PCB Assembly

After the PCB manufacturing process, where the board structure is completely finalized, the PCB assembly process occurs. During PCB manufacturing, the holes have been pierced to create spaces with specific dimensions for the attachment of designed electric components. Several actions sequentially happen during the assembly phase, with the final aim to enable firm and permanent fixture of the electronic components to the board. Since Hemeixin commonly delivers between 5 000 to 500 000 units of unique PCBs for a single client, there is a need for a highly automated and micro precise PCB assembly process. circuit board assembly Design Guide

The first stage of the PCB assembly process is applying the solder paste onto the PCB surface. The primary goal is to fill the holes with the appropriate amount of solder paste so that electrical components can be attached later. The solder layer must end up in apertures, while the flat PCB surface should remain intact. Therefore, applying a highly selective technique is mandatory to fill holes of various sizes with appropriate film thickness. One of the most widely used techniques is solder paste printing, representing a standardly used technique in our production plant.

SMT Assembly

Surface mount technology (SMT) is the most commonly used process in the industry when it comes to Surface Mount (SMT) PCB Assembly. Not without any reason, it allows for components to be mounted directly on the surface mount PCB. The technique lends itself to miniaturization of assemblies, which is the order of the day. Also, SMT Assembly (Surface Mount Assembly) known for their high mechanical strength. The SMT printed circuit boards are a preferred choice for high-speed circuits.

Surface mount technology assembly is a technique in which electrical and electronic components are mounted directly on the surface of a circuit board. Electrical and electronic components that follow this mounting technique are known as surface mount devices (SMD). This technology minimizes fabrication costs and increases efficiency.

At Hemeixin, we have over 15 years of experience in SMT PCB Assembly. With automated SMT Assembly process our boards ensure optimal performance in the most challenging applications.

Hemeixin provides customers with decades of leadership and experience in advanced PCB assembly technology, with proven processes and a full range of services. From prototyping, low volume high mix to high volume global manufacturing, we provide printed circuit board assembly services in China.

Hemeixin is a recognized leader in PCBA and SMT production and develops solutions for our customers using the latest in PCB assembly and surface mount technology. Capabilities include support for:

• 01005 components, fine pitch and high count BGAs, Package on Package (POP), Chip on Board, fiber optics, RF microelectronics, press fit connectors
• Hybrid processes (tin-lead and lead-free), pin through hole, wave & selective soldering, double and single sided reflow, wide body and backplanes
• Quick turn prototype assembly, RoHS compliance certification, conformal & parylene coating, laser marking
• Inspection and testing using the latest SPI, AOI, Flying probe and X-Ray equipment
• Comprehensive electrical testing and test system development for boundary scan, in-circuit test (ICT), functional test and burn in test (BIT)

Prototype pcb assembly

Printed Circuit Board (PCB) prototypes are used to reduce the number of errors or defects in the design of a circuit board at an earlier stage.

Printed Circuit Board (PCB) prototypes are widely used to reduce the number of errors in a PCB design. These prototypes help original equipment manufacturers (OEMs) analyze the strengths and weak areas of their proposed circuits. Prototyping helps manufacturers save on costs that otherwise would be spent on rectifying defects and minimizing product recalls. This is why most companies prefer to invest in a prototype PCB assembly before high-volume production. Partnering with an experienced PCB assembly services provider like Hemeixin Assembly offers several advantages to them. We can handle prototype PCB assembly in quantities from 1 to 100 boards.

Highlights of Hemeixin Assembly’s Prototype PCB Assembly Services

At Hemeixin Assembly, we have acquired capabilities that enable us to serve our clients better. All these years, we have worked on several complex prototype PCB assembly projects, and we believe the following capabilities have helped us serve our clients better.

Printed Circuit Board Engineering Services: We can provide prototype PCB assemblies for design for manufacturability (DFM) and design for testing (DFT). In addition to this we can perform process failure mode effects analysis (PFMEA) and devise control plans.
Prototype PCB Assembly Services: We specialize in the following prototype printed circuit board assembly services.

• SMT: We can provide single-sided and double-sided surface mount PCB assemblies indifferent specifications.
• Plated Through Hole: We offer plated through hole assembly with selective soldering.
• Mixed Assemblies: We often work on projects involving mixed assemblies – through-hole and SMT and electromechanical assemblies.
• In addition to this, we also support new product introduction (NPI) projects.

