center point. The TCP is the working point you actually care about, the tip of the weld wire or the pinch line between gripper fingers, expressed as an offset from the faceplate. Teach the TCP correctly and the robot rotates and moves relative to that point; teach it wrong and every taught position drifts.

How it differs

Tool Center Point (TCP) · The end-effector is the physical hardware; the TCP is a single point on it that the controller uses as the reference for motion. You bolt on an end-effector, then you teach its TCP. The end-effector is steel and pneumatics; the TCP is three offsets and an orientation.
Tool Frame · The tool frame is the coordinate system anchored at the TCP; the end-effector is what that frame is attached to so the robot can move in tool coordinates. The frame is the math, the end-effector supplies the metal.
Payload · Payload is the total mass the wrist can carry. The end-effector spends part of that budget before you've picked up a single part, so a 25 kg rating with a 6 kg gripper leaves you 19 kg for the workpiece.

Where you meet it in the field

FANUC M-20iD/25 · The faceplate on this arm is where the end-effector bolts on, and its payload rating is what the tool plus workpiece has to fit inside.
Arc welding · In an arc-welding cell the end-effector is the torch itself, with the TCP set at the tip of the weld wire.

Common questions

Is the end-effector included in the robot's payload rating?: No, it eats into it. The payload figure is the total the wrist can carry, so the end-effector's mass plus whatever it's holding both have to fit under that number. A gripper that weighs 6 kg leaves you that much less for the part.
Do I have to re-teach the TCP every time I swap tools?: Yes, or select the tool frame that already has that tool's TCP stored. A different end-effector puts the working point at a different offset from the faceplate, and taught positions are relative to the TCP, so an unmatched TCP means everything lands off target.
Why does a heavy end-effector cause wrist wear even when I'm under the payload limit?: Payload is only one spec. A tool's center of gravity sitting far out from the faceplate multiplies the load on the wrist axes through leverage. Two tools of equal mass can load the wrist very differently depending on how far out their CG sits.
Are gripper and end-effector the same thing?: A gripper is one kind of end-effector, the kind that clamps parts. End-effector is the umbrella term that also covers torches, vacuum cups, dispensers, nutrunners, and anything else that mounts to the faceplate to do work.

Related terms

tool center point tool frame payload