USB Cable Manufacturing Process

Do you want to know how USB cables are manufactured before being tied with a twist tie? All USB cables are made through a similar process: connecting cable and connectors. In the following paragraphs, we’ll explain how USB cables are made and checked for quality before being packaged and shipped. 

The manufacturing process goes through different steps to ensure the quality, longevity, and smooth functioning of the USB cables. Keep in mind that this is a simple overview of the process while the actual production process undergoes more testing with attention to details.

Step 1: Making connectors

The manufacturing process starts with making connectors using circuit boards, shells, and plastic backing material. Connectors are being made using the semi-automated machine in which shells are injected into the machine, and then circuit boards are injected into shells. Finally, plastic backing pieces are attached to the connectors to make them ready for the next process.

Step 2: Cable manufacturing

Next, the cable is manufactured through different stages. The process starts with acquiring metal (copper/aluminum) wires by pulling the copper/aluminum rod through a series of synthetic diamond dies on the drawbench. During drawing, tremendous pressure is applied to a metal rod to form a thinner wire, and then annealing is done to make the wire soft and flexible.

Further, wisting and stranding of wires are executed using a proprietary formula to acquire a precise twist length. Stranded wires offer better flexibility and electrical performance. When the wires become soft and flexible, they are passed through an extruder for coating of insulating material, typically plastic, to obtain a cable, which is then cooled and coiled on reels.

Step 3: Cutting cables

Raw cables are then cut in appropriate lengths: 1m and 2m, using a high-speed cable cutting machine to satisfy the customers’ demands.

Step 4: Stripping cable jacket

Raw cables are made up of different wires which are braided and foiled to prevent electromagnetic interference. In this step, the outer jacket is stripped using a stripping machine to reveal the inner conductors so they can be linked to the connector properly. After stripping, the foil is trimmed, and the inner wires are twisted by machine.

Step 5: Soldering connectors to the cable

Soldering can be done using a semi-automated connector solder machine to attach the conductors with the connectors’ pinpoint properly. The conductor wires are arranged in a row in the lining panel to solder the connectors.

Step 6: Primary injection molding (internal molding)

The primary mold is applied to the connector using an injection molding machine to protect the soldered connections. Primary or internal molding is the first layer of protection that makes the cable more stable, strong, and durable. Soldered connectors are pressed with hard material (typically with plastic SGP) for protection.

Step 7: First electrical performance test

Once the primary molding is done, the USB cables are sent to the testing unit to check 100% electric conduction capability. An electrical test device is used to check the electrical efficiency of semi-finished products.

Step 8: External injection molding

After performance testing, the semi-finished products will be brought to the external injection molding machine to mold the final layer of protection. Solders are then hard-pressed with a PVC soft material (Poly Vinyl Chloride) for an extra layer of protection. When the overmold is cooled and hardened, the finished product will be sent to final testing.

Step 9: Second electrical performance test

The final electrical test ensures effective electrical performance by checking if the cables are working fine even after being pressed hard with a heated PVC material.

Step 10: Visual inspection

Next, a visual inspection is done to identify the overall appearance and flaws that might compromise the quality of the USB cable. Each cable has been visually tested on both sides to see if there’s any hole or puffiness due to excess heat, reshaping, or improper molding. Finally, the defective cables are cleared out.

Step 11: Logo printing for branding

When the product is perfectly ready, the brand’s logo is imprinted on the connector shell using a laser machine or silk print machine.

Step 12:Packaging

Lastly, when everything looks great, USB cables are twisted, tied, packaged, and sent to the warehouse for shipment.


Though the process of manufacturing USB cables seems similar, not all USB cables are made of the same quality. Some manufacturers don’t put the primary mold, and some conduct only one electrical performance test. So, if you are planning to wholesale this high in-demand product, make sure to find a reliable USB cable manufacturer.

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