Manufacturing process of multi-channel cable assembly

Abstract

The invention discloses a manufacturing process of a multi-channel cable assembly, and belongs to the technical field of cable assembly manufacturing. According to the method, the internal stress of a material is eliminated by selecting a foamed extruded obliquely-wrapped cable with the transmission rate consistency of 85% + / -1% and combining five times of temperature circulation, and grouping and phase matching are performed according to delta L < = + / -1% and delta phi < = + / -1.5 degrees and 26.5 GHz based on data of a vector network analyzer, so that the yield of batch production is greater than or equal to 92% for the first time. Experiments show that the method reduces the phase difference by 80% and improves the test efficiency by 75% compared with a traditional process, is especially suitable for high-density interconnection systems such as GJB599 III type cluster connectors and micro-rectangular mixed loading assemblies, and promotes the military / civil millimeter wave communication standardization process.

Description

Technical Field

[0001] This invention relates to the field of cable assembly manufacturing technology, and in particular to a process and method for controlling the length and phase consistency of cable assemblies for high-frequency, multi-channel interconnection systems, specifically applicable to 5G Massive MIMO, satellite communication, phased array radar, and high-end civilian interconnection systems. Background Technology

[0002] With the rapid development of technologies such as millimeter-wave communication and high-density phased arrays, multi-channel cable assemblies, as key components for signal transmission and distribution, have seen the consistency of their electrical length (represented by transmission phase) become a core indicator affecting the overall system performance. The traditional manufacturing process of multi-channel cable assemblies mainly faces the following technical bottlenecks: Insufficient basic material properties: Conventional solid polyethylene (PE) insulated cables have poor consistency in the velocity of propagation (VOP), typically fluctuating by only ±5%. This inherent inconsistency in the material directly results in inherent phase differences between channels exceeding ±5° even at millimeter-wave frequencies (such as 26.5GHz), even with the same physical length, severely restricting the synchronization of multi-channel signals.

[0003] Limitations of mechanical matching processes: Traditional processes rely on high-precision mechanical cutting to control the physical length, with tolerances reaching ±0.1mm. However, the internal stress generated in the cable material (especially the insulation layer) during processing and cabling gradually releases during subsequent storage, assembly, or temperature changes, leading to unpredictable physical length drift in the cable, with measured drifts reaching ±1.5mm. This time-varying instability renders the initial precision mechanical matching meaningless.

[0004] Inefficient testing and calibration: To compensate for material and process variations, a time domain reflectometer (TDR) is typically used to test the electrical length of each channel individually and perform manual fine-tuning calibration. This process is extremely time-consuming, often exceeding one hour for a single batch of products, and heavily relies on operator skills, making it unsuitable for large-scale mass production and resulting in high costs.

[0005] Lack of standardized mass production control methods: The above problems result in low batch pass rates (usually ≤65%) and large performance dispersion of cable assemblies produced by traditional processes, making it difficult to meet the stringent requirements of high-standard military and industry specifications such as GJB599 Type III, MIL-DTL-38999 series, and Micro-D mixed assembly for the consistency of multi-channel components. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a complete, mass-producible manufacturing process and phase matching method for multi-channel cable assemblies. This method, through the synergy of three core processes—material selection, stress relief, and intelligent grouping—fundamentally solves the defects of traditional processes, achieving the following objectives: in terms of production efficiency, it increases the average pass rate of batch production to over 92% (compared to ≤65% of traditional processes) and significantly shortens testing and calibration time.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A manufacturing process for a multi-channel cable assembly includes the following steps: S1, selecting foamed extruded bias-wrapped cables with a transmission rate consistency of 85%±1%; S2, subjecting the cables selected in S1 to temperature cycling treatment after they are unloaded, with a cycling temperature of -55℃ to +85℃ and a cycle count of 5 times; S3, grouping the cables after S2 treatment according to a physical length difference of no more than ±1%, and ensuring that the phase difference after assembly is no more than ±1.5° at 26.5GHz.

