Today I’d like to share what’s the difference between Adhesive PI and Adhesiveless PI.
Item 1: Adhesiveless PI stack up
As you can see in above stack up, there is no adhesive connect the Copper layer and Polyimide.
There are four advantages of adhesiveless PI:
As you know, the thickness of adhesive is around 12.5um, 15um, 20um. If you have strict requirement for the whole board thickness, it will be a good choice to use adhesiveless PI.
Adhesiveless substrate is thinner than adhesive substrate, so it’s bending is better.
3. Heat resistance
Due to the adhesive have poor performance in heat resistance, so without the adhesive, the adhesiveless base material have better heat resistance.
Under the same temperature, such as 200℃，the tearing strength of adhesiveless PI change a little. But the tearing strength of adhesive PI material rapidly decrease.
4. Dimensional stability
The dimension of adhesiveless board change very small when the temperature increase. Even under the temperature of 300℃, it’s dimensional changing rate is no more than 0.1%.
Good dimensional stability will be great help for fine wiring process.
5. Chemical Resistance
The adhesiveless substrate have good performance of chemical Resistance, it’s tearing strength have no obvious change with time increased.
The adhesive base material has poor chemical resistance, so it’s tear strength decreases greatly with the increase of time.
The only disadvantage for adhesiveless PI is it’s a little expensive than adhesive PI.
Item 2: Adhesive PI stack up
As you can see, the thickness of 2 layer adhesiveless FPC is 0.19+/-0.03mm.
The thickness of 2 layer adhesive FPC is 0.23+/-0.03mm.
If you need thicker thickness, the adhesive PI might can meet your requirement, the cost will be much lower than increase copper thickness or PI thickness.
There are two mainly advantages for adhesive PI:
Anyway, if your project need thinner thickness or smaller line width and space (0.05mm), adhesiveless PI will be the best choice. Welcome to contact us at email@example.com if you need to know more details.
Have you ever been heard about the dual access flexible circuit? Why it named dual access flexible circuit? After you read my e-mail, you will find the answer.
Dual access flexible circuit board is similar to double side FPC, but it has different stack up to double side FPC. Why it named dual access FPC? Dual access can access to both side by copper, so it named the dual access flexible circuit. Dual access flex PCB only have 1 layer copper, and coverlayer on both side. They can connect both side by layout through coverlayer opening, and do not need to drill the holes like 2 layers flex PCB to connect both side.
Working principle: The coverlayer play the role as an insulator, the copper is a very good kind of conductor. One side is anode, and the other side is cathode. If they the current flow, they form a closed loop circuit.
It can be connected to both side through copper, and do not need to make a through hole. If it is 2 layers FPC. You have to make a through hole to connect both side.
2. The appearance will be more beautiful than 2 layers flex PCB. Because we can conduct by trace, it will be more beautiful than through holes to conduct.
Dual access circuit disadvantages:
Complex production process: The production process is similar to 2 layers flex circuit, but it will be more difficult and complicate compared with 2 layers flex PCB. It is easy to scrap. And many factories can not make dual access circuit board due to production technique.
Easy to wrinkle. Because the dual access is very thin. Only one copper and two coverlayers, it will be easy to tear up. When it comes to laminate process, is also very easy to laminate wrinkles and blister.
If you have any questions or would like to learn more details, please feel free to contact us.
Recently, Best Technology has completed 14 years of its glorious journey. Every small step is worth celebrating. On June 26, 2020, our founder, Peter, Emily, group leaders and all the employees spent this unforgettable festival in union.
On Best Technology successful journey, Peter stressed- “These past 14 years have been a period of growth and a learning experience for us as we went through several trials and errors till we deliver successful business. Today we are proud of the fact that our employees can make great progress day by day after training with us and feel confident taking on tough project-related challenges,thanks for all the endeavour from employees and thanks for the great support from our suppliers and customers. Best Technology’s continuous development can not do without them.”
We have come a long way from 2006 when we started off with just 1 people(Peter). Today we are proud to announce that we have nearly 100 employees and many sister companies spread all over China mainland and also have customers in over 150 countries around the world.
From above, it is evident that there has been a staggering growth in the number of employees in the span of 14 years. This enhanced employee strength has built the roadmap to Best Technology’s success.
