Views:41 Author:Site Editor Publish Time: 2021-10-26 Origin:Site
The design content of pluggable terminal blocks includes the overall structure design, parts structure and material selection, stamping parts plating method, assembly process, the product in the package of anti-fluff structure. The pluggable terminal block structure design is the main terminal design, the two points to be connected between the design of a suitable terminal structure and then designed to connect all the other parts of the plastic reliably. The choice of iron feet or shell design allows for a more rational connection to the plastic. The design of the finished connector must take into account the offset of the centre of gravity, the connector warp, the position of the SMT nozzle and the size of the pad.
The design of pluggable terminal block: common terminal designs include contact area, cantilever, barb, solder foot and strip and plating designs. The contact area design, general contact method has three contact methods: face, line and point. Among them, the point contact method is the most reliable. Mobile phone connectors in order to ensure contact reliability, the contact area in the terminal through the convex package. In addition, attention should be paid to the contact area to choose the appropriate bending radius, the smaller the bending radius, the more likely to cause cracks. The smaller the bend radius, the more likely it is to cause cracks. In addition, the contact area of the terminal must not have a burr to avoid affecting the contact reliability with the connected device.
Solder foot design: Consider the exclusion of the seesaw phenomenon to ensure the common surface of the terminal requirements, all solder foot exposed plastic bottom surface is generally 0.05mm, solder foot and the surrounding plastic to retain the gap to prevent the short circuit caused by the creeping tin phenomenon. The design of the strip should mainly consider the impact on stamping, plating, assembly and cost, so the stamping, plating and assembly should be consulted, or the stamping engineer should decide on the layout of the strip under the premise of meeting the plating and assembly requirements. The selection of the strip hole diameter should take into account the requirements for standardisation of the assembly cut-out or automated assembly. In the case of terminals that are easily deformed by pressure during packaging, protective feet are added to prevent deformation of the terminals. In order to meet the requirements of strip removal in production, the connection between terminal and strip is often pre-broken.
Plastic design: the role of plastic is to fix the terminals and maintain insulation between them. Due to the limitations of the filling properties of the plastic material, the plastic wall thickness of 0.2mm or less, filling will be more difficult, the larger the area of the thickness, the more likely it is to occur unsaturated phenomenon. The insulation resistance and voltage resistance of the connector is mainly determined by the thickness of the plastic material between the terminals, and in the event of a non-filling situation between the terminals, the terminals are likely to break (a serious quality problem). The wall thickness of the plastic between the terminals should be at least 0.25 mm and the length of the thin-walled section should be minimised. The structural design of the plastic part should be designed to minimise the use of unnecessary sliders, consult a moulding engineer to assess the rationality of the structure. The thin wall (0.3mm or less) that often occurs on both sides of the plastic part due to size constraints should be thickened, otherwise it will easily become unfilled or too low strength and be damaged during injection moulding and packaging and turnover. The plastic of the connector to be SMT-mounted must have a place for the vacuum nozzle on the uppermost surface of the connector in its actual state of application, and the surface quality of this area must be such that it does not lead to vacuum leakage.
Dimensioning: how to mark the dimensions and the tolerance value of the size of the appropriate, not the designer or mark the size of the person said, is the requirements of the product (function, process requirements, process capability) to decide. The key dimensions for the finished product are usually the dimensions that are more important to the customer such as the contact height of the terminal, the height at the card, the co-planarity, or some other dimensions that the customer specifically requires to be controlled; there are also some dimensions that are more important in production control, such as the depth of the terminal press-in. The design also takes into account assembly, plating, automatic production and other factors.