What Are Turnkey PCB Assembly and EMS?
Turnkey PCB assembly is including all the steps complex in making a PCB, beginning from the fabrication process all the time to the assembly process.
The circuit board is made from cut with the routes tracked according to the schematic the customer offered.
In PCB manufacturing, turnkey PCB assembly is meaning the electronic manufacturing service (EMS), since it takes hands of the entire process of designing, manufacturing, and testing the printed circuit board.
What's the Difference Between Turnkey PCB Assembly and Consigned PCB Assembly?
Turnkey PCB assembly points to the process of manufacturing and assembling the printed circuit board from cut and going through all the manufacturing and assembly processes under one draw.
On the contrary, consigned PCB assembly refers to decomposes the PCB manufacturing process into parts and distributing each part to a different vendor/person to hand on. For instance, if you are someone who wants to manufacture a PCB.
you have two options: either go for a company, like Venture, that will run the entire process of PCB fabrication and assembly and deliver the final printed circuit board to you.
What Other EMS Solutions Are There Apart from Turnkey PCB Assembly?
Beside from Turnkey PCB assembly, Venture offers other EMS solutions as well. These include electronic component sourcing and PCB layout.
Finding genuine and original components can be a very difficult work because of the availability of low-quality components that looks very similar to original ones. With Venture, you don’t have to worry about component sourcing.
We know where to get 100% original and unused electronic components at the best prices, without the risk of fake components. We get our components from genuine factories, which delect the chance of getting used or unoriginal electronic parts and components.
Your Reliable Turnkey PCB Assembly Supplier
Venture provides Kitted PCB Assembly Service, Partially Kitted PCB Assembly Service and Turn-Key PCB Assembly Service, among these three services, 60% of our customers will choose turnkey PCB assembly services.
Why customers like our turnkey PCB assembly service?
Turnkey PCB assembly means customer provides all the design files, we produce PCBs(bare printed circuit boards), prepare SMT stencil(if needed), and purchase all the components, and then return assembled circuit boards to you.
In the past producing the PCB assembly especially the first prototype was a very expensive and slow process. Keeping up with multiple vendors all around the world, slow lead-times, and out-of-stock components become a headache. Managing multiple vendors to coordinate together on one assembly job had brought Frustration, miscommunication, and delays.
Now you can sit back and relax, let us do it all for you. Our turnkey PCB assembly service can get your PCB assembly job done more effectively and efficiently, you don’t need to worry about managing multiple vendors. Getting your product to market quickly and affordably has never been easier.
Your Leading Turnkey PCB Assembly Supplier in China
Venture provides reliable full turnkey PCB assembly service solution from prototype quantities, small-volume to mid-volume production runs. As a provider of one-stop PCB assembly services, our company provides expert consulting in Design for Manufacturing (DFM). We handle the whole Turnkey PCB Assembly process including:
- Ordering all the components,
- PCB manufacturing,
- PCB assembly,
- Testing and final shipment.
Venture PCB Assembly division has a workshop with 1800 square meters and 150 employees include 4 SMT lines and one prototype assembly station. We handle all types of Turnkey PCB Assembly projects with any quantity especially small batch assembly and low volume Turnkey PCB Assembly, from basic through-hole PCB assembly technology to standard surface mount assembly, mixed assembly, kit assembly to ultra-fine pitch BGA assembly.
Our PCB types include: rigid PCB, Metal Core PCB, flex PCB and rigid-flex PCB..etc.
Venture Turn-key printed circuit board assembly can work with BGA of 0.35mm pitch with X-ray testing, Passive Components minimum 01005 (0602) package, Fine Pitch Components minimum 0.38mm pitch.
Our Test types include visual inspection, X-ray inspection, AOI testing, In-Circuit test and functional test (customer provide functional test instructions).
For low volume turnkey PCB assembly projects, our quick turn Turnkey PCB Assembly delivery time goes from 8 hours to 48 hours when components are ready.
Venture has relationships with all top distributors such as Digi-key, Mouser and Element 14. Our engineers will give you expertise in DFM (Design for Manufacturing) checking for your every turnkey PCB assembly order, we verify all details of your files including BOM and Gerber files to allow you to correct your PCB design before we build it, saving significant time and cost and avoiding unnecessary repeats of the turnkey PCB assembly process.
Our headquarters and turnkey printed circuit board Assembly manufacturing facility is based in Shenzhen, China, this allows us to provide low-cost PCB manufacturing, parts procurement, and PCB assembly using local supply chains, while at the same time, our sales, customer service, and engineering team runs 3 shift 24 hours to staying in close contact with all time zone customers.
No matter you are an electrical engineer, a product designer, a system integrator or a maker, looking for a turnkey PCB assembly manufacturer, Venture will be your perfect choice.
