FAKRA is a high-performance automotive harness for transmitting high-frequency signals. With the rapid development of automotive technology, FAKRA harnesses have been widely adopted in key areas of the industry, including in-vehicle navigation systems, infotainment systems, telematics, 360° panoramic cameras, autonomous driving, and remote information processing systems, facilitating the intelligent, connected, and information-driven evolution of new energy vehicles. FAKRA harnesses are categorized into traditional types FAKRA and miniaturized Mini-FAKRA variants. The development and application of automated manufacturing technologies and equipment for FAKRA cable harnesses represent a critical technical challenge. Implementing error-proofing techniques in automated manufacturing equipment, starting from the initial production stages, can effectively prevent batch defects, enhance equipment stability and production line yield, and reduce manufacturing costs for FAKRA cables.

Introduction
The advancement of connected vehicle technology (V2X), Advanced Driver Assistance Systems (ADAS), and the widespread use of high-precision automotive radar demand that FAKRA harnesses—key components linking communication and data exchange systems—possess high precision, fast connection capability, durability, and superior reliability. Further progress in vehicle intelligence, connectivity, and 5G technology imposes even higher performance requirements on FAKRA cable. Applying automated manufacturing technology not only improves production efficiency but also ensures product consistency and harness reliability. Integrating error-proofing techniques into automated or semi-automated manufacturing processes effectively prevents non-conforming products, elevates overall production management standards, and lowers manufacturing costs.

While traditional manual production lines can manufacture FAKRA cable harnesses, they struggle to guarantee consistency, signal transmission performance, and product reliability. The evolution of FAKRA raw materials from machined single-part versions to stamped versions has enhanced production efficiency, automated manufacturing levels, and reduced costs, creating prerequisites for automated harness manufacturing. Therefore, the design of FAKRA automated manufacturing solutions and the research and application of error-proofing technologies on automated production stations are particularly important.

FAKRA Automated Manufacturing Equipment Solution Design
FAKRA automated production line equipment integrates multiple processes such as wire cutting, coiling, stripping, crimping, and testing. Utilizing a modular structural design and precise servo-driven mechanisms, it achieves fully automated production. The line is equipped with a CNC human-machine interface (HMI) system, allowing individual workstation modules to operate independently. It supports non-standard customization based on client requirements, enables flexible expansion of additional functions, and permits individual control of each module via the HMI.

There are typically two types of FAKRA automated production lines:

The first is a fully automated solution encompassing wire cutting, coiling, bundling, automated wire handling, outer jacket stripping, crimping, outer conductor assembly, housing installation, continuity testing of finished harnesses, and wire collection.

The second is a semi-automated, human-machine collaborative solution. This approach separates the automatic wire cutting, coiling, and bundling machine from the main automated line. Subsequent processes like housing installation are performed manually, while the automated line handles intermediate steps such as stripping, center contact crimping, outer conductor assembly, and dielectric withstand voltage testing. After intermediate harnesses are offloaded, manual processes include housing installation, dielectric testing, SI (Signal Integrity) testing, visual inspection, and packaging.

For enterprises with high automation requirements for FAKRA harness production, selecting a fully automated FAKRA production line is optimal. This requires only one operator to load coaxial cables and terminal materials, operate the HMI, handle final qualified product collection and transfer, and manage anomaly resolution and defect analysis during line operation. For companies prioritizing efficiency and equipment stability, a semi-automated dedicated line designed for human-machine collaboration is suitable. It minimizes material and product changeover, maximizing equipment utilization.

Whether designing a single-end or dual-end cycle automated line, the preliminary design phase must involve thorough analysis and solution review based on actual enterprise needs, harness project product types, process flows, inspection parameters, and client technical specifications. This effectively avoids subsequent equipment modifications. Additionally, the design should aim to minimize structural complexity, as higher complexity often reduces overall line stability and equipment operational availability.

FAKRA Cable Harness Automated Process Design and Error-Proofing Application
Error-proofing techniques for equipment or processes must be integrated during the solution design or process layout stage for FAKRA automated or semi-automated manufacturing. This effectively mitigates numerous uncertainties during later equipment debugging, harness production, and acceptance testing.

1. Wire Cutting Process Design and Error-Proofing Application
In a fully automated line, the automatic wire cutting and coiling machine is mechanically linked to the FAKRA main line, but this combination has limitations. For wire lengths below 800mm, the cable is coiled once (coil diameter D=120mm) with 200mm of wire left free at each end, secured by tape or ties. For lengths between 800-1200mm, where coiling less than two full cycles may not ensure 200mm free ends, a coil winding fixture with an adjustable diameter must be considered. The automatic wire cutting and coiling machine should incorporate a flexible mechanism that calculates the coiling diameter based on input wire length. An optimal coiling diameter ranges from 150-300mm. The industry standard is to shape the coil into two semicircles (diameter ~100-120mm) connected by a rectangular middle section (~300mm apart), requiring a minimum cut length of 800mm. The maximum length is determined by the bundling mechanism size.

