Manufacturing and assembly process of medical PCB board

In modern medicine, medical equipment plays a key role in saving patients’ lives, and some daily examinations also require the help of related medical equipment. For example, the new coronavirus outbreak has played a very important role in medical equipment. The world’s demand for medical equipment has greatly increased, and it has also promoted the development of the PCB industry.

Due to the special importance of medical devices, the quality standards of medical PCBs are higher than that of other industries. Safety, durability and accuracy are the most critical requirements for medical PCBs. Only PCB manufacturers with higher production levels can meet the requirements of medical PCBs. In recent years, people have attached great importance to the PCB assembly and manufacturing process. Every medical product and PCB manufacturing requires high-end customization. Regardless of the production of high, medium, and small batch PCB, PCB members must continue to develop chemical and electroplating processes, and suppress, wiring, and drilling processes under high temperature/vacuum in order to obtain high output in batch production. The medical market also pointed out how to make equipment compact, multifunctional, user -friendly and cost -effective.

Medical PCB market

The medical application of electronic equipment has continued to improve with the development of electronic technology, becoming more efficient and dense, resulting in unlimited new possibilities. The development of medical PCB applications is as fast as the medical device industry itself. Some of the most common medical PCB applications include: monitor, scanning technology, control systems, internal equipment, scientific instruments, etc. The core of this medical device is PCB. Medical PCB is often a special high density interconnect PCB, which will stimulate the growth of high density interconnect (HDI) PCB in the market.

With the development of a new generation of information science and technology, the traditional fixed product model of the medical industry has become the past, and the advancement of technology has completely changed the industry. Medical equipment products have become “high-demand products” in the medical field. In electronic diagnosis, research and treatment systems and tools, this change is more evident. This growth has greatly benefited the PCB industry to a large extent. PCB medical equipment was born on the market. The detection and management of health indicators can be used as a technical solution to intervene and assist medical care, and quickly become a breakthrough in smart medicine.

Medical PCB design

Step 1: Make PCB schematic of medical equipment
PCB schematic diagram is the visual representation of the electronic components and connections that make up the printed circuit board (PCB). The schematic diagram shows the circuit connected by the circuit connection of the PCB board. This can be more intuitive to understand the wiring of the product. This is done by a professional PCB manufacturer. Customers need to provide all the basic product information to the manufacturer to design the best PCB board.

Step 2: Medical electronic component layout
In order to ensure the reliable and efficient operation of the medical PCBA board, it is important to plan a reasonable layout of a reasonable PCB component (SMD component and DIP component) and PCB node.

In modern medical electronics, components are usually placed as close as possible to reduce the size of the circuit board, especially in implanted medical devices. In addition, we must carefully consider the power requirements of the component, the overall power consumption of the circuit, electromagnetic interference (EMI) and thermal management to ensure that the medical PCBA board is error-free.

Step 3: Consider and Add Key Factors
In order to produce accurate and effective medical PCB, several key factors need to be considered during the design phase. Some of these key factors include dividing planes, sorting, number of pins, and their choices.

Step 4: Properly allocate the power supply
Perform power separation at this stage of the design process to reduce noise and wiring levels in the circuit board. Diversification of this power should be properly pursued in order to achieve effective results. To help reduce SNR and noise levels, PCB substrates require multiple layers. Multi-layer also makes the medical PCB reliable and improves its performance.

Step 5: Review the BOM (BOM) list
The next step is to view the material list BOM of the medical PCB. The Material List is a list of all materials and components containing medical PCBs. The final list can be formed after the component list is checked.

Medical PCB manufacturing

Step 1: Design imaging
In this step, the medical PCB manufacturing plant participated in the process. Medical electronic PCB board manufacturers use the drawer printer to convert the design file of the circuit board into a membrane. These files show the negative effects of the pictures in the picture.

Step 2: Copper printed on the inner layer
This PCB manufacturing step marks the beginning of the actual PCB manufacturing process. The process started with PCB substrates. PCB is a pressure plate made of a substrate material. Generally, epoxy resin and glass fiber are used as basic materials.

In the PCB manufacturing process, the first step is to superimplement the copper layer on each side of the glass fiber substrate. The film and copper layer are then aimed at the top, and the entire stack is exposed to ultraviolet rays. This process creates a transparent region on the membrane and protects the copper below. Then develop a board in the chemical solution, which clearly removes unprecedented transparent ink, leaving copper marks and circuits. The black ink on the film can ensure that the engraved copper is eroded only in the unnecessary area, which makes the required circuit mode intact.

If your electronic product requires a multilayer medical PCB, repeat the above steps until all the internal circuits required for printing and etching the multilayer PCB are complete. These circuits are then aligned with layers to form a complete inner layer.

Step 3: Combine different layers
In the inner layer of all the necessary layers, printing and laminate layers, and cleaning the laminate plate, combining laminate alignment and combining them together to form a complete printed circuit board. Then press the outer copper layer to the stack and connect to the inner layer by drilling.

As a professional PCB assembly company (manufacturing and components), every step of our manufacturing process aims to pave the way for subsequent PCB assembly. For the medical PCB drilling process, we use optical rigs to ensure accuracy. This is a machine that can drive through the alignment holes to align the inner and outer layers, so as to ensure the effectiveness of the drilling hole, so that PCB components are subsequently replaced.