Through our 2 hours rapid response services from our 24/7 sales and tech support team, and excellent after-sales service, we will be your best turnkey PCB assembly manufacturer in China.
At Venture we can answer any turnkey PCB assembly questions that you may have, pls feel free to contact us anytime for your turnkey PCB assembly projects.
Turnkey PCB Assembly: The Ultimate Guide
Today we are going to learn about Turnkey PCB Assembly. It is one of the most significant developments in PCB assembly.
I will start by defining what turnkey PCB assembly is, then give you some basic outline of what it means to the PCB industry.
We will then look at the different techniques in the turnkey assembly process.
We will also be able to look at the benefits of using turnkey PCB assembly, before we delve into how the process goes.
- What is Turnkey Assembly?
- Benefits of Turnkey PCB Assembly
- Alternatives to Turnkey PCB Assembly
- Techniques in Turnkey PCB Assembly Process
- Turnkey PCB Assembly Solution and Capability
- Turnkey PCB Prototype Design Process
- Actual Turnkey PCB Assembly Prototyping
- Step by Step Process in Turnkey PCB Assembly Process
- Hiring the Right PCB Assembly Service Provider
- Who Should Use Turnkey PCB Assembly?
What is Turnkey Assembly?
Owing to the hassle of traditional PCB assembly approaches, it became necessary to work towards a consolidated assembly process.
The involvement of many players makes the process very slow and expensive. This is what led to the rise of Turnkey PCB assembly.
Turnkey PCB assembly
The word Turnkey in its general use refers to the provision of a complete service or product, in a state that is ready for use.
You just place your order, the manufacturer makes the quote, and the rest is left to him. What you get is a ready product, where you only “turn the key” and you’re good to go!
Turnkey PCB assembly, therefore, involves consolidating the entire PCB assembly process.
What this means is that you just place an order, and the contractor takes care of all the steps involved in creating the final PCB.
Some manufacturers have gone ahead to include body works in their turnkey PCB assembly services.
Benefits of Turnkey PCB Assembly
Turnkey PCB assembly has made work easier. The convenience of this approach over the traditional options can be seen in the benefits outlined below.
Turnkey PCB Assembly
1) Reduced costs
The adoption of turnkey PCB assembly approach has made the overall cost of production much cheaper.
Normally, the service is packed-up, meaning several expenses are eliminated.
One of the areas where this relief is felt the most is in freight costs.
Imagine having to ferry the boards and the components from their respective sources to the assembly workshop.
Procuring the components is also easier. The electronic assemblers are always able to secure good deals with the component manufacturers or distributors.
It is because they have developed long-term cooperation between them.
2)Good component quality
The procurement of parts is left for the professional assemblers. Their expertise and long-term cooperation with the suppliers help them to get the best component quality.
There are high chances of being given a raw deal if you were to procure the components yourself. This is because you may not have the expert ability to scrutinize the quality. This gets even worse if you are a one-time buyer.
Remember, the supplier has nothing to lose; hence he can comfortably give you a raw deal.
3)Shorter Lead Time
Now think about having to go through all the faces of PCB assembly separately. You will have to first contract a company to do PCB fabrication.
After that, you will move to procure the components, before finally contracting for the assembly.
This process takes even longer if the companies are located in different countries.
In full turnkey PCB assembly, all these are done together. The procurement process is reduced to one.
All that communication with several partners is also eliminated.
Reducing the number of communication and quotations reduces chances of project distortion.
Having to give three different quotations opens a wide space, within which mistakes can occur. This is increases the likelihood of a compromised product.
4)Ease of Monitoring
Apart from reducing the lead time, full turnkey PCB assembly also ensures easy and smooth monitoring.
Following the disintegrated step would require you to have different experts to monitor each of the stages.
The whole process is monitored as a single process because the sub-sectional monitoring is handled within the contractor’s structures.
There are qualified engineers within the company’s ranks to ensure every stage is perfected. Yours is to see that the final product is of the desired quality.
By just logging in to the vendor’s website, you can follow the entire process real time.
The implication of having only one vendor to manage can be even more comforting if the vendor goes up to assembling the final product.
In traditional PCB assembly, you will have to do prototypes for each of the stages involved.
Full turnkey PCB assembly gives you a leeway by reducing the cost and time spent on prototyping. The vendor takes care of it all, based on your product specifications.
This further helps to reduce the production time.
Prototyping by the vendor’s seasoned experts also means you are bound to get a better product than if you did it from your end. Your customers will be sure to get the products in good time for their use.
6)Early problem detection
One painful experience you want to avoid is realizing a mistake when you have already spent too much on the PCB.
An error that occurs during prototyping for the printed circuit board is better detected before the boards are produced.
Ordering parts separately exposes you to that danger. You may order for the PCB board or the components, only to realize during the assembly that there was an error, and so they won’t match.
