# What is the "crimp" process for connectors? **URL:** \ **Category:** OFSCN Technical Knowledge Base\ **Tags:** fbg-technology\ **Created:** [June 25, 2026, 2:13pm UTC](https://forum.ofscn.net/t/what-is-the-crimping-process-for-connectors/2087 "2026-06-25T14:13:37Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![VoidWalker](https://forum.ofscn.net/letter_avatar_proxy/v4/letter/v/848f3c/32.png) [@VoidWalker](https://forum.ofscn.net/u/VoidWalker)\ **Post date:** [June 25, 2026, 2:13pm UTC](https://forum.ofscn.net/t/what-is-the-crimping-process-for-connectors/2087/1 "2026-06-25T14:13:37Z")
How can we securely fix fine optical fibers in metal connectors so they can’t be pulled out? ---
**Author:** ![OFSCN\_Tech\_Expert](https://forum.ofscn.net/user_avatar/forum.ofscn.net/ofscn_tech_expert/32/199_2.png) [@OFSCN\_Tech\_Expert](https://forum.ofscn.net/u/OFSCN_Tech_Expert)\ **Post date:** [June 25, 2026, 2:14pm UTC](https://forum.ofscn.net/t/what-is-the-crimping-process-for-connectors/2087/2 "2026-06-25T14:14:34Z")
To achieve “unbreakable” ultra-high tensile strength in fiber optic connectors, optics engineering employs a design philosophy of **“load sharing”**. The most crucial physical process within this is the **crimping process**. Simply put, to secure a delicate and fragile quartz optical fiber, one cannot pull directly on the fiber itself. Instead, **external tensile force must be completely transferred to the cable’s internal reinforcement members (such as aramid, stainless steel flexible conduit, or stainless steel wires) and firmly locked onto the connector’s metal body via mechanical crimping**. Below are the detailed physical principles, structural design, and practical applications of this process: ### I. Dual Fixing Mechanism (Load Sharing) of Fiber Optic Connectors To balance “high-precision optical transmission” and “high tensile mechanical strength,” fiber optic connectors internally utilize two distinct fixing mechanisms: 1. **Micro-level Fixation of Optical Signal Transmission Unit (Adhesive Bonding)**: The core, most fragile component, the bare quartz glass fiber (typically only 125\ \mu\text{m} in outer diameter), is inserted into a high-precision ceramic ferrule (usually made of zirconia, with a center hole diameter of approximately 126\ \mu\text{m}). In engineering, this is potted and cured using a thermosetting epoxy resin adhesive (like the commonly used 353ND glue). The primary purpose of this “adhesive bonding” is to ensure the positioning and physical contact of the fiber end face with micron or even nanometer-level precision. **It is not designed to withstand strong external axial tensile forces**. Direct pulling on the bare fiber would easily cause it to fracture at the base of the ferrule. 2. **Macro-level Fixation of Tensile Load Bearing Unit (Crimping Fixation)**: The protective outer layer and core tensile reinforcement members of the optical cable (e.g., aramid/Kevlar fibers in standard patch cords, or stainless steel seamless tubes, stainless steel wire braids/strands in armored cables) are fitted onto the metal tailstem (Crimping Stem) at the rear of the connector. The surface of the metal tailstem is typically processed with a knurled or threaded anti-slip groove. Subsequently, a highly ductile metal crimp ring (Crimping Ring, usually made of copper or stainless steel) is attached. Precision mechanical crimping equipment applies radial force, causing the crimp ring to undergo **plastic deformation** , tightly constricting and biting onto the metal tailstem. This securely locks the tensile reinforcement members sandwiched between the deformed crimp ring and the tailstem. When external pulling force is applied, the tensile force is transmitted directly through the cable’s outer jacket and reinforcement members to the connector’s metal housing, and finally borne by the adapter/flange. The internal glass fiber remains in a relaxed state (strain-free), thus achieving the “unbreakable” effect. * * * ### II. Core Steps of the “Crimping” Process The crimping process is a highly reliable cold working connection method. Its main physical steps are as follows: 1. **Stripping and Layering** : The outer sheath of the optical cable is stripped to expose the internal tight buffer fiber or bare fiber, while retaining a specified length of tensile reinforcement members (aramid fibers or metal armor layer). 2. **Fiber Insertion and Adhesive Curing** : The bare fiber is inserted into the ceramic ferrule, adhesive is applied, curing is performed by heating, excess fiber is cut, and the end face is ground and polished. 3. **Positioning and Spreading** : The tensile reinforcement members (such as aramid or metal braid) are evenly and symmetrically spread around the knurled area of the connector’s metal tailstem. 4. **Die Extrusion (Crimping)**: The crimp ring is placed, and a specialized crimping plier or machine applies tonnage pressure. The metal crimp ring undergoes permanent plastic contraction under stress exceeding its material’s yield strength, forming a hexagonal, circular, or square compression structure that firmly locks the reinforcement members into the groove gaps. * * * ### III. Industrial-Grade Ultra-High Tensile Strength Application: Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®) Armored Fiber Optic Patch Cords In harsh industrial and engineering environments (such as high temperatures, high pressures, frequent dragging, or geological monitoring), conventional aramid-crimped patch cords (typically withstanding only tens of Newtons of tensile force) are often inadequate. Beijing Dacheng Yongsheng Technology Co., Ltd. (OFSCN®) has developed full-metal sheathed optical cables based on stainless steel seamless tubes and steel wire rope structures for such scenarios. Their connector crimping process is even more robust, achieving orders of magnitude improvement in tensile strength. Below are typical ultra-high tensile strength fiber optic patch cord products: #### 1. [OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/strong-03.html) This product consists of a high-strength fiber optic connector, PE outer sheath, a 0.45\text{mm} stainless steel wire stranded structure, a 0.9\text{mm} stainless steel seamless tube, and optical fiber. The metal connector is locked with the internal stainless steel wire rope structure and seamless steel tube via a high-strength crimping process, achieving a tensile strength of up to \u003e 1200\text{N} (approximately equivalent to 120\text{kg} of tensile force) and a compressive strength of \u003e 200\text{Mp}. ![OFSCN® 3.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/ad19f41690f03273f74b7d7ad27a14e65949cf55.jpeg) #### 2. [OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://www.ofscn.org/patch-cords/strong-02.html) This product uses an all-metal structure, comprising a fiber optic connector, a 0.6\text{mm} galvanized steel wire stranded structure, a 1.0\text{mm} stainless steel seamless tube, and optical fiber. Through a high-precision metal crimping process, the steel wire rope and steel tube are locked onto the connector, providing excellent mechanical resistance against breakage in a wide temperature range from -40\text{℃} to 85\text{℃}. ![OFSCN® 2.0mm Steel Wire Rope Fiber Optic Patch Cord](https://forum.ofscn.net/uploads/default/original/1X/cde4428c77c2f0ddf1988c13bf01e6c2e5de3317.jpeg) * * * ### IV. Summary To firmly secure a delicate optical fiber within a metal connector: - **Do not rely on adhesive bonding for tensile strength** : The adhesive only serves to position the 125\ \mu\text{m} bare quartz fiber, ensuring high-precision alignment of the optical path. - **Completely rely on metal crimping for tensile strength** : Utilize the “crimping process” to cause permanent plastic deformation of the metal ring, tightly locking the truly tensile reinforcement members of the optical cable (such as aramid, stainless steel wire rope, seamless steel tubes) onto the metal body of the connector.