PCB Assembly
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16+ Years Experience in PCB Assembly
- SMT assembly, PTH assembly, SMT+PTH mixed
- PCB Fabrication, Component Sourcing & Turnkey PCB Assembly
- Small to Medium Volume Production
- ISO9001:2015, ISO 13485:2016 Certified & UL Listed
- 100% AOI, X-RAY, ICT & FCT
- No MOQ & Competitive Pricing
Our PCB Assembly Capabilities
- Surface Mount (SMT) assembly
- Thru-hole (PTH) assembly
- Mixed Technology (SMT & Thru-hole)
- Single or double-sided placement
- Rigid, Flexible PCB and Rigid-flex PCB Assembly
- High pin count press fit capable
- Manual assembly
- Kitted/Consigned
- Partial Turnkey
- Turnkey PCB Components sourcing
- Passive Components as small as 0201
- Ball Grid Arrays (BGA) as small as .35mm pitch
- BGA, uBGA, QFN, DFN, SOP, PLCC, POP, CGA, CSP and Leadless chips
- All kinds of passive and active components
- Reels
- Cut tape
- Tube and tray
- Loose parts and bulk
- Smallest size: 0.2″ x 0.2″
- Largest size: 20” x 28″
- AOI (Automated Optical Inspection)
- X-ray for BGA
- ICT (In-circuit Test)
- FCT (Functional Test)
- E-test
- Manual visual inspection
- Burn-in test
- Box Build Assembly
- IC Programming, System Integration
- Conformal coating
- Mechanical Assembly
- Electromechanical Assembly
- Cable and Wire Harness Assembly
- Repair/Rework services
- DFM Analysis
- No minimum order quantity
- Engineering prototypes
- Low-cost first article
- Small series production
- Mass production
- 1 week for Consignment PCB assembly
- 2-4 weeks for turnkey PCB assembly
- Low-cost first article
- 4-10 weeks for full turnkey box build assembly
- Quick turn available
Viasion- One of the Best PCB Assembly Manufacturers
Viasion Technology is one of the best PCB & PCBA manufacturers in China with leading advantages. For example, our one-stop solution for PCB assembly and high-quality products at an affordable price are the reasons why Viasion has gained the recognition and trust of many customers.
16 years of experience
Viasion has been producing top-quality products of PCB & PCBA for 16 years. We all understand how important sufficient production experience is in the PCB & PCBA industry, which demonstrates the high reliability of our company.
High-quality production
Our company attaches great importance to the quality of products and has established a strict quality control system from the check of raw materials, the manufacturing process, and quality inspection to the operation of the production equipment to carry out comprehensive control. Furthermore, Viasion has the following certifications: ISO 9001:2015, ISO 13485:2016, ISO 14001:2015, UL E358677, RoHS/REACH compliance.
Competitive price
Through our relentless efforts, we can provide low-cost PCB manufacturing and assembly services in our company. We try to think out various methods to reduce the cost, but always stick to the high-quality standard since the management of quality and cost is very essential.
99% customer satisfaction
We are so proud that there are 99% positive comments from customers about Viasion. And our company has won the trust and praise of many customers for our high-quality products, competitive and reasonable prices, and excellent after-sales service.
What is PCB Assembly?
PCB assembly means soldering electronic components on the printed circuit board. Normally both SMT assembly and PTH assembly are used in a completed electronic pcb board assembly. Here we would like to introduce a little about SMT assembly and PTH assembly.
Benefits of PCB Assemblies
The core part of all electronic products is composed of PCBA; all the functions can not be realized without PCBA. Therefore, PCBA is the basic unit of all functions in the electronics industry. In other words, PCBA is the most important component of all electronic product components, similar to the human body’s neural network. The life span, operating speed, reliability, and stability of general consumer electronics are most directly related to PCBA. It is no exaggeration to say that the quality of PCBA is also the most direct determinant of the overall quality of electronic products.
- To provide support for the soldering and fixing of various electronic components.
- To provide electrical connection or insulation between various components.
- To ensure the welding quality of all kinds of components and quickly improve the efficiency of maintenance.
- To Provide the electrical characteristics, electromagnetic compatibility, and characteristic impedance required by the circuit in high-speed and high-frequency circuits.