If you go for turnkey PCB assembly, it will be upon the vendor to ensure he gets it right because all liability falls to them in case anything goes wrong.
The vendor has been to this severally and has mechanisms for early detection.
Alternatives to Turnkey PCB Assembly
Turnkey PCB assembly has several attractive benefits, but it is not the only approach to PCB assembly. The other options include:
1.Kitted PCB Assembly Service
This is where you provide the assembly service provider with parts to be assembled.
It means you order for the printed circuit boards and components without the intervention of the assembling company.
Upon receiving the components, the assembler follows the right assembly procedure as per your agreement. The assembled board is then taken through the necessary checked to ensure it meets your description.
Finally, it is shipped to you, or your preferred destination.
The advantage of this method is that you always have full control over the cost of the parts.
This is a positive departure from the turnkey method where the vendor has control over the parts. There is no risk of being duped into getting the wrong parts.
Kitted PCB Assembly
However, if you choose kitted assembly, you will need to triple-check all the ordered parts. Also, in case of any wrong ordering, the liability falls squarely on you.
The other challenge is that you will also have to place your orders per the assembler’s specifications for packaging. If you use incompatible packaging, they include an additional charge.
Kitted PCB assembly may also be expensive, especially if you have to order the parts from different countries.
2.Partially Kitted PCB Assembly Service
This can also be called half-turnkey Assembly.
In this approach, you will provide some of the parts to be assembled, while the assembler provides the rest.
For example, you may choose to get the printed circuit boards from the assembler and only source for components from another company.
This approach is, therefore, a hybrid between full turnkey and kitted PCB assembly.
It may be adopted either because the assembler does not produce the other parts, or you prefer parts from another vendor.
This approach allows you to combine the services and parts of your preferred assembler with the quality parts from your preferred parts vendor. It means the quality of the final product lies mostly in your decisions and choices.
The assembly process is relatively faster compared to kitted assembly.
Partially kitted PCB Assembly
However, you will always need to double check the quantity and quality of the parts delivered to the assembler.
You will also incur more costs in ordering extra parts to take care of any damages during the assembly process.
This is because the assembler does not produce these parts, or you just prefer to get them from elsewhere.
Techniques in Turnkey PCB Assembly Process
Turnkey assembly can be done using different techniques. It all depends on your choice, which will be determined by the attributes of your preferred product.
Let us now look at the different techniques in turnkey PCB assembly.
In this technique, through hole components are mounted onto a bare printed circuit board. Through hole components have leads, which go through the drilled holes.
Once the leads have been inserted through the holes, the assembler solders the leads on the opposite side of the board. The soldering can be done manually or using automated insertion machines.
The components or through hole PCB assembly techniques are of two types:
- Axial Lead Components-they have leads that go through the component from one end to the other.
- Radial Lead Components-Have leads that protrude from the component’s body on the same side.
Now I will briefly take you through the process of PCB assembly using the through hole technique (you can get in-depth details of this in our other guide)
Step1.The very first step in through hole PCB assembly is to prepare the surfaces to be soldered. The reason you have to do this is so that the surface can properly catch the solder.
Step2.Secondly, place the components on the board. The component leads are inserted through the right holes, ready to be soldered
Step3.After the leads are inserted, the next step is to heat the leads and the pads, so as to enable melting of the solder.
Step4.The next step is to apply solder to the joint.
Step5.Touch the meeting point of the solder and the joint with the iron until adequate solder has flown. The soldered board is then left to cool.
Finally, the assembled board is inspected to see if everything went on right, before it is packaged and dispatched.
Figure 6Through hole PCB assembly
The advantages of through hole technique include:
- Easy prototyping
- High heat tolerance
- Better power handling capability
- Stronger physical connections
However, through hole technique has the following weaknesses
- Longer production time
- Less space for mounting the components
- Board production is very expensive
- Slower operation speed
As the name suggests, this technique involves mounting the components to the surface of the Printed Circuit Board.
This method came to be more prominent from around 1980. Today, it has widely overtaken THT as the most widely used PCB assembly technique.
The components are not inserted through holes as in the case of through hole technique.
The leads of surface mount components are located beneath packages, which make contact with the surface of the board
The surface mount process is usually more sophisticated, and cannot be done manually.
Surface mount technology
The SMT process is usually automated and is simpler and faster.
SMT is suitable for making smaller and lighter, but more powerful designs. This is because both sides of the board are available for mounting components.
Also, SMT is popular due to its higher lead count compared to through hole assembly. SMT components have lower resistance and inductance
This technique also offers higher production capacity than through hole technique.
SMT requires higher capital investment and requires higher levels of skill
There are also higher chances of defects since the components are very small and are packed within the board.
It is not suitable for high voltage components
Because the components are very small. Sometimes they do not have adequate surface area for marking the component names and ID codes.