[0008] Furthermore, the foamed extruded bias-insulated cable includes: The conductor is made of silver-plated copper wire with a surface roughness Ra≤0.5μm; The insulating layer covering the conductor is made of foamed polyethylene with a foaming degree of 80% and a dielectric constant εr=1.5. The outer sheath covering the insulation layer is a slanted silver-plated copper wire braided layer with a braiding density of ≥98%.

[0009] Furthermore, the specific parameters for the temperature cycling process are as follows: Cooling phase: Reduce from room temperature to -55°C at a rate of 5°C / min; Low temperature holding phase: Hold at -55°C for 1 hour; Heating phase: Increase from -55°C to +85°C at a rate of 10°C / min; High temperature holding phase: Hold at +85°C for 1 hour; Repeat the above cycle 5 times.

[0010] Furthermore, the grouping phase includes: The S21 phase of the cable at 26.5 GHz was measured using a vector network analyzer. Based on the measured phase data and physical length data, the cables were grouped in multiple dimensions according to phase difference Δφ ≤ ±1.5° and length difference ΔL ≤ ±1%. The grouped cables were then marked using a laser coding system.

[0011] Furthermore, the manufacturing process is applicable to GJB599 type III cluster connector assemblies and micro rectangular mixed assembly assemblies.

[0012] Compared with the prior art, the present invention has the following beneficial effects: Source control, superior performance: By using high-consistency foamed cables, the fluctuation of transmission rate is controlled within ±1% from the source of materials, laying a physical foundation for high phase consistency and reducing the high-frequency phase difference by more than 80% compared with traditional materials.

[0013] Stable process and consistent dimensions: The unique temperature cycling pretreatment process actively and thoroughly eliminates the internal stress of the insulation material, solving the industry problem of cable physical length changing with time and usage environment, and ensuring the long-term stability of product performance.

[0014] Standardization and High Yield: This process has a clear flow and controllable parameters, making it easy to standardize and promote. It can steadily increase the batch production yield from around 65% of traditional processes to over 92%, significantly reducing quality costs.

[0015] Wide range of applications: This method is not only applicable to the GJB599 III type and micro rectangular components, but its core concept of "material-stress relief-electrical performance grouping" can also be extended to the manufacturing fields of other radio frequency coaxial cables and high-speed differential cables that require high consistency transmission. It has positive significance for promoting the standardization and modularization of military and high-end civilian communication equipment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the cross-sectional structure of the foamed extruded oblique cable selected for this invention.

[0017] Figure 2 This is a flowchart showing the process parameter settings for the temperature cycling pretreatment of the present invention.

[0018] Figure 3 This is a flowchart illustrating the implementation process of the grouping and phase coordination process of the present invention.

[0019] Figure 4 This is a schematic diagram comparing the transmission rate (VOP) distribution of a traditional solid PE insulated cable and the foamed PE insulated cable of this invention.

[0020] Figure 5 This is a schematic diagram of the phase consistency test curve of the cable assembly manufactured using the process of this invention at a frequency of 26.5 GHz.

[0021] The numbers in the diagram are: 1. Outer sheath; 2. Braided shielding layer; 3. Diagonal wrapping structure layer; 4. Foamed polyethylene insulation medium; 5. Silver-plated conductor core wire. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific production embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] Example: Manufacturing of a 24-channel GJB599 Type III bundled cable assembly 1. Material preparation: Custom-designed foamed extruded bias-insulated cables with a nominal transmission rate of 85% ± 1%. Each batch is sampled and tested to confirm compliance with requirements.

[0024] Cable structure inspection: The conductor is silver-plated copper wire with a diameter of 0.9mm and a smooth surface; the insulation layer is foamed polyethylene with an outer diameter of 2.50±0.02mm; the shielding layer is oblique braided with a density higher than 98%.

[0025] 2. Stress relief treatment: Cut the reel cable into the required length (e.g., 1 meter).

[0026] The wires were neatly placed inside the ESPEC PL-3KPH high and low temperature test chamber, which has a temperature control accuracy of ±0.5℃.

[0027] Set the temperature cycle program on the device control panel: cycle 5 times, each cycle includes dropping from 25℃ to -55℃ at 5℃ / min and holding for 60 minutes; then raising to +85℃ at 10℃ / min and holding for 60 minutes; finally returning to 25℃.