PCBA Testing: All the PCBA functional testing is performed in-house at our well-equipped facility at China. Over the years, we have invested in various test fixtures and equipment, which helps us ensure the quality of PCBA. Currently, we provide the following types of PCBA testing services:

• Flying probe testing also including boundary testing
• Functional testing including system and board-level testing

General PCB Assembly Capabilities: Our general PCB assembly capabilities are not limited to these:

• RoHS, leaded, clean and no chemistries
• PCB components including various types of QFNs, BGAs, CSPs, POP, 01005, 0201,08004, and press fit components in small quantities
• Paste-in hole

Turnkey PCB Assembly

PCB fabrication with utmost quality is at the heart of Hemeixin Electronics Co., Ltd. We specialize in various types of PCB assembly projects, including full turnkey PCB assembly. With our full turnkey PCB assembly services, we handle all aspects of PCB fabrication. We offer fast, and reliable turnkey PCB assembly as we are experts in procuring components, assembly, testing, delivery, aftermarket service and warranty support.

We’ve worked with small hardware startups and large defense companies, and one thing they tend to need is help navigating the electronics supply chain and manufacturing landscape. If you’re not involved in the industry, PCB manufacturing services can seem opaque and difficult to navigate, just like many other specialized services.

Therefore, it’s often the case that clients will look to a manufacturer that can help guide them through the production process. Turnkey PCB manufacturing services, turnkey PCB assembly services, and contract manufacturing services can help guide you through the process by taking on many of the important management tasks needed to complete a manufacturing run. Sometimes, it makes much more sense to contract these services through your design firm, rather than through a manufacturer. With a single source approach, we can take any complex project, and turn it around in a short lead time, whilst not compromising on the quality. Being a leading form of electronic assembly, turnkey PCB assembly services bring several benefits to the customers as follow.

• Our full turnkey PCB assembly is a highly-efficient and fast form of electronic assembly. You don’t need to worry about managing multiple vendors as we take care of the entire fabrication.
• With our full turnkey PCB assembly services, you can build and refine prototypes faster, easier, and cost-effectively.
• We are all equipped to handle (through-hole, surface mount, mixed) small batch of boards or full production runs.
• We have verified supply chain networks to support the entire process of turnkey assembly. With end-to-end solutions from a single provider, you can gain significant cost savings, too.
• We have a team of highly qualified staff who are experienced in working on turn-key circuit board assembly. They not only help meet your expectation in terms of quality, but also complete your projects faster.

We offer instant quotes for your turnkey PCB assembly order and you don’t need to wait for long to know how much the order would cost. Also, you can see the real-time status of your project. This helps you to monitor the PCB manufacturing stage. With a single point of contact, and flexible services, Hemeixin Assembly’s full turnkey electronics assembly meets the unique needs of small businesses, large corporations, and entrepreneurs.

BGA Assembly

Implementing complex and small-size chips in PCB designs is necessary to match the technological advancements taking place around us. Such ICs increase the packaging I/O density. Thus, high-density and low-cost packaging methods are in great need. BGA is one among them.

BGA assembly is a process of mounting ball grid arrays (BGAs) onto a PCB using the solder reflow process. BGAs are surface mount components that use arrays of solder balls to make electrical interconnections. These solder balls melt and establish interconnection when the board passes through the solder reflow oven.

What are the advantages of a BGA assembly?

• Improves both electrical and thermal performance while making efficient use of space.
• Reduces the overall thickness of the board.
• Minimizes the chances of PCB damage since BGA leads are made from solid solder balls, consequently reducing maintenance and repair times.
• Suitable for miniature packages with high pin count.
• Offers improved solderability, resulting in a speedy assembly procedure.
• Dissipates heat quickly due to low thermal resistance.

BGA (Ball Grid Array) Assembly Services with X-ray Inspection

Hemeixin has been providing BGA assembly, including BGA Rework and BGA Reballing services in the Printed Circuit Board Assembly industry since 2003. With state-of-the-art BGA placement equipment, high-precision BGA assembly processes, cutting-edge X-Ray Inspection equipment, and highly customizable Complete PCB Assembly solutions, you can rely on us to build high quality and high yield BGA boards

BGA Assembly Capability

We have a wealth of experience handling all types of BGAs, including DSBGA and other Complex Components, from micro BGAs (2mmX3mm) to large size BGAs (45 mm); from ceramic BGAs to plastic BGAs. We are capable of placing minimum 0.4 mm pitch BGAs on your PCB.