These are just some of the advantages and disadvantages (you will find more of this on our guide on Surface Mount PCB Assembly)
Mixed PCB Assembly – Both Through Hole & Surface Mount Assembly
If you are handling applications that require the capabilities of both SMT and THT, then we recommend this technology.
Using this method, you are able to have both the THT components and SMT components assembled in one PCB.
Let us look at a brief description of the procedures involved.
Step1.Component-side SMDs are placed on the PCB and reflow soldered
Step2.On the opposite side, glue the “solder-side” SMDs in place
Step3.Through hole devices are then inserted into the holes on the board
Step4.Soldering-All the components are soldered in one wave
Step5.It is then time to solder the components that need hand soldering. Here, a lot of care must be taken so as not to interfere with the already soldered components.
Step6.Finally, the assembly is tested and packaged, ready for delivery to the client.
This technique has many applications. Below, I have listed a few areas where the technique is widely used.
- In video processing
- Communication hardware
- Sensor boards
- Smartphone Accessories
- Industrial Controller Assemblies
- Led lighting products
- Server Boards
- IoT Hardware
Let us now see some of the benefits of using the mixed technique of PCB assembly
Larger components with high power handling capabilities, and the smaller but highly functional SMT components are assembled on one board.
Also, components are mounted on both sides of the PCB, just like in pure SMT. There is, therefore, enough space for more components
This means the resulting devices are better performers in both power handling and processing speeds.
In general, we can say that PCB assembled by the mixed technique produces boards with a combination of both SMT and THT strengths.
Turnkey PCB Assembly Solution and Capability
With turnkey assembly, you can handle many PCBs such as:
1.Flex Turnkey PCB Assembly
Here, the main attributes is the use of flexible plastic.
This enables the board to turn without getting damaged. They can be single, double or multisided.
Flex PCB assembly
They are best where there is a need to minimize on weight and space use, like in satellites. However, they are relatively expensive to create.
2. Rigid Flex Turnkey PCB Assembly
Figure 10 Rigid flex PCB
It involves joining together flex PCB and rigid PCB. Follow the recommend process for assembling rigid and flexible PCBs.
The resulting PCB, therefore, has capabilities of both PCB types-they have the ability to turn. They are also widely used in the aerospace industry.
3.Rigid Turnkey PCB Assembly
In this assembly, a solid substrate material such as fiberglass is used. The board, therefore, cannot be twisted.
Remember, these boards are not suitable for applications where space and weight is limited.
An example of a Rigid PCB is the computer motherboard. Rigid turnkey assembly tends to be relatively cheaper.
4.RF Turnkey PCB Assembly
Any PCB with a frequency of more than 100HZ is generally considered to be a Radio Frequency PCB.
They are generally designed to operate high-frequency signals with small wavelength.
RF boards have a multitude many applications they are used including in smartphones, robotics, sensors, and wireless technology.
5.High Voltage Turnkey PCB Assembly
This is generally used to assemble PCBs for applications that require very high voltages to operate.
High voltage PCB
Factors to consider when designing and assembling these PCBs include insulation, altitude and clearance.
Typical areas of application include: High altitude aircraft, High-tech lasers, and power supplies for particle colliders
6.Metal Core Turnkey PCB Assembly
These PCBs use metallic material as the base. This is mainly because metals are suitable for distributing heat.
Metal core PCB
Copper and aluminum are some of the most commonly used metals.
The main application areas for metal core PCBs include:
- Power converters
- Street safety applications like streetlights, lighting, etc
- General lighting applications
- System automotive LED applications
- Hybrid/electric motor control applications
7.High Power Turnkey PCB Assembly
High power PCB
The main characteristic of the PCBs is that they are designed to tolerate large amounts of power by use of thick copper.
One of the main areas of application is in the military radar.
Using high power PCBs, smaller and much flatter transformers are used to provide power to the radar systems.
This eliminates the problems of bulk and weight, while still maintaining the high power capabilities of the large conventional transformers.
8.High Speed Turnkey PCB Assembly
For these PCBs, equipment signals are interrupted so as to produce high.
This is achieved by altering the packaging, interconnections and layout, leading to signal interruption.
High speed PCB
High Speed PCBs are mostly used in electronics such as ATMs, radios that require high impedance control, and some medical equipment.
9.Gold Finger Turnkey PCB Assembly
In this technique, the terminal of a card-edge connector is plated with gold. It involves fabricating the “fingers” by flash gold.
Gold finger PCB
The primary purpose of the gold finger is to protect the PCB prototype from wear and tear because such boards are plugged several times.
One of the areas where this technique is used is in making memory cards.
10.HDI Turnkey PCB Assembly
High-Density Interconnect PCBs are designed to allow denser assembly of components. The components assembled in HDI assembly are usually smaller.
