A robot tool changer lets one robot use several end effectors, for example a gripper for machine loading and a vacuum tool for sheet parts. It has two halves: the master plate on the robot flange and a tool plate on each tool. Here is what to check when you choose one.
1. Payload and moment
Add up the mass of the heaviest tool and the heaviest part it carries. Then check the moment: the further the center of gravity is from the tool changer face, the higher the bending load on the coupling.
- Compare your total mass with the rated payload.
- Compare mass × offset distance with the allowable static and dynamic moment.
- Add margin for fast robot motion and emergency stops.
2. Air passages
Count the air lines each tool needs. A parallel gripper needs 2 lines (open and close). A vacuum tool with an ejector needs 1 supply line, plus 1 for blow-off if you use it. Choose a tool changer with enough passages for the most complex tool, and check that the port size gives enough flow.
3. Electrical signals
If the tool has sensors (gripper position switches, vacuum switches) or valves, the signals must cross the tool changer. Add matching signal modules to both plates. Count the number of contacts you need and keep one or two spare.
4. Locking safety
The tool changer must never drop a tool. Check for:
- Fail-safe locking: the tool stays locked if air pressure is lost.
- Lock and unlock sensing: the robot controller confirms the lock state before moving.
- Tool present sensing: confirms that a tool is attached.
5. Repeatability
Repeatability tells you how accurately the tool returns to the same position after each change. Values around ±0.01 mm are typical for pin-located tool changers and are enough for most handling tasks without re-teaching the robot.
6. Tool stands
Each tool needs a stand where the robot can drop it off and pick it up. Plan the stand position, the approach path and any covers that protect the tool plate from chips and dust.
Checklist
| Check | Your value |
|---|---|
| Heaviest tool + part mass | |
| Center of gravity offset | |
| Air lines needed | |
| Electrical signals needed | |
| Robot flange | |
| Number of tools |
Send us the completed checklist and your robot model, and we will recommend the right HITREE tool changer and modules.