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| Our PCB Assembly Capabilities | |
|---|---|
| Assembly type | SMT assembly, PTH assembly, SMT+PTH mixed, manual assembly |
| PCB type | rigid PCB, flex PCB, rigid flex PCB |
| PCB parts | turnkey, partial turnkey, consigned assembly |
| Components type | all kinds of passive and active electronic components |
| SMT components type | SOP, BGA, uBGA,QFN, DFN, PLCC, POP, CGA, CSP |
| Min. SMT component size | 0201 |
| Min. PCB dimensions | min. 0.2 *0.2” |
| Max. PCB dimensions | max. 20*28” |
| Inspections | AOI (automatic visual inspection), X-ray |
| Testing | ICT (in-circuit test), FCT(functional test) |
| Cable assembly available | |
| Conformal coating | |
| IC programming | |
| Box build assembly | |
| Electro-mechanical assembly | |
| PCB Repair services | |
| Lead time | 1-5 days |
| Quantity available | 1 to 10,000pcs |
How to Order PCB Assembly Service on Viasion?
PCB Assembly Process
Generally speaking, PCB files(usually Gerber format) and BOM (bill of material) lists are needed in PCB assembly services.
Firstly we need Gerber files. Gerber files contain the pattern of each copper layer, solder mask layers, and components notation layers. We need Gerber files to produce SMT stencil, and also our CAM engineer needs to check the Gerber files to compare the details when doing DFA (design for assembly). For example, sometimes the component size is bigger or smaller than the actual PAD in the PCB, then our engineer can notice the problem and ask customer’s advice in advance.
BOM and Pick & Place file with the X/Y coordinates are extremely important for printed circuit board assembly. BOM means bill of material. All the parameters of the electronics components will be listed in the BOM, including manufacturer, part number, detailed parameters, quantity used on one PCB, or remaking like substitution, formation details for the pins of PTH component, etc. Pick & Place file is the coordinator of every component. Pick & Place machine can identify where the components should be placed.
Sometimes customers may also supply assembly drawings and 3D drawings of the assembled PCBs, which is very helpful to us as well. Schematics are also helpful for problems shooting. But all these files are helpful supplementary files, they are not what we must have for PCB assembly services. If you are not sure which files should be sent to us for quote and production, just simply send all the design packages for PCB fabrication and assembly.
Generate production files needed in PCB assembly
After DFA checks and all engineering questions are solved with the help of our customers, we will generate a production file (process card) with all the details of each process. Such details include IQC (Incoming Material Quality Control) requirements, SMT parameters such as solder paste type and reflow oven profile, details of PTH assembly for each PTH component, special processes like conformal coating, protective material dispensing, testing, IC programming, box build assembly, etc, and all other processes or specialties we need to pay attention to.SMT assembly processes
Prepare SMT stencil
Before SMT assembly, we must get a SMT stencil first. SMT stencil can be etched and laser cut and polished. We always use laser cutting and polished stencil to get the best result in solder paste printing. Usually, the steel sheet is 0.15mm, but it can also be thinner or thicker depending on the requirement for certain PCBs and components. The stencil opening is also a little smaller than the pads on the PCBs, but it always varies depending on the design of the PCB and the components used. So an experienced engineer needs to get the most proper stencil for a certain circuit card assembly project, which is very helpful to get good soldering quality the first time.Generate Pick & Place files
SMT equipment engineers should generate Pick & Place files for our Pick & Place machine, which is always automatically done if the Pick & Place files with the X/Y coordinator are complete. Engineers can also annually input the X/Y coordinator if it is missing, but it is very time-consuming and also with the possibility of mistakes. An experienced engineer needs to generate perfect files and get excellent SMT assembly quality.Prepare production tools if needed
In most occasions, PCBs are always supplied as panels with frames, then the PCBs can run through the automated. But sometimes, PCBs may be supplied as single ones, and the distance from the board edge to the closest components is less than 3mm, if then we need to produce an assembly pallet with nails to stabilize the PCB on it. We put the PCBs on the pallet first, and the pallet runs through the production line.
Besides, assembly pallets are always needed in flexible PCB assembly and rigid-flex PCB assembly. Since flexible PCB and rigid-flexible PCB are not flat enough, SMT components may not be put on the center of the PCB pads by the pick and place machine.
Print solder paste on the PCB
When all needed tools and materials are prepared well, then it is time to print solder paste on the PCBs. Firstly, we put the stencil on the PCB and stabilize it, then apply some solder paste on the stencil, and move the scraper on the stencil with pressure. Now we can see the solder paste run through the stencil opening and adhere to the PCB pads. We always use a fully automatic paste printing machine to get the stale quality, and the speed is very quick as well. But sometimes annual solder past printing is needed from special PCBs or quick turn prototype printed circuit board assembly.
