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For OEM projects, a cable assembly is rarely just a cable with connectors attached. The assembly may need to fit a limited installation space, meet specific electrical requirements, withstand repeated movement, and remain consistent from prototype to mass production.
This is why specifying a custom cable assembly at the beginning of a project is important. A cable that looks suitable on paper may still create problems during assembly, signal transmission, mechanical testing, or production.
A good specification gives the cable assembly manufacturer enough information to evaluate the application, select suitable materials, identify potential design issues, and develop a solution that can move from prototype to production.
A practical OEM cable assembly specification should normally cover six areas:
| Requirement | Typical Information |
|---|---|
| Cable construction | Coaxial, twisted pair, multi-core, micro coax, fine wire, etc. |
| Electrical performance | Impedance, voltage, current, frequency, attenuation, shielding |
| Connectors | Connector type, mating interface, quantity, orientation |
| Mechanical requirements | Length, bend radius, flexibility, pull force, movement |
| Environmental conditions | Temperature, moisture, chemicals, sterilization, vibration |
| Production requirements | Prototype quantity, annual volume, testing, documentation |
Not every project requires every parameter. The important point is to identify the requirements that can affect cable design and assembly performance.
One of the most common mistakes in cable sourcing is starting with a product name instead of the actual application.
For example, an OEM may request a "flexible coaxial cable" without specifying how the cable will move, what frequency it will carry, or how it will be installed.
The same basic cable construction can behave very differently depending on the application.
A cable used inside a stationary electronic device may have very different requirements from one installed in a robotic joint, drone gimbal, or medical imaging probe.
Before selecting the cable, define:
Where the cable will be installed
What signal or power it will carry
How often it will move
How much installation space is available
What temperature and environmental conditions it will experience
How the cable will connect to the rest of the system
This application information gives the manufacturer a better starting point for cable selection and engineering review.
Electrical requirements should be specified according to the actual system interface.
For high-frequency coaxial cable assemblies, common parameters include:
Characteristic impedance
Operating frequency
Insertion loss or attenuation
Return loss
Shielding requirements
Capacitance
Maximum voltage, where applicable
For example, a 50 Ω coaxial assembly may be required for an RF system, while other interfaces may use different impedance requirements.
For differential interfaces such as LVDS, the specification may include a target differential impedance and electrical-length matching requirement.
The important point is that impedance should not be specified independently from the complete signal path. The cable, connector, termination, PCB transition, and receiving device can all contribute to signal discontinuities.
This is common during early-stage development.
In that situation, the OEM can provide the interface information and application requirements instead of attempting to define every cable parameter independently.
A cable assembly manufacturer can then review factors such as:
Signal type
Frequency or data rate
Interface
Cable length
Connector configuration
Space limitations
Flexibility requirements
The manufacturer can use this information to recommend a suitable cable construction and identify parameters that should be verified during prototyping.
Electrical performance is only one part of cable assembly design.
For moving equipment, mechanical requirements can be equally important.
A custom cable assembly may need to withstand:
Repeated bending
Torsion
Vibration
Pulling
Routing around tight corners
Connector movement
Repeated insertion and removal
For robotic and gimbal applications, for example, the cable may move continuously while the equipment is operating.
In medical equipment, the cable may also need to maintain flexibility while being exposed to cleaning or sterilization procedures, depending on the device design.
A useful specification should therefore include the expected movement and installation conditions rather than simply asking for a "flexible cable."
For example:
Required bend radius: application-specific
Movement: repeated bending and torsion
Installation: compact routing around moving mechanism
The manufacturer can then evaluate conductor construction, insulation, shielding, jacketing, and strain-relief design together.
Connectors should not be treated as an afterthought.
The connector affects:
Available installation space
Electrical transition
Mechanical strength
Mating reliability
Cable routing
Assembly cost
For high-frequency applications, the connector and cable transition can also introduce impedance discontinuities.
For compact electronics, connector size can become a major design constraint. In some applications, the cable itself may fit within the available space while the connector does not.
The specification should therefore include:
Connector manufacturer and part number, if already selected
Interface type
Plug/receptacle configuration
Number of connectors
Connector orientation
Keying or locking requirements
Plating or material requirements, where relevant
If the connector has not yet been selected, providing the available installation dimensions can allow the cable assembly manufacturer to evaluate suitable options.
For signal cables used in RF, medical imaging, high-speed electronics, and other noise-sensitive applications, shielding requirements should be considered together with cable construction and termination.
Common shielding structures include:
Metallic foil
Braided shield
Spiral shield
Combined foil and braid structures
The appropriate structure depends on the application and frequency range.
Simply specifying a high percentage of braid coverage does not completely define shielding performance. Shield construction, grounding, connector termination, frequency, and system configuration can all affect electromagnetic performance.
For this reason, an OEM specification should describe the actual electromagnetic requirement where possible.
