Glossary

Look up industry jargon and terminology

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

A

Absorptivity(absorption coefficient): Absorbance per unit thickness of a medium.
ACCU-CAL™:  Line of Dymax intensity meters that measure UV and/or visible light energy
Acrylic:  A synthetic resin made from acrylic acid or a derivative thereof. Acrylics possess the property of transparency, as well as flame resistance.
Actinometer:  A chemical system or physical device that determines the number of photons in a beam integrally or per unit time. For example, solutions of iron (III) oxalate can be used as a chemical actinometer, while bolometers, thermopiles, and photodiodes are devices whose electrical response can be correlated with the number of photons detected.
Actinometry: Determination of the number of photons in a beam per unit time, or integrated over time.
Activator: A substance that enhances the ability of a flux to remove oxides and other contaminants from surfaces being joined.
Additive lamps: Medium pressure mercury vapor UV lamps (arc or microwave) that have had small amounts of metal halide(s) added to the mercury within the bulb. These materials will emit their characteristic wavelengths in addition to the mercury emissions. [This term is preferred over doped lamps].
Adhesion: The state in which two surfaces are held together by interfacial forces. These forces may be valence forces, interlocking action or both.
Adhesive Failure: The failure of the bond line between substrates and an adhesive; the adhesive separating entirely from the substrate.
Adhesive: A substance capable of holding materials together by surface attachment. Adhesive is the general term that includes cement, glue, mucilage, and paste (among others).
Anaerobic Adhesives: Fast-setting adhesives that cure in the absence of oxygen. They need to be packaged in oxygen-penetrating containers and usually filled only partially to allow plenty of oxygen-rich headroom in the container. These adhesives cure when the oxygen is cut off by the bond line, so close fitting surfaces are desirable. Commonly used in thread lockers and machine fasteners.
ASTM: American Society for Testing Materials.

B

Baking Temperature: A temperature above 150°F (65.6°C). Refers to curing materials at these elevated temperatures.
Bandwidth: The range of wavelengths between two identified limits, expressed in the same units as wavelength (nm). In radiometry, it is important that the basis of the limits (i.e. % response of the instrument used) be specified or known. Band (wavelength range) must be communicated with radiometric data.
BlueWave®: Line of DYMAX UV and/or Visible light curing spot lamps used for small area curing of UV light curing adhesives and coatings.
Bond Strength: The unit load applied in tension, compression, flexure, peel, impact, cleavage, or shear, required to break an adhesive assembly with failure occurring in or near the plane of the bond. The term "adherence" is often used in place of "bond strength".
Bond: The union of materials by adhesives.
Bonding: Joining two materials.
Brightness, also known as Luminance: Description of energy in the visible region of the spectrum (approximately from 400 to 700 nm) and recorded in photometric units. “Intensity” (see below) of visible light energy is called Illuminance.
Brookfield Viscometer: An instrument for measuring the viscosity of formulated adhesives under standard conditions of temperature.
Bulb: Light source generating Ultraviolet, Visible, and Infrared radiant energy from burning matter stimulated by electrical power conditioned by a proper power supply which is an integral part of a Lamp. A light source is usually placed into a reflector (of various geometry) to increase light source efficiency by collecting and directing radiant energy of selected spectra (for a given curing process).

C

Catalyst: A chemical that speeds up the curing of an adhesive when added in a minor quantity, compared with the amounts of the primary reactants.
Centigrade: A scale of temperature which features 0° and 100° as the freezing and boiling point of water respectively. To convert centigrade to Fahrenheit multiply by 1.8 and add 32. (100° x 1.8) + 32 = 212°F. View our Fahrenheit and Centigrade conversion chart.
Centipoise: 1/100th of a poise; (dyne-sec/cm2); a viscosity measurement unit.
Coating: A thin layer of material, conductive or dielectric, applied over components or a base material.
Coefficient of Linear Thermal Expansion: Once cured, a measure of the change in length of an epoxy system over a given temperature range. It is expressed in inches per inch per degree C. ASTM D696-44.
Coefficient of Thermal Expansion (CTE): Change in a unit of length or volume that accompanies a unit change in temperature.
Cohesion: The state in which the particles of a single substance are held together by primary or secondary valence forces observed in the tendency of the substance to stick to itself. As used in the adhesives field, the state in which the particles of the adhesives (or the adhered) are held together.
Cohesive Failure: Failure within the adhesive under a stress, resulting in a broken bond with all adhered surfaces still covered with adhesive.
Cold mirror: A type of dichroic reflector that has low reflectance to IR compared to its reflectance of shorter wavelengths, visible or UV. Also see dichroic.
Color: The color of a fully cured adhesive sample.
Compressive Modulus: The ratio within the elastic limit of compressive stress to corresponding compressive strain (deformation per original length). It is expressed in pounds per square inch. ASTM D695-54.
Compressive Strength, Ultimate: The maximum load in pounds that can be carried per square inch of cross section of the material under test.
Compressive Strength: The crushing force necessary to break a bond, divided by its cross-sectional area.
Conductive: Having the quality of power of conducting or transmitting heat, electricity, or static electricity.
Conductivity: Reciprocal of volume resistivity. Conductance of a unit cube of any materials.
Conformal Coating: A thin non-conducting coating that is either plastic or inorganic and is applied to a circuit for environmental and mechanical protection.
Cosine response: Description of the spatial response to incident energy where response is proportional to the cosine of the incident angle. A radiometer with a diffuser or a photo-responsive coating will exhibit nearly cosine response.
Cross-Link: Tying together large molecules and changing the physical properties of the material. Cross-linking usually involves formation of a three-dimensional molecular network and is associated with thermosetting resins.
Cure Cycle: The amount of time periods at specified temperatures to which a reacting thermosetting plastic or rubber composition is subjected in order to reach certain specified properties.
Cure Time: The amount of time required to reach 90% cure at room temperature (75°F =/-2).
Cure: To change the physical properties of an adhesive by causing a material reaction. This reaction can be initiated by a chemical process or energy.
Curing: The process of irreversibly polymerizing a thermosetting plastic by subjecting it to a temperature-time profile.
Cyanoacrylates: Have the ability to polymerize very quickly at room temperature with no catalyst required and are suitable for use with a variety of bonding surfaces. These adhesives have been widely used for thread locking applications, and sometimes are subject to hydrolic degradation when exposed to moisture. They are thermoplastic when cured and consequently are limited in temperature capabilities and chemical resistance.