We should be aware that solder paste needs to be stocked in refrigerators with 2-10
Celsius degrees. And solder paste must be unfrozen by 1.5-2 hours in advance just before SMT assembly, and then stirred and mixed by a solder paste mixer for 5 minutes. A bottle of solder paste should be used once when it is unfrozen and stirred. Never keep the used solder paste too long, because the activity will be less and less, and the soldering quality may not be good.
Solder paste quality is extremely important for SMT assembly. In Viasion, we only use the best solder paste brand: Alpha and Senju, to get the best SMT assembly quality.
After solder paste printing, the solder paste quality needs to be checked, either by an automatic SPI (Solder Paste Inspection) machine or by QC staff.
Place the components on the PCB
Now it is time for the most essential step: placing the PCB components on the PCB surface after solder paste printing. We use a high-speed and high-accuracy Yamaha machine to place the components on the PCB. No matter it is a 0201 passive component, or it is a big BGA with 500 soldering points, we can mount the components in good quality. Normally the machine will advise where to load the Feeders with the reel of components, to get the best efficiency. Engineers will input and pick & place files, and advise loading the Feeders, and then the operator which monitors the running of the SMT machine also changes the components when it is run out.
IPQC is very important in the SMT process, to make sure that solder paste is properly printed and that components are placed with good accuracy, and also checks and makes sure the correct reels of components are changed when they are run out.
First article inspection
We know first article inspection is extremely important to avoid production loss to both customers and ourselves. So in every new batch of production, no matter the new order or repeat order, we will do the first article to check if it is correctly assembled before producing the rest of the orders.
In this process, when the SMT components are placed on the PCB, our QA engineer will check and test every component with first article equipment with relative software, to make sure all components are correctly placed.
We need to pay attention that only experienced and skilled QA engineers can do the first article inspection properly.
Run through reflow oven
This process is used to solder the components on the PCBs. Normally there are 4 zones in the reflow oven which are the Pre-heat zone, Soak zone, Reflow zone, and Cooling zone. The following is the detailed introduction:
4 zones in reflow oven
1, Pre-heat zone
The purpose of this zone is used to pre-heat the electronic components and volatilize the moisture in the solder paste. Besides, the flux will be activated and cover the solder components pins. In this zone, the temperature is around 150 Celsius degrees.
The key point in the zone is: the temperature rising should be slow and smooth to avoid damage to some electronic components and some soldering defects such as voids, collapse, poor wetting, solder ball, tombstone effect, false soldering, etc.
2, Soak zone
The purpose of this zone is used to fully pre-heat the electronic components and PCB, to avoid damage to components and avoid PCB because of suddenly high temperatures. In these zones, moisture or other elements in the solder paste will be volatilized completely, and any oxide on PCB or components’ surface will be volatilized as well.
The temperature in the soak zone is around 150-190 Celsius degree. The temperature rising speed and the moving speed are all important, or the flux may be over-volatilized. Then defects like failure soldering, solder residue, and dark soldering joint may occur.
3, Reflow zone
In this zone, the temperature will reach the peak, the solder paste will be melted and Sn-Cu alloy will be formed, then the components will be soldered on the PCB pads.
This zone is extremely critical. If the peak temperature is too low, the solder paste will not be melted properly and failure soldering will happen. If the temperature is too high, some components which can not withstand high temperatures will be damaged.
We should understand the real temperature may not be the same as the temperature you set in the equipment, because the absorption of heat will be different for different PCBs and components. So we need to test the real temperature in the oven for daily or for every new batch production.
4, Cooling zone
In this zone, the solder joints and electronic components will be cooled down. This zone seems to be easy to operation, but it is still very important.
The key point is the speed of cooling down. Normally speaking, quick cooling will be helpful to get good soldering, but voids may happen because some gas has no time to escape before the Sn-Cu alloy is consolidated. If the cooling speed is too low, the solder joints may not be robust enough because of larger eutectic particles.
About reflow soldering profile
As we have mentioned above, there are 4 zones in the reflow oven usually. But how to set the running speed and the temperature? This is a reflow soldering profile, which is extremely important to get good soldering. There are 2 things we should pay attention to:
1, The reflow soldering profile for every PCB assembly project may be different
Every PCB project has its unique design, such as PCB dimension, PCB thickness, component quality, density, type, and component dimensions, and tooling fixtures used in PCB assembly services, all of these will affect the heat absorbing rate. So unique reflow soldering profile should be set for every printed circuit card assembly project.
2, The reflow oven temperature needs to be tested frequently
Due to the unique PCB and components on different projects, the real temperature of the PCB and component may be different from the temperature we set on the equipment. And also, the temperature may be not accurate because of heating units aging or unexpected defects from the heating units in the reflow oven. So we need to test the reflow oven temperature every day or for every project.
