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Digital Image Correlation For Electronics
Digital image correlation analyses have applications in material property characterization, displacement measurement, and strain mapping. As such, DIC is becoming an increasingly popular tool when evaluating the thermo-mechanical behavior of electronic components and systems. CTE measurements and glass transition temperature identification The most common application of DIC in the electronics industry is the measurement of coefficient of thermal expansion (CTE). Because it is a non-contact, full-field surface technique, DIC is ideal for measuring the effective CTE of printed circuit boards (PCB) and individual surfaces of electronic components. It is especially useful for characterizing the properties of complex integrated circuits, as the combined thermal expansion effects of the substrate, molding compound, and die make effective CTE difficult to estimate at the substrate surface with other experimental methods. DIC techniques can be used to calculate average in-plane strain as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Image Correlation
Digital image correlation and tracking is an optical method that employs tracking and image registration techniques for accurate 2D and 3D measurements of changes in images. This method is often used to measure full-field displacement and strains, and it is widely applied in many areas of science and engineering. Compared to strain gages and extensometers, the amount of information gathered about the fine details of deformation during mechanical tests is increased due to the ability to provide both local and average data using digital image correlation. Overview Digital image correlation (DIC) techniques have been increasing in popularity, especially imicro- and nano-scale mechanical testingapplications due to its relative ease of implementation and use. Advances in computer technology and digital cameras have been the enabling technologies for this method and while white-light optics has been the predominant approach, DIC can be and has been extended to almost any imaging techno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Transition
The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. ISO 11357-2: Plastics – Differential scanning calorimetry – Part 2: Determination of glass transition temperature (1999). An amorphous solid that exhibits a glass transition is called a glass. The reverse transition, achieved by supercooling a viscous liquid into the glass state, is called vitrification. The glass-transition temperature ''T''g of a material characterizes the range of temperatures over which this glass transition occurs (as an experimental definition, typically marked as 100 s of relaxation time). It is always lower than the melting temperature, ''T''m, of the crystalline state of the material, if one exists. Hard plastics like polystyrene and poly(methyl methacrylate) are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Analysis
Thermal analysis is a branch of materials science where the properties of materials are studied as they change with temperature. Several methods are commonly used – these are distinguished from one another by the property which is measured: * Dielectric thermal analysis: dielectric permittivity and loss factor * Differential thermal analysis: temperature difference versus temperature or time * Differential scanning calorimetry: heat flow changes versus temperature or time * Dilatometer, Dilatometry: volume changes with temperature change * Dynamic mechanical analysis: measures storage modulus (stiffness) and loss modulus (damping) versus temperature, time and frequency * Evolved gas analysis: analysis of gases evolved during heating of a material, usually decomposition products * Isothermal titration calorimetry * Isothermal microcalorimetry * Laser flash analysis: thermal diffusivity and thermal conductivity * Thermogravimetric analysis: mass change versus temperature or time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Transition
The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. ISO 11357-2: Plastics – Differential scanning calorimetry – Part 2: Determination of glass transition temperature (1999). An amorphous solid that exhibits a glass transition is called a glass. The reverse transition, achieved by supercooling a viscous liquid into the glass state, is called vitrification. The glass-transition temperature ''T''g of a material characterizes the range of temperatures over which this glass transition occurs (as an experimental definition, typically marked as 100 s of relaxation time). It is always lower than the melting temperature, ''T''m, of the crystalline state of the material, if one exists. Hard plastics like polystyrene and poly(methyl methacrylate) are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strain Gauge
A strain gauge (also spelled strain gage) is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. As the object is deformed, the foil is deformed, causing its electrical resistance to change. This resistance change, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the gauge factor. History Edward E. Simmons and Professor Arthur C. Ruge independently invented the strain gauge. Simmons was involved in a research project by Dätwyler and Clark at Caltech between 1936 and 1938. They researched the stress-strain behavior of metals under shock loads. Simmon came up with an original way to measure the force introduced into the sample by equipping a dynamometer with fine resistance wires ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extensometer
An extensometer is a device that is used to measure changes in the length of an object. It is useful for stress-strain measurements and tensile tests. Its name comes from "extension-meter". It was invented by Charles Huston who described it in an article in the ''Journal of the Franklin Institute'' in 1879. Huston later gave the rights to Fairbanks & Ewing, a major manufacturer of testing machines and scales. Types There are two main types of extensometers: ''contact'' and ''non-contact''. Contact ''Contact extensometers'' have been used for many years and are also subdivided into two further categories. The first type of contact extensometer is called a ''clip-on'' extensometer. These devices are used for applications where high precision strain measurement is required (most ASTM based tests). They come in many configurations and can measure displacements from very small to relatively large (less than a mm to over 100 mm). They have the advantage of lower cost and ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Grid Array