D

Delamination: A separation between plies within the base material, or between the base material and the conductive foil, or both.
Density: The ratio of a substance's mass to its volume at a given temperature and pressure. Example: water at 25°C, 1 atmosphere of pressure = 1.0 gr/cm3 = 8.35 lb. per gallon.
Dichroic: Exhibiting significantly different reflection or transmission in two different wavelength ranges. Dichroic reflectors that have reduced reflectance to long wavelengths (IR) are called "cold mirrors", while reflectors having enhanced reflectance to long wavelengths are called "hot mirrors".
Dielectric Constant: When electrical energy is applied in a circuit, the insulating material of the electrical charge and releases it when the current is broken. Capacitance is the ratio of charge absorbed to the potential (voltage applied). Dielectric Constance is the ration of an insulator's capacitance to that of dry air. (1.0) A dielectric constant of 5 means an insulator will absorb 5 times more electrical energy than air.
Dielectric Strength: The voltage which an insulating material can withstand before breakdown occurs, expressed in volts per Mil.
Diffuse: A characteristic of a surface that reflects or scatters light or UV equally in all directions (often confused with spread reflectance).
Diluent: A reactive or non-reactive additive whose primary function is to lower the viscosity and extend the material to which it was added.
Discoloration: Any change from an initial color possessed by a material, either due to environmental or internal conditions.
Domed: Showing a symmetrical distortion of a flat or curved section of an object so normally viewed. Term often used when clear "epoxy domes" are applied to labels, pins, magnets, key tags, etc.
Doped lamps: Term applied to UV lamps having metal halide additives to the mercury to alter the emission spectrum of the lamp. (Historically this term has been used by UV arc lamp manufacturers. It is an imprecise usage, as the added chemical does not alter the properties or another). [The preferred term is additive lamps].
Dose: Irradiance integrated over time, or Irradiance (W/cm2 ) x Time (s) = Dose (Joules/cm2). Note: Watt is the power that gives rise to the production of energy at the rate of 1-joule (J) per second (s).
Dual-Cure: Light and secondary moisture cure technology formulated into DYMAX conformal coatings allowing shadowed components hidden on PCBs to fully cure after light exposure. Dual-Cure™ products cure with UV/Visible light and secondary moisture cure
Dynamic exposure: Exposure to a varying irradiance, such as when a lamp passes over a surface, or a surface passes under a lamp, or lamps. In that case, energy is the time-integral of the irradiance profile.
Dynamic range: The span between the minimum irradiance and the maximum irradiance to which a radiometer will accurately respond. Expressed as a ratio, or in measured units (e.g., watts/cm2).
Dyne: Measurement typically used for measuring surface tension. 1 dyne = 10 u-Newton's.