The above graph presents our company’s growth against the years 2006 to 2020. It can be seen that the growth rate is very high from 2006($8000) to 2019($6560,000). At this year 2020, Best Technology still keeps growing with increasing sales volume in spite of COVID-19 outbreak.
Best Technology’s unique journey has been a brick-by-brick progress and has entailed years of efforts. Our company’s commitment in becoming world class distinctive solution of printed circuit board and metal domes in 2025 has paved the way to the series of milestones achieved. These are equally appreciated by the correct leadership of our chairman, Peter.
The primary aim of our company has been to equip the professionals with all possible accoutrements to tackle on-job challenges. Today’s ever changing face of businesses demands deeper knowledge, quality, and on-time delivery. Customers are always looking out for continuous and improved delivery. The best means to achieve the same is to keep improving.
We will continue our journey towards innovating the new ways of learning, delivering excellence to the customers and lending a hand to achieve professional goals.
What’s more, Best Technology’s 14th-year anniversary celebration is a solemn procession of efforts and dedication of the trainers and staffs who have spent their quality time to provide the best services and meet more expectations of the ever evolving PCB world.
Recently, I was having a few discussions with someone very new to flex design. I was trying to be helpful and going through several things that are specific to flex and rigid flex design which should be considered as you start your first design. So, this blog is written for those of you who are new to flex and rigid flex, and may be unfamiliar with some of the terms that get volleyed around in conversation.
A pattern of conductive traces bonded on a flexible substrate. There are several different substrates available, the most common being polyimide. Different than rigid materials, these laminates will have rolled annealed (RA) copper for improved flexibility.
This is a hybrid construction, using flex materials in areas that need to bend or flex and rigid materials in areas with dense component areas, surface mount components on both sides of the PCB, and applications with higher layer count, dense routing areas. Most common rigid materials can be incorporated into a rigid flex construction.
Typically refers to the areas of flex extended out past the rigid portions of the rigid flex. This may be one flex region, or several bands of flex areas that extend in various directions. Rigid flex is often used to solve packaging issues and connect on multiple planes. Flex tails enable this.
Often used to accommodate a shorter flexible area if there is no room for a service loop. Instead of using the full width of the flex region between areas for each inner layer, the area can be divided into smaller bands of equal width for each inner layer, eliminating buckling and stress in that area.
This is a protective barrier material often used in rigid-flex fabrication. Often, this is a coverlay material used to protect exposed flexible materials during processing and is removed from the flexible portion of the board before shipment.
A layer of insulating material applied to the flexible circuit to insulate the conductor pattern. Coverlay is typically a layer of polyimide with acrylic adhesive. Film based coverlay is much more flexible than cover-coat materials and highly recommended for dynamically flexing applications or flex that will have a tight bend radius. It is important to be sure to spec enough adhesive to fully encapsulate the copper conductors.
This is the ratio of the bending radius measured to the inside of the bend to the overall thickness in that area. Typically, recommendations for non-dynamically flexing designs is 10:1 for single and double-sided construction, and 20:1 for multilayer construction. These can be exceeded but should be evaluated carefully. Dynamically flexing applications should be discussed with your fabricator for a recommended stack up.
I always wrote a blog about how to calculate the bending radius of fpc.
Fabrication process to selectively electroplate copper to vias and onto the pads capturing the vias. The remaining copper traces do not have electrodeposited copper, increasing the flexibility of the circuit.
Stacking conductors on adjacent layers directly on top of one another, increasing the stiffness of the circuit in the bend or fold areas. Staggered conductors are recommended if possible, to retain the maximum flexibility of the circuit.
I hope this helps explain some of the common terminology with flex and rigid-flex materials and design. Please reach out to me with any questions for further information!
Best Technology, a China- based assembly manufacturer will be exhibiting at electronica Munich2020 in Bavaria, Germany at booth No. 623(Hall B1) from November 10, 2020 to November 13, 2020(Western Time). Actually, we have participated in this exhibition for continuous 2 years. Here are some pictures for your reference.
For interested professionals, Best Technology had on hand experts to offer detailed insights and experience on PCB assembly, covering PCB prototype and low/high-volume production. For more information on PCB assembly and fabrication, welcome to visit our booth.