BGA Assembly Process/Thermal profiles

Thermal profile is of utmost importance for BGA in the PCB Assembly Process. Our production team will conduct a careful DFM Check to review both your PCB files and the BGA datasheet to develop an optimized thermal profile for your BGA assembly process. We will take the BGA size and BGA ball material composition (leaded or Lead-Free) into consideration to make effective thermal profiles. When the BGA physical size is large, we will optimize the thermal profile to localize the heating on the internal BGA to prevent joint voids and other Common PCB Assembly Faults. We follow the IPC Class II or Class III Quality Management guidelines to make sure any voids are under 25% of the total solder ball diameter. Lead-free BGAs will go through a specialized lead-free thermal profile to avoid open ball problems that can result from the lower temperatures; on the other hand, leaded BGAs will go through a specialized leaded process to prevent higher temperatures from causing pin shorts. When we receive your Turn-Key PCB Assembly order, we will check your PCB design to review any considerations specific to BGA components during our meticulous DFM (Design for Manufacturability) review. The full verification includes checks for the PCB Laminate Material compatibility, Surface Finish effects, maximum warpage requirement and Solder Mask clearance. All these factors affect the quality of BGA assembly.

BGA soldering, BGA Rework & Reballing

You may have only a few BGAs or fine pitch parts on your PCB boards that require PCB assembly for R&D prototyping. Hemeixin can help — we provide a specialized BGA soldering service for testing and evaluation purposes as a part of our focus on Prototype PCB Assembly. Additionally, we can assist you with BGA rework and BGA reballing at an affordable price! We follow five basic steps to perform BGA rework: component removal, site preparation, solder paste application, BGA replacement, and Reflow Soldering. We guarantee that 100% of your boards will be fully functional when they are returned to you.

BGA Assembly X-Ray Inspection

We use an X-Ray machine to detect various defects which might occur during BGA assembly. Through X-ray inspection, we can eliminate soldering problems on the board, such as Solder Balls and Paste Bridging. Also, our X-Ray support software can calculate the gap size in the ball to make sure it follows IPC Class II or Class III standards, as per your requirements. Our experienced technicians can also use 2D X-rays to render 3D images in order to check such problems as broken PCB vias, including Via in Pad BGA Designs and Blind / Buried Vias for inner layers, as well as cold solder joints in BGA balls.

Whether your requirement is BGA PCB design, BGA PCB, BGA PCB layout, BGA Assembly or BGA rework, you can rest assured that you will get superior quality and performance, that will in turn, positively impact the performance of your final product.

Thru-Hole Assembly

Through-hole assembly is the process of mounting leaded components to a PCB that involves drilled through holes. Later, the components are soldered to the pads on the opposite side of the board either by manual soldering or automated soldering machine. The solder flux ratio is established carefully as it is essential to maintain the quality of the solder joint between the pad and the component lead. During the THA process, the component leads are inserted from the top of the board to the bottom through drilled holes, followed by soldering. These drilled holes could be plated through holes (PTH) or non-plated (NPTH). PCB manufacturers and designers should stick to IPC 610 A and J-STD-001 for through-hole assembly

Automated Through-Hole PCB Assembly

Why assemble your PCBs using manual through-hole technology when you can have a through-hole PCB assembly company automate and streamline the process? More and more industries use automated technology in manufacturing industries today than ever before. Automated through-hole PCB assembly allows machines to place and solder PCB components faster than employees could do the job manually, which is why the practice of combining manual and machine assembly has become so widespread.

We have a variety of machines that make assembly faster and more efficient. We automate processes using equipment such as the Universal 6287A axial insertion machine, the Hollis Future I SMT and the Ace KISS-103. We are constantly working to integrate new ways to maximize safety, productivity and effectiveness at our company so that we can deliver you high-grade equipment components.

In addition to our machines, we have over 50 individual workstations with ESD protection to maximize safety. We use both technology and human hands to help ensure that the soldering process runs smoothly and that the PCBs we develop and their components will create a strong, durable bond.

