Changing a Workpiece on a Rented Robot: Questions Before the Next Job

A rented robot may arrive configured for a demonstration, then be asked to handle a different workpiece at the customer's site. That change affects more than the rental schedule. The parties need to identify the new tool and load, agree who may change the configuration, and review the application before operation. A robot's headline payload rating alone is not a complete approval for every combination of tool and workpiece.

Describe the change before scheduling the work

Record the robot and controller supplied, the existing tool, and the task covered by the rental agreement. Then describe the proposed workpiece, fixture, grasping method and operating environment. If the workpiece varies, record the range and how variation will be controlled. The rental provider and site integrator can use this information to determine what further engineering work is needed.

A request such as “the new part is lighter” is incomplete. The tool and attachments also contribute to what is mounted on the flange, and the distribution of that mass matters. Universal Robots' payload documentation for a specified software version describes payload as the combined weight attached to the tool flange. Other manufacturers and versions require their own documentation.

Do not confuse mass with center of gravity

Two assemblies can have the same total mass but different centers of gravity because their components are arranged differently. The distance and direction of the load from the mounting point can matter to the application. The renter should provide accurate information; a qualified person should determine how the robot's documented limits and configuration apply.

Universal Robots' payload and center-of-gravity explanation describes how its robots use configured payload and center-of-gravity information during motion. The article's programming examples are specific to the identified software and include deprecated functions; they are not a universal method for another robot. Consult the applicable manufacturer's data for the actual equipment.

Assign configuration responsibility

The rental agreement or work order should identify who supplies the tool, who provides the workpiece data, who configures the robot and who approves the changed application. If a different program or gripper is introduced, document its version and the authorization for the change. A rental provider's original demonstration does not automatically validate a later customer modification.

For example, imagine a rented arm initially handling an empty plastic fixture. The customer later proposes a heavier fixture holding a metal component. The team would need to account for the complete assembly and the different operating state, then have the responsible specialists review it. This is a hypothetical scenario, not a measured load or an instruction to operate a robot.

Review the cell, not only the arm

A change in part shape can affect clearances, gripping reliability, dropped-object hazards and interactions with surrounding equipment. The site team should use its established risk assessment and change-management process, involving the rental provider and integrator where appropriate. Required safeguards and validation depend on the whole application and local requirements.

Do not adjust safety settings, bypass a guard or test a new load around people because an online example appears similar. Work on configuration and validation belongs to trained, authorized personnel following the manufacturer's instructions and the site's procedures. This article does not provide operating values or a commissioning sequence.

Keep the approval and test evidence with the rental record

Document the agreed load description, configuration version, responsible reviewers and the result of the checks required by the project. Keep a clear distinction between an intended change, a change actually performed and an application approved for use. If a required datum is missing, mark it as unresolved and follow the site's procedure rather than substituting an estimate.

Also agree what will happen when the rental ends. The provider may need a record of the customer-supplied tool, configuration changes and condition of the returned equipment. Backup and data transfer should use the approved channels and respect the customer's confidential information.

Ask questions before the next job

If the customer plans several different workpieces, agree how each variation will be assessed and who is authorized to introduce it. A one-time test with one part does not prove that every later part is covered. Clear ownership helps the team schedule engineering support before the robot is needed on the production floor.

The handover can also identify the point of contact for unexpected differences between the supplied part and the agreed description. Staff should know how to stop and escalate a change that has not been reviewed. That practical communication path makes the written agreement useful during the rental, rather than leaving it as a document consulted only at return.

Related rental topics on this site cover delivery and return records and gripper wear responsibilities. More material is available in the robot rental section. This guide supports planning and does not replace a qualified application review.