3, Experienced engineer is a must
There are many parameters we need to consider when setting a reflow soldering profile. And also any imperfection may lead to serious quality problems. So we need very experienced engineers to set the reflow soldering profile.
Viasion is one of the most trustful PCB assembly manufacturers in China. To ensure good quality soldering, we use 10 temperature zone reflow ovens to make sure smooth temperature rises, without experienced engineers to set the reflow soldering profile. We are very confident in perfect SMT soldering quality.
AOI inspection
AOI means automatic optical inspection. It is used to be a substitution for visual defect inspection by humans Since human beings are easier to get tied and then make mistakes.
There are 2 kinds of AOI machines, fully automatic and partially automatic. Fully automatic AOI can pick the PCBs automatically, and separate “pass” or “fail”. As for partially automatic AOI, QA staff is needed to load and unload the PCB, and judge if the PCB will “pass” or “fail” when the AOI machine finds any imperfections.
But no matter the fully automatic and partially automatic AOI machine, the principle is the same: the AOI machine compares every component with the first article, and the one with any difference will be judged as a “fail”.
We regard automatic optical inspection as a substitution for visual defect inspection by humans, but experienced QA staff is always needed to judge if any imperfection is acceptable or not according to IPC standards or customer’s standards.
In-circuit test
The in-circuit test is used to check if there is an open/short in the components and the soldering. We can regard it as a more advanced Multimeter. But the main difference is that the ICT tester can test many components once about the resistance, capacity, and voltage, so the speed is much quicker.
In the ICT test, we can detect the defects like open/short, wrong components, missing components, failure solder, wrong polarity, etc. The components which are possible to be tested are resistor, capacitor, inductor, diode, relay, IC, connector, etc.
We always need to produce a testing fixture for every circuit board assembly project since different PCB has a different layout and testing points.
We should know that an in-circuit test is not usually possible to test all the components. But it is still very helpful to find printed circuit assembly defects. Together with AOI inspection, we can find out most of the defects in PCB assembly services.
X-ray for BGA
We can inspect most of the components by AOI or manually, but the situation is different for BGA. The reason is that the soldering joints of BGA are hidden under the BGA after reflow soldering. Then we can not make sure if the BGA balls are soldered properly or not.
By using x-ray inspection equipment, we can find the defects such as solder connection, solder ball, voids, open, false soldering, broken solder point, etc. It will be greatly helpful to us to find a problem in BGA assembly.
Visual inspection
When we have completed the AOI inspection, ICT inspection, and X-ray inspection for BGA, we are confident that our projects are qualified. But still, we need to do a visual inspection by our QA staff, to find if there are any other defects. Undoubtedly we always want to supply perfect printed circuit assembly.QA check
Once all quality inspections and tests are done. Our QA supervisor with spot-check the batch randomly. If there are no defects found, then the PCBs can go to the next step. If there is any defect found, the whole batch will be inspected again. QA check is a must for PCB manufacturing and assembly.PTH assembly processes
Prepare tooling fixture
In most cases, tooling fixtures are needed as a carrier of PCB in the PTH assembly process. Because only the parts with PTH pins need to be soldered, other parts should be covered by the fixture. Besides, some components are very heavy, so the fixture will be helpful to withstand the weight when running through the waving soldering machine, to avoid the PCB being bent because of heat.
Insert the component pins into the PCB holes
In this step, we will need to insert the component pins into the PCB holes. It can be done manually and automatically. But due to the variety of PTH assemblies, fully automatic PTH assembly seems to be impossible, especially for prototype and small-volume production. In the same cases, the pins of PTH components need to be formed in a certain shape, since it is impossible to be done after wave soldering.
Run through wave soldering
When all the components are properly inserted into the PCB holes, it is time for the PCBs to run through the waving soldering. Why is it called waving soldering? Because after adding enough heat, the tin in the solder stove will spray upward like a “wave”, and the tin will stick on the component pins and run through the PCB holes when the PCB runs through the “wave”. Wave soldering seems to be easy, but still, experienced engineers are needed to set the temperature and speed for different circuit card assembly projects.
Cut extra pins
There are always long pins existing on the PCB after PTH soldering, which will affect the usage of customers. So we need to cut the extra pins. At the same time, the PCBs look much more beautiful without long pins.
Quality inspection
Since we have already done a quality inspection for SMT assembly, here we just need to inspect the quality for PTH assembly to prevent wrong components, failure solder joints, shorts, etc., and to guarantee good quality of pcb assembly board services.