Partially automated through-hole assembly saves time and finances while lowering the risk of errors in production. This leads to the use of more reliable equipment and machinery in industries on a global level, which has a positive impact on security and efficiency. As a result, automation has fundamentally changed PCB manufacturing and will continue to influence it for years to come.

Testing Through-Hole PCBs

A large part of manufacturing and assembling PCBs involves the process of testing the products once they have been completed. Living up to quality expectations is important to our company, which is why we have implemented a thorough, accurate testing and inspection method into our business operations.

Assembling electrical components and delivering them to customers without first running them through careful inspection leaves room for error and increases the risk of equipment malfunctions, which slows down operations for businesses. Our automated testing and inspection system catches defects before PCBs go out the door and prevents these types of issues.

At Hemeixin, we use a 2 Mirtec MV-3L optical inspection system that searches for mechanical and manufacturing issues in new PCBs.

Using all these tools, we can accurately detect many types of defects in the design and construction of the PCB through-hole assembly board, such as damage or cracks, inaccurate component placement, incorrect polarity and other potential issues. We only allow our customers to purchase our through-hole assembled PCB services after we have completed the inspection process.

With Hemeixin’s PCB thru-hole assembly services, you can focus on other elements of your industry or company by trusting us to build and test critical electrical components for your equipment. Our thorough testing process protects your investments and helps ensure that the PCBs we offer will act as long-term solutions for your industry.

Mixed Technology PCB Assembly

The mixed technology PCB assembly has the properties of both surface mount technology (SMT), and through-hole technology, hence the name. Thus, these assemblies are most commonly used in the applications, which require the combination of both through-hole and SMT assemblies. This type of PCB assembly does not use any solder paste. Hemeixin is one of the most experienced and reliable manufacturers of these assemblies in the China. We have the capability to manufacture circuit boards with single sided, double sided, as well as multilayer mixed technology.

Mixed Technology PCB Assembly Capabilities

We employ independent automated mixed technology assembly lines for PCBs. This allows us to provide complete PCB assemblies, and prototypes at short turnaround times. Our customers can benefit from our following capabilities:

• State-of-the-art Automated Assembly Equipment
• Automated Laser Sighting and Flux Dispensing
• Fast Production of Densely Populated Mixed Technology Assemblies
• Fast Placement Machines for Ultra-Small and Ultra-Thin Chip Components
• Automated Aqueous Cleaning at Multiple Stages of Production
• Wave and Soldering Machines
• Chassis Wiring and Assembly

Mixed Technology PCB Assembly Testing and Inspection

We follow rigorous testing and inspection procedures, which allow us to ensure high accuracy of circuit boards:

• Automated Optical Inspection:

  

  Our AOI equipment provides comprehensive fault coverage. It helps us to inspect components thoroughly for their optical placement, orientation, value, color differences, short circuits, dry joints, etc. This is the most effective way of inspecting all mixed technology PCBs, as well as SMT, Through-Hole, and BGA assemblies.

• X-Ray Testing:

  We employ a state-of-the art automated X-ray system to ensure highest quality inspection of PCBs. This type of testing helps us to inspect the quality of PCB components and any hidden faults that are otherwise invisible during visual inspection. This type of testing helps us remove any manufacturing defects in the preliminary stages, and avoid various expensive performance problems in the long run.

• Functional Testing:

  This is performed to ensure the proper functioning of the PCB assembly. Mixed technology PCB Assembly works best for applications that demand surface mount and through-hole components. At Hemeixin, we offer a full range of process and assembly options including assembly on circuit boards with single sided, double sided, flex, and rigid flex, as well as multi-layer mixed technology.

Lead-Free Assembly

The demand for lead-free PCBs is on the rise for varied applications across industries. There are several reasons for the immense popularity of this PCBs, including zero emissions of lead to the environment along with decreased Toxic Release Inventory (TRI). Considering the benefits these PCBs bring, we at Hemeixin produce lead-free PCBs using specific toxic-free components and board finishes. Thus, complying with the RoHS directives, we are also contributing towards reducing e-waste and working towards environmental sustainability. Our lead-free PCB assembly services are offered to those customers who are concerned about the environment and its protection.

