PCB Assembly

Quickturn PCB prototype assembly

Publish Date:2020-11-27

We are a professional manufacturer of PCB circuit board. PCB processing, SMT SMT chip welding, and plug-in assembly are carried out in our factory.
Make board: single side, double side, four-layer board—proofing, batch, supporting file types: PCB, PCBDOC, Gerber, etc.

Quickturn PCB prototype assembly

Plate: FR-4
Thickness: 0.5-3.0mm
The solder resists: green, blue, red, black, white.
Process: ordinary tin spray, pure tin, OSP, chemical gold
Molding: CNC milling, V-CUT, die stamping
SMT SMT: Yamaha Mounter has high precision and high efficiency, and it is not afraid of 1206080506030402. Constant temperature 16-way reflow soldering effect of satisfying customers!
Dip plug-in welding: each component is stable, proper, and proper, without bias and leakage. It is full of front-line workers’ enthusiasm—manual welding, tin dipping welding, clean and neat.
Packaging: the welded finished products are inspected to be qualified, packed independently, and packaged with recyclable cartons for external use, to prevent damage caused by long-distance and prevent customers from receiving them;
You determine satisfaction, if you are satisfied with our service and products, please give us 5 points of praise, after all, with your support, we will go better and more stable, thank you for your evaluation and print, we work together to do better ourselves!

Quickturn PCB prototype assembly

Common design mistakes of quick turn PCB prototype assembly

  1. Our company can’t make a square hole
  2. The orifice cap oil is a standard industrial-grade design requirement for mass production. We default to cap oil (no matter if your document is not equipped with Gerber). If you need to change it, please make a separate explanation. The via hole in the Gordon document is produced according to the drawing document, even if there is a via description, it is invalid. Please know!
  3. MPlayer does not spray tin: when designing, please pay attention to it. It looks like it is the same as the pad. In fact, it will not be made into a pad, and there will be wiring at both the top and bottom layers. Please pay attention!
  4. As for the mistakes caused by the design being locked, we often find that the mounting holes in the PCB files designed by customers are locked (if you click the figure to view the properties, the check after locked represents locking). In this case, we must find the unlocking one by one to output effective graphics. For example, if you look at it all over, it will cause leakage or slot, so in order to avoid leakage and slot, please do not lock the design We will not be responsible for the leakage caused by the leakage.
Quickturn PCB prototype assembly
  1. The mechanical layer and keep out layer are wet, resulting in full processing. Generally, the mechanical layer is used for shape development, and keep out layer is a prohibited wiring layer. We usually make the appearance and installation holes according to the mechanical layer. If there is no mechanical layer, only the keep-out layer is used to make the shape and installation hole. If the design does not conform to our requirements, please modify the design to indicate the details in the order details Let’s go. There are also some design isolation slots that are neither in the mechanical layer nor in the keep-out layer. It is very difficult for us to find that more than 90% of them will be missed. Please design engineering to avoid this practice. We are not responsible for the problems caused by mixing
  2. If there is a problem in the design, don’t say that it was right last time, but it must be right this time. In other words, we have done two things at the same time, one is right and the other is wrong. Many times, our engineers will help you to correct, but the wrong design will make mistakes one day. We must improve and use the problem of perfect standard design.
Quickturn PCB prototype assembly