[0028] Start the program and complete all 5 cycles. After processing, let the cable sit at room temperature for 24 hours.

[0029] 3. Grouping and matching operations: Calibrate the vector network analyzer (VNA), set the center frequency to 26.5 GHz, ensure appropriate bandwidth, and select the S21 phase measurement mode.

[0030] Connect each of the temperature-cycled cables to the VNA port and record the S21 phase value (φ) and physical length (L) of each cable at 26.5 GHz.

[0031] Enter all data into the computer. Run the grouping algorithm: a) First, sort all cables by their physical length L, and group cables with a length difference within ±1% into a preliminary large group.

[0032] b) Within each initial large group, calculate the phase difference between each wire. Through optimized combination, form several final groups, ensuring that the phase difference Δφ between any two wires within each final group is ≤ ±1.5°. c) In this example, 500 wires were successfully divided into 25 groups (G01-G25), with 20 wires in each group, for assembling a 24-channel component. Using a laser marking machine, clearly engrave the group code on the sheath of each wire.

[0033] 4. Component assembly and verification: Select 24 wires from the same group (e.g., group G07) and assemble them onto a GJB599 III type 24-pin bundled connector.

[0034] After assembly, the entire 24-channel assembly was tested for S21 phase using a network analyzer.

[0035] Test results: According to statistics, among 10 modules (240 channels in total) manufactured using this process, the maximum phase difference between channels within the module was ±1.4° and the average phase difference was ±0.8° at 26.5GHz. The batch production pass rate (with phase difference ≤ ±1.5° as the pass criterion) reached 92.3%.

[0036] Efficiency vs. Cost: Traditional TDR calibration, wire-by-wire, takes approximately 12 hours to process 500 wires. In this invention, VNA rapid testing combined with automatic grouping reduces the total processing time to approximately 2.5 hours, improving efficiency by about 79%. Simultaneously, it avoids the manpower and material waste associated with manual calibration.

[0037] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for a multi-channel cable assembly, characterized in that, Includes the following steps: S1. Select foamed extruded bias-wrapped cables with a transmission rate consistency of 85%±1%; S2. After the cables selected in S1 are unloaded, perform temperature cycling treatment, with a cycling temperature of -55℃ to +85℃ and a cycle count of 5 times; S3. After the cables are treated in S2, group them according to the physical length difference of no more than ±1%, and ensure that the phase difference after assembly is no more than ±1.5° at 26.5GHz.

2. The manufacturing process of a multi-channel cable assembly according to claim 1, characterized in that, The foamed extruded bias-insulated cable includes: The conductor is made of silver-plated copper wire with a surface roughness Ra≤0.5μm; The insulating layer covering the conductor is made of foamed polyethylene with a foaming degree of 80% and a dielectric constant εr=1.

5. The outer sheath covering the insulation layer is a slanted silver-plated copper wire braided layer with a braiding density of ≥98%.

3. The manufacturing process of a multi-channel cable assembly according to claim 1, characterized in that, The specific parameters for the temperature cycling process are as follows: Cooling phase: The temperature is reduced from room temperature to -55°C at a rate of 5°C / min; Low-temperature holding phase: Hold at -55℃ for 1 hour; Heating phase: Temperature increases from -55℃ to +85℃ at a rate of 10℃ / min; High-temperature holding phase: Maintain at +85℃ for 1 hour; Repeat the above cycle 5 times.

4. The manufacturing process of a multi-channel cable assembly according to claim 1, characterized in that, The grouped ligands include: The S21 phase of the cable at 26.5 GHz was measured using a vector network analyzer. Based on the measured phase data and physical length data, the cables were grouped in multiple dimensions according to phase difference Δφ ≤ ±1.5° and length difference ΔL ≤ ±1%. The grouped cables were then marked using a laser coding system.

5. The manufacturing process of a multi-channel cable assembly according to claim 1, characterized in that, The manufacturing process is applicable to GJB599 type III cluster connector assemblies and micro rectangular mixed assembly assemblies.

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