They are assembled in very close proximity; thus the paths between the components are very short.
Some areas of application include smartphones, computers and medical equipment.
The advantage of HDI PCB assembly is that it allows for the incorporation of more technology in less space.
11.LED Turnkey PCB Assembly
Light emitting diode (LED) is a semiconductor with two leads, which emits light whenever current passes through. These two leads are soldered onto a PCB that has a metal base.
This is because the LEDs produce a lot of heat. The metal base, therefore, helps to dissipate the heat.
LED PCBs are used to make LED bulbs. Their main advantage is that they are cost-effective.
12. Amplifier Turnkey PCB Assembly
As the name suggests, this assembly technique is used to assemble PCBs for audio devices, especially power amplifiers.
The main factors to consider when assembling Amplifier PCBs is the power supply and signals.
13.Aluminum PCB Assembly
Here, aluminum is used as the base metal. The benefit of this is highly efficient heat dissipation and component cooling.
The advantages include:
- It is environmentally friendly
- High heat dissipation
- Higher durability
Aluminum PCB assembly is used in computes CPU boards and power modules, among many other areas of application
14.High Frequency Turnkey PCB Assembly
This is used to assemble PCBs for high speed and high frequency products, such as for the communication sector.
High frequency PCB
The features of high frequency PCBs include:
- Low water absorptivity
- High heat resistance and impact endurance
- Thermal expansivity that is similar to that of copper foil.
15.High TG PCB Assembly
High TG PCBs are made up of highly flame resistant boards. They have high glass transition temperatures; meaning it takes a lot of heat for the epoxy to change state.
High TG PCB
High Glass Transition Temperature PCBs have the following characteristics.
- Higher heat resistance;
- Lower Z-axis CTE;
- Excellent thermal stress resistance;
- High thermal shock resistance;
- Excellent PTH reliability
16. Heavy Copper Turnkey PCB Assembly
Here, 3-ounce copper or higher is used in the inner or outer layers of a printed circuit board.
It is mainly used where there is high heat dissipation, higher current conductivity, and better mechanical strength.
Thick copper PCB
Some of the uses of Heavy Cu PCBs include planar transformers and power conveyors.
17.Ceramic PCB Solution
Ceramic PCB is used when you need a high frequency, high temperature, and high insulation products.
The main areas where it is used include:
- Electric power electronic control module
- High insulation and high-pressure devices
- High power LED
- Solar panel modules
- Electric power transmitter modules
Turnkey PCB Prototype Design Process
Prototyping is a very critical process in making a PCB.
Before you start the PCB assembly process, there is need to fully understand the PCB that you intend to come up with.
The main benefit of prototyping is that it helps to avoid many mistakes. This is because it helps you draw the path you want to walk before the journey begins.
Normally, the prototype acts as a map that guides you to your destination. It is therefore very important when doing a project for the first time.
Prototype turnkey PCB assembly
If the project is a continuation of another, you may not need a prototype because the design of the PCB is already available.
Most companies do just part of the PCB prototype and assembly process, but today the turnkey method is gaining popularity more and more.
Here, the entire process of designing the PCB prototype takes place within the same company, which also goes ahead to assemble the PCB.
So then, how does turnkey PCB assembly prototyping go?
The process takes the following stages.
If the company produces its own PCB boards, then the process begins from prototyping the PCB itself, before getting to the assembly.
Let us briefly look at the PCB prototyping, before we can delve into how the assembly prototyping is done.
I will explain a few of these steps because of their relevance to our main focus, then the rest we will just mention.
(We have discussed the entire PCB prototyping process in our other outline)
Step1.Get a proper description of the PCB
Before you start to prototype, you must know what the client wants. Some clients are able to define the specifications of the board that they want, while others are not, and must be helped.
When preparing to design a prototype for a PCB, first of all ensure you have the following information about the desired PCB.
The number of layers you need
- Board thickness
- Board dimensions
- Copper thickness and weight
- Minimum tracing and spacing
- Minimum hole size
- Minimum annular ring
- Surface finish
- Soldermask and color
- Silkscreen legend and color
- Drill file NC Excellon
- Drill file tool list
Step 2.Design the PCB
The first thing in the process of turnkey PCB assembly is to come up with the design of the PCB.
You already have the specific attributes of the PCB that you intend to make.
You are therefore able to make a design of what it ought to be. Always adhere to the specifications given by the client
Step 3.Schematic Design
This is where you define the crucial information like the materials and the components that will be used during the assembly process.
Now, this is where you also describe how the components will be placed.
At the end of this phase, a preliminary check is run to detect any defects, and any that shows up is then corrected.
After that, you will use a specialized design tool to run simulations. This is to confirm the functionality of the board.
If that goes through successfully, the electronic design is then converted into a netlist. This is a description of the interconnectivity of all the included components.
