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What Are the Benefits of DFM in PCB Manufacturing?

Monday, March 18th, 2024

In the PCB manufacturing, we always heard a word – DFM, do you know what is DFM? And how does it affect the manufacturing? Herein, Best Team would like to explain the DFM and its benefits for you.

What is DFM?

DFM stands for Design for Manufacturing. It is an engineering approach focused on designing products in a way that optimizes their manufacturability, testability, and reliability right from the beginning stages of product development.

The goal of DFM is to simplify the manufacturing process, reduce production costs, and improve the overall quality of the final product. This involves considering manufacturing constraints and capabilities early in the design phase to minimize complexities, facilitate assembly, and enhance efficiency in production. By integrating DFM principles, manufacturers and engineers/designers can achieve cost savings, faster time to market, and higher-quality products.

What We Should Considered About Design for Manufacturing?

Design for Manufacturing (DFM) is guided by several key principles aimed at optimizing the design of products for efficient and cost-effective manufacturing processes. Here are five fundamental principles and considerations must know of DFM:

Design

We all know the more complex the design, the greater the risk during the manufacturing. Therefore, keep the design as simple as possible while meeting the functional requirements of the product. Simplifying the design including reduce the number of parts, assembly steps, and manufacturing processes involved, which in turn lowers production costs and minimizes the risk of errors or defects.

Standardization

In the PCB industry, there is an IPC standard to standardized all the elements design in PCB, this involved the line width, line spacing, solder mask thickness, text height and so forth. By using standardized parts and processes, manufacturers can take advantage of economies of scale, reduce lead times, smooth the manufacturing process and simplify supply chain management. Standardization also ensures the interchangeability, repair, and maintenance of products.

Design for Assembly (DFA)

If you are trying to mount some components to keep and enhance the performance of product, then DFA is must to take into account. Arrange components on the PCB layout in a way can minimize signal interference, reduces trace lengths, and simplifies assembly. Placing components strategically can improve signal integrity, reduce electromagnetic interference (EMI), and facilitate automated assembly processes.

Material

Select materials and manufacturing processes that are readily available, cost-effective, and well-suited to the intended application. Consider factors such as material properties, availability, recyclability, and environmental impact when making material choices. Designing for materials involves optimizing designs to minimize material waste and maximize efficiency in material usage.

Testability and Debugging

Design PCBs with features that facilitate testing, troubleshooting, and debugging during manufacturing and assembly. Include test points, debug headers, and built-in self-test (BIST) circuitry to simplify testing and diagnostics. Design PCBs with clear labeling, documentation, and accessibility to aid in maintenance and repair.

What Are the Benefits of DFM Analyzing?

The mainly benefits of using DFM is save cost. You know, when creating a new project, we need put much money and time in designing and prototyping. DFM helps identify potential manufacturing issues early in the design phase, allowing for cost-effective modifications before production starts. By optimizing designs for manufacturability, companies can avoid expensive rework and reduce overall production costs. Statistically, we can save around 170 thousand dollars one year by adopting DFM analyzing (human cost, trail-production cost and repair cost). In addition, DFM offers numerous benefits including:

Reduce potential quality defects
Facilitate production process improvement
Decrease trial production cycles
Quick time to market
Enhanced product quality and stability
Mitigate risks associated with personnel changes

How to Find a Manufacturer with DFM Service?

Finding a reliable DFM manufacturer is essential for ensuring the success of your product development. Best Technology engaging in PCB manufacturing for more than 17 years, and we have many experts that can help to solve and provide PCB solution for you. Meanwhile, we have professional DFM system that can help to quickly diagnose the design exception such as components missing, trace layout, open/short circuit. With our expertise and advanced tools, we ensure that your PCB designs are optimized for efficient manufacturing, resulting in high-quality products that meet your specifications and exceed expectations. Trust Best Technology to be your partner in achieving excellence in PCB manufacturing.

What is the Working Principle of IGBT?

IGBT combines the features of a transistor and a switching circuit, making it a new type of electronic component that can control current efficiency. Its structure allows it to achieve current control from turn on to off without generating excessive leakage current, as well as not affecting the operation of other circuits.

The working principle of IGBT modules including two parts – the current control of MOS gate and BJT transistor. When the voltage of MOS gate changes, it affects the conduction of the transistor, thus controlling the flow of current. When the BJT comes into play, it controls the flow of current, so that improve the working efficiency of the IGBT.

How Does A Ceramic PCB Protect IGBT Modules from Overheat?

As you know, IGBT modules have been applied for many years in various industries such as automotive, industrial, aerospace, consumer electronics, and more. However, optimizing the thermal dissipation of IGBT packaging is crucial to enable the modules to operate at higher power conditions. If heat dissipation is improved, IGBT modules can be used in more advanced applications.

You might be wondering how much heat does an IGBT module generate during running? It’s equivalent to the heat produced by 100 electric furnaces. This substantial amount of heat must be dissipated immediately from the IGBT chip, that’s why the ceramic circuit board stands out.

In IGBT modules, ceramic PCBs are placed beneath the IGBT chip, or we can say the chip is assembled on the ceramic circuit board. The ceramic PCB connects and supports the chip, rapidly dissipating heat to the outer package. This method protects the chip from the adverse effects of heat.

Why ceramic PCBs Are Suitable for IGBT thermal dissipation?

