Technical Topic: Process Design Planning for Plastic Terminal Blocks

As a kind of connector, plastic terminal block is an important component in the electrical industry. It plays an irreplaceable and non-negligible role. The design of terminal block is particularyly important because when in maintenance engineers firstly check the interface, that is, terminal block.

Product design is comprehensive which focuses on product standard, material, structure, plating, certification, mold, and manufacturing process. And terminal blocks are no exception.

Product standard plays a general guideline. Almost all considerations of copper bar terminal blocks are based on it. Our terminal design standards are based on UL and CSA firstly, but some electrical parameters can also be based on other standards, such as high and low temperature test.

The choice of material directly affects the performance of the  product and is the key to design. Take plastic as an example, if the design is based on UL94 and V-0 flame retardant, it is necessary to check the technical parameters of each material physical property table carefully whether it can meet the standard, such as whether the impact withstand voltage and aging resistance test can be passed.

In terms of hardware materials, the selection of TP‘s tabletting material is particularly important because this tabletting must meet a certain electrical conductivity (current) and also have a definite elasticity. It has brought difficulties to our engineers in selecting materials, and that is precisely the trend that manufacturers of connecters are pursuing in elastic components. Many manufacturers of hardware are working hard in this regard. Electrical conductivity directly affects temperature rise and contact resistance. The elasticity are related to the chemical elements, elastic modulus, hardness, and tensile strength of the material. Electrical conductivity directly affects temperature rise. The contact resistance and the elasticity are related to the chemical elements, elastic modulus, hardness, and tensile strength of the material. The elastic modulus is selected based on the fourth strength theoretical formula of material mechanics. The greater the conductivity of the material, the smaller the contact resistance and the lower the temperature rise. The relationship between the insertion force and the contact resistance forms a quadratic curve. The contact resistance is mainly divided into compression resistance, film resistance and volume resistance (the resistance of the conductor itself) ).

Terminal blocks apply to connect wires easily. It is actually a piece of metal sheet enclosed in an insulating plastic. There are holes at both ends for inserting the wires and screws for fastening or loosening wires. For instance, two wires sometimes need to be connected and sometimes disconnected. At this time, you can use terminal blocks to connect them, and it can be disconnected at any time, without having to weld them or twist them together. It is very convenient and suitable for a large number of wire interconnections. In the power industry, there are special terminal strips and terminal boxes, all of which are terminal blocks, single-layer or double-layer, for current or voltage, regular or can be disconnected, and so on. A certain crimping area is to ensure reliable contact and withstand sufficient current.

With the development of industrial automation and industrial control requirements are becoming more stringent and precise, the use of terminal blocks has gradually increased. With the development of the electronics industry, terminal blocks are used more widely and category becomes more. In addition to PCB board terminals, the most widely used are hardware terminals, nut terminals, spring terminals, etc.