Tooling design and validation makes the difference.

Robotics has been gaining visibility the past few years in everything from media reports to commercials. Robotics serves many different industry sectors to assist in everyday life, from our homes to medical facilities, manufacturing plants and even the military. Behind every robot is the manufacturing assembly process of how the robot was built. Here, the author details some key areas of the Benchmark Electronics New Hampshire division Robotics manufacturing process, from a prototype or new-build stage to steady-state production. Working with our local customer’s design team, Benchmark specializes in complex electromechanical assembly work. In the past five years, a total of six robotics programs ranging in size from a throwable unit to an eleven-foot-tall giant have been assembled. The programs manufactured serve the full range of applications above, and include a design build-stage to steady-state production phases.

Supply-chain involvement. Early involvement and communication with the supply chain becomes very important to understand supplier capability and design for manufacturing (DfM) issues that may arise. No matter what stage the supplier may be on the chain, this early involvement gets the supplier engaged in the design phase and pre-production ramp to volume.

Early supplier involvement gives time to develop tooling, work out process issues and “Lean” and streamline the manufacturing process. This partnership with the supplier also builds a product knowledge base if a DfM issue occurs with integration or, in the event of engineering change orders, when quickturn results are needed for proving the new design.

Skilled workforce. With any manufacturing workforce, skill and experience to perform the task are important. Robotics assembly requires specific talents and skills given its complex electromechanical assemblies. Attention to detail, mechanical skills, feedback and continuous improvement orientation are some of the key attributes of the workforce.

Required skills may be different during the prototype or design phase in comparison to the production stage or steady-state product build. During the first build or prototype, the assembly learning curve and design for manufacturing concerns are steep. With any new design, this includes determining if the assembly goes together correctly, identifying modification needed, and reacting to changes along the way such as design updates, ECOs and other assembly roadblocks.

During the production stage, different skills may be required, given that the assembly process is steady-state and production-ready, with detailed work instructions completed to provide visual aid to the assembly operator. At this point, the ability to focus on quality, efficiency and incremental process improvement becomes more critical.

Tooling design and turnaround. During any complex electromechanical assembly introduction, designing and developing tooling assists the operation in manufacturability. Tooling designed and developed during the initial build stage requires a quick turnaround, given the need to test and evaluate the final product, and time-to-market requirements. Tooling can be designed and machined by a drawing or using a picture of the actual product. In some cases, the final part will be required to validate the tooling. Modifications may be required to change the specific tool, depending on fit checks or functionality.

When the complex mechanical assembly has been transitioned to production, additional production tooling may be helpful to reduce assembly cycle time or assist the mechanical assembler for ease of manufacturing. Additional tooling may also be helpful to poka-yoke or mistake-proof an operation. This may be helpful during an inspection or validation of product stage.

Figure 1 is a tool used in the mechanical assembly operation. The tool is a mistake-proofing tool used to verify product is built correctly. The product is a motor that is built in two different configurations (left and right) that has an opportunity to be assembled incorrectly given similar base part numbers. Use of the tool shown in Figure 1 quickly verifies that the motor has been assembled for the correct side.

With any tooling developed, a validation will be required. The validation of the tooling will confirm that the tool is not causing defects or other issues that may impact form, fit or function at a next-level assembly operation. The key is to validate the tooling on one piece of product to prove out the design concept. A tooling validation checklist may be helpful to assist in this operation to detail the key steps of the assembly process and points for inspection. A few key points of validation are:

• Verification of product in next-level assembly operation to ensure the tool did not affect form, fit or function. (Example: Damage to a screw hole.)
• Inspection of product to ensure no damage occurred, and the product meets inspection criteria. It is important to sample several assemblies, to develop confidence in the tool’s ability to work within normal range of variation.
• Inspect the tool regularly, on a schedule, to make sure no damage occurs.

Prototype to production. During the prototype stage, the main goal is to develop and prove out tooling, work instructions or visual aids and to work out any DfM issues. During this production readiness, a baseline should be known of how many production units will be required, thus determining assembly space, flow, equipment and tooling needed to meet customer demand. Opportunities will exist to implement Lean manufacturing principles such as point-of-use material storage or assembly pass along line. Cycle time may be reduced by implementing additional tooling or modification to tooling that will assemble a piece part faster: for example, press-fit tooling that can do multiple pieces at the same time or electric drivers for mechanical assemblies with many screw locations at an operation.

Robotics assembly requires many skills and talents from all involved within the manufacturing assembly process and team. From supply-chain communication, to quickturn manufacturing tooling design, to streamlining an assembly process for steady state production volume, all is required for a successful robotics assembly process from prototype to production.

Scott Mazur is a manufacturing staff engineer supporting various robotics assemblies and programs at Benchmark Electronics New Hampshire Division (benchmark.com); scott.mazur@bench.com.