#ems partner

Looking for a trusted EMS partner to support your product from idea to launch? At EWME, we deliver end-to-end electronics manufacturing services from prototyping and PCB assembly to full-scale production, testing, and lifecycle management. Our solutions are built on precision, reliability, and flexibility.

Whether you're developing cutting-edge medical devices or rugged industrial systems, EWME ensures quality, speed, and scalability at every stage. Proudly made in the USA, we're your go-to partner for turning innovation into reality.

As we all know, the PCBA manufacturing process is a quite complex process. The entire PCBA process seems to be only one word different from PCB. However, as a matter of fact, it varies a lot, that is PCBA has a series of back-end processes based on PCB, such as solder paste printing, SPI (Solder Paste Inspection), SMT Assembly, reflow soldering, DIP soldering, wave soldering/selective wave soldering, PCBA first article inspection, etc. These PCBA process is that the PCB does not come with it.

Just because all subsequent processes are based on the PCB board, the quality of the PCB determines the quality of the entire PCBA. So which aspects of the PCB have an impact on the PCBA?

1. Dirty Board

Dirty board surface is mainly caused by high flux solid content, too large coating amount, too high or too low preheating temperature, too dirty PCB gripper of conveyor belt, too much oxide and tin dross in tin bath, etc.

The main solution is to choose the appropriate flux; control the amount of flux coating; control the preheating temperature; Check the cleaning effect of the automatic cleaning PCB gripper and take measures; clean the oxide and tin slag on the surface of the tin bath in time.

2. White Residue

The white residue on the PCB is often referred to as white frost. Although it does not affect the surface insulation resistance, the customer does not accept it.

Solution: First of all, we can try to use flux and then use solvent to clean; If it cannot be cleaned, it may be due to the aging of the flux, or it may be exposed to the air to absorb water vapor, or it may be due to the high moisture content in the cleaning agent (solvent), or the The flux does not match the cleaning agent, please ask the supplier to help solve or replace the flux cleaning agent.

3. PCB Deformation

PCB deformation is mainly caused by excessive PCB quality or uneven component layout.

When designing the PCB, try to distribute the components as evenly as possible. Design a support strip in the middle of the large-size PCB (the design width of the non-layout component area is 2~3mm); Or use a mass balance tool to press the sparse components on the PCB during the soldering process to achieve mass balance.

Grande PCB Manufacturing Pros

1)Energy production 2 to 14 layers, 14-22 layers can be produced by prototype 2)Minimum line width/spacing: 3mil/3mil BGA spacing: 0.20MM

3)Minimum aperture of finished product: 0.1mm Size: 610mmX1200mm 4)Solder Mask: Japan Tamura, Taiyo, Futoken;

5)FR4: Shengyi, Kingboard, Haigang, Hongren, Guoji, Hazens, South Asia, (Shengyi S1130/S1141/S1170), Tg130℃/ Tg170℃ Tg180℃ and other high TG plates)

6)High frequency board: Rogers (Rogers), Taconic, ARLLON; 7)Surface technology: spray tin, lead-free spray tin, immersion gold, full board gold plating, plug gold plating, full board thick gold, chemical immersion tin (silver), anti-     oxidation (OSP) blue glue, carbon oil.

Grande has its own SMT factory, which can provide SMT Assembly services for the smallest package 0201 components, and supports various Assembly forms like based on sample Assembly and PCBA OEM. Now let’s talk about the stencil manufacturing requirements in SMT Assembly.

1. Dimensions & Frame of The Stencil

Before PCBA SMT Assembly, custom designed stencils are required to make the SMT Assembly Printing more perfect and suitable. The most important thing about the stencil that is the size and frame. As you probably know, the stencil adopts the stretching method of AB glue and nylon mesh, and a layer of protective paint (S224) must be scraped evenly on the seam between the aluminum frame and the glue. Furthermore, in order to ensure that the stencil has enough tension (specified more than 35N/cm, generally 30~50N/cm) and good flatness, the distance between the stencil and the inside of the frame is required to be no less than 25mm, preferably within the range of 50-100mm . As shown in Figure 1.

Since the stencil to the inner side of the frame, the bonding area between the stencil and the nylon mesh, and the bonding area and the printing area need a certain distance, the inner size of the frame is not the maximum size available for the stencil, and the most useful maximum printing size is the inner side of the frame. size. Go to 220mm or larger size. Of course, this also depends on the width of the press rails, the size of the wiper mechanism and the size of the frame. For instance, the DEK265 press has a frame size of 29″x29″ and a maximum printing area of ​​510mmx489mm.

2. Tension

Stencil tension refers to the tension of the nylon applied to the stencil, which can be measured with a tensiometer. The principle is to test the thrust required for the part of the stencil to sink per unit distance, in N/cm, as shown in Figure 2.