You are warmly welcome to see how we can manage the components wastage and efficiency to help save your time, money and energy.
About electronica Munich:
Electronica is the international trade show for electronic components, systems and applications and shows the full range in all its diversity in width and depth as the world’s leading trade fair. It reflects the high degree of innovation throughout the industry. Exhibitors and users in the areas of systems, applications and technologies of electronics can receive the information of the latest innovations and developments in the fields of system peripherals, power engineering to printed circuit boards or EMS.
Welcome to visit us at Booth 623 from November 10, 2020 to November 13, 2020(Western Time).
Regarding HS code and duty rate of face masks in some major countries, we collected some information in main trade partners (US, Japan, EU, Korea, Taiwan, Australia, New Zealand) of China. This is aimed at the face masks such as personal protective masks without special function components, including medical face masks and disposable face masks. All of below information were published by the custom officially.
According to Harmonized Tariff Schedule of the United States, HTSUS, the HS code of face masks in the US is 6307909889. And the duty rate imported from China is 7%. Regarding tariff imposed, according to announcement from the United States Trade Representative on March 12, 2020, the tariff is excluded for the face masks belonging to this HS code since September 1, 2019. Since then, all the face masks imported from China has been exempted from tariff. You can refer to the below chart for more information.
The HS code of face masks in Japan is 630790029. The duty rate imported from China is 4.7%. To learn more, see below:
The duty paragraph for face masks imported from China in EU is 6307909899 and the duty rate is 6.3%. You can see below for more information:
The duty paragraph for face masks imported from China in Korea is 6307909000, and normally, the tariff is 10%. However, from March 18, 2020 to June 30, 2020, Korea has been suspending imposing tariff for face masks from China(0 tariff currently), see below for more information:
The HS code(also referred to as duty paragraph) of face masks imported from China mainland in Taiwan is 63079050.
And, the duty rate for face masks imported from China mainland is 7.5%. However, from February 27, 2020 to May 26, 2020, provisional tax rates (also referred to as“flexible tax rate”in Taiwan area) for face masks was carried out in Taiwan area, i.e. the tariff is zero. You can see below for more information:
The HS code of face masks imported from China in Australia is 63079099 and the duty rate is 5%. See below for more information:
The HS code of face masks imported from China in New Zealand is 63079028. Zero tariff is applied to the face masks imported from China according to “New free trade agreement”. See below for more information:
If an end user will specify the copper thickness of a printed circuit, there must be many reasons. For example, current carrying capacity, but copper thickness also directly impacts thermal performance and impedance. All these are vital properties, which have a great influence on the functionality and reliability of a flexible circuit.
At the point, it is important to understand the functional needs driving a copper thickness requirement.
Some of the common functional requirements could be:
1.Minimum thickness in a connector area to assure robust contact.
2.Adequate current carrying capacity directly related to the cross sectional area of the trace.
3.Proper conductivity, a function of cross sectional area and metal type of the trace.
4.Proper impedance in high speed circuits driven by the cross sectional area of the copper, the surrounding dielectric constant, and distance from signal trace to ground plane.
5.Thermal properties directly related to metal type and trace profile.
Copper weight is used in the industry as a “thickness” measurement. Circuit manufacturers commonly purchase copper foil with descriptions of ½ ounce, 1 ounce, 2 ounce and so on. The number is the weight of copper in a square foot of foil. Also, +/- 10% is the industry accepted tolerance for copper foil thickness from the material supplier.
Drawing specifications will frequently define a flexible PCB copper thickness using weight. For example “circuit to be 1 ounce copper”. This can lead to some ambiguity, as copper plating on double sided circuits can easily add an ounce of copper to the surface of a trace. So by specifying thickness in this fashion, it is not clear if this is intended as a finished thickness or an original thickness. Additionally, controlled impedance designs work best when copper plating is restricted to the vias with no copper plated on the surface of the traces. This will minimize trace thickness variability and suggests a specific product category requiring a process known as “Pads Only Plating” or “Button Plating”. For controlled impedance designs, one of these terms should be called out in the drawing notes.