Manual assembly
Manual assembly means that the electronic components are soldered by hand. First, we turn on the soldering iron and let the iron head temperature reach 300-400 Celsius degrees, and then place the component in the correct place. Lastly, melt the tin wire and solder the component on the PCB. The quality of manual assembly highly depends on the skill and experience of the worker, and the deficiency is also low compared with PCBA manufacturing by machine.
The disadvantages for manual assembly
Why manual assembly is needed
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Functional Testing
When all the components are assembled on the PCB, we can do functional testing (FCT) if required by customers. A testing fixture is always needed, and it can be supplied by customers or we can produce it according to the customer’s testing process and instructions.
Sometimes, a program or firmware needs to be written in the memory chips before functional testing. If the PCBs pass the functional testing, we are sure the printed circuit assembly is functionally acceptable.
We should know that some functions can only be best tested by when loading the assembled PCB in the equipment.
FQC
FQC means final quality control which is the last process for quality control. In this process, our quality inspector will check if there is any defect in all aspects. When the electronic PCB assembly passes FQC, it means the product is perfect and ready to ship out.
Viasion is one of the best PCB assembly manufacturers in China that focus on small to medium volume production. And we have very experienced workers to do final quality control ensuring the delivery of high-quality pcba assembly services to our customers.
Labeling
Sometimes, customers need us to print and stick labels on the PCB as their requirements, such as part number, and QR code. Or the mark needs to be engraved on the PCB by laser. We can do all of these as per customers’ requirements.
These labels are always used to trace each product. Then the customer can use them directly in their devices after receiving the PCBs.
Packaging
Since we started supplying PCBs to overseas customers in 2007, we understand how important it is to pack the PCBs in good condition to avoid damage during transportation.
Usually, we will seal the single PCBs in individual ESD bags, and then surround them with bubble tapes as buffers. Only robust cartons will be used, and all 6 sides will be filled with thick foam.
With such robust packages, our PCBs can always be protected in good condition, no matter if it is a one week delivery by air, or one month delivery by sea.
Differences between Reflow Soldering and Wave Soldering
Different types of components
- Reflow soldering is used to assemble SMT components on the pads of the PCB surface while wave soldering is used to assemble DIP/PTH components into the plated through holes of the printed circuit.
Different equipment and processes
- The equipment used in reflow soldering and wave soldering is different, and the processes are different as well.
- In reflow soldering, a reflow soldering oven is needed. A reflow soldering oven is a very big oven with 6 to 12 temperature zones. The temperature will begin rising from the first zone, then reach the peak in the last few ones, and cool down in the last zone. Solder paste on the PCB will be melted and components will be soldered on the PCB.
- In wave soldering, reflow soldering machines need to be used. The reflow soldering machine is just like a big rectangular pot with boiling tin. When the PCB and components are running through the boiling pot, tin will spray up into the PTH holes and the components will be soldered on the PCB
- These processes of reflow soldering and wave soldering are also different. Please refer to the following brief introduction:
- Reflow soldering: print solder paste - place components - run through reflow oven - AOI inspection - X-ray inspection - QA check
- Wave soldering: prepare tooling fixture - insert DIP components into the PTH hole - run through wave soldering machine - Quality inspection - QA check
Different types of solder are used
- In reflow soldering, we used solder paste. Solder paste is a kind of paste containing tin mainly, also copper, silver, flux, and water. It can adhere to the pads on the PCB and melt in the reflow oven at high temperatures.
- In wave soldering, solder bars are used. A solder bar is a metal bar containing tin mainly, and also copper, and silver. It will melt into liquid in the wave soldering tank at a high temperature.
Differences between PCB and PCB Assembly
- PCB fabrication and assembly are very critical for electronic devices. But we may not clearly understand PCB and PCB assembly. Here we would like to share with you the difference between PCB and printed circuit board assembly.
- PCB is short for printed circuit board, also called printed wiring board. It is the carrier of electronic components. All the components will be connected by PCB and then achieve electronic functions.
- PCBs can be classified as layers, such as single-layer PCB, double-layer PCB, 4-layer PCB, 6-layer PCB, or even up to 100 layers. PCBs can also be classified according to flexibility, such as rigid PCB, flexible PCB and rigid-flex PCB, semi-flex PCB, etc.
- There are many more clarification methods for PCBs. Please check PCB manufacturing on our website to know more about our PCB production.