Throughout the process, keep running all the relevant checks so as to ensure that you correct every anomaly as early as possible.
Step 4. Prepare a Bill of Materials
From the simulation, you are now sure of all the components and materials you will need. You can also calculate the quantities based on the number of boards you are to assemble.
The BOM will help you to ensure you do not leave out any material or component that you will require.
You will be able to if there are any components and materials you will need, which you don’t produce, and therefore have to be ordered for.
Some of the information to include in the BOM are:
- The number of components required.
- The codes used you will use to identify individual parts.
- The specific characteristics of each component, such as the resistivity in ohms
- Where each component will be positioned on the board
After compiling the BOM, the component engineer and the layout engineer should then put together the parts.
Step 5. Routing Design
In the next stage, create a routing design. Here, you design the traces that will be used to connect the elements of the PCB.
The main factors to consider include the noise sensitivity and power levels.
Remember, the routing design should be designed based on the netlist that you already developed.
You will be able to calculate the routes based on the factors described on the netlist.
It is important to keep checking the design regularly to see if there are any functionality issues. Before you begin fabrication, do another thorough check to confirm that the design has no problems.
At this point, check for thermal issues. Also, do a design rule check and all other relevant checks and assessments before proceeding to fabrication.
After this, you are now ready to move to the fabrication stages as follows.
Step 6.Creating the photo film
The film made using a plastic sheet.
A special printer called a plotter is used to create the film. Here, the parts that will be conductive, and those that will be non-conductive are marked.
Step 7.Printing the inner layers
Here, you start by applying copper to the substrate material.
First, pre-bond copper to the substrate, followed by applying a photosensitive film called photoresist.
Ultraviolet light is then used to harden the photoresist.
Any place where copper should not be is blocked by black ink from the plotter so that it is not hardened. This unhardened part is then removed.
The hardened photoresist is then removed, thus revealing the copper in the spots where the design indicates should be.
After this, align the layers. If multiple layers are involved, ensure you align them accurately, then punch accurate registration holes.
I will just mention the subsequent steps, so that we can get to our main focus for today, which is Turnkey PCB Prototyping.
You can get more on these steps on our other outline. They are as follows:
· Step 8.Fusing of the layers
· Step 9.Drilling holes
·Step 10.Copper plating
· Step 11.uter layer imaging
·Step 12.Copper and tin layer plating
·Step 13.Final etching
· Step 14.Solder mask application
·Step 15.Surface finishing
·Step 16.Applying silk screen
Actual Turnkey PCB Assembly Prototyping
Once you have the PCB board prototyped and produced, you can now work on the assembly prototype
If the PCB is produced in the same company, this will actually be a continuation of the above process. However, if the boards are sourced from another company, then the prototyping starts right here.
If the company does not produce some or all of the materials and components required during the assembly, the first stage is to source for these materials.
The descriptions in the BOM must be adhered to when sourcing so that you do not get parts that will not lead to the desired outcome
Once you have successfully sourced for the components and materials, the assembly prototyping process takes the following steps.
Step2.Solder paste stenciling
A solder paste is applied to the board. In order to make the solder melt, the solder paste mixes with a flux. The solder paste is, therefore, able to bond to the surface of the PCB. A stencil made of stainless steel is placed over the PCB to ensure that the applicator applies solder paste only to destination points of the components.
Step3.Pick and Place
Using a pick and place machine, place the surface mount components
We then use a pick and place machine to place surface mount components, or SMDs, on the PCB. This device places these non-connector components on top of the soldering paste in preprogrammed locations.
Step4. Reflow Soldering
The PCB is moved on a conveyor belt through a reflow oven with a series of heaters. The heaters slowly heat the PCB to around 480 0F to melt the solder on the solder paste.
From there, the temperature is reduced; hence the melted solder is solidified. This leaves the SMD components permanently attached on the PCB.
If the PCB is to be assembled on both sides, stenciling is done, and reflow is conducted separately on each side.
Step5.Inspection and Quality Control
After the reflow stage is completed, check for errors. Conduct evaluations to check for any accidental movement that might have occurred in the process.
Checks to be conducted include manual examination, x-ray inspection, and automatic optical inspections. Check also for connection quality.
Step6.Insert through hole components
If the design of the board also includes through hole components, this is the stage to insert them.
The board is placed on another conveyor belt that takes it through another oven. This oven is designed to completely cover the bottom of the board (where the leads are to be soldered) with molten solder.
However, if the board is double-sided, this method will not work because it will damage the components on the solder side of the PCB. It, therefore, means that the through hole components will have to be soldered manually.
This is the final stage of the turnkey PCB assembly prototyping. The boards are attached to relevant systems as intended for the real boards to see if it is really up to expectations.