Consider the PCB example of the Medical pacemaker. This example needs to be the highest accuracy in the drilling process, because even the smallest error can cause huge losses. The typical pacemaker PCB has more than 100 drills, and the drilling process requires a lot of time and resources.

Step 4: Medical PCB external imaging

The outer layer of the imaging medical PCB is a key step in the PCB manufacturing process. Another photoresist is applied to the PCB medical panel, which involves transferring the PCB-designed image to the copper layer outside the board. However, as you can imagine, light dirt is only applied to the outer layer. This process takes place in a clean and safe area.

The imaging process begins on the surface of clean copper to ensure that dirt or debris that may interfere with image transmission may be present. The pins are used to hold the black ink transparent paper in the correct position and prevent it from slipping out of line. Afterwards, the PCB medical panel was coated with a light hole and entered the yellow chamber. Ultraviolet explosions harden the light vibrator and remove the resistance covered by black ink.

Step 5: outer correction

In the process, any copper that does not belong to the outer layer will be removed, and electrophoresis plating is used to add a layer of copper. Tin plating is used to protect copper in critical areas after the first copper bath. Once the outer layer is etched, the PCB panel can be made and welded. AOI ensures that the copper layer of the medical aesthetics of a complex circuit meets the required specifications.

Step 6: Welding mask

Thereafter, the outer layer of the medical printed circuit board was used to protect the outer layer of the medical printed circuit board, and to prepare for the welding process by hiding parts that did not require welding.

First, clean the PCB panel to remove any dirt or excess copper that may interfere with the welded mask. Epoxy ink and solder film are then applied to the surface of the plate. UV rays are used to harden welded surface masks without welding. Then remove the area without the mask and place the wooden board in the oven to cure the welded mask.

Step 7: Silk screening

During silk screening, the inkjet printer prints the details directly on the board. These details usually include company ID, manufacturer’s logo, symbols, component numbers, pin positions, and other differential marks or functions.

Step 8: Surface decoration

Almost complete medical PCBs need to be conductive materials according to customer specifications. This provides more space for welding. After the coating process, the PCB surface will be decorated.

Medical PCB component

PCB assembly is the key to product molding. Whether the device can be used normally in the end, PCB quality is very important. When assembling, we cannot put a component error, even if it is a very small one. Therefore, when assembling PCBs, you must be careful and rigorous, check carefully to ensure that it is correct. The following is the process of preparing the medical PCB:

1. PCB board preparation

Before PCB assembly, you need to prepare the PCB board. This includes cleaning and checking the surface of the PCB board to ensure that it has no dirt, oxide or damage. In addition, the size and location of the PCB board must be checked to ensure that the components can be installed and welded correctly.

2. Component installation

Before the component is installed, layout and positioning are required according to the circuit diagram. Then install the component on the PCB board, and it can be done manually or automatically. When installing components, you also need to pay attention to the direction and location of the component to ensure that it is installed correctly.

3. Welding

After installing the component, welding is required. Welding can be done manually or automatically. Hand-welding requires the use of a welded pen or welding gun to weld the component with the PCB board. Automated welding usually uses surface paste technology to weld metal components and PCB boards together.

4. Test

After welding is completed, testing is required to ensure the performance and reliability of the circuit board. Automated testing or manual testing can be used. Automated testing usually uses test instruments, such as multi-purpose tester or network analyzer. Manual testing usually requires the use of test tools such as universal meters or oscilloscopes.

5. Packing and delivery

After testing the circuit board, packaging and delivery are required. Different packaging methods, such as anti-static bags, foam boxes or cartons. In addition, before packaging and delivery, a final inspection is required to ensure that there are no problems with the circuit board.

Application of medical PCB assembly

Plant-type medical device

Medical PCB is one of the core components of implanted medical devices. Due to the accuracy of the implants, the manufacture and assembly of such PCBs should follow the strictest requirements. Common implanted medical devices include:

Plane: This kind of device allows people who are damaged to process sound and really hear it.

Purbin defibrillation: They can help protect high-risk people with heart disease from sudden trauma.

Response nerve stimulator (neural network): It is a kind of implantation device (in the brain) for patients with epilepsy. Patients with epilepsy with poor drug control usually use RNS as a last resort. The device monitors brain activity throughout the day. Whenever it feels abnormal brain activity, it produces electric shocks.

Medical imaging and diagnostic equipment

Medical imaging and diagnostic equipment are very important in the medical industry because these advanced equipment provides useful information to help doctors and medical care professionals better diagnose and treat. PCB is widely used in medical imaging and diagnostic equipment, including nuclear magnetic resonance, MRI (Magnetic Resonance Imaging), X-ray machine, ultrasound equipment, CT scan, etc.

Monitoring equipment

Medical PCB is also widely used in monitoring equipment such as body temperature monitors, life signs, blood sugar monitors, respiratory monitors, blood pressure meters, etc. In addition to these medical devices mentioned above, medical PCBs can also be used for blood analyzers and blood analyzers, immune analyzers and other laboratory medical equipment.