- PCB assembly is short for printed circuit board assembly, it is the process of soldering the components on the PCB. PCBs and components have their functions, but they can only work as fully functional products after soldering all of them together.
- The components can be soldered by reflow soldering, wave soldering, or manual soldering. These are the most commonly used technology/methods used in PCBA manufacturing.
Consigned PCB Assembly & Turnkey PCB Assembly
- Consigned PCB assembly means customers will supply all material to us, and we just assemble the PCBs. In Viasion, we accept consigned PCB assembly or partially consigned PCB assembly. You may supply any components you have, and we handle all the rest.
- Turnkey PCB assembly means except for PCB assembly, we also need to produce or outsource all components and materials for the electronic PCB assembly project, such as printed circuit board, electronic components, cable/wire, and all supporting materials.
- As a small-volume PCB assembly manufacturer in China, we are very flexible and we accept all kinds of PCBA manufacturing, such as turnkey PCB assembly, consigned PCB assembly, and partially consigned PCB assembly.
Normally Used Components in PCB Assembly
When the currency runs through the conduct, there will be resistance. The resistor is specially designed to increase the resistance, it is used to limit the current in the circuit, to make sure other components can work stably with the required currency.
In the BOM list, resistors always start with an “R”, so we can easily recognize where one re resistors. Most of the resistors are very cheap, except for some special types or the ones with an extremely small tolerance.
We can simply regard capacitors as electricity containers. Capacitors are widely used in electronics, and there are many types of capacitors, such as ceramic capacitors, aluminum electrolytic capacitors, tantalum electrolytic capacitors, film capacitors, polymer capacitors, silver mica capacitors, glass capacitors, supercapacitors etc.
In the BOM list, capacitors always start with a “C”, it is also easy to recognize in the BOM. Most ceramic capacitors and aluminum electrolytic capacitors are not expensive, but some special capacitors are very expensive. So we need to pay attention.
The diode has two electrodes but only allows the currency to pass through from one direction. There are many different types of diodes, such as crystal diodes, zener diodes, varactor diodes, light-emitting diodes, rectifier diodes, schottky Diodes, etc.
The diode is also one of the three most widely used components, together with Resistors and capacitors.
Generally speaking, an inductor is a coil. The coil is made of insulated wire (used copper) wound on a frame. The inductor can form magnetic field induction when electricity runs through the coil.
Inductors can be classified according to if it is fixed value or variable value, Core material, the method in wire wounding, usage, etc. Field Effect Transistor (FET) is the most widely used type among them.
Transistor is used as a switch and amplifier, it can control and adjust the signal of electronic devices.
There are many different types of transistors according to their structure, function, power, frequency, and package.
A sensor is a device used to detect information, such as pressure, color, sound, temperature, humidity, speed, heat, etc, and then pass such information to the processor as electronic signals. The sensor works just like the organs of the human body.
There are many different types of sensors to meet the demand of different applications, such as pressure sensors, thermal sensors, position sensors, speed sensors, acceleration sensors, temperature sensors, humidity, speed, heat sensor, radiation sensor, etc.
Connectors are used to connect with wires or cables. Normally female connectors will be soldered on the PCB, and male connectors with cables can be plugged in on the connector easily in usage.
Small connectors can be designed and soldered as surface mount technology. But for the big connectors which need to be plugged in and pulled out frequently, it is better to be designed as a PTH assembly, which is more robust.
The transformer is mainly used to change the currency and voltage, but it also has other functions such as isolation, voltage stabilization, or impedance adjustment.
Transformers are widely used in power printed circuit board assembly. Normally we can raise or reduce the voltage to fit the demands of electronic devices.
A relay is a device used to control the electricity connection in the circuit, such as the connection or disconnection, switch, adjustment, etc. The process is automatic and will occur in certain situations. Relay is normally used for circuit production, automatic adjustment, and circuit switching.
Relay can be classified according to the technology, dimensions, power, and working principle.
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Basic Glossary in PCB Assembly
We can find many glossaries about PCB assembly easily on the internet. Here we would like to share only the very basic ones, with easy-to-understand explanation.
