Inside be quiet!

27.05.2015
How be quiet! power supplies are produced, using Straight Power 10 as an example

A step by step photo story reveals the secret!
As discussed in our last article, we at be quiet! attach great importance to high levels of quality management during product development. So of course we also insist that quality control cannot be skipped during or after production.

Now we would like to give all interested parties an insight into the production line of the Straight Power 10. In this installment of INSIDE be quiet! we show you step by step how a be quiet! power supply is created and which tests it has to undergo during production before it makes its way to the warehouse and ultimately to you.

The beginning of the production process takes place in our placement machines. Production starts with an empty circuit board that is prepared with numerous small, predetermined openings and clearly defined component positions. The wires connecting the conventional components are guided by these small assembly holes. They are soldered on the back of the circuit board in a later stage.
Surface-mount technology (SMD) components are fitted to this board, straight from the carrier strip onto the circuit board. They are glued at first and then soldered later. Despite the convenience of the automatic insertion process, a power supply is a complex device which requires many components, assemblies and cables that cannot easily be applied by a machine. Therefore, the first production step for the partially assembled board ends here.
Now fabrication passes to our trained professionals: all remaining assembly steps can only be done by human hands. To discover individual errors and to detect, correct or weed out faulty products during production, our elaborate quality control is executed after each step, providing a consistently high level of quality. This important work of our quality control procedure begins with an optical inspection of the automatically assembled boards. Once this is passed, the boards move on to the manual production line.
The important work of our employees begins with an optical quality control of the automatically assembled boards, before they are completed in the manual production line.
Heavy components such as coils, transformers and larger capacitors require a lot of care and precision when they are inserted, so that nothing wobbles or is crooked later on.
After the initial assembly of heavy components, the rest of the connection wires are loosely fixed to the backside so that they have a fixed and defined position.
Preassembled components such as separate circuit board sub-assemblies and heavier heatsinks are now carefully mounted on the board. This step is followed by another visual check.
Next, the 24-pin motherboard connection cable is attached. Even though we’re dealing with a modular PSU, this cable is always required by the end user and so is hardwired. In addition, permanently attaching this cable reduces the number of mechanical contacts and therefore means a higher contact reliability, leading to a higher reliability of the power supply.
In the same operational step, the wires of the board holding the sockets for the other modular cables are inserted through their holes on the main board.
Next the cables and wires are temporarily fixed so the ends can’t fall into the hot solder bath in a later stage. It also ensures that further assembly processes are not disrupted by loose cable ends.
Then the staff again visually checks the PSU with special attention to the tinned wire and cable ends.
After this production step, other components and build elements are mounted; the secondary side of the power supply is now almost fully constructed and so the rest of the assembly gradually takes shape.
Next the optimal fit of the connection wires is checked, and after this step we execute one more visual check before the main board can be sent to the solder bath.
At this point, the nearly-complete board is prepared for the wave solder bath. The solder side of the printed circuit board is first dipped in rosin flux. Air extraction prevents flux vapors from escaping the fluxer and threatening the health of our employees.
Now the board is preheated. This is necessary both to prevent flexing or warping of the PCB and to facilitate the flow of the solder. It further prevents uneven distribution of solder (bad soldering quality) and protects the components from a rapid temperature rise when they are subjected to the solder bath.
In the next production phase, the PCB is moved over a solder wave, which is generated by pumping liquid solder through an opening. The board comes out of the wave solder machine, cools, and then an employee checks the soldering result with a very comprehensive visual inspection.
If necessary, the solder is manually redone or corrected until the soldering result meets our requirements.
When everything is as it should be, the next step is the manual removal of excess solder.
We attach great value to a consistently high soldering quality, and not just because this step is necessary to keep failure rates as low as possible. This is also simply about quality. None of the closely spaced interconnects can be short-circuited by excess solder, and if necessary the solder is manually corrected or redone until the soldering result meets our stringent requirements.
Yet another quality control of the board after soldering and corrections is, of course, only normal for us.
Only after it passes this final check is the back of the board polished by a rotating brush so that the last of any flux residue disappears. All boards are labeled at this point with a barcode, so they can be fully tracked in the system. And now we finally have an actual, official product—even if it’s not yet complete.
The next production step is, as you may have guessed, another phase of quality control—this time in the form of a first functional test. Only if this assessment is successfully completed can the board continue for further processing. After main assembly and first electric checks have been completed, the combination of board and case is prepared.
For this, the required grounding cables are attached to the case, which is protected by a film against any scratches and fingerprints.
Once the grounding cables are ready, the components on the input-side are soldered into place.
Then the board is ready to be placed in the case and screwed down tight.
Next our employee secures the newly developed SilentWings 3 fan to the inside of the case cover.
After that, the power supply is closed, screwed shut, and put in a special cloth jacket that will protect the surface. The next quality control checks the correct values of the voltage rails.
If the values meet our strict specifications, we perform a Hi-Pot and ATE test. The Hi-Pot (high potential, high voltage) test is used to ensure the dielectric strength of the power supply and is a sensitive part of our extensive quality control. In the ATE test (automatic test equipment) the full functionality of all the components will be tested for the first time in one fully automated run.
Next, our employees put all individual connections of the modular power supply through their paces again. We want to identify any potential errors in jacks, plugs and cables before packing. This is a part of our very thorough quality control as well.
At this point, each power supply that meets our requirement receives its final sticker with technical data and product details – the so-called “label”.
Before packing we do one more thorough check so that no errors can have gone unnoticed. And then finally our power supply is really done and ready.
Packaging the power supply and the required accessories is also done by hand. Whether it’s the connecting cables, the manual, or simply a couple of screws—nothing should be missed.
Once each PSU has been marked externally with its individual label and serial number, it is moved into a shipping master pack, ready to be sent to its destination. Yet even now we are not done; we still need to carry out one more QC step.
According to the OQC (Outgoing Quality Control) in the AQL guidelines (Acceptable Quality Limit is an established statistical system for the random determination and definition of the limits for the acceptancy of the produced product line), a certain number of randomly selected power supplies per batch need to be completely unpacked and subjected to a full functional and mechanical inspection. If this test fails, the entire batch has to be returned and fully tested. Only when this test is completed successfully are the power supplies finally packed and allowed to leave the warehouse.

A final word

During the entire production process, we place the highest demands on quality. To meet these demands, we have implemented many additional QC checks in various individual steps of the process. You might think this would have a negative effect on the cost of production, but in fact production efficiency—in the form of minimal rejects and failures—plays an important role in keeping costs manageable. Put another way: skimping on quality control does not lower total cost.

The ultimate goal for us is, of course, the overall quality that results from our precision and attention to detail. “That’s German attitude, and that’s the be quiet! way.”