Ceramic materials exhibit excellent thermal dissipation and electrical insulation properties. Unlike aluminum metal core PCBs, ceramic PCBs do not use insulation layers that hinder heat dissipation. In the manufacturing process of ceramic PCBs, copper foil is directly bonded to the ceramic substrate under high pressure and temperature (it depends on the different technology and different copper thickness). During PCB manufacturing, IGBT and other components are mounted on the circuit board through assembly technology.

Ceramic materials have extremely high insulation capabilities, enduring breakdown voltages up to 20KV/mm. At present, there are three ceramic materials that can be used for IGBT modules, they are 99% or 96%　Alumina (Al₂O₃), Aluminum Nitride (AlN), and Silicon Nitride (Si₃N₄).

The thermal conductivity of alumina PCB is 15-35W/mK, aluminum nitride PCB is 170-230W/mK, and silicon nitride PCB is 80+W/mK. In contrast, aluminum core circuit boards only have a thermal conductivity of 1-12W/mK.

Applications of Ceramic PCBs in IGBT Packaging

Alumina PCBs are the most commonly used circuit boards in IGBT modules due to their lower cost. But if IGBT modules have higher power or precision requirements, AlN ceramic PCBs and Si3N4 PCBs are the most suitable choices. Because they have higher thermal dissipation and thermal expansion coefficients (CTE) close to semiconductors. Since different ceramic substrate has different features, the uses of ceramic PCB should depend on the specific requirements of IGBT modules.

In addition, with the development of Silicon Carbide (SiC) and Gallium Nitride (GaN) materials, they are starting to be used for IGBT chips due to their high-frequency, high-power, and high-temperature characteristics. Maybe in the future, aluminum nitride PCBs and silicon carbide PCBs will be increasingly applied to high-power IGBT modules in high-density three-dimensional packaging.

Common Properties of Using Ceramic Circuit Board

Excellent thermal conductivity and voltage resistance of ceramic substrates.
Copper trace layers has extremely high current-carrying capacity.
Strong adhesion and reliability between circuit layers and ceramic substrates.
Good soldering performance, suitable for wire bonding.

How to Solve the Overheat Issues in IGBT?

Though the ceramic PCB is good at heat dissipation, there still some overheat occasions happened if small power or long-time operation. Here we summarized some solutions for such issues.

1. Clean the heat sink to ensure tight contact between the IGBT and the heat sink.

2. Clean the fan, including the fan blades and lubricate the bearings if needed.

3. Clear the airflow path of the fan.

4. Replace with higher power IGBTs, ensuring the withstand voltage is not lower than the original IGBT’s value.

Above all are the information that we’d shared, welcome to contact us if you want to know more. Best Technology is a historic company which has over 17 years PCB manufacturing experience, here you can enjoy the one-stop ODM & OEM service, one-to-one after sales, quick delivery and high-quality products.

Manufacturing processes of printing silkscreen

Screen fix

Step 1, we need to fix the screen on the base or workbench with a fixture, and leave 3-5mm distance away from the positioning plate when put the screen.

Align and position

Step 2, we need to place the circuit board on the positioning plate with right-angle positioning method or stud registration method (generally use 2 positioning pieces), make it fixed and aligned, then put down the stencil frame and adjust the positioning button, so that the PCB outline is roughly overlapping with screen. Next step, perform initial align boards according to the positioning holes or outline line, then gradually adjust to the optimal position based on pads.

Silkscreen ink selection and fine-tune

Step 3, we need to select the silkscreen ink according to the customer requirements, put down the screen frame and poured ink into the screen frame, and then select the length of the appropriate scraper for trial printing sample, and fine-tune the positioning until accurate.

Trial printing

Step 4, we will need to do trial printing the prototypes with transparent character alignment film and check to see if there is a legend deviation, if no, then we can proceed with mass production, but if not, then the positioning should be fine-tuned again, rip off the defective film and affixed with the new one then printing again, repeat trail until qualified.

Screen printing (manually)

Step 5, let’s place the circuit board (which have finished surface treatment process) on a fixed position, put down the screen frame, and then hold the scraper with both hands, at an Angle of 50°- 60 ° with even force on the scraping screen surface from front to back or from back to front. The printing material is subjected to the pressure of the scraper through the printing mesh hole and printed on the circuit board. After the scraper passes through, the screen recovers by its own tension. After the scraper is finished, the screen frame is lifted, and the sealing screen printing material is scraped back.

Screen printing (auto printer)

Step 6, the Angle of the scraper is an external “eight” font, usually between 20-30 degrees, you can choose the printing times according to the actual needs.

In the past, most of the factories make the screen printing manually, it is time consuming and limited to relatively short lengths of 60 yards. So, in our manufacturing line, we have imported the automatic flat-bed screen printing.

Here I would like to share some features of the PCB silkscreen printer with you:

Features of Auto-Printer

High speed: the automatic screen printer has its own unique frequency conversion speed regulation device, the printing speed can be adjusted from 20 to 70 times per minute auto screen printing machine.
Cost-effective: the auto printer has its own electronic counter, which can automatically shut down according to the pre-designed total number, saving a lot of manpower and ink material.
Good quality: the automatic screen printer is very accurate in point and color, because it is equipped with a multi-color printing electric eye device, which can improve the quality of printing.
Good adhesive: the adhesion of the screen machine is very good, and the ink layer is relatively thick, so the text legend is not easy to fade.
Multi-aspect: the fully automatic screen printer can not only be used alone, but also can be connected to a UV dryer, or a slitting machine, a reminder, and other auxiliary machines.

With the help of Automatic silkscreen printer, we are able to provide “faster” and more “efficient” service to our customers, warmly welcome to contact us, we are ONLINE always!