The coiling mechanism must be servo-controlled and adjustable. Operators input parameters like wire length, type, and length compensation via the HMI. The software system then automatically calculates the coiling diameter, directs the servo system to adjust the winding fixture, and ensures 200-300mm of free wire at each end to meet the FAKRA main line fixture requirements.

To improve the utilization rate of the cutting/coiling unit, a wire collection mechanism should be added at its end. When the main FAKRA line is idle or producing single-ended products, the main unit can be fed manually. The front-end cutting/coiling unit continues operating, delivering coiled and bundled wires to a designated location for manual collection into containers, increasing the cutter/coiler's utilization by 30-40% and overall equipment efficiency by approximately 5%.

2. FAKRA Main Automated Line Design and Error-Proofing Application
The main FAKRA automated line typically performs major stripping, metal shield crimping, foil cutting, braid folding back, core wire stripping, center contact crimping, outer conductor assembly, outer conductor crimping, CCD inspection, dielectric withstand voltage testing, laser marking, and wire collection. Some fully automated lines also handle housing assembly, lock installation, and NG (No Good) product separation. This main section is the core component of the entire production line.

The first or second station of the main line must include a manual wire loading station, even in fully automated lines integrated with a cutter/coiler. This serves two main purposes: accommodating very short or very long wires, and enabling manual feeding if the cutter/coiler malfunctions, thereby increasing main line utilization.

After braid folding and core stripping, an ionized air cleaning module must be installed. Typically employing top-blowing and bottom-sucking, it removes stray shield filaments and metal debris from the cable end. An additional ionized air cleaner before outer conductor assembly may be necessary to ensure the center contact is clean and free of contaminants before insertion.

Braid Fold Inspection: A module must be added at the station immediately before center contact crimping to inspect for incomplete braid folding, preventing potential short circuits caused by shield wires contacting the core. Industry practice often uses low-voltage continuity testing between the core and shield at the inner insulation area, but this contact-based method might alter the core's state. A preferred non-contact alternative is 360° rotational CCD imaging. By setting a sensitive zone around the inner insulation and core area in the captured image and requiring it to be free of foreign objects, incomplete folds can be detected.

Center Contact Straightening Module: After crimping, the center contact terminal is ejected from the crimp die. Under certain conditions, this ejection can cause varying degrees of bending between the terminal and the wire. To ensure smooth insertion into the outer conductor assembly, a center contact straightening module must be designed before the assembly station. It uses soft plastic surfaces to apply 3-5N of pressure to straighten the terminal. When straightening a defective terminal (e.g., with protruding strands), copper fragments might fall into the straightening area and potentially adhere to the next good terminal, causing a short circuit. Therefore, a blowing device should be added to the straightening module. During the idle cycle time after a pair of terminals is straightened and leaves the module, the blowing device cleans the straightening area to prevent metal debris from adhering to subsequent good terminals.

Scrap Carrier Isolation Component: On dual-end simultaneous processing lines, the left-side center contact is typically assembled and its outer conductor crimped first, leaving the right-side center contact exposed. If the scrap carrier cutting blade on the left-side crimping unit becomes dull and fails to cut the scrap carrier cleanly, the excess carrier may curl upward and interfere with the right-side folded braid. When the crimping unit retracts, it could snag and pull the properly folded braid into the center contact area, causing a short circuit when the right-side outer conductor is assembled. Therefore, a scrap carrier isolation plate must be added on the scrap carrier side of the left-side outer conductor crimping die to completely separate the scrap from the right-side cable, preventing severe short-circuit defects or products with latent quality risks from escaping.

Dielectric/Continuity Test Module Error-Proofing Design: For dual-end FAKRA automated lines, the left and right test contact mechanisms for dielectric/continuity testing should ideally be controlled by two independent servo motors for separate extension/retraction adjustment. When processing identical FAKRA products on both ends, both modules move the same distance. When processing different products, the test contact position and required stroke differ due to variations in outer conductor length and center contact tip location, necessitating independent control. This dual-motor design offers high control precision but increases mechanism complexity and cost.

An alternative design uses a single motor to control both test contacts' movement, suitable for lines processing identical products on both ends. This scheme offers more stable, reliable mechanics and lower module cost. For processing different products, quickly interchangeable adapter modules can be used. The drawback is the need to design and manage multiple adapter modules for different product combinations.

