Customized wire harnesses are essential components in countless industries, but their complex nature can introduce manufacturing challenges. Applying Design for Manufacturing (DFM) principles early in the design phase is crucial for ensuring efficient, cost-effective, and high-quality production. Here are key DFM principles specifically for customized harness processing:
- Standardize Components and Processes (Where Possible):
- Specify standard, readily available wires, connectors, terminals, seals, and backshells unless absolutely necessary.
- Use common wire gauges and insulation types from your supplier’s preferred inventory.
- Standardize crimping profiles, terminal types, and connector families.
- Design to leverage the manufacturer’s existing tooling (crimpers, applicators) and test equipment capabilities.
- Prioritize Component Accessibility and Ergonomics:
- Ensure connectors, terminals, and splice points have adequate space around them for efficient crimping, insertion, or splicing operations by hand or automated equipment.
- Avoid “burying” components deep within the harness or in locations requiring awkward tool angles.
- Provide sufficient clearance for gripping and manipulating connectors during assembly and testing.
- Design for Protection and Strain Relief:
- Clearly specify necessary protection like convoluted tubing, braided sleeving, corrugated conduit, tape wrapping, or molded boots in the drawings.
- Design effective strain relief at connector backshells, pass-throughs/grommets, and branch points using clamps, grommets, or overmolding.
- Eliminate sharp bends near connection points that could cause wire fatigue.
- Optimize Routing and Branching:
- Define the routing path clearly, considering bundle diameters and space constraints in the end application.
- Plan branch points logically. Minimize complex branching or avoid overly dense branching clusters.
- Keep branch lengths sufficient to allow for bundling and termination without excessive tension.
- Specify appropriate bundling methods (cable ties, lacing, tape, etc.) and intervals clearly.
- Simplify Assembly Sequences:
- Design the harness so it can be logically assembled in a step-by-step manner, avoiding steps that require significant rework or backtracking.
- Consider the lay board/fixture design during the electrical design – can the wires be placed sequentially without constant repositioning?
- Minimize the number of different assembly actions (e.g., staggering terminations reduces simultaneous insertions).
- Clarity in Documentation and Identification:
- Provide exceptionally clear, complete, and unambiguous assembly drawings. Include detailed views of complex areas.
- Mandate wire markers, labels, or printed legends from the design stage for every wire, connector cavity, and major component. Specify location and orientation.
- Use consistent and industry-standard color coding where applicable.
- Clearly identify the pin-out for every connector on the drawing.
- Incorporate Testability Features:
- Design to facilitate continuity testing and Hi-Pot (dielectric withstand) testing.
- Ensure test points are accessible, either through exposed pins or designed-in test probes/labels. Avoid designs where only the final mating connector provides access, limiting intermediate testing.
- Clearly define the testing requirements and connection points within the documentation.
- Minimize Unique or Custom Features:
- Carefully evaluate any request for custom-molded connectors, specialized lacing, or unique processes. Standard alternatives are often faster and cheaper.
- If customization is unavoidable, engage with the harness manufacturer early to understand feasibility and cost drivers.
- Specify Tolerances Realistically:
- Define clear, manufacturable tolerances for lengths, bend radii, and bundle dimensions. Avoid unnecessarily tight tolerances that drive up cost without benefit.
- Understand the wire cutting/stripping and assembly process capabilities of your chosen manufacturer.
By rigorously applying these Design for Manufacturing principles during the development of customized wire harnesses, designers and engineers can significantly improve manufacturability, reduce costs, shorten lead times, enhance quality, and ensure reliable performance in the final product.
