Why USB 3.1 Type-C Isn’t on More Cases & Cable Factory Tour in Dongguan, China

By Published March 25, 2019 at 11:25 pm

This is the article version of our recent tour of a cable factory in Dongguan, China. The factory is SanDian, used by Cooler Master (and other companies you know) to manufacture front panel connectors, USB cables, Type-C cables, and more. This script was written for the video that's embedded below, but we have also pulled screenshots to make a written version. Note that references to "on screen" will be referring to the video portion.

USB 3.1 Type-C front panel cables are between 4x and 10x more expensive than USB2.0 front panel cables, which explains why Type-C is still somewhat rare in PC cases. For USB 3.1 Gen2 Type-C connectors with fully validated speeds, the cost is about 7x as expensive as the original USB3.0 cables. That cost is all because of how the cables are made: Raw materials have an expense, but there’s also tremendous time expense to manufacture and assemble USB 3.1 Type-C cables. Today’s tour of SanDian, a cable factory that partners with Cooler Master, shows how cables are made. This includes USB 3.1 Type-C, USB 2.0, and front panel connectors. Note that USB 3.1 is being rebranded to USB 3.2 going forward, but it’s the same process.


This factory is located in Dongguan, China, and is where Cooler Master sends its requirements for cables made for its cases. As you’ll see in this video, making a cable is more complicated than it may originally seem.

cable factory machine 1 0

cable factory machine 1 1

The first machine we saw is semi-automated with human operator oversight for quality control at the end of the line. Prior to arrival here, this factory’s other location hand-makes the inner wiring of the cable and houses it, at which point it’s passed to this factory. At the time we visited, this machine was being used to make case front panel connectors, but the next group of machines and workers will be working on USB 3 cables. This first machine uses a reel of cabling in one giant, uncut run, then uses motorized arms that move up and down to stretch the cable as it gets pulled through the machine. These keep the cable tension appropriate during the cutting process. As the cable is fed into the machine, it is first cut by the cutter moving left-to-right, then stripped at the cable ends so that the pins can be applied. The machine pulls the cable in, cuts and strips it, pulls it in again, and then presses the pinout or cable end onto the cable. The pins are fed in on what amounts to an ammo belt, then press fit onto the cable ends. At this point, the machine spits the cable out and an operator quality checks the cable. Fewer than 1% of cables fail quality inspection, and any cables that are rejected as poor quality in this factory can get fixed by the factory to minimize waste.

cable factory bundle usb2

Moving upstairs, we get to the room currently manufacturing USB cables for multiple partner companies, including for Cooler Master’s front panel Type-C connectors. This factory manufactures about 22,000 to 25,000 USB cables per day. If you count front panel connectors and other relatively simple IO cables, unlike the complex USB cables, then the factory manufactures a total of about 80,000 cables per day. That’s about 2.2 million cables per business month, for anyone doing the math. Most of these factories run 5-6 days per week and keep 8-hour shifts, with overtime offered for workers who push to 10-12 hours. Some factories in our tours also offer double-time pay for working on weekends.

IO cables are easy to make. Like we saw in the previous machine, being flat means that they’re easy to automatically cut, strip, and press into the pin. It’s the round USB cables that are difficult, where much of the process remains manual labor.

cable factory cardboard box

The first step of making a USB cable is to cut the cable from the reel, but a different machine is used due to the complexity of managing round cables. Workers manually cut the external housing at a semi-automated station, where the cutting machines are contained within cardboard boxes because they easily collect the cable waste. Cable ends are cut two at a time, then stripped to expose the bare wire at the end. As these boxes fill, workers empty them and continue to the next step. A machine is used to press-fit pins to the end of the cables when necessary, like for USB2.0 headers or HD Audio cables. Operators next manually add heatshrink toward the cable end, leaving the heatshrink loose until done splaying and arranging the wiring.

The next step is to quality check the cable and ensure the crimping location and quality are both good. Pin insertion into housing is also checked to ensure no unwanted bends, with internal cabling checked to ensure the right wire lengths. Several more quality checks will happen along the way, all of which help find bad cables before getting to the final QC step. This helps reduce waste, as nearly 100% of bad cables caught early in the process can be fixed in-house.

Heat guns are built into the table for operators to shrink the sleeving once the cables are ready for next steps. It only takes a couple seconds of exposure to seal the heatshrink.

cable factory laser cut

After the cables are cut from the initial spool, they’re brought in to a laser cutter to remove internal protective shielding. Here, a technician manually secures the cables to a tool that holds them in place, eventually inserting groups of cables into a laser cutter to dice the protective coating at the ends. The operator then removes the protective sleeving, thus preparing the cable for the assembly line that follows.