During testing, design flaws and areas that need to be improved are taken note of. If you had assembled multiple prototypes, pass them through identical tests so that you can gauge the functionality of each of the prototypes.
If they are found to be of the required quality, the real assembly is then commenced.
If you realize problems while testing the prototype, you will need to correct the issues and design another prototype.
Step by Step Process in Turnkey PCB Assembly Process
Whether on a large scale or a smaller scale, turnkey PCB assembly process is justifiably a long one.
However, compared to the bit-by-bit assembly process, this method is far much faster.
Let us now look at the main steps in the turnkey assembly process.
Turnkey PCB Assembly
Step1.Confirm the necessary files and order details
At this stage, the order details are thoroughly checked to ensure that there are no inconsistencies.
The BOM, gerber, centroids and any other relevant order documents are verified to ensure they correspond accurately.
Descriptions such as footprint accuracy and part spacing are also looked into.
This procedure is meant to ensure that design errors in the final product are minimized as much as possible.
It will therefore help to ensure that production goes on once so that no time is wasted in doing rework
The client will need to maintain touch with the company. If any anomalies are detected, the company will always inform the client and recommend the necessary corrective measures.
The client will need to respond in good time because production won’t proceed until the company receives the response.
Step 2.Order and receive PCB and components
After keenly looking at all the required materials, the company places an order for all the materials and components. Only materials and components that are not manufactured within are to be ordered.
The components and materials must be ordered in excess of the actual number to be used. This is because there are bound to be some damages during the assembly process.
If the company manufactures the boards, then move to step 3. Otherwise, if the boards are also ordered from elsewhere, skip to step 4
Step 3.PCB Fabrication of the board
The PCB fabrication process is one of the longest processes in turnkey PCB assembly. The bare PCB goes through a series of material lamination. It is then drilled and etched.
Also, the other steps here include: creating stencil for solder pasting, addition of solder mask and surface finish, and printing of silkscreen.
Finally, electrical testing is done to confirm conformance with the specified design requirements.
We will just mention that much on PCB fabrication today.
This process has been well explained in our other outline. We also saw quite a bit of it earlier in this guide, when we explained the PCB board prototyping process.
Step 4. Inspection of incoming materials and components
Before you can use the ordered components and materials, you must thoroughly inspect them. Check whether all the materials meet the requirements as outlined in your order documents.
Test also to see that they are of good quality.
This will help in realizing any problems early enough.
Normally, this process is usually undertaken by the company’s quality control unit.
Step 5. Solder Paste Screening for SMT components
We are now entering the actual assembly process, having made sure that everything is ready.
The very first step is to apply solder paste to the bare PCB.
The stencil is fitted over the surface of the board so that only the pads for SMT components remain uncovered.
Solder paste is then applied over the uncovered spaces using an applicator. After this, the QC must confirm that the pads are well covered with solder paste.
Also, check to ensure that only the correct parts have received the solder paste. Do this for both sides in the case of double-sided SMT boards.
Step 6.Component Placement
In the next stage, a pick and place machine is used to mount the components in their respective positions on the board.
Again, inspect the board to confirm that all the components are well placed before soldering starts. For two-sided boards, the placement is done one side at a time.
Step 7.Reflow soldering
After placing the components, reflow soldering is done to melt the solder paste and ensure it holds the components stable.
For double sided boards, apply adhesive on the already soldered components. This is to keep them from falling off when the opposite side goes through wave soldering.
Because this process is usually heat intensive, most SMT components are designed to withstand a lot of heat.
Step 8.X-Ray Inspection
Using X-Rays allows for a more in-depth and more accurate inspection.
The X-Ray machine generates images that are analyzed to determine solder joint quality.
The outcome is looked at vis-à-vis the client specifications to see whether the right standards have been met.
Analyzing the X-Ray images also helps to understand the causes of the defects.
It may have been due to insufficient solder paste, improper placement of parts or poor reflow profile.
Step 9.Placement and wave soldering of Through hole components
The leads of the through hole components are inserted into the correct through holes. They are placed on a conveyor belt, which takes it through molten solder.
Also, the solder is applied to the component leads and pads, hence bonding them together.
The board is then cooled to let the solder dry and firmly hold the components in place.
Step 10. Manual soldering
Manual soldering is done when the through hole components are too few to warrant wave soldering.
Also, it can be done if there are specific components that require just that.
Step 11. Final Inspection
Most of the inspection work is done in between the steps.
However, a final inspection must be done on the fully assembled board to ascertain its full functionality.
One of the main inspection methods used here is visual inspection. Well trained quality control personnel look at the components one-by-one to see if there are any defects.
Automated Optical Inspection is also done, especially for high volume projects.
Some companies also offer Functional Circuit Testing (FCT), but this usually comes at an additional cost.
Once the products successfully pass these checks, they are ready for shipment to the client.