Our Lead-Free Assembly services include:

• Lead-Free Materials Analysis
• SMT and PTH Lead Free Board Assembly
• Lead-Free Rigid or Flexible Circuits
• Lead Free Selective Soldering
• Lead Free Wave Soldering
• Lead Free Circuit Board Rework
• Lead Free Encapsulation and Conformal Coating
• Wave Solder Flux Evaluation and Component Evaluation

The lead free SMT Assembly Process

The RoHS PCB assembly process requires that none of the hazardous materials listed in the RoHS Directive are used in the boards, components or solders. Bare printed circuit boards used in the typical "leaded process" are often coated with a lead-tin finish, so the finish on the board must be modified significantly to be compliant with lead-free and RoHS standards.

The lead-free prototype process also requires that boards to be assembled at higher temperatures usually 30-50 degrees or higher. The higher temperature may require the substrate of the circuit board itself and various components to be modified to withstand the higher temperatures in the oven. In addition, the IC moisture sensitivity level that indicates how long the board can be exposed to the air is approximately 2 classes higher for lead-free boards. The shelf life of the materials used in lead-free boards may also be shorter.

Profiling

To ensure proper oven reflow temperature profiling, we ask for one additional lead free PCB along with an extra set of any temperature critical parts; i.e. BGAs, heat slug parts, etc. These can be actual parts, non-functional actual parts or thermally equivalent dummy parts. Most manufacturers of large and expensive components can supply non-functioning "Mechanical Samples" specifically for this purpose. Additionally, suppliers, such as Practical Components provide thermally equivalent parts specifically for this purpose.

Inspection

Due to the metallic composition of lead-free solder, the visual appearance may differ significantly from that of a standard leaded solder joint. Frequently, a first look will give the impression of a cold solder joint. Our inspection staffs are trained to IPC-610D standards to ensure that the solder joints are solid and of high quality.

Starting from temperature profiling, board finish selection and components analysis, board stencil and solder paste application, to component placement, testing, and packaging, we assure compliance with lead-free and RoHS PCB assembly standards. This stringent quality assurance has made us gain comprehensive competitive advantage and huge customer base from industries such as defense, military, marine, electronics, among several others.

On time delivery of quality products has been our motto since our inception. The same is applicable to our lead-free PCB assembly services as well. We own the technique, manufacturing excellence, and the right people, to produce standard as well as customized Lead free PCB assembly beyond customer expectations. Be it a prototype, small or large scale production, we at Hemeixin is equipped to meet the challenges. Additionally, with a highly skilled team of personnel, we ensure meeting the technical specifications given by the customers as it is in the final assembly.

Low Volume PCB Assembly

Low volume, as the term implies, is a batch with limited number of assembly batches. While some OEMs manufacturing electromechanical products require PCBAs in bulk, a low volume PCB assembly may be required for a limited edition product or one with very specific requirements. In such a scenario, it is crucial to first make a low volume prototype PCB assembly as that would give an idea about the final product and if it requires any changes. Hemeixin is an experienced full service electronics contract manufacturer; however, volume has never been an issue for us. We offer PCB assembly services including prototyping even for low volume orders and regardless of the complexity of the requirement.

Low Volume PCB Assembly Capabilities

• Our state-of-the-art facility with advanced tools and machines, experienced teams, and the budget which can cater to low volume prototypes assemblies enable us to achieve low volume PCBs to required specifications. By budgets we mean, we may require tooling for only a small quantity of boards or merely a prototype; however, that is worth the cost and effort as it serves as a future reference for PCB assemblies for many OEMs.
• We have strict testing and inspection procedures in place. The testing techniques include automated optical inspection (AOI), microscopic inspection, x-ray inspection, flying probe test (FPT), and visual inspection.
• We offer single and double sided boards which are mostly flexible or rigid-flex for our low volume PCB assemblies which may comprise barely 200-250 boards or lesser than that.
• For our low volume prototype and PCB assembly, we use different component mounting techniques such as surface mount technology (SMT) and plated through hole (PTH) technology. Additionally, we provide ball grid array (BGA), uBGA/Micro BGA, chip-scale packaging (CSP), and so on.
• We use leaded as well as RoHS-compliant solder types and advanced soldering techniques such as selective wave soldering, pb88 soldering, high melting point (hmp) soldering, and au80 soldering.
• We accept PCB designs in Gerber RS-274X, 274D, Eagle and AutoCAD’s DXF, and DWG file formats. You can share this along with your Bill of Materials (BoM).