For USB2.0 or HD Audio connectors, the next step would be to add the connector header to the end of the cable, case-side, and then plug the cable into a custom continuity tester that’s built into the table. The technician plugs each side in and checks to ensure the wires are continuous down each pin. If a cable fails, it is fixed prior to the next stage.

cable factory splay cables

We’re focusing on Type-C, though, so we’ll travel to the next station for this. At this point, connectors haven’t been applied to Type-C cables just yet. Although USB2.0 and HD Audio connectors would already be near the end of the process, the Type-C cables are just beginning. The next step is for the cables to travel to a manual station where the internal wires are splayed and separated to get wired into headers. For Type-C cables, this process is extremely slow and time consuming, as the complexity of the wiring bogs-down the process. One worker can only route the wires for 6 cables per hour, illustrating precisely why it costs so much to add USB Type-C to cases. If the cable isn’t Type-C, this process is much faster and the cable can go straight to soldering. The cable ends aren’t very exposed yet for Type-C, so the worker tapes the cables to secure the correct order for the next station.

cable factory white plastic

The next step is optional. Cooler Master pays extra to have white cable molding added half-way down the wire, which strengthens the cable to survive more connection cycles than a cable without this plastic support. This is added by seating the cable into a machine to press-fit the cable end, so the process is semi-automatic, like most the other. It requires human operation, but uses a machine to ensure a secure fit. The same machine cuts excess wiring at the end and exposes the wires, almost guillotine-like in fashion.

cable factory solder lake

cable factory solder flow

Immediately after this step, the wires at the cable end are dipped into a pool of hot solder sitting atop a hotplate. Depending on the project, the solder can be kept at upwards of 250 degrees Celsius, with PCBs running through solder machines demanding the most heat. It’s in the next step that the Type-C connector and its accompanying PCB are added to the cable end. The PCB is connected to the wires that were dipped into the solder just before.

Next, the USB cables are plugged into a custom-made carrier with the optional white housing installed, as this is a Cooler Master cable spec, so that the accompanying machine can press fit the housing firmly onto the cable. Next, the cable is plugged into another carrier with the white housing now secure in place. The machine presses down on top of the group of cables, using a tank of resin above the machine to inject plastic into a mold. This forms the USB connector ends you’re all used to. The worker we filmed was manufacturing mostly Type-A housing, but the same step applies for USB Type-C. This factory keeps one type of cable assigned to each line per day to ensure smooth operation, so you’d need to be at one location for several days to capture every single stage of the pipeline.

cable factory testing

The next step is also option, but is one that Cooler Master insists upon for its cables. This is a speed test, where workers connect each cable off the line into the test system to ensure the speed meets the spec defined by Cooler Master. This test is the most abusive on the test computer, which will occasionally require motherboard replacements or test board replacements because the high count of connection cycles will eventually break the receiving connector. Finally, the cables are moved downstairs and function tested to ensure they work for their advertised use cases. If it’s a fan cable, it’ll be tested for voltages and RGBW LED functionality. If it’s HD Audio, it’ll be tested to ensure the signal carries down the cable. After this final round of QC completes, the cable is bundled and shipped to the customer for inclusion in its products. For Cooler Master’s part, this means traveling to the Cooler Master assembly line, from which we have footage of SL600M and C700M cases being assembled. Each of these receives the cables from the factory, along with screws from one of the other factories we toured.

If you’re curious about the customer-facing side of business, the factory also does internal validation on its cable quality. Customers can buy high, average, and low-quality cables, all depending on budget, and the factory will test to ensure cables meet the demand set by the customer. One such test is a connection cycles test, where a machine will automatically press power switches or plug and unplug USB cables. At time of visiting, the factory told us of a recent customer that wanted its cables to survive 5,000 connection cycles, which can be validated with this machine. The most common point of failure is the connection point between the solder and the housing, which is why Cooler Master added that white plastic to strengthen the cable.

Watch the video above for the full video walkthrough!

Editorial: Steve Burke
Video: Andrew Coleman

Steve Burke

Steve started GamersNexus back when it was just a cool name, and now it's grown into an expansive website with an overwhelming amount of features. He recalls his first difficult decision with GN's direction: "I didn't know whether or not I wanted 'Gamers' to have a possessive apostrophe -- I mean, grammatically it should, but I didn't like it in the name. It was ugly. I also had people who were typing apostrophes into the address bar - sigh. It made sense to just leave it as 'Gamers.'"

First world problems, Steve. First world problems.

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