| Word | Description |
|---|---|
| PCB | Printed circuit board is the carrier for assembly of the electronic components, then to achieve the electronic functions. |
| PCBA | Printed circuit board assembly, is alternatively known as PCB assembly. It means the process of assembling the electronic components on the PCB bare board. Normally there are SMT assembly, PTH assembly, and manual assembly. |
| Solder paste | It is a mixture of tin, flux, and water used to be printed on the pads of PCB when doing SMT assembly. In the SMT assembly process, we need to print the solder paste on the PCB surface first, and then let it run through the reflow oven. Then the solder paste will melt and the components will be soldered on the PCB. |
| Pick & Place machine | It is the machine used to pick out the small SMT components and then place the components in the right place. High speed and high accuracy are needed, which is why Pick & Place machine is always expensive. The most famous brands of Pick & Place machines are Panasonic, FUJI, SIEMENS, MYDATA, YAMAHA, ASM, Samsung, JUKI, and Universal. |
| BOM | BOM is short for bill of material. It is the document to list the components, such as component brand, type, parameters, the quality needed, etc. We can know where components need to be placed from the component notation in the BOM. |
| Gerber | It is the most common type of file for PCB fabrication and assembly. We can see the pattern in all the layers. Together with BOM, these are the two most important files to get PCB fabrication and assembly done. |
| Reflow soldering | It is the process to solder the SMT components on the PCB bare boards. After solder paste printing and components placement, the PCB will run trough a reflow soldering oven to melt the tin. Components will be soldered when the tin is melted and cooled down. |
| Wave soldering | It is the process of PTH components soldering. The tin bar will melt in the solder stove. And the liquid tin will spray up like a wave. Then the pins will be soldered on the PCB when the PCB runs over the tin wave. |
| AOI | AOI is short for automatically optical inspections, and optical methods. And relative software will detect solder SMT defects, such as wrong components, fake soldering, and failure soldering. It is used as a substitution for manual inspection since the human will tend to get tired for long hours concentrating and using of eyes. The most outstanding advantage is the high efficiency. |
| ICT | ICT is short for the in-circuit test. It is useful to test failure circuit board assembly by electric connections, such as open, short, wrong components, fake soldering, etc. A testing fixture is always needed in the ICT test. |
| FCT | FCT means functional test. It works to test the electronic functions of the PCB assembly to check if the PCB will perform as designed intentions. A testing fixture is always in functional test. |
| X-ray inspection | We can see the soldering condition for most components with our eyes after PCB assembly. But for BGA assembly, the solder joints are hidden under the BGA, which is impossible to see by the naked eye. Then we use x-ray equipment to defect the possible soldering defects, such as short, open, voids, connectors, solder balls, etc. |
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Frequently Asked Questions
What is PCB assembly?
As mentioned before, PCB assembly means soldering electronic components on the printed circuit board. PCBs and components have their functions, but they can only work as fully functional products after soldering all of them together.
Do You offer quick-turn PCB assembly?
Definitely“Yes”. We strive to offer our customers quick turnaround PCBA service by all means so that your needs for quick turn PCBA will be satisfied.
Do you offer multi-layer PCB assembly services?
Of course, we can offer multi-layer PCBA services. We can offer any kind of PCB assembly service according to your expectation and requirements.
Do you offer RoHS or leaded compliant assembly?
Yes, we offer RoHS-compliant assembly. Viasion strictly sticks to the environmental protection policy. Materials and process operations in Viasion are standardized, taking human health and environmental protection into consideration. Please cooperate with us for ordering products and services without any concern.
What is your standard turnaround for PCB assembly?
Standard turnaround time varies from the types and the quantity of the PCB assembly. The following are some examples.
1) Quick turn PCBA service takes 1-5 days.
2) It takes 1 week for only PCB assembly.
3) Two to four weeks are taken for turnkey PCB assembly or mass production.
4) Four to ten weeks are spent on Turnkey box build assembly.
What’s the PCB assembly cost?
The following is a brief overview of some of the factors that affect PCB assembly costs.
1) Technology used: The assembly process may use either surface mount or through-hole technology. Sometimes, certain assemblies may require the use of both technologies, but this can add to the cost.
2) The number of layers of the board: The cost of a single-sided PCB assembly will usually be lower than the cost of a double-sided or multi-layer PCBA.
3) The size of the component: Typically, the use of smaller components and the fabrication of densely assembled boards will increase the cost.
4) The total number of components
5) Compliance: Multiple tests which are often performed to ensure assembly compliance also add to the cost.
6) Processes required: Some PCB assemblies may require a series of processes, such as wave soldering, X-ray inspection, automated optical inspection, manual soldering, and other processes. These may significantly increase the cost.
7) Flexible or rigid PCB assembly: Usually, the cost of flexible PCB assembly is higher than the cost of rigid PCB assembly.
8) Conformal coating: Costs are also affected by conformal coating requirements. The number of layers of the conformal coating can affect the cost.
9) Testing: From thermal cycling to circuit testing, many tests are required before shipping the products.
10) Packaging requirements: Special packaging requirements may result in increased costs.
