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【 Popular Science】 Five Connection Methods of Wiring Harness Terminals, Core Advantages and Standardized Process Specifications！
- Categories:Industry News
- Author:Guangdong Deke Electric Co., Ltd.
- Origin:https://www.de-ke.cn/
- Time of issue:2026-07-07 15:42
- Views:
【 Popular Science】 Five Connection Methods of Wiring Harness Terminals, Core Advantages and Standardized Process Specifications！
- Categories:Industry News
- Author:Guangdong Deke Electric Co., Ltd.
- Origin:https://www.de-ke.cn/
- Time of issue:2026-07-07 15:42
- Views:
Wiring harness terminals serve as critical connection nodes for power and signal transmission. Different connection processes directly determine the mass production efficiency, long-term electrical stability, as well as vibration and temperature resistance of wiring harnesses. The five mainstream industry processes include soldering, crimping, wire wrapping, IDC insulation displacement and screw locking.
In accordance with IPC/WHMA-A-620 and SAE wiring harness standards, Guangdong Dekor Electric systematically sorts out the process principles and applicable scenarios of each connection type. It elaborates on the comprehensive advantages of the most widely adopted crimp connection and the standardized full-process process control requirements, providing reference for hardware R&D engineers, wiring harness process specialists and quality personnel in terminal selection and production control.
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DEKEELEC—— —— —— —— —— —— —— —— —— —— —— —— —— —— —— ——
I. Classification and Basic Introduction of Five Major Wiring Harness Terminal Connection Processes
1. Soldered Connection
A traditional industry connection process that relies on molten solder to wet the contact surfaces of wires and terminals and form a metallurgical bond for electrical conduction. The core acceptance criterion requires complete fusion between solder and copper conductors without cold solder joints, voids or partial wetting areas. It is mostly applied to small signal terminals on PCB boards and wiring for low-current static equipment. Limitations: High temperature may damage wire insulation; manual soldering yields inconsistent quality; solder joints tend to crack under vibration, so long-term use in high-current and vibration-prone automotive environments is not recommended.
2. Crimp Connection (Mainstream Standard Process in the Industry)
Mechanical pressure is applied to terminal barrels via dedicated tools to induce plastic flow of metals and wires, creating an air-tight cold-welded joint. Compliant crimps contain no air gaps and deliver far superior resistance to vibration and thermal cycling compared with soldered joints. This process is mandatory for high-power wiring harnesses in new energy, automotive and industrial control fields, forming a permanent one-time connection that cannot be disassembled and reused after crimping. Crimping pliers or fully automatic crimping machines of matching specifications must be adopted, and terminal barrels shall be selected strictly according to wire gauge.
3. Wire Wrapping Connection
Stripped wires are tightly wrapped around angular metal posts, and the angular edges cut the conductor surface to achieve metal-to-metal contact. It is mainly used in communication cabinets and low-voltage signal terminal blocks, only compatible with solid thin wires, and rarely adopted for high-current or stranded flexible harnesses.
4. ID Insulation Displacement Connection (IDC)
Wire stripping in advance is unnecessary. U-shaped metal spring blades pierce insulation directly to clamp copper conductors and complete termination in one step. Its advantages lie in simplified working procedures and compatibility with automated ribbon cable assembly; its disadvantage is poor long-term vibration resistance, and it is only used for low-power internal signal ribbon cables of equipment.
5. Screw Clamping Connection
Conductors are compressed by screws to establish electrical continuity, commonly seen in ring, fork pre-insulated terminals and DIN rail terminal blocks. It features easy assembly and disassembly for convenient after-sales maintenance. However, screws are prone to loosening under prolonged vibration, so spring washers shall be fitted and torque retesting performed regularly.
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II. Eight Core Comprehensive Advantages of Crimp Connections
Crimping is currently the preferred process for automotive, industrial and new energy wiring harnesses, boasting irreplaceable strengths compared with other connection methods:
1. Excellent adaptability for mass production Compatible with manual ratchet crimpers, semi-automatic and fully automatic crimping machines, applicable to both small-batch and mass production.
2. No risk of high-temperature damage The whole process is mechanical forming at ambient temperature, avoiding scorching or discoloration of wire insulation.
3. Hidden risks of solder joint defects eliminated Typical soldering defects such as cold solder joints, incomplete fusion and solder voids are completely avoided.