What affects final copper thickness is the variety of manufacturing processes that add or subtract copper thickness. Micro-etching is a common “cleaning” process used to prepare a surface for plating or coating. This process removes a small amount of copper. Likewise copper plating will add thickness. The circuit fabricator will directly measure added (or subtracted) thickness in mils (1 mil =.001”) or microns (25 μm=.001”).
The most accurate method for determining thickness is to do a micro section. This is a destructive test, so it is common to use coupons located in unused areas of the processing panel. These coupons are located and sized to be “representative” of the circuitry copper thickness. Copper thicknesses will vary slightly across a panel depending on current density from electroplating. Current density can be a function of the copper trace pattern so differences among various part numbers will occur. As a general rule, copper plating thickness will tend to be thinner on the outer edges of the panel and thicker toward the center.
In summary, when defining the specific copper thickness for an application it is highly recommended to start with a discussion of the myriad functional requirements. Also, the manufacturer can help recommend copper thicknesses and tolerances as well as the best methods for measurement.
Best Technology is the professional vendor of flex circuits, from 1 layer to 10 layers, 2 layers rigid-flex circuits to 16 layers rigid-flex circuits, and one-stop service including components purchasing, assembly, IC programming, testing. Choose us, you can always enjoy our best service at a good price.
Global demand for supplies used by our customers to treat and help protect people, such as respirators, is currently exceeding supply. Best Technology expects demand for respirators to outpace supply for the foreseeable future.
Throughout all the recent developments, Best Technology is working hard to uphold the commitments we made to supporting your business. We are very focused on protecting the health and safety of our workforce while maintaining the ability to keep serving you.
With more than 10 years of domain expertise in the industries we serve, we are here to help you adjust to whatever may happen next.
The COVID-19 pandemic continues to affect all of us, and all Best Technology colleagues are working around-the-clock to help provide critical tools for the fight. Our current focus: supporting health care and front-line workers as well as our regular and new customers around the world by providing products they need to help protect their lives.
We are seriously in choosing partners who can provide various kinds of respirators as well as medical products:
The partners who can double their global output rate to nearly 100 million respirators per month are in our priority;
Also, we anticipate doubling global capacity of our partners to almost 2 billion respirators in the next 12 months.
We have not increased the prices we charge for our respirators in this crisis.
Our efforts are guided by our value of Caring – for our people and their families, our consumers, and importantly, for those most in need right now. We want to share a few of the ways that we are responding to this global health crisis.
Moreover, after our efforts, all of our face masks, KN95 masks and all of other medical products have passed GB2626-2006 and CE standard. You can also find out the certificates from the above website.
Anything I can do for you? If there is a need, contact us anytime. Our sales team will be here to reply you instantly. Please keep safe and take good care of yourself and your families. Come on, our friends, wish the pandemic will end asap and everything can return to normal soon.
China’s fight against COVID-19 epidemic has achieved victory at this stage. Infected patients were found in 337 cities in China but now only 28 cities remaining patients in cure. So far till March 31st, there were 82545 confirmed cases in China, while 76225 cured and only 3006 remaining now. Most importantly, many of the areas finds only one figure number increase and others stop increasing for quite some days. If the first half of COVID-19 fighting is inside China national territory, the second half will be on the international stages while noticeable growth on COVID-19 infected cases are spreading all over the world now.
Best Technology has been collecting the measures in China on epidemic controls so in order to provide a more objective and useful reference for overseas professionals which we hope they could refer to and protect better themselves from the COVID-19.
During the height of the outbreak, trains didn’t stop at the disease’s epicenter, Wuhan
Trains, as well as other tightly packed forms of transportation, can serve as vectors of illness. The more people, the more closely packed, and the more poorly ventilated the space, you can imagine that’s a bad situation because there are a ton of people, they’re in very close quarters, and they’re a totally captive audience. Cutting off transportation was considered on the top three measures to contain the spread of the virus.
China built new hospitals in a rush, with workers toiling night and day to get them done.
China built two new 1,000-1,300-bed hospitals to fight the corona virus, one created in six days, and the second in 15 days, using prefabricated modules.
Corona virus testing was easily accessible and free
In China, patients who were confirmed to have the corona virus were either sent to an isolation center or hospital. The government also made clear that testing for the new virus was free, and COVID-19-related charges that weren’t covered by a person’s insurance would be paid for by the government.
