留言板
用户：匿名用户
2025-03-07 11:22:58
- 留言：
- Home page
- 内容：
- https://donvard.ru/
用户：匿名用户
2025-03-07 11:08:27
- 留言：
- pranurnackalluP hrshk
- 内容：
- darknet markets url [url=https://github.com/aresmarketlink0ru72/aresmarketlink ]darkmarkets [/url]
用户：匿名用户
2025-03-07 10:48:36
- 留言：
- pranurnackalluP adhrd
- 内容：
- darkmarket url [url=https://github.com/darknetmarketlinks2025/darknetmarkets ]dark web link [/url]
用户：匿名用户
2025-03-07 10:45:48
- 留言：
- pranurnackalluP atkuj
- 内容：
- darkmarkets [url=https://github.com/tormarkets2025ukaz1/tormarkets2025 ]dark market onion [/url]
用户：匿名用户
2025-03-07 10:36:43
- 留言：
- 아울러, 구독형 모델의 온,오프라인 비즈니스에서도 신세계현금화가 중대한 역할을 합니다.
- 内容：
- 컬쳐랜드현금화는 한편 마이크로 페이먼트의 한 형태로, 일상 송금에도 활용됩니다. 예를 들어, 카페에서 커피를 사고 싶은데 카드를 가지고 있지 않을 때, 스마트폰 앱을 통해 카페에서 소액 결제를 하여 간편하게 결제할 수 있을 것이다. 이처럼 결제 방법은 소비자들의 편의를 높이면서 한꺼번에 사업자들에게도 이익을 제공합니다. [url=https://mypinticket.co.kr/]컬쳐랜드현금화[/url]
用户：匿名用户
2025-03-07 10:01:00
- 留言：
- imp source
- 内容：
- site https://brd-wallet.com
用户：匿名用户
2025-03-07 09:50:05
- 留言：
- pranurnackalluP ttcvr
- 内容：
- onion dark website [url=https://github.com/nexusdarkneturlwrf4t/nexusdarkneturl ]best darknet markets [/url]
用户：匿名用户
2025-03-07 09:46:56
- 留言：
- Introduction to Flexible Printed Circuit (FPC)
- 内容：
- 1. Introduction to Flexible Printed Circuit (FPC) A printed circuit board made of flexible substrates has the advantages of small size, lightweight, 3D assembly capability, and dynamic flexing. 2. Basic Materials 2.1 Copper Clad Laminate Composed of copper foil + adhesive + substrate. There is also an adhesive-free substrate, which consists only of copper foil + substrate. This type is more expensive and is currently less commonly used unless there are special requirements. 2.1.1 Copper Foil Copper foil is classified into two types: Rolled Annealed Copper Foil (RA Copper Foil) and Electro Deposited Copper Foil (ED Copper Foil). In terms of characteristics, RA copper has better mechanical properties and is generally preferred for applications requiring flexibility. The thickness of copper foil is categorized into three standard specifications: . 1/2oz (0.7mil) . 1oz . 2oz Most applications use 1oz copper foil. Ounce (oz) Conversion Reference . Weight unit: 1oz = 28.35g . 1 ounce = 16 drams . 16 ounces = 1 pound (lb) Different Types of Ounces . Troy Ounce (oz.tr / oz.t): Used for measuring precious metals such as gold and silver. 1 oz = 31.1035g, 12 oz = 1 lb. . Apothecary Ounce (ap oz): Used in pharmaceuticals. 1 oz = 31.1030g. . Fluid Ounce (fl oz): Used for liquid measurements. . 1 UK fluid ounce = 28.41 ml . 1 US fluid ounce = 29.57 ml 2.1.2 Substrate Substrate materials are classified into two types: . PI (Polyimide) Film: More expensive but has better flame resistance. . PET (Polyester) Film: Less expensive but not heat-resistant. For applications requiring soldering, PI material is commonly used. Standard thickness options include 1mil and 2mil. 2.1.3 Adhesive There are two common types of adhesives: Acrylic Adhesive Epoxy Adhesive (most commonly used) Adhesive thickness ranges from 0.4mil to 1mil, with 1mil being the most commonly used. Explore our [url=https://www.zxcprint.com/book-printing/]book printing[/url] services on the [url=https://www.zxcprint.com/]printing in China[/url] page. 2.2 Coverlay The coverlay consists of a substrate + adhesive. The substrate is classified into PI and PET, matching the material of the copper-clad substrate. The adhesive type of the coverlay is the same as that of the copper-clad substrate. Coverlay thickness ranges from 0.5mil to 1.4mil. 2.3 Stiffener A stiffener is a rigid material added to specific areas of the flexible circuit board to reinforce certain regions, such as for soldering components or structural support. 2.3.1 Stiffener Materials PI and PET stiffeners FR-4 (Epoxy-based material) FR-4 Material Overview The term FR-4 is commonly spoken as "FR-4," but its formal designation in written documents is FR-4. FR-4 refers to a flame-retardant material grade, meaning that the resin material must be capable of self-extinguishing when exposed to flame. It is not a specific material but a classification standard. Currently, there are many types of FR-4 materials used in printed circuit boards (PCBs), but most are composed of Tetra-Function Epoxy Resin combined with fillers and glass fiber to create a composite material. Common Names for FR-4 Epoxy Glass Cloth Laminates: FR-4 epoxy glass cloth, insulation board, epoxy board, epoxy resin board, brominated epoxy resin board, FR-4 glass fiber board, FR-4 stiffener, FPC stiffener, flexible circuit stiffener, FR-4 epoxy resin board, flame-retardant insulation board, laminated board, PCB drilling pad, and many others. Technical Features and Applications: FR-4 is widely used in high-performance electronic insulation applications, such as: . FPC stiffener . PCB drilling pad . Glass fiber spacers . Potentiometer carbon film printed glass fiber boards . Precision planetary gears (for wafer grinding) . Precision test boards . Electrical and electronic insulation components (e.g., transformer insulation boards, motor insulation parts, insulating spacers, and grinding gears) FR-4 Epoxy Glass Cloth Laminates are available in various colors: . Yellow FR-4 . White FR-4 . Black FR-4 . Blue FR-4 FR-4 is the most commonly used base material in PCBs. Classification of PCB Substrate Materials PCB substrate materials are categorized based on their reinforcement materials: 1. FR-4: Glass fabric-based substrate 2. FR-1, FR-2: Paper-based substrate 3. CEM Series: Composite substrate 4. Special Material Substrate: Includes ceramic-based and metal-based materials FR-4 is produced by impregnating specialized electronic glass fabric with epoxy phenolic resin and then subjecting it to high temperature and high-pressure lamination.
用户：匿名用户
2025-03-07 09:36:14
- 留言：
- pranurnackalluP dfgpf
- 内容：
- dark market 2025 [url=https://github.com/aresmarketlink0ru72/aresmarketlink ]dark websites [/url]
用户：匿名用户
2025-03-07 09:35:02
- 留言：
- pranurnackalluP tsyek
- 内容：
- darknet market [url=https://github.com/darknetmarketlistv8tg0/darknetmarketlist ]bitcoin dark web [/url]
我要留言
855007870