For example:
The cable assembly must provide adequate shielding for the specified operating frequency and system environment.
If a specific shielding test method or performance target is required, it should be included in the project specification.
Environmental conditions can change the cable design significantly.
Important factors may include:
Operating temperature
Storage temperature
Humidity
Water or fluid exposure
Chemical exposure
UV exposure
Vibration
Sterilization
Cleaning procedures
Medical devices are a good example.
An ultrasound probe cable may require a combination of flexibility, signal integrity, mechanical durability, and resistance to the cleaning or sterilization process used by the device.
Similarly, UAV and robotics cable assemblies may experience vibration, repeated movement, temperature changes, and compact routing.
Environmental requirements should therefore be specified before finalizing materials rather than added after the cable design has already been developed.
A cable assembly designed for ten prototypes does not necessarily have the same manufacturing considerations as one intended for long-term volume production.
An OEM should ideally indicate:
Prototype quantity
Expected production volume
Target production timing
Expected annual demand
Required inspection
Documentation requirements
Packaging requirements
This allows the supplier to consider manufacturability from the beginning.
For example, a prototype may be assembled manually while a higher-volume project may require dedicated tooling, process controls, automated inspection, or a more standardized assembly process.
Discussing production requirements early can help avoid redesigning the cable when the project moves from engineering validation to mass production.
Before placing a prototype order, OEM engineers can ask several practical questions:
A capable cable assembly supplier should be able to identify obvious manufacturing or assembly issues before production begins.
The supplier should be able to explain the relationship between cable geometry, dielectric material, shielding, conductor construction, and the required electrical performance.
For flexible applications, the supplier should evaluate the complete assembly rather than focusing only on the cable itself.
The prototype should ideally be designed with future manufacturing requirements in mind.
Testing should be based on the project's actual requirements. Depending on the cable design, this may include dimensional inspection, continuity testing, electrical testing, impedance verification, tensile testing, or flex-life testing.
The most effective custom cable projects usually involve engineering discussion before production rather than treating the cable as a standard purchased component.
During the early stage, the manufacturer can review:
Application → Cable Construction → Connector → Assembly → Testing → Production
This process helps identify potential conflicts between electrical, mechanical, and manufacturing requirements.
For example, reducing cable diameter may improve installation space but affect mechanical strength or electrical performance. Increasing shielding may improve electromagnetic protection but increase diameter and stiffness.
A custom cable assembly therefore requires balancing multiple requirements rather than optimizing a single specification.
HOTTEN focuses on customized cable and cable assembly solutions for applications where standard off-the-shelf cables may not meet the required combination of size, flexibility, electrical performance, and mechanical requirements.
Our capabilities cover applications including:
Micro coaxial cable assemblies for compact and high-density electronic systems
Medical cable assemblies for ultrasound, endoscopy, imaging, and other medical equipment
UAV and drone cable assemblies for lightweight and moving platforms
Robotics wire harnesses for systems with repeated movement
RF coaxial cable assemblies for high-frequency signal applications
Fine and ultra-fine electronic wire for compact electronic devices
For OEM projects, HOTTEN can support the process from application review and cable selection through prototyping, assembly, testing, and production.
The exact cable construction and inspection plan are defined according to the requirements of each project rather than applying one standard configuration to every application.
A custom cable assembly is a cable manufactured or configured to meet the electrical, mechanical, connector, dimensional, and environmental requirements of a specific application.
Typical information includes cable type, cable length, connector configuration, electrical requirements, mechanical requirements, environmental conditions, quantity, and testing requirements. If some specifications are not available, the application and interface information can still provide a useful starting point.
Development time depends on cable construction, connector availability, tooling requirements, testing, and project complexity. Prototype development and production qualification should be considered separately.
Yes. A project can be developed around specified connectors when the connector part number and interface requirements are available. Connector compatibility should be reviewed together with cable dimensions and assembly requirements.
A cable assembly generally refers to a finished cable with one or more connectors or terminations. A wire harness can contain multiple wires, cables, branches, terminals, and protective components. The terminology varies between industries and manufacturers.
Neither should always be selected independently. Cable construction, connector interface, available space, electrical performance, and assembly requirements should be evaluated together.
A good custom cable assembly specification does more than list a cable type and connector. It describes how the assembly will function inside the finished product.
For OEM projects, the most important information usually includes:
Application and signal requirements
Electrical performance
Mechanical movement and installation
Connector configuration
Environmental conditions
Testing and production requirements
When these requirements are defined early, the cable assembly manufacturer can make better decisions about materials, construction, connectors, assembly methods, and validation.
For OEMs developing compact medical equipment, UAVs, robotics, RF systems, or other high-performance electronics, early engineering collaboration can help turn a basic cable requirement into a manufacturable and production-ready cable assembly.
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