Requirements for crimping of automotive connection terminals

Requirements for crimping of automotive connection terminals Today, with the rapid development of the automotive industry, automotive electrical systems are becoming more and more prosperous. Various types of electrical appliances with different characteristics are constantly emerging in automobiles, and their performance requirements for automotive wiring harnesses are also getting higher and higher. Automobile connection terminals occupies an important position in automobile wiring harnesses and vehicle electrical systems, so mastering the characteristics and usage requirements of the terminals plays an important role in improving the performance of automobile wiring harnesses. However, in the use of automobile connection terminals, the most important and most problem-prone part is the permanent connection between the wire and the plug or socket. Most of the permanent connections between terminals and wires in automotive wire harnesses are realized by crimping. This paper analyzes the specific performance requirements of the terminal in crimping and several factors that affect the crimping of the terminal, and proposes a method to improve the crimping performance. 1 Terminal crimping 1.1 Definition of crimping crimping is a very important process in the production of automotive wiring harnesses. It is an effective and reliable conductor connector between wires and plugs or sockets. Crimping is an important process in which raw materials (terminals, wires and sealing rings) are combined with copper wires and terminals through the jaws of the crimping die to produce wire harness components (circuits). 2.2 Electrical properties of terminal crimping The electrical properties of terminal crimping mentioned here are actually the crimping resistance of terminal crimping. After crimping, we must ensure that the terminal has a low and stable electrical impedance. When testing the crimping resistance, at least 10 sample wires must be connected to the wooden test bench in an orderly manner. 2.3 Physical properties of terminal crimping After crimping the terminal, ensure that there is no problem with the physical properties of the terminal to insert and wear the sheath, such as profile, wire stripping, conductor end, insulation crimping, bell mouth, etc. 2.3.1 Crimping profile We know that the evaluation indicators for the mechanical and electrical performance of the automotive connection terminal crimping are the tensile force and voltage drop, so how can we ensure that the crimped terminal can easily pass the mechanical and electrical performance tests? We have introduced a very important tool of profile analysis. Failure of the mechanical and electrical performance tests may be due to uneven distribution of copper wires, incomplete closure of the crimping wings, voids, and bottoming of the crimping wings. Therefore, the profile analysis is only a tool. Its purpose is to find out the reasons for the failure of mechanical and electrical properties. Mechanical and electrical properties are what we ultimately want to guarantee. 2.3.2 Wire stripping requirements. Special wire stripping tools must be used for stripping. Irregular insulation layer cuts, insulation layer damage, incomplete insulation peeling, conductor cuts or missing, wire running, loose conductors, and excessive conductor distortion are not allowed. happened. If the conductor of the wire is silver-plated, it is necessary to touch the conductor of the wire by hand during the stripping process, and it must be operated with gloves. 2.3.3 Conductor end After crimping, the end of the conductor should protrude out of the front plane of the conductor crimping area, but the maximum length is 1 mm. The protruding part of the conductor is not allowed to affect the plug-in function, self-locking function or screw fixation of the terminal work area Features. For socket type terminals such as wire connectors, the end of the conductor must not enter the screw-fixed circular surface area. 2.3.4 Terminal working area After the terminal is crimped, the terminal working area must not be damaged or deformed. After crimping, the terminal working area must still meet the size and performance requirements of the terminal drawing for the working area. 2.3.5 The crimping of the bell-mouth conductor must be closed in the crimping area. The rear bell mouth is required, and the width of the rear bell mouth is not allowed to be greater than the width of the insulation crimping. The size of the front bell mouth is smaller than the rear bell mouth. 2.3.6 The cutting edge should still be visible after crimping, but the length cannot be longer than the thickness of the terminal material, and the maximum should not exceed 0.5 mm. The material edge and material edge burrs must not affect the terminal penetration into the sheath or the terminal's mating function. 3 Factors that affect terminal crimping The main factors that affect the quality of terminal crimping are: the characteristics of the terminal itself, the characteristics of the wire used for crimping, and the nature of the crimping equipment. 3.1 The influence of terminal characteristics on crimping The quality of terminal crimping is affected by the material, plating, shape, feature size and crimping range of the terminal. 3.1.1 The influence of terminal material and plating on crimping The terminal material is generally copper alloy. We take the most commonly used copper alloy as an example: Qsn6.5 -0.1 (tin bronze alloy) and H65 (brass alloy) . Table 3 shows the performance comparison of the two materials. The common plating layers of terminals are tin plating, silver plating, and gold plating. After the copper material is electroplated, the material becomes relatively hard. In actual production, the performance of crimped terminals will be better than that of unplated terminals. 3.1.2 The influence of terminal size and crimping range on crimping The design size of the terminal and the size of the crimping tail play a decisive role in crimping. As shown in Figure 9. How much wire the terminal can press is determined by the cross-sectional area of u200bu200bthe terminal's tail and the characteristics of the tail (chamfered teeth, knurling). The cross-sectional area of u200bu200bthe terminal tail is determined by the thickness of the terminal, the fin length and the fin width of the terminal crimping fin. The size of the wire that the terminal can press depends on how large the square of the copper wire can be enclosed by the inner circumference of the terminal's tail! Therefore, the larger the fin length and width of the terminal crimping fin, the larger the crimping range. The thickness of the terminal has a great influence on the crimping of the terminal. The greater the thickness, the larger the crimping range. The chamfered teeth of the crimping fin and the knurling of the crimping fin play an important role in the tight crimping of the automobile connection terminal.