For high-speed transmission lines, impedance, attenuation, delay, delay difference, near-end crosstalk, etc., are all important transmission indicators. When producing high-speed cable products, material selection, process parameters and process control, and specialized laboratory testing of electrical parameters all play a key role.
1. Insulated core extruding
Insulated core is the basis of cable production, and the quality of the insulated core has a crucial impact on subsequent processes. The insulated core is made of physical foamed polyolefin material, with skin-foam-skin insulation structure through SFS Insulation Tandem Extrusion Line. The insulated core pores are of uniform size and evenly distributed, with high mechanical strength and insulation adhesion. In this process, the production equipment is required to have online monitoring and control functions to ensure that the insulated core is uniform and stable. The controlled process parameters include the diameter, water capacitance, concentricity, etc.
2. Two insulated core twisting and wrapping
The two insulated core and the ground wire are assembled together, and a layer of aluminum foil and a layer of self-adhesive polyester tape are wrapped on the outside to shield the wire pair and stabilize the structure of the wrapped core wire. This process has an important impact on the performance of the wire, including impedance, delay difference, attenuation, etc. Therefore, it must be produced strictly according to the process requirements and the electrical performance must be tested to ensure that the wrapped core wire meets the requirements.
3.Cabling
Cabling is to gather the wrapped cores together through a cabling machine, and wrap them with a layer of polyester tape and a layer of aluminum foil Mylar tape on the outside to shield the wire pairs and stabilize the structure of the cable core wires. The cabling process affects the overall performance of the cable, so the consistency of each wrapped core wire must be strictly controlled during the production process, and the electrical properties such as impedance, delay difference, and attenuation must be tested to ensure that the cable core wires meet the requirements.
4.Braiding
Braiding is to cover a metal shielding layer on the outside of the cable core wire through a braiding machine to enhance the shielding effect of the wire and make the wire have good performance. The density and material of the braiding will affect the shielding effect. The braiding process will also have a certain impact on the overall performance of the wire, so it is necessary to control the wire tension.
5.Sheathing extruding
The outer sheath is a layer of polyolefin material that is extruded on the outside of the braided or cabled wire by an extruder to protect the wire. This process will also have a certain impact on the overall performance of the wire. The tightness of the outer sheath will also affect the appearance of the wire and the customer's finished product processing, so it is necessary to control the tension, cable arrangement, extrusion method, etc.
6.Finished product test
After the finished product is completed, the electrical performance test is required to determine whether the wire meets the requirements, so the accuracy and precision of the test data are very important. The test items mainly include impedance, attenuation, delay difference, delay, etc.
Summary
High-speed transmission lines basically use silver-plated copper wire as conductor. The wires use a pair shielding and total shielding structure, which has a good shielding effect and prevents external interference to the signal. The line pairs of high-speed transmission lines adopt a parallel structure, so they have low latency difference and can achieve high-frequency broadband transmission. The wire specifications range from 30 to 24AWG, with 2P, 4P, 8P and other structures, which can meet a variety of application occasions.