The country implemented large-scale contact tracing in the early 2000s
During the SARS outbreak in 2002-2003, China set up large-scale surveillance systems that included contact tracing, a front-line public-health strategy that involves identifying and following up with people who may have come into contact with an infected person.
The country postponed non-urgent medical care and moved many doctor’s visits online. Not all patients were given the critical care they needed during the outbreak, though
In China, elective surgeries and other non-critical doctors’ visits were delayed, and many medical services were moved online. Someone in one place said 50% of their consultations are now done online; they just moved a whole bunch of what was normally done physically online to be able to keep the regular health services going.
Centers for Disease Control exploring a way of therapeutic plan combing Traditional Chinese medicines and Western medicines.
The combination of Traditional Chinese medicines and Western medicines had been proven effective on the SARS fights. Doctors of traditional Chinese medicines had volunteered for consulting and participating into the virus fights.
China used technology that aims to trace every single COVID-19 case
Traditional epidemic prevention manufacturers speed up and similar production lines integrating to make more necessary products
Many medicinal and pharmaceutical substances manufacturers launched automation assemble lines and increase manpower to speed up the mass production of necessary drugs, masks, ventilators to meet the huge consumption during virus fighting. Many of these companies arranged 24-hour shifts for maximizing the production.
Meanwhile other manufactures such as automotive OEM had change their assemble line into masks productions machines.
At the blast of COVID-19, returning Chinese carrying back epidemic products from overseas as much as they can
Returning travelers carried extra masks on their flights back to China and donated them to the hospital and governments in need. Some overseas Chinese unions also had helped ordering these products and sending to China.
Chinese citizens did their part to curb the disease’s trajectory on an individual level, too, though we may never know the true scale of their complaints or sacrifices in this outbreak.
In contrast to reports in the US of people clamoring over the last hand-sanitizer, the attitude of people in China was that they were all in this together. People stay at home for self-quarantine, lockdown and response to the postpone returning to work and school.
People who thought they might have the corona virus could go to one of the nation’s many fever clinics
People who thought they had the novel corona virus in China would often be sent to a special fever clinic, which have been widespread since the country dealt with an aggressive SARS outbreak in 2002. Their temperature would be taken, and they’d discuss their symptoms, medical history, travel history, and any prior contact with anyone infected with a doctor.
If necessary, patients might receive a CT scan, which is one way to do an initial screening for COVID-19. Each machine did maybe 200 a day. 5-10 minutes/scan. A typical hospital in the West does one or two an hour.
People quickly shifted jobs in order to assist during the outbreak
When it came to the non-medical response, there was a nationwide sense of solidarity with Hubei. Other provinces sent 40,000 medical workers to the center of the outbreak, many of whom were volunteers.
Workers in transportation, agriculture, and clerical positions were encouraged to new positions such as delivery, courier and epidemic prevention manufacturing, too.
While staying home, it’s been relatively easy for Chinese people to get extra food and supplies
China essentially mandated a country-wide shut down, demanding that every Chinese resident stay home until the curve was flattened. But in West, unlike China, a country-wide shutdown would be difficult to enforce.
Fifteen million people had to order food online. It was delivered. Yes, there were some screw-ups. But few said: every now and again there’s something missing from a package, but food supply is pretty much normal via ordering online.
Since electronic products tend to be shorter, smaller, lighter and thinner, flex pcb is more and more popular with people and the demand is increasing.
FPC coverlay is a functional film normally used in PCB industry, and it is used to protect copper foil from oxidation, cover for surface treatment subsequently and play the role of solder mask in SMT process.
Speaking of fpc coverlay opening, that is, at bare copper foil point, open a hole in coverlay according to the shape of design solder pad, so that fpc traces or traces at golden finger or solder pad can be exposed, which contributes to subsequent surface treatment by connection and placement.
We often adopt 2 ways for fpc coverlay opening. One is to open a tool. This is the first choice, very suitable for production in large batch. The other is uv laser cutting, very suitable for prototyping and production in small batch.
These are what we have sorted out about fpc coverlay opening. Hope it is helpful to you. If you are still confused, please contact us, we have professional staff who can answer your inquires for 24 hours a whole day.