The Entire Process Of Making Terminal Blocks: From Materials To Finished Products
As the core component of electrical connections, the production process of terminal blocks includes four major steps: material selection, precision machining, surface treatment, and assembly testing. Each step must strictly follow the process standards to ensure stable performance.
1、 Material selection and pretreatment
The basic material is mainly copper alloy, such as purple copper (T2) with excellent conductivity for conductors, wear-resistant brass (H62) for screws and wire frames, and high elasticity phosphor bronze (C5191) for spring contacts. Aluminum (6061/6063) is used in lightweight scenarios. Surface treatment requires enhanced performance through electroplating: tin plating (3-8 μ m) for oxidation resistance, silver plating (0.5m Ω contact resistance) for high-frequency scenarios, and gold plating (0.2-0.5 μ m) for medical/aerospace applications. Engineering plastics are selected as insulation materials, such as PA66 (nylon 66) with flame retardant grade UL94 V0 for universal shells, and PBT (polybutylene terephthalate) with hydrolysis resistance for humid environments.
2、 Precision machining of metal components
Stamping forming: High speed punching machines (600 times/minute) are used to process contact pieces, with an accuracy of ± 0.01mm. Complex structures such as ball joint terminals need to be rolled in three steps to ensure stable angles.
Turning machining: CNC lathe machining threaded terminals, with surface roughness controlled within Ra0.8.
Electroplating process: The process includes degreasing → pickling → activation → pre nickel plating → plating the main layer (tin/silver/gold) → passivation → drying, which takes 30-60 minutes. The environmentally friendly process adopts cyanide free electroplating (such as citric acid gold plating) and trivalent chromium passivation, which complies with RoHS standards.
3、 Injection molding of insulation components
Insert injection molding: Integrating metal conductors with plastic to reduce assembly processes. For example, the bending modulus of PA66+30% fiberglass reinforced material is increased to 10GPa, and the temperature resistance reaches 265 ℃.
LCP application: Liquid crystal polymer (LCP) has a temperature resistance of 300 ℃ and a dimensional accuracy of ± 0.02mm. It can replace metal for micro terminals and has a molding cycle of only 20-40 seconds.
4、 Assembly and Testing
Ultrasonic welding: Weld metal and plastic components at a frequency of 20kHz for 0.5 seconds to ensure airtightness.
Laser marking: The marking is resistant to over 1000 washings and meets traceability requirements.
Performance testing: The standard wire tester is used to test the voltage resistance (≥ 1000V), impedance (<1m Ω), short circuit and other indicators. The insertion and extraction life should reach more than 5000 times.
5、 Typical application scenarios
Industrial control: PBT shell+silver plated copper alloy, resistant to vibration/chemical corrosion.
Automotive electronics: PA66+tin plated phosphor bronze, with a temperature resistance range of -40 ℃~125 ℃.
Photovoltaic system: LCP+nickel plated aluminum conductor, UV/high temperature resistant, with a service life of over 10 years.
From material selection to finished product delivery, the production of wiring terminals requires the integration of multidisciplinary technologies such as material science, precision machining, and surface engineering, ultimately achieving high-performance indicators of contact resistance<1m Ω and insulation resistance>1000M Ω.