3. Application of CCD Imaging Inspection Technology in FAKRA Automated Lines
Advancements in semiconductor and digital image processing technologies, coupled with improved CCD chip resolution and dynamic range, deliver higher imaging quality. The integration of CCD inspection with new technologies like artificial intelligence, supported by powerful computing systems for advanced image analysis algorithms, significantly enhances detection accuracy, reliability, and efficiency, promoting wider adoption in FAKRA automated lines.

CCD inspection configurations include fixed-lens with prism for 360° view, fixed-lens for single-side view, and 360° rotating lens for full peripheral view. The configuration should be selected based on specific inspection needs during process design. For example, inspecting shield braid cut quality and completeness of braid folding is optimal with a 360° rotating lens. For inspecting center contact crimp appearance/dimensions and outer conductor crimp appearance/dimensions, a fixed-lens with prism for 360° view is preferred. For checking FAKRA harness concentricity, core wire count, or housing condition recognition, fixed-lens inspection provides finer and more accurate imaging.

Using CCD imaging to inspect coaxial cable shield braid cuts for stray filaments and to verify thorough braid folding after metal ferrule crimping offers significantly higher efficiency and reliability compared to traditional low-voltage contact testing methods.

FAKRA Harness Concentricity Inspection: The currently optimal method employs fixed-camera CCD imaging. Software calculates the distance between the center contact circle center and the outer conductor circle center from the captured image in real-time. If the distance conforms to the design standard, the product is marked as qualified; otherwise, it is marked as defective (NG) and automatically segregated by the line's final module. Different equipment manufacturers use similar calculation methodologies.

For FAKRA plugs, the center distance D between the center contact circle and the major outer conductor circle is typically ≤0.15mm. For FAKRA jacks, the center distance D between the center contact (or insulator) circle and the major outer conductor circle is also ≤0.15mm, and the area within a D=0.1mm circle around the jack's center contact must be free of foreign objects. The CCD system makes judgments based on these computed measurements, marking products exceeding limits as NG.

4. Defect Analysis for FAKRA Cable
Defects such as short circuits, open circuits, failed dielectric tests, insufficient center contact insertion depth, excessive concentricity deviation, shield wire protrusion (whiskering), or outer conductor deformation may occur during FAKRA harness manufacturing. Defects must be analyzed to identify root causes, enabling corrective actions on equipment and process controls to prevent batch defects and mitigate the risk of defect outflow.

X-RAY Non-Destructive Testing: Applicable for analyzing open or short circuits. Defective samples are examined using X-RAY. By adjusting the equipment to magnify or reduce specific areas, the fault point and defect type can be identified.

Industrial CT Scanning: For FAKRA outer conductors with thicker metal layers where X-RAY penetration is insufficient, industrial CT provides full-dimensional scanning of both harness ends. The 3D scan data is then analyzed via slicing software within the CT control system for precise internal defect identification.

Domestically, some companies have begun applying in-line X-ray inspection, primarily for defect analysis rather than 100% non-destructive screening. Our company pioneered using industrial CT for non-destructive defect analysis. For qualified products, industrial CT can perform dimensional measurements on sample groups alongside SI (Signal Integrity) signal transmission testing. This helps identify the optimal crimping and assembly parameters that yield the best SI performance, ensuring processes are set for optimal signal data.

Digital Microscope Inspection: A 100x-200x digital microscope can inspect for defects like nicked/cut shield wires, nicked/cut core wires, center contact crimp appearance, or inner insulation damage if X-RAY or CT is unavailable. For internal inspection without such equipment, a sample can be potted in resin, sectioned, and polished. The cross-section is then examined under a digital microscope to reveal the true state of the fault, facilitating root cause analysis and subsequent equipment or tooling improvements.

Conclusion
Numerous automated manufacturing and error-proofing technologies exist for FAKRA Cable. Equipment manufacturers must engage in thorough communication with end-users during the preliminary design phase. By researching and analyzing FAKRA automated solutions from domestic and international peers and incorporating robust error-proofing strategies, equipment debugging and mass production cycles can be significantly shortened, reducing trial-and-error probability.

Enterprises must select appropriate FAKRA automated line types based on internal and client requirements, product design specifications, and quality inspection criteria. Integrating these considerations with the company's raw material supply chain enables the establishment of efficient high-speed data harness manufacturing workshops, ultimately maximizing production efficiency and profitability.

About Aichie Tech

Aichie is a professional provider of connectivity solutions, focusing on the design and manufacturing of high-quality connectors, wires, and cable assemblies. It creates value for customers through technological innovation and exceptional quality, driving industry advancement. We produce high-quality and cost-effective Fakara Cable.

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