Technical Library | 2011-02-17 18:03:21.0
Copper ground pours are created by filling open unused areas with copper generally on the outer layers of the board then connecting the copper fill with stitching vias to ground. Usually, small isolated areas
Technical Library | 2011-10-27 18:03:53.0
Leadless, near chip scale packages (LNCSP) like the quad flat pack no lead (QFN) are the fastest growing package types in the electronics industry today. Early LNCSPs were fairly straightforward components with small overall dimensions, a single outer row
Technical Library | 2022-10-04 16:43:10.0
In this paper I will discuss the different methods and equipment used to detect counterfeit electronic parts, specifically integrated circuits as well as demonstrate some of the "red flags" that help to identify a part as being suspected counterfeit. We will begin with the initial receipt of the parts and the examination of the outer packaging, the basic visual inspection of the parts, the visual inspection and documentation at high magnification, permanency marking, blacktop test, scrape test, XRF (RoHS), decapsulation, X-ray, basic electrical testing, C-SAM, full function testing and limited function testing.
Technical Library | 2018-07-18 16:28:26.0
Reduction of first pass defects in the SMT assembly process minimizes cost, assembly time and improves reliability. These three areas, cost, delivery and reliability determine manufacturing yields and are key in maintaining a successful and profitable assembly process. It is commonly accepted that the solder paste printing process causes the highest percentage of yield challenges in the SMT assembly process. As form factor continues to get smaller, the challenge to obtain 100% yield becomes more difficult.This paper will identify defects affecting SMT yields in the printing process and discuss their Root Cause. Outer layer copper weight and surface treatment will also be addressed as to their effect on printability. Experiments using leadless and emerging components will be studied and root cause analysis will be presented
Technical Library | 2023-11-06 17:08:44.0
A new process has been developed for RF shielding on compact electronic communications devices using automated solder paste dispensing. The process is known as Shield Edge Interconnect (SEI). SEI designs enable parts to be processed though underfill before placing of the RF shield and allows more complete use of valuable PCB real estate to achieve reduced form factor requirements and/or for added components on products such as smartphones and tablets. The reduced form factor creates challenges for the assembly of those devices. This process, enabled by Speedline dispensing technology, relies on extremely accurate dispensing of solder paste on copper traces located along the outer edge of the PCB. The result is a robust process solution for SEI in which proprietary closed loop dispenser, pump, vision, and software technologies enable a high volume manufacturing (HVM) process.
Technical Library | 2019-04-08 23:21:29.0
Climatest Symor® adopts molecular sieve to dry air, the whole system is controlled by microcomputer, when humidity is high, It will start to absorb moisture,when the humidity reach the pre-set value, it will stop absorbing, and then discharge the water to outside the cabinet by heating,again and again by automatic control. The most effective and environment-friendly moisture-absorbing desiccant is molecular sieve, molecular sieve is the microporous crystal material synthesized by silicon and aluminium oxide. In order to keep the crystal net discharge to be zero, atoms with cations are located in the crystal structure.and the cation used in these synthetic crystals is usually sodium. At present, there are two kinds of molecular sieves widely used in the dry box industry: Class A and Class X. Molecular sieves are synthesized, shaped and activated under strictly controlled production processes. The whole controlled sythesis process can ensure consistency of the three-dimensional pore size. 3A molecular sieve pore size is 3 angstroms, 4A molecular sieve pore size is 4 angstroms; 13X molecular sieve pore size is 8.5 angstroms. The working principle of molecular sieve: Molecular sieves adsorb molecules onto the crystal surface by physical attraction force. Since 95% surface area of the molecular sieve is within aperture,it needs to screen the adjacent molecules by different size. Only small size molecules can enter into the inner adsorption surface of the molecular sieve through the crystal aperture. This selective adsorption phenomenon is called molecular sieve effect. The molecular sieve adsorption capacity and charge density (polarity) are further related to the adsorbed molecules. The molecular sieves can further distinguish which of the mixed molecules can be adsorbed and determine to what extent the charge density can allow the molecules to be adsorbed onto the crystal. Water molecules are particularly small (2.6 angstroms), that belong to highly polar molecules (very strong positive and negative electron density), and are easily adsorbed by molecular sieves, even under very low moisture condition,once the water molecules are adsorbed,they will be firmly fixed on the crystal. The environment-friendly moisture absorption device is equipped with molecular sieve. When it’s absorbing, the memory alloy controller is in tensile state, and the spring is in contractive state,which just make the valve contact the outer baffle, this insulates the outside air from inside dry box air to achieve dehumidification purpose; and after molecular sieve absorbed moisture inside dry box and become saturated, the program will automatically control the memory alloy device to shrink it so that the valve reaches the inner baffle position. Meanwhile, due to the shrinkage of the memory alloy, the spring is stretched and the valve is pulled out of the outer baffle,so that the moisture in molecular sieve will be discharged into the outside. after the dehumidifying process finished, the program automatically control and reset the memory alloy and spring,to restart absorbing status.
Technical Library | 2019-04-07 23:34:10.0
Ingress Protection Test Chamber is used to determine the protection degree of product enclosures,the protection level provided by the enclosure is called IP code,our IP test chamber compeletely follow the standard IEC60529 and others. IP protection grade is an important index of electrical equipment safety protection. Protective-grade systems such as ip, which provide a method of classifying products in terms of dust-proof, waterproof and anti-collision levels of electrical equipment and packaging, which have been recognized by most European countries, as drafted by the International Electrotechnical Association (iec (international electro technical commission). And announced in ied529 (bs en 60529 / 1992) outer packing protection grade (ip code). The level of protection is expressed in terms of IP followed by two numbers, which are used to define the level of protection. The first number indicates the extent of the equipment‘s resistance to dust, or the degree to which people are protected from harm in sealed environments. I represents a level that prevents solid foreign matter from entering, with a maximum level of 6; The second number indicates the extent to which the equipment is waterproof. P represents the level of protection against influent and the highest level is 8. Such as the protection level of the motor ip65. Contact electrical equipment protection and external material protection level (first digit) Electrical equipment waterproof protection level (second digit) . IP is the international code used to identify the protection grade ip grade consists of two numbers, the first number for dust, and the second number for waterproof, the larger the number means the better protection level.
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