In order to ensure the flatness of the stencil, sufficient tension is required, generally greater than 35N/CM, usually in the range of 30-50N/cm.

3. The Shape & Roughness of The Stencil Hole Wall

Ideally, the opening portion of the stencil should be inverted tapered; For example, the dimension below the opening is about 0.01mm wider than the dimension above (depending on the thickness of the stencil). As shown in Figure 3:

In the above cases, the stencil openings should be ground: QFP, SOJ, PLCC, SOP, socket, and CSP devices with 0.5mm pitch and below, all printed stencils.

4. Dimensional Tolerance

At present, the processing accuracy of electro-polished stencil of major domestic stencil manufacturers is as follows.

1. Opening dimensional accuracy: 0-0.010mm. 2. Opening position accuracy: 0.005～0.03mm. 3. The outside opening accuracy of the screen frame: within 2mm. 4. Material thickness: 0.030～0.600mm. 5. The centering accuracy of the graphics in the frame: within 1mm. 6. Material thickness accuracy: within 0.003. 7. Roughness of side wall (hole wall): 0.005～0.006mm.

The precautions for applying PCBA potting material

1. If the potting material exceeds the shelf life, it is prohibited to use.

2. The storage container should be kept tightly closed after opening.

3. It is forbidden to pour the remaining potting material back into the original storage container, and keep it separately and tightly closed.

4. If the workshop or storage room is not opened for a long time (more than 12 hours), it should be ventilated for 15 minutes before entering.

5. If accidentally splashed into the eyes, immediately open the upper and lower eyelids, rinse with running water or normal saline, and then seek medical treatment.

6. If you feel unwell when brushing, you should quickly leave the job site to fresh air, give oxygen if you have difficulty breathing, and then seek medical treatment.

The components cannot brush potting material

1. High power with cooling surface or radiator components, power resistors, power diodes, cement resistors.

2. DIP switch, adjustable resistance, buzzer, battery holder, fuse holder (tube), IC holder, tact switch.

3. All types of sockets, pin headers, terminals and DB heads.

4, plug-in or stick-type light-emitting diodes, digital tubes.

5. Other parts and components specified by the drawings that cannot use insulating potting material.

6. The screw holes of the PCBA board cannot brush potting material.

The areas should not brushing & brushing potting material

1. Areas that cannot brush:

① Areas that require electrical connection, such as gold pads, gold fingers, metal through holes, test holes; ②Battery and battery holder; ③Connector; ④Fuse and shell; ⑤Cooling device; ⑥Jumper; ⑦The lens of the optical device; ⑧Potentiometer; ⑨Sensor; ⑩There is no sealed switch; ⑪Other areas where the coating will affect performance or operation.

2. Areas that mustbrush:

All solder joints, pins, component conductors.

Finding the right electronics manufacturing services provider (EMS) for your project can prove highly frustrating and this is certainly true when it comes to conventional methods. It’s true, crawling through endless directories and search results is only the beginning of an extremely drawn-out process.

At the same time, even after identifying, reaching out and explaining the outline of your project to every provider, you still need to be qualified by the EMS providers themselves, which means the entire strategy is time consuming and endless. 

We aim to be the leading platform and the most efficient solution for connecting OEMs and EMS providers.  

Here are some of the pain points that OEMs face in their search:

Researching the right EMS provider is an incredibly time-consuming process.

After identifying the most suitable provider, OEMs still need to be qualified by the EMS provider.

Explaining the outline of a project to each and every EMS provider is literally exhausting.

Third-party companies charge significant commissions to locate the best EMS provider.

The vast majority of EMS providers fail to respond to email or phone call enquirers.

Here’s how Find an EMS can help:

You do not need to research the options available. EMS providers come to you.

No more rejections. Only relevant and suitable EMS providers will respond to your posting.

You will only need to explain your products manufacturing needs once.

OEMs can post their project for FREE.  

Provide as much or little detail. The 10 questions you answer in your posting don't require any confidential information about your product, you can even post your project anonymously. 

With an easy sign-up process and absolutely no fees, we can save you time and money, while helping you partner with the very best electronics manufacturing service provider for your product.

Check out our Preview page to see how an OEMs posting appears on the EMS dashboard. 

Electronics manufacturing services (EMS) is a term used for companies that design, manufacture, test, distribute, and provide return/repair services for electronic components and assemblies for OEMs.

Electronics manufacturing services (EMS) is a term used for companies that design, manufacture, test, distribute, and provide return/repair services for electronic components and assemblies for OEMs.

The EMS industry came into being in the late 1970s when Solectron, world’s first EMS provider, was established. At the time, most electronics manufacturing for large-scale production was handled by an in-house assembly.

BGA (Ball Grid Array) is a type of surface mount component packaging which is used for integrated circuit; And many functional chips adopt BGA such a packaging like CPU, DDR, ARM, DSP, FPGA, CPLD, etc.