Robot Tool Center Point System: An Unsung Hero in Avoiding Downtime and Sunk Costs

Robots performing tasks such as MIG welding, sealant dispensing, or adhesive application require a high level of precision, since the robots must repeatedly run the same motion path and position an end-of-arm tool (EOAT) in a repeatable spot.

Crashes, collisions, or tool changes have the potential to throw the entire process off course and can lead to downtime, sunk costs, and unusable parts. Production facilities can update the robot’s motion path to compensate or opt to deploy the advintec TCP (tool center point) tool from LEONI Engineering Products & Services (LEPS) to efficiently automate recalibration.

The advintec TCP system uses a two-channel infrared (880 nm) photoelectric laser sensor pulsed at 2 kHz to calibrate a tool or fixture electronically in up to six dimensions (three axes plus angular rotation around each axis) without touching or contacting the EOAT. The TCP does this by comparing the path of the robot to its master/reference moves. The system records the robot’s path and when a process changes or the robot requires recalibration, the TCP determines any variation from the original reference and establishes that the robot has shifted. Typical cycle times range from as little as 5-7 seconds for a 3D offset and only 10-15 seconds for a full 6D correction.

“Even if the robot has moved 5 mm in a given direction, for example, the advintec TCP takes this information and applies an offset on the robot side,” said Jim Reed, Vision Product Manager, LEPS.  

Avoiding Disaster

In an automotive adhesive application, a robot must guide a nozzle or dispenser to the precise location. If something bumps into the nozzle, the nozzle no longer follows the same path, but the robot does. If this process continues for an hour or even an entire shift, mistakenly applying glue to the wrong spot on a vehicle, the number of incorrectly assembled vehicles could be catastrophic in terms of wasted parts, time, and money.

With the advintec TCP, manufacturers can set up their process so that after every vehicle or every 10 vehicles, for example, the system performs a quick check to ensure proper robot calibration. If advintec TCP finds something off, it performs a correction offset, potentially reducing the damage to one vehicle or none at all.

Consider the Human Factor

In many cases, when a crash or collision event takes place, an operator will correct it, but everyone has a slightly different method, said Reed.

“In these scenarios when a nozzle is bent, an operator will come over and bend it back or replace it, and then confirm the new tool center point,” he said. “Variation between different people exist, but our tool makes it a more consistent approach and takes the human element out of it. ”

LEPS’ TCP tool provides automated calibration capabilities in precision applications such as those dealing with ultrasonic cutting blades, sealant dispensing, MIG or stud welding, adhesive applications, and any other application that requires high-accuracy robot positioning.

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