SZFitech

 Solder paste printing needs to be realized through a stencil. The stencil opening needs to be aligned with the substrate pad to achieve accurate printing. It can be said that the stencil quality has a significant impact on the printing effect. The influences of the stencil opening on the printability and release of solder paste cannot be ignored. If the apertures have burrs, the smooth printing of solder paste will be blocked. If the aperture walls are rough, the solder paste sticks to the wall during release, which makes the solder pad have insufficient solder volume and uneven solder shape. After reflow, it will lead to the thermal slump of solder joints and uneven solder joints. Different stencil manufacturing processes will bring different aperture wall quality. At present, the most common stencil manufacturing processes include chemical etching, laser cutting, and electroforming. The stencil is mainly made of nickel and stainless steel. Nickel can provide bette...

 Anisotropic Conductive Adhesive (Anisotropic Conductive Adhesive, ACA) is a special kind of conductive adhesive, its conductivity has a directional, that is, after hot pressing and curing in one direction (usually vertical) with good conductivity, while in another direction (such as the horizontal direction) is manifested as insulation.This characteristic makes ACA have unique application value in the field of electronic encapsulation and connection. The following is a detailed explanation of the principle of anisotropic conductive adhesive: 1. Conductive particle distribution and directionality control Vertical Conductivity and Horizontal Insulation: ACA controls the concentration of conductive particles below the percolation threshold to ensure that the particles are spaced sufficiently far apart to form random conductive paths when unpressurised.When vertical pressure is applied, the particles are compressed into contact in the Z-direction, creating localised co...

  1. The concept of IoT When you start your day, the alarm goes off, and the coffee maker starts brewing. The lights come on as you walk through the house. Some invisible computing device responds to your voice commands, reads your schedule and news, and turns on TV news when you're ready. Your car will drive you to work through the least congested routes, allowing you to find time on the road to read or prepare for a morning meeting. We've read and seen those things in science fiction for decades, but they're either possible or imminent. All these new technologies are forming the basis of the Internet of Things (IoT). As the name suggests, IoT is an internet that connects everything. As a new technology, the definition of IoT is very different. Currently, a broad definition is that IoT uses information collection equipment such as RFID readers, sensors, Infrared sensors, GPS, and laser scanners to connect any item to the Internet according to the protocol. Io...

  In order to make QFN soldering climb tin height of more than 50%, it is necessary to optimise the stencil design, solder paste selection, soldering environment control, pretreatment process in four aspects.The following are specific programmes and validation cases ：     I. Optimisation of stencil design (adjustment of key parameters) Hole opening method: Adopt the inner cut outer pull design: inner cut to reduce the size of the pad cross-cut (to avoid even tin), the outer expansion to increase the amount of solder paste. Case: a customer will be stencil external expansion from 0.15mm to 0.30mm, the thickness of 0.12mm adjusted from 0.13mm, climb the height of tin from 25% to more than 50%. Around the small pad opening width is recommended 0.22 ~ 0.24mm (to meet the 5-ball principle), the length of the flared 0.15 ~ 0.25mm. Heat dissipation pad processing: Open hole area according to the pad size of 40% ~ 60% of the design, and bridging (field type) to avoid solder paste...

 With the continuous development of LED technology, the luminous efficacy and brightness of LEDs have been improved, especially in the field of solid-state lighting, the market demand for high-power LEDs continues to grow. High-power LED devices have the advantages of high brightness, high efficiency, long life and environmental protection, but they also face challenges in heat dissipation and reliability. In order to solve these problems, gold-tin solder, as a high-performance brazing material, has become an ideal choice for encapsulating and connecting high-power LED devices due to its high strength, high thermal conductivity, and no need for flux. This article will introduce the physical properties of gold-tin solder, as well as its applications and advantages in high-power LED devices. LED Chip Package Form Currently, there are two main types of LED chip packages: wire-soldered (front-loaded) LEDs and flip-chip (FC) LEDs. Compared to wire-soldered LEDs, flip-chi...

 In the surface assembly process of electronic products, especially in the high-volume reflow soldering process, the tombstone effect of passive chip components to the PCBA assembly soldering adds a lot of trouble. With the SMC / CMD micro/miniaturisation, reflow soldering of these chip components will appear upright, this phenomenon is also known as the Manhattan effect. Figure 1. Tombstone phenomenon This phenomenon occurs mainly in small chip components, they are soldered on the opposite poles of the surface mount pads, in the soldering process, the components stand up vertically, as shown in the figure. Sometimes it is partially upright, and sometimes the component is completely upright on a pad, like a tombstone in a cemetery. With the miniaturisation and lightweighting of chip components and the application of high-temperature lead-free solders, the effect of tombstone defects has become more significant. Tombstoning effects tend to occur in gas-phase reflow a...