A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The traces connecting the package's leads to the wires or balls which connect the die to package are also on average shorter than with a perimeter-only type, leading to better performance at high speeds. BGAs were introduced in the 1990s and became popular by 2001. Soldering of BGA devices requires precise control and is usually done by automated processes such as in computer-controlled automatic reflow ovens. Description The BGA is descended from the pin grid array (PGA), which is a package with one face covered (or partly covered) with pins in a grid pattern which, in operation, conduct electrical signals betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head-in-pillow Defect
In the assembly of integrated circuit packages to printed circuit boards, a head-in-pillow defect (HIP or HNP) is a failure of the soldering process. For example, in the case of a ball grid array (BGA) package, the pre-deposited solder ball on the package and the solder paste applied to the circuit board may both melt, but the melted solder does not join. A cross-section through the failed joint shows a distinct boundary between the solder ball on the part and the solder paste on the circuit board, rather like a section through a head resting on a pillow. The defect can be caused by surface oxidation or poor wetting of the solder, or by distortion of the integrated circuit package or circuit board by the heat of the soldering process. This is particularly a concern when using lead-free solder, which requires higher processing temperature. Since the warping of the circuit board or integrated circuit may disappear when the board cools, an intermittent fault may be created. Diagno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflow
Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux) is used to temporarily attach one or thousands of tiny electrical components to their contact pads, after which the entire assembly is subjected to controlled heat. The solder paste reflows in a molten state, creating permanent solder joints. Heating may be accomplished by passing the assembly through a reflow oven, under an infrared lamp, or (unconventionally) by soldering individual joints with a desoldering hot air pencil. Reflow soldering with long industrial convection ovens is the preferred method of soldering surface mount technology components or SMT to a printed circuit board or PCB. Each segment of the oven has a regulated temperature, according to the specific thermal requirements of each assembly. Reflow ovens meant specifically for the soldering of surface mount components may also be used for through-hole components by filling the holes with solder paste and inse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Modulus
An elastic modulus (also known as modulus of elasticity) is the unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it. The elastic modulus of an object is defined as the slope of its stress–strain curve in the elastic deformation region: A stiffer material will have a higher elastic modulus. An elastic modulus has the form: :\delta \ \stackrel\ \frac where stress is the force causing the deformation divided by the area to which the force is applied and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. Since strain is a dimensionless quantity, the units of \delta will be the same as the units of stress. Specifying how stress and strain are to be measured, including directions, allows for many types of elastic moduli to be defined. The three primary ones are: # ''Young's modulus'' (E) describes tensile and compressive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermomechanical Analysis
Thermomechanical analysis (TMA) is a technique used in thermal analysis, a branch of materials science which studies the properties of materials as they change with temperature. Thermomechanical analysis is a subdiscipline of the thermomechanometry (TM) technique. Related techniques and terminology Thermomechanometry is the measurement of a change of a dimension or a mechanical property of the sample while it is subjected to a temperature regime. An associated thermoanalytical method is thermomechanical analysis. A special related technique is thermodilatometry (TD), the measurement of a change of a dimension of the sample with a negligible force acting on the sample while it is subjected to a temperature regime. The associated thermoanalytical method is thermodilatometric analysis (TDA). TDA is often referred to as zero force TMA. The temperature regime may be heating, cooling at a rate of temperature change that can include stepwise temperature changes, linear rate of change, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Material Property
A materials property is an intensive property of a material, i.e., a physical property that does not depend on the amount of the material. These quantitative properties may be used as a metric by which the benefits of one material versus another can be compared, thereby aiding in materials selection. A property may be a constant or may be a function of one or more independent variables, such as temperature. Materials properties often vary to some degree according to the direction in the material in which they are measured, a condition referred to as anisotropy. Materials properties that relate to different physical phenomena often behave linearly (or approximately so) in a given operating range. Modeling them as linear functions can significantly simplify the differential constitutive equations that are used to describe the property. Equations describing relevant materials properties are often used to predict the attributes of a system. The properties are measured by standardiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
