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In manufacturing cable assemblies, production speed is often constrained by factors beyond factory capacity. In many cases, delays are caused by selecting an assembly’s design without considering the optimal manufacturing approach.
The process of designing an assembly with the intent to manufacture it (DFM) is an important consideration because it will not only ensure the assembly is electrically functional but also provide a manufacturable, testable, and repeatable method for high-volume production. By applying DFM early in the design process, multiple companies can save time and money and reduce quality risk when manufacturing cable assemblies in high-volume or mixed-volume production environments.
This guide outlines practical, production-proven DFM tips to help OEMs and engineers accelerate cable assembly manufacturing without compromising reliability.
What Is DFM in Cable Assembly?
Cable assembly is an example of DFM principles in action; specifically, cable assembly manufacturing involves designing cables to support or accommodate manufacturing processes, including cutting, stripping, terminating, crimping, overmoulding, and electrical testing.
Compared to PCB DFM, cable assembly DFM must consider:
- Manual and semi-automated assembly steps
- Material flexibility and handling behavior
- Length tolerances and routing constraints
- Connector orientation and harness layout
Ignoring these factors often leads to rework, unclear instructions, longer production cycles, and inconsistent quality.
Design Simplification and Standardization
Keep the Design Simple
By eliminating unnecessary components, deviations from the standard procedures, and specially engineered parts, you decrease complexity, thereby increasing your production rate. Reducing the number of special requests and unique items increases manual assembly during production, thereby increasing the risk of human error.
Simple designs:
- Assemble faster
- Require less training
- Scale more reliably
Use Standardized Materials and Components
If at all possible, always use standard, readily available materials (wires, connectors, terminals), not custom-engineered components or niche parts.
Standard components:
- They are easier to source
- Support existing tooling
- Reduce supply chain risk
- Enable bulk purchasing and shorter lead times
Design for Automation and Efficient Assembly
Design for Automated Processing
Automated cable assembly processes that use repeatable, simple patterns are easier to automate through cutting, stripping, and crimping than those that do not.
Automation-friendly designs typically feature:
- Consistent wire lengths and strip specs
- Uniform termination methods
- Minimal variation across assemblies
Minimize Part Variety
Using a limited set of wire gauges, terminal colors, and terminal sizes will reduce machine setup time and operator errors. Fewer variations to set up will enable faster changeover times between jobs and ultimately higher production yields.
Simplify Cable Structure and Geometry
Reduce Branches and Breakouts
Manual processes like measuring, taping, and fixture tooling are introduced with every cable breakout. Slowed assembly due to excessive branching remains a leading contributor.
Where possible:
- Combine signals into fewer connectors
- Use modular sub-assemblies
- Avoid unnecessary split points
Use Realistic Length Tolerances
Cables are flexible components. Overly tight length tolerances increase scrap and slow production.
A practical approach is:
- Avoid millimeter-level tolerances unless functionally required
- Use percentage-based tolerances for longer cables
Termination and Connection Design
Prefer Crimping Over Soldering
For most production environments, crimping is faster, more consistent, and better suited for automation than hand soldering.
Soldering should be reserved for:
- Specialized high-power applications
- Specific electrical or regulatory requirements
Standardize Strip Lengths and Termination Methods
Setting up and inspecting assemblies with varying strip lengths and/or mixed termination processes takes longer than if they had been standardised.
Standardising cables improves throughput and enables consistent process repeatability.
Assembly Efficiency and Error Prevention
Design for One-Directional Assembly
When designing a cable assembly, try to add components from a single direction to reduce time spent handling and reorienting them. This will help minimize operator fatigue.
Incorporate Error-Proofing Features
Error-proofing (Poka-Yoke) is critical for fast, reliable production.
Effective methods include:
- Keyed or polarized connectors
- Clear connector orientation
- Physical features that prevent incorrect insertion
Material Selection That Supports Fast Production
Choose Manufacturing-Friendly Insulation Materials
Material choice directly affects stripping speed, flexibility, and handling.
From a production standpoint:
- Extremely hard jackets, slow stripping
- Overly soft materials may deform during crimping
Select materials that balance electrical performance with manufacturing efficiency.
Evaluate Overmolding and Strain Relief Carefully
When protection from harsh environments is required or long-term strain relief is necessary, overmolding may improve lifespan; however, it will increase tooling costs and cycle times, so it should be used sparingly.
Documentation and Drawing Best Practices
Provide Clear and Complete Cable Drawings
Incomplete or ambiguous drawings are one of the biggest production bottlenecks.
A production-ready drawing should clearly define:
- Overall cable length and tolerances
- Wire specifications and colors
- Connector and terminal part numbers
- Pin assignments and orientation
Use Visual Assembly References
Nailboard drawings and photos, as well as assembly notes, will help minimize misinterpretation of instructions and reduce reliance on highly trained assembly labor. This will allow for a more efficient and consistent build process.
Cable Assembly DFM Checklist for Faster Production
Component & Material Selection
- ☐ Use industry-standard connectors and terminals
- ☐ Limit wire gauge and color variations
- ☐ Select materials compatible with automated processing
Cable Structure & Geometry
- ☐ Minimize branches and breakouts
- ☐ Avoid overly tight length tolerances
- ☐ Design a sufficient bend radius for easy routing
Termination & Assembly
- ☐ Standardize termination methods (prefer crimping)
- ☐ Ensure consistent strip lengths
- ☐ Avoid unnecessary mixed processes
Automation & Error Prevention
- ☐ Use keyed or polarized connectors
- ☐ Enable one-directional assembly
- ☐ Ensure adequate clearance for tools and fixtures
Testing & Documentation
- ☐ Reserve access for electrical testing
- ☐ Provide clear drawings and nailboard references
- ☐ Include a complete BOM with manufacturer part numbers
Frequently Asked Questions (FAQ)
What does DFM mean in cable assembly?
DFM in cable assembly means designing cables that are easy to manufacture, assemble, test, and scale while reducing cost, lead time, and production risk.
How does DFM reduce cable assembly lead time?
DFM reduces lead time by simplifying designs, standardizing components, enabling automation, and minimizing manual assembly steps.
Why are standard connectors important for faster production?
Standard connectors are easier to source, compatible with existing tooling, and reduce both procurement delays and assembly errors.
Is crimping better than soldering for cable assemblies?
For most production applications, crimping is faster, more consistent, and better suited to automation than hand soldering.
When should DFM be reviewed in a cable assembly project?
DFM should be reviewed early—before drawings are finalized—to avoid costly redesigns and ensure smooth transition from prototype to mass production.
About the Manufacturer
This guide is based on real-world cable assembly manufacturing experience gained through continuous DFM reviews, pilot builds, and volume production projects.
Working in partnership with OEM engineers and their sourcing team, we develop cable assemblies that perform as intended while being easy to manufacture, assemble, test, and ultimately mass-produce. This innovative design for manufacturability(DFM)-driven method of developing cable assemblies provides OEM customers with the ability to decrease lead time, increase cost contro,l and achieve consistent quality throughout their entire production run of prototypes.