If hardware engineers need to produce urgent samples, they should often deal with a quick turn PCB assembly factory, and they must fully understand the basic process and principle of the SMT factory.
PCBA=PCB Assembly。 Assembled PCB. Strictly speaking, PCBA = PCB + components + SMT production + firmware + test.
With so many components on the circuit board, it’s impossible to solder by hand. It’s necessary to rely on the machine to mount the chip. Whether you have been to the factory of a quick turn PCB assembly or not, you must have seen such a picture on TV: a manipulator moves onto the circuit board and pokes it down several times, then there are components on the circuit board. This is a link in PCB becoming PCBA, SMT.
The machine welding circuit principle is the same as that of the manual welding circuit, tinning, swinging components, and heating. It’s just that the machine’s speed is much higher than that of the human hand, and several components can be placed in one second, so quick turn PCB assembly can quickly deliver samples to customers to meet their delivery time.
On tin:
First, in the circuit board. As mentioned earlier, there is a paste mask file in the Gerber file used to open the steel mesh. Steel mesh is a thin sheet of steel, very flat; the thickness is about 0.1 mm. According to the graphics on the paste mask file, there are corresponding hollowed-out holes. Put the steel mesh on the circuit board and align it. At this time, you can see that all the pads that need to be welded will be exposed. Steel mesh is the template of solder paste. Brush a layer of solder paste on the steel mesh. The solder paste with holes will be printed on the circuit board pad, and there will be no solder where there are no holes. The thickness of solder paste is the same as that of steel mesh, which is 0.1 mm.
The equipment for tinning is called a “printing machine”. Insert the steel mesh into the machine, and then put the circuit board in. The equipment will automatically lift the circuit board, position it well, and press it tightly under the steel mesh. There is a brush on the top of the steel mesh, pushing a lot of solder paste from the steel mesh layer back and forth, and a layer of solder paste will pile up in the position of the steel mesh opening and the groove formed by the circuit board. Takedown the circuit board again, and the tin on the circuit board is finished. Next, you need to go into another machine and start placing components.
The holes in the steel mesh correspond to the component pads of the circuit board.
Solder paste is printed on the circuit board through the steel mesh.
The equipment for tinning is called a “printing machine”. Insert the steel mesh into the machine, and then put the circuit board in. The equipment will automatically lift the circuit board, position it well, and press it tightly under the steel mesh. There is a brush on the top of the steel mesh, pushing a lot of solder paste from the steel mesh layer back and forth, and a layer of solder paste will pile up in the position of the steel mesh opening and the groove formed by the circuit board. Takedown the circuit board again, and the tin on the circuit board is finished. Next, you need to go into another machine and start placing components.
The holes in the steel mesh correspond to the component pads of the circuit board.
Solder paste is printed on the circuit board through the steel mesh.

SMT / SMT

SMT, surface mount technology. As the name suggests, the components are mounted on the surface of the circuit board. It is called paste because the solder paste has a certain viscosity, which can also adhere to components without melting. SMT is also called a patch. It means to stick the chip on the circuit board.
Because the placement is the most important link in the whole PCBA processing process, the quick turn PCB assembly factory is also called a fast placement factory.
The principle of SMT is straightforward; manual welding is to use tweezers to clamp the components on the circuit board, SMT machine is to use a manipulator to clamp the components on the circuit board.
However, the patch’s actual situation is very complex, and the equipment is also exact. If there is no technical content, why does the video of quick turn PCB assembly always play the lens of putting the patch, rather than printing or heating in the back?
We can look at the following questions first:

Where are the components going?
Small size components, including chips, are tape storage. The components are embedded into the tape one by one in the same order through the paper or plastic tape and then rolled one by one. There are many standard size holes on the material belt, which can be stuck on the material conveyor’s gear, and the gear carries the material forward bit by bit.
The material conveyor is called Feida. The name is purely transliterated, feeder. The original meaning is a feeder, breeder—the very vivid expression of the role of this thing: feeding materials to the placement machine.
Feida is neatly arranged at both ends of the placement machine. According to the program, the manipulator of the placement machine picks up components from Feida and places them on the circuit board.
For large-size components or bulk materials that are not rolled, they can also be placed on the pallet, and the manipulator can pick up materials from the pallet.
How does the manipulator grasp such a small component?
In fact, the placement machine’s mechanical arm does not grasp the components by fingers but by vacuum suction. There are many suction nozzles on each arm, and each suction nozzle can suck up a component. With more suction nozzles, the mechanical arm can absorb many components at one time and place them many times so that the production efficiency will be higher.
The suction nozzles are different for different sizes of components. It can be seen from high school physics that under the same pressure, the larger the area is, so the suction nozzles for heavy materials such as chips and connectors should be larger, the suction nozzles for resistance and capacitance should be smaller, and the suction nozzles for 0201 components should be smaller.
Things with relatively large weight also have relatively large inertia when moving, so the placement opportunity is divided into several areas. The robot arm in the large component area moves slowly, while the robot arm in the small component area moves much faster.
It’s not difficult to understand from the principle of chip mounter sucking components. For sharp components such as pins and thimbles they all have a plastic cover when the materials leave the factory. Because there is no flat surface, they can’t be sucked up. For components with small openings on the surface, such as a USB port, a small piece of high-temperature adhesive tape will be posted when they leave the factory. The purpose is to prevent air leakage from the suction nozzle.
How does the manipulator know where to put the components?
In the production data of quick turn PCB assembly, there will be a coordinate file indicating each component’s coordinates on the circuit board. Before online placement, the production line engineer will input each component’s placement information into the operating software of the placement machine according to the production data. In this way, the mounter will know how many components to take from which Feida and where to put them on the circuit board.
This process is called programming in the quick turn PCB assembly factory. SMT factory has a special program engineer who is responsible for inputting this information. It takes more than half a day to program a circuit board with hundreds of components.
How to align circuit boards and components?
The circuit board is sent to the placement machine through the conveyor belt. The components are in the material belt, and they are not tightly stuck. They will shake. The placement machine must be able to judge the exact position of the circuit board and put the components in place accurately.
Mounter is through the camera on the manipulator to identify the circuit board and components. After each component is picked up, it will be taken a picture. Through the image recognition of this picture, we can see whether it is crooked. If it is crooked, according to the crooked data on the image, the system will automatically make certain compensation for the chip’s position, such as slanted movement and crooked rotation. Similarly, there will be several mark points on the circuit board, a circular pad. The camera can identify the current position of the circuit board according to the pad’s position and then find the position of the components according to the coordinates of the components relative to the circuit board.

Reflow/wave soldering

In China PCB assembly manufacturing factory, the reflow soldering furnace with cover opened.
After all the components are put in place, the circuit board will be pushed out of the SMT machine for manual visual inspection or AOI machine inspection to see if components are sticking askew or wrong. If there’s no problem, it’s going to be over.
Through a furnace, through a furnace. The solder paste has to be heated to melt, and it’s melted to hold the components together. The whole circuit board is gradually heated through the reflow soldering furnace until the solder melts and then gradually cooled down. The whole process usually lasts about eight minutes. At present, reflow soldering furnaces are mainly heated by hot air. Divided into multiple temperature zones, heating step by step, the time above the solder’s melting point is not long, at most dozens of seconds.
When it comes to the name reflow soldering, almost everyone doesn’t know what reflow is. It doesn’t mean that the wind inside will flow back and forth, let alone that the solder flows from here to there. Reflow soldering comes from reflow soldering. The real meaning of reflow soldering is to change the solid solder paste back into a flowing liquid.
In the process of passing through the furnace, the solder paste will melt, and the melted solder paste presents the characteristics of liquid: it can be adsorbed to the place where it can be adsorbed and produces tension. It often happens that when the patch is pasted correctly, it will be crooked after passing through the oven. This is often caused by the different pulling force between pads, such as chips with large pads and small pads. This problem can be solved by controlling the amount of tin and the shape of solder paste or dispensing and fixing before passing through the furnace.
There is also a kind of soldering method for pin type, wave soldering, which is still used in old circuit boards and large-size simple circuit boards and is specialized in soldering pin circuits. The wave crest of wave soldering refers to that after the solder melts, the solder is sprayed out through the equipment’s nozzle, like a small fountain, forming a wave shape. When the component’s pin is inserted into the wave crest, the solder can be stained, and the pad and pin can be welded under the solder adsorption force.
Now in the field of intelligent hardware, there are almost no full board plug-in components. Most of them are full board SMT. Occasionally, some large-size connectors may need wave soldering.