Delivery: Costs may increase if expedited delivery times are required.
At the same time, do you accept multiple orders?
Yes, all you need to do is just contact our sales representatives and tell them your requirements. We will deal with your order and answer your questions quickly. Above all, if you have any requests or concerns, please contact our sales staff and we are looking forward to serving you.
How long have you been in the industry of PCB manufacturing?
Viasion was established in 2007. We have been in the industry of PCB manufacturing for 16 years.
What is the difference between PCB and PWB?
PCB and PWB refer to the same item which is called differently. PCB is short for printed circuit board while PWB is an abbreviation for printed wiring board. So they are the same without a difference.
How is a PCB assembled?
There are many steps involved in the PCBA manufacturing process. In brief, the main steps are as follows.
Step 1: Adding solder paste: This is the initial stage of the assembly process. In this stage, the solder paste is added to the component pads in all the places where soldering is required. The solder paste is placed on the pads and pasted in the correct position with the help of a solder screen.
Step 2: Placing components: After adding the solder paste to the component pads, it is time to place the components. The PCB passes through a machine that places these components precisely on the pads. The tension provided by the solder paste holds the components in place.
Step 3: Reflow soldering: This step is aimed at permanently fixing the components on the board. After placing the components on the board, the PCB passes through the reflow oven conveyor. The controlled heat of the oven melts the solder added in the first step, thus permanently attaching the components to the boards.
Step 4: Wave Soldering: In this step, the PCB is made to pass through waves of melted solder. This creates an electrical connection between the solder, PCB pads, and component leads.
Step 5: Cleaning: By this step, all soldering processes are complete. During the soldering process, a large amount of flux residue is formed around the solder joint. As the name implies, this step involves cleaning the flux residue. Flux residue is cleaned with deionized water and solvent. With this step, the PCB assembly is completed. Subsequent steps will ensure that the assembly is completed correctly.
Step 6: Test: In this stage, the PCB assembly is completed and inspection begins to test the position of the components. This can be performed in two ways.
1) Manual: This check is usually performed for smaller components. The number of smaller components does not exceed one hundred.
2) Automatic: This check is performed to check for bad connectors, incorrect components, misplaced components, etc.
What is the minimum order quantity for PCB assembly?
There is no minimum order quantity for PCB assembly in Viasion. By the way, Viasion focuses on low-volume to medium volume PCBA service.
Where do you manufacture your products?
Viasion is located in Shenzhen, China. Shenzhen has outstanding location advantages such as a prosperous economy, a complete manufacturing industry chain, high level of scientific and technological innovation, which means that we can provide you with an efficient one-stop solution for PCB & PCBA relying on the city’s resources.
What is the difference between PCB and PCBA?
As mentioned above, PCB is short for printed circuit board. It is the carrier of electronic components. All the components will be connected by PCB and then achieve electronic functions. PCB assembly is short for printed circuit board assembly. It refers to the process of soldering the components on the PCB. PCBs and components have their functions, but they can only work as fully functional products after soldering all of them together.
Do you offer testing and inspection services?
Inspection and testing services offered by Viasion include:
1) First Article Inspection
2) Solder Paste Inspection
3) AOI (Automated Optical Inspection)
4) Visual Inspection
5) X-ray Inspection for BGA
6) Incoming Quality Control
7) In-Process Quality Control
8) Quality Assurance
9) ICT (In-circuit Testing)
10) FCT (Functional Testing)
11) Open/short Testing for PCB
12) Flying Probe Testing
What standards and certifications does Viasion follow?
Viasion follows IPC guidelines, ISO9001:2015, and RoHS/REACH standards, demonstrating that our company is trustworthy. Undoubtedly, we can offer high-quality products to our customers.
Which PCB equipment you are using to make PCB assembly and PCB fabrication?
Honestly speaking, there are many devices used to make PCBA and fabricate PCB. The main equipment is listed here.
In the process of assembling PCBs, the following production equipment is required.
1) PCB cleaning machine
2) Solder paste automatic printing machine
3) Solder paste inspection (SPI) machine
4) SMT machine
5) Reflow soldering machine
6) Wave soldering machine
7) AOI tester
The following production equipment is required in the PCB production process.
1) Film exposure machine
2) Drilling machine
3) Laminating machine
4) Grinding machine
5) Lamination machine
6) LDI exposure machine
7) Etching machine
8) Silkscreen printing machine
9) Equipment for surface finish
10) Punching machine
11) Electrical measuring machine
12) V – CUT machine
13) Flying probe tester
14) Impedance tester