Hiring the Right PCB Assembly Service Provider
Looking at the turnkey PCB assembly process, you wouldn’t want to do trial and error with your project. So are you wondering how to get the best PCB assembly service provider?
Let us now look at the process of ensuring you get a service provider (company) which will meet your expectations.
Step 1.Have your timelines, and be ready to follow them
This is a long process. It may not be the best news, but the truth is that the process will have to take some good time.
Do not try to speed up the process as this may lead to you getting compromised products. Instead, start early enough so that you are not time-barred.
Establish contact with the company you are thinking about and take time to understand exactly what services they offer.
If possible, have a few companies in mind, and check their services to see which one best agrees with your requirements.
Now look at your first shortlist and see which company can deliver within your specified timeline.
Step 2.Check Experience
You have just seen how complicated and delicate the turnkey assembly process is.
This demands that a service provider has good experience in handling similar services for some time.
There are several areas in which lack of experience can lead to serious mistakes.
An assembly service provider that has been in practice for long must have mastered all the error-prone stages.
They are therefore most likely well equipped with the right remedies for these risks.
But how will you know that you are selecting the most experienced company?
Go to the company’s website and check the following information.
For how long has the company or service provider been in practice?
For how long have they done turnkey PCB Assembly?
Check to see what type of firms they have served before?
How relevant are their products to your desired product?
If you cannot get these answers on the website, you can contact the company and ask for this information.
Step 3.Check Quality Indicators
There are several aspects that you can look at to check whether the products of the company are of good quality. Some of the leading indicators include:
- Equipment used: Do they have the best technology for the job? Using a state of the art technology in most cases means good product quality
- Feedback from former customers: What do the company’s previous clients have to say? Look at the company’s website to see the reviews of the company by the clients.
Also, if you know any of their former customers, you can get their views on the performance of the company.
If most of the reviews and comments are good, then chances are high that the company does a good job
- Certifications and Awards: A good company will always receive recognition for its good work.
The first thing to look at is whether the company has valid operating license. Of course, most companies are licensed to operate, so that might not be a big issue.
Next, look at other certifications, especially by independent parastatals.
Having these certifications is a sign that the company’s performance has satisfied the parastatals.
Also, check to see if the company has received any awards as a sign of exemplary performance
Step 4.Check the company’s testing methods
In PCB assembly, the only way to ascertain that the products are well assembled is by carrying out specific tests and inspections.
If there are no proper testing and inspection procedures done, chances are high that the product might not be of good quality.
Always insist on verifying that the company has exactly the relevant tests for each product assembly level.
Check out for functional equipment for optical inspections, internal circuit verification, and component level checks, among others.
Step 5.Does the company have a good customer support system?
A company’s seriousness can be estimated by looking at how well and promptly the customer’s queries are handled.
Of critical importance is whether they are always willing to accommodate the customer’s views. With what gravity do they treat the customer’s views?
If the company’s customer service takes too long to respond to queries, leave it and move on. That is always a sign that they do not have the correct response.
They are therefore still looking out to fabricate a response to soothe you.
This is the first thing to come to everyone’s mind when the term business is mentioned.
Before you choose to do business with that PCB assembly company, check whether their prices agree with the services they offer.
Remember price alone cannot be the determinant of your choice of a company to contract.
After looking at the other factors, see whether your best company’s prices are affordable. Affordability must always be accompanied by quality to avoid regrets.
Always take time to ask questions. Take note of any hidden costs.
Make sure all costs are taken care of in your negotiations. Let nothing be left to come up when production is already on.
Who Should Use Turnkey PCB Assembly?
We have seen that turnkey PCB assembly eases the client’s work. The client simply places an order, then waits to receive the final product.
Turnkey PCB Assembly process
Let us now see what type of clients and companies are most likely to benefit from using turnkey PCB assembly. They include:
- Clients that need quick delivery of their orders-the fact that the entire process takes place at one point means that the production time is reduced.
- This is mainly because there is no time lost in ordering for the boards and parts separately.
- The several levels of consultation and project monitoring are also reduced. The client is therefore sure to save time and meet customer deadlines.
- Start-up PCB assembly companies-the costs of shipping parts may be so expensive for small companies. Turnkey assembly helps them to eliminate all these costs.
- Companies working on PCB prototypes for new products-the only way to fully understand the quality of a prototype is to be fully involved throughout its development.
- Companies will, therefore, want to do all the stages of developing a new prototype within their systems.
- Companies that always want to upgrade and refresh their products also find it cheaper to come up with improved products without incurring many costs
Today we have been able to look at the whole concept of Turnkey PCB assembly.
We hope you found this guide very useful.
We also believe that your knowledge of turnkey PCB Assembly is now well established. Based on this guide, you are now able to make serious decisions regarding this PCB assembly method.
Keep checking here for more high-quality guides on PCBs.