At Hemeixin, we understand these difficulties and have made it our goal to raise the bar on our low-volume PCB assembly services to set it apart from our competition. We are pleased to provide the highest levels of quality you would expect from a premier circuit board assembly facility while retaining the flexibility of a low-volume manufacturer.

Kitted PCB Assembly Services

Kitting is the process of putting together a set of components as a kit required to assemble circuit boards. Here the customer provides all the components that go on the board. Kitting brings all the materials/parts into one single package. It is extremely beneficial for the commencement of assembly since all the required components are available, verified, and placed in appropriate packaging.

Every board design and quantity requirements vary according to the customer. Hence, the kit criteria for each assembly project are different. In spite of these, there are particular rules to consider and standards to follow. The analogy could be that of cooking a recipe when all the ingredients are collected either from the market or from the kitchen and pantry. All these ingredients are brought together on the kitchen table and then cooked.

In this type of assembly, a customer provides all components to the manufacturer for assembling. The components to be provided include bare printed circuit boards, electronic components, and all requisite PCB design files, and the manufacturer will assemble the components using automated equipment. This type of PCB assembly is also referred to as consigned PCB assembly. There has been an increasing demand for kitted PCB assembly services, owing to the following reasons:

• This is one of the most economical ways of PCB manufacturing.
• A customer can be assured that components and PCB boards supplied by them are used and no inferior parts are used in the process.
• A customer has better control over the cost of production.

In short, kitted assembly helps OEMs to avoid quality-related issues, and improve their time-to-market capabilities.

Highlights of Hemeixin’s Kitted PCB Assembly Services

At Hemeixin, we offer assistance on the Bill of Material if needed, else we simply accept your list. The Bill of Materials (BoM) is an extremely important aspect of a kitted PCB assembly since it has the list of materials, quantities, minimum order quantity, prices, part numbers, estimated completion time, and so much more. After you provide us with the details, we analyze the details such as feasibility, compatibility with your application requirements, component quality, and so on. We can easily offer you a quote based on your kitted PCB assembly requirements. We off er the following features as part of our kitted PCB assembly services

PCB Assembly Types: We offer the following kitted PCB assembly types.

• Surface Mount (SMT)
• Thru-hole
• Mixed Technology (SMT/Thru-hole)
• Single and double sided SMT/PTH
• Large parts on both sides
• BGA on both sides
• We also support new product introduction (NPI) projects.

PCBA Testing: We carry out in-house testing using manual as well as automated methods at every stage of PCB assembling. This includes functional testing as well as component mounting, the physical design, and so on. Our facility in China is equipped to handle this.

If you are an OEM of electrical, electronic or electromechanical devices, and need assistance with regards to kitted PCB assembly, you can totally rely on us. We have an expertise inoffering kitted PCB assembly services.

PCB assembly process

The PCB assembly process occurs after PCB manufacturing, where the board structure is completely formed according to client requirements. The PCB assembly covers actions from stencil preparation and solder paste printing to SMD parts placement, bonds formation in the curing oven, and final inspection of the PCB functionality. After stencil preparation, the solder paste printing takes place. At this stage, tiny apertures that present mounting spots for electrical components must be filled with exceptional precision. Otherwise, some serious issues such as bridging may occur. The bridges often have a micro size and are not visible to the bare eye. That makes them hardly detectable if state-of-the-art inspection devices are not used. Still, they are the most common issue in the PCB assembly process, leading to short circuits or even component burning up. Thus, we at Hemeixin utilize the latest solder paste printing technology, ensuring that every single printed circuit board operates appropriately at the end of the assembly line.

Another critical part of the PCB assembly process is the positioning of electronic components using the pick and place machine. The conductive lines at the board are very tiny, and they must be aligned with the conductive parts of the electronic components. Hence, the electronic devices must be orientated and posted on the board with the highest precision. We use the most precise three fiducial points optical systems to place the surface mounting devices. Finally, at the end of the PCB assembly line, the firm and stable connection between SMDs and board is achieved in the curing oven. The paste soldering enables the PCBs' longevity and durability, which are our ultimate goals besides the PCBs' highest quality.