4. Terminal elastic structure remains intact No high-temperature annealing damage occurs, so the clamping force of terminal springs stays stable long-term.
5. Eco-friendly and safe production No solder or flux required, eliminating heavy metal fumes and volatile irritating solvents.
6. Wire flexibility preserved No rigid solder joints at the connection point, so the harness resists breakage under bending.
7. Stable process consistency Standardized dies and fixed pressure output deliver uniform electrical and mechanical performance across batches.
8. Superior durability under harsh working conditions The airtight joint blocks moisture and oxidation, resulting in minimal resistance fluctuation under temperature cycling and continuous vibration.
DEKEELEC—— —— —— —— —— —— —— —— —— —— —— —— —— —— —— ——
III. Standardized Full-Process Process Requirements for Crimp Connections
To achieve stable and qualified crimp quality, strict control must be implemented across three key stages: tool matching, wire stripping pretreatment and crimp forming, all carried out in accordance with IPC wiring harness specifications.
(I) Matching Specifications for Tools, Terminals and Wires
The crimper die, inner diameter of the terminal barrel and nominal cross-sectional area of the wire must correspond one-to-one. It is forbidden to crimp thin wires with oversized terminals or force thick wires into undersized terminals, so as to prevent under-crimping or over-crimping.
(II) Mandatory Specifications for Wire Stripping Pretreatment
1. Graded standard for stripping length
- For wire gauge ≤ 1 mm²: stripping length = terminal barrel length + 1 mm
- For 1 mm² ＜ wire gauge ≤ 10 mm²: stripping length = terminal barrel length + 2 mm Ensure all conductors fully enter the crimp zone without excessive exposure that may lead to short circuits.
2. Conductor integrity requirements The depth of the stripping blade shall be precisely controlled to avoid cutting or damaging individual copper strands. The proportion of broken strands shall be lower than the industry allowable limit. After stripping, twist the stranded wires gently along their original twist direction to prevent strand scattering. No insulation debris, oil stains or impurities shall remain on the conductor surface.
(III) Key Control Points for Crimp Forming Process
1. Place the wire centrally into the terminal barrel, with all copper strands fully contained within the crimp zone; conductors shall be clearly visible through the inspection window of closed barrels.
2. Compliant gap between insulation and crimp zone: gap ＜ 1 mm for wires ≤ 1 mm²; gap ＜ 2 mm for wires ranging from 1 mm² to 10 mm².
3. Crimp indentation shall be centered with depth calibrated to the standard crimp height, without offset or damage to the front and rear structures of the terminal.
4. Keep the wire coaxial with the terminal throughout crimping to avoid unilateral stress and partial insufficient crimping caused by tilting.
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IV. Core Quality Inspection Criteria for Crimp Connections
Mechanical pull-out strength serves as the core benchmark for judging crimp qualification. National and ISO standards specify minimum pull force thresholds for terminals of different wire gauges. The crimp indent shape, crimp depth and crimp position all exert a direct impact on pull-out performance:
1. Insufficient crimp depth: Incomplete wrapping of conductors results in inadequate pull resistance, and the entire wire may pull out under load.
2. Excessive crimp depth: Copper strands are crushed and fractured, leading to wire breakage under tension and continuous rising contact resistance during long-term service.
3. Offset crimp indent: Uneven unilateral stress easily triggers intermittent open circuits under vibrating conditions. Regular crimp cross-section metallographic testing and destructive pull force sampling inspections shall be performed during mass production to guarantee uniform compression of internal copper strands without voids or fractures.
DEKEELEC—— —— —— —— —— —— —— —— —— —— —— —— —— —— —— ——
Each of the five terminal connection processes has its own applicable scope. Crimping is the preferred process for high-power, automotive and long-term vibration-resistant wiring harnesses; IDC insulation displacement connection is suitable for mass automated ribbon cable assembly; screw clamping fits equipment requiring frequent on-site maintenance; soldering can be adopted for static small PCB signal terminals. To achieve stable crimping results, it is mandatory to properly match tools, standardize wire stripping procedures, adopt standardized crimping parameters, and implement regular pull force and cross-section inspections.
All series of pre-insulated and bare terminals from Guangdong Dekor Electric are compatible with standardized crimping processes. We can provide supporting crimping parameters, pull force test standards and process control solutions, catering to wiring harness supporting demands across automotive, energy storage, industrial control and consumer electronics sectors. Feel free to contact us for inquiries about terminal selection and process debugging issues.
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