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9 Abilities For Supplier Can Print Circuit Board Assembly Ability

In the PCB market, many vendors say that they can manufacture your printed circuit board. On the other hand, some of them may also mean that they offer printed circuit board assembly. As a beginner, you may feel that printed circuit board assembly and manufacturing are the same thing. But in reality, they are not.


These processes are different, and you must know them. So, in today’s article, we will tell you about nine aspects through which you can identify the differences between the printed circuit board assembly and manufacturing. Determine if your supplier has PCB assembly technology. Let’s begin then.

Check PCB Supplier Can Solder Electronic Components

In the Print Circuit Board Assembly Ability, the PCB vendors would solder your electronic components on the board’s surface. You will provide them the design, and their job is only to solder the parts and assemble the PCB. They have high-tech machines for that purpose.

However, if you are contacting a PCB layout of your project and then develop the printed circuit board prototype. After going through these processes, the PCB manufacturer will then do the printed circuit board assembly. 

A soldering iron is soldering a component on PCB.jpg

Check PCB Suppliers Use Pick and Place Machine

The pick and place machine is an automatic robotic device that places electronic components on the on the PCB. In the past, a manual process utilizing tweezers would do this job. The technicians would manually need to pick and place components by this hectic procedure.

Fortunately, this automatic machine is more consistent and accurate than humans. So, it has taken over. The device can work at any time, and there is no tension, such as eye strain or fatigue. It picks up the printed circuit board with the vacuum grasp and then moves it to the required place. Then finally, it places the electronics component in their predefined positions. The sites are predefined using the solder. So, if your PCB vendor is using this machine, they would assemble your PCB rather than just making it. 

SMT machine of printed circuit board assembly.jpg

Check Whether the PCB Vendor is Offering Reflow Soldering

In the printed circuit board assembly, you need to ensure that the electronic components remain at their places. This means that the solder paste should solidify so that it can stick the parts to the board. The PCB board assembly does this via the process of reflow soldering. It happens after the pick and place machine performs its job.

The assemblers send the PCB board to a conveyor belt that goes into a considerable reflow oven. You can picture it as a commercial pizza oven. The heaters in this oven slowly heat the board to up to 25 degrees Celsius. It will melt the solder. After that, it passes through the cold radiators that cool down the solder. So, it solidifies in a systemized manner.

Reflow oven open for cleaning and maintenance.jpg

Check if The PCB Vendor is Offering Functional Test

In printed circuit board assembly, the board is complete. So, it is only then the PCB can be tested for its functions. In this case, only the PCB assemblers can offer you functional testing. If the vendor is a PCB manufacturer, it cannot provide a practical test as manufacturing does not include the complete PCB. 

The PCB assemblers simulate the operating environment of the PCB and make it go through it. The simulated signals and power go into the PCB, and a tester monitors its electrical connections. The printed circuit board assembly process ensures that current and voltage do not fluctuate or reach any peak values outside the nominal range. If the test shows negative results, your PCB can either be replaced or recycled depending upon the company’s policies. 

The functional test is crucial in PCB assembly, as it determines the success rate of your project. And this test will only show positive results if the PCB vendor is regularly inspecting the assembly process. 

printed circuit board assembly, manual installation by staff.jpg

Check Whether the Printed Circuit Board is Complete

In PCB circuit board components, wne can complete the PCB. Whereas PCB manufacture only makes a bare circuit board. You would see that the board consists of Glass epoxy resin or similar material. Mostly, the bare PCB boards are of 6 or 4 layers, but it will depend upon the number of signal layers.

Shows the complete PCB board.jpg

Print Circuit Board Assembly Ability– Check Whether the PCB Vendor is Offering Dip or SMT Process

If your PCB vendor has made the offer to use DIP and SMT processes, they are assembling printed circuit boards. However, dip soldering is a traditional method now, as wave soldering has taken over. In dip soldering, PCB assemblers would manually put your bare PCB board into a container of molten solder. In this way, the melted solder glues to the visible metallic areas of the PCB.

But before soldering, the electrical components need to be put in place; for that purpose, many PCB assemblers use surface mount technology. Through this process, the electronic components directly go over the surface of the PCB. They do not need to make holes in the PCB. Therefore, in the printed circuit board assembly, this speeds up the entire process. However, this method of component placing has more chances of defects. 

DIP technology in printed circuit board assembly.jpg

Print Circuit Board Assembly Ability– Check PCB Supplier to Provide PCB Design Printing

Printed circuit board assembly does not include the distribution of the PCB layout. If the PCB vendor is providing this facility, it will only make your PCB and not assemble it. After checking the design for manufacturing errors, the PCB manufacturers will print your design.  

PCB manufacturers don’t use a regular paper sheet; they would instead use a plotter printer. This printer will develop a film on the bare circuit board, and its movie is a photo negative of the PCB. It appears as a transparent sheet. 

The print will be in two ink colors, both for the inner and outer layers. For the inner layers, the black ink color represents the copper traces of the PCB. And the transparent part represents the non-conductive parts of the circuit. However, this trend is opposite to the outer layers of the PCB. The bright ink will describe the copper areas, and the black ink will serve the non-conductive areas. 

(Surface mount machine is in action.jpg

Print Circuit Board Assembly Ability– Check Your PCB Supplier Can Optically Check

The PCB manufacturers do a visual control and then adjustment of layers of your printed circuit board. This step comes after they have published the PCB and then cleaned any unnecessary copper. So, you will not usually see this in printed circuit board assembly. They align the outer and inner layers via the already made holes. 

An optical punch machine aligns these layers. It pulls down a pin via the aperture for the alignment of layers. It is not it; another computer rechecks the optical inspection to ensure that there is no fault. This process is very crucial before the printed circuit board assembly can begin. If any errors remain at this stage, they cannot rectify later—the need to discard the whole PCB. And, the PCB manufacturer will do the entire manufacturing process again. 

printed circuit board assembly, optical microscope for inspection.jpg

Print Circuit Board Assembly Ability– Check PCB Supplier Can PCB Layer Lamination

The printed circuit board assembly process does not include the lamination of PCB layers. So if any supplier does this, it means that it provides correct PCB service provider. Thankfully, there are various PCB manufacturing instead of assembly. They laminate the printed circuit board after making sure that the layers are error-free. Metal clamps fuse the sheets on a specific press table.

A specialized pin fits every layer on the press table. The technician would place a pre-coated epoxy resin on the alignment portion of the table. After that, a substrate layer is put on this layer, followed by a copper foil layer. Then again, they put more layers of pre-impregnated resin, and finally, the process finalizes with a press plate.


Therefore, as a beginner, check the facilities provided by the PCB vendor. They will tell you whether the printed circuit board assembly is being made or assembled. In a nutshell, the printed circuit board assembly means the soldering and placement of components to make the PCB ready for functional testing. And, WellPCB. We will provide you with one-stop service and high-quality products. You can send us the documents you need to make and get a quote immediately! What are we waiting for? We have ten years of PCB manufacturing only involves the making of a bare PCB board.

If you need PCB assembly technology and PCB production, WellPCB can provide you with quality service and first-class technology. We have technical and contact us today. 

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Emma Lu
Our professional engineering support saves our customers a lot of trouble and loss. >>>>>> After you place the order, our engineer will conduct technical reviews to make sure the parts can be mounted well/correctly on the boards. We will check if the component packages match well with the Gerber footprints, if the part numbers you provided match well with the descriptions, and if the polarity is clearly marked. >>>>> When your design is ready, please send your Gerber and BOM so we can quote and start!