E

Effective energy density: Radiant energy, within a specified wavelength range, arriving at a surface per unit area, usually expressed in joules per square centimeter or millijoules per square centimeter (J/cm2 or mJ/cm2). Is expressed in a specified wavelength range (without wavelength specification, it is essentially meaningless). Commonly accepted abbreviations are Wl or El. [An alternate term is exposure].
Effective irradiance: Radiant power, within a specified wavelength range, arriving at a surface per unit area. It is expressed in watts or milliwatts per square centimeter (W/cm2 or mW/cm2) in a specified wavelength range (without wavelength specification, it is essentially meaningless). For brevity, when the wavelength range is clearly understood, the term is shortened to irradiance. Commonly accepted abbreviations are El or Il. Compare spectral irradiance.
Einstein: One mole of photons. Sometimes equated to the energy of one mole of photons – although this use is discouraged.
Elasticity: That property of materials by virtue of which they tend to recover their original size and shape after deformation.
Elastomer: A material that, at room temperature, can be stretched repeatedly to at least twice its original length. When the stress is removed, the material immediately returns to its approximate original length.
Elastomeric: A material that at room temperature can be stretched repeatedly to at least twice its original length, and upon release of the stress, will return with its force to its approximate original length.
Electrically Conductive adhesives (including epoxy): Systems that are usually heavily filled (greater than 70%) with electrically conductive fillers. The most common fillers are silver, copper, gold, nickel, and carbon. Conductivities of 0.001 ohm/cm and less can be achieved with many of these systems. Typical applications include replacement for solder in electrical connections, connections to substrates that can't be soldered or where heat would be a problem. These adhesives also tend to have excellent thermal properties.
Electromagnetic spectrum: An extremely wide range of radiation that travels at the speed of light, and characterized by wavelength. Extends from radio waves (~104 meters), through visible and UV (~10-4 meters), to gamma rays (~10-14 meters).
Elongation (%): Ability of a material to stretch or become longer.
Emission spectra: Radiation from an atom or atoms in an excited state, usually displayed as radiant power vs wavelength. Emission spectra are unique to each atom or molecule. The spectra may be observed as narrow line emission (as in atomic emission spectra), or as quasi-continuous emission (as in molecular emission spectra). A mercury plasma emits both line spectra and continuum simultaneously.
Encapsulant: The material used to cover COB devices to provide mechanical protection and to ensure reliability.
Encapsulation: Used interchangeably with Potting. Refers to the enclosure of an item in a substance. Sometimes used specifically in reference to the enclosure of capacitors or modules.
Energy density: Radiant energy arriving at a surface per unit area, usually expressed in joules or millijoules per square centimeter (J/cm2 or mJ/cm2). It is the time-integral of irradiance. Same as exposure. For a parallel and perpendicularly incident beam, not scattered or reflected, energy density and fluence become identical. Compare fluence. [Not equivalent to dose].
Epoxy Resin: A material that forms straight chain thermoplastic and thermosetting resins.
Evacuation: The removal of entrained air from an epoxy system by vacuum. Also referred to as degassing.
Exotherm: The liberation of heat energy during a chemical reaction. Exotherm is increased in large masses.
Exposure: Effective radiant energy density at a surface; the time-integral of irradiance within a specified bandwidth, expressed in J/cm2 or mJ/cm2. The time-integral of fluence rate, in J/m2 or J/cm2. Also radiant exposure. In solar UV exposure applications, larger units may be used – J/m2 or even MJ/m2. Compare fluence. [Not equivalent to dose]. The definition varies in radiation chemistry in clinical chemistry.

F

Filler: A substance, often inert, added to a system to improve properties and/or decrease cost.
Flame Retardance: The ability of an epoxy system to resist combustion or burning. Some materials tend to extinguish themselves when subjected to a flame. Such materials are classified as self-extinguishing. ASTM D790-63.
Flash Point: The temperature at which the material gives off flammable vapor in sufficient quantity to ignite momentarily on the application of a flame under specified conditions.
Flex Circuits: Flexible printed circuit boards made using thin polymide or polyester film with copper circuitry on one or both sides of the flex.
Flexural Modulus: The ratio, within the elastic limit, of flexural stress to the corresponding strain. It is expressed in pounds per square inch (psi). ASTM D-790-63.
Flexural Strength: The ability of a material to withstand failure due to bending.
Flip Chip: Any packaging scheme in which the active circuitry of an IC is placed facing the surface of the substrate.
Fluence rate: The radiant power of all wavelengths passing from all directions through an infinitesimally small sphere of cross-sectional area dA, divided by dA. For a parallel and perpendicularly incident beam, not scattered or reflected, irradiance and fluence rate become identical. Units are typically W/cm2 or mW/cm2.
Fluence: The total radiant energy of all wavelengths passing from all directions through an infinitesimally small sphere of cross-sectional area dA, divided by dA. Units are typically J/cm2 or mJ/cm2.
Flux (radiant flux): The flow of photons, in einstein/second; one einstein = one mole of photons.
Functional Test: The electrical testing of an entire assembly that simulates the intended function of the product.

G

Gardner Color Scale: A system of color standards based upon stable solutions of ferric chloride used in the evaluation of resins, lacquers, oils, and varnishes. The Gardner Scale can be correlated roughly with other color standards such as FAC, ASTM, and NPA.
Gel: The initial jelly-like solid phase that develops during the transition from a liquid to a solid.
Glass Transition Temperature (Tg): Approximate midpoint of the temperature range over which a material undergoes a phase change from brittle to rubbery or vice versa.

H

Hardener: A substance or mixture of substances added to an epoxy resin to promote or control the curing reaction by taking part in it.
Halogen-Free:
Halogen-Free Dymax Products
A material having less than 900 parts mer million (ppm) of chlorine, less than 900 ppm of bromine and less than 1500 ppm total level of both combined. Learn which Dymax products are Halogen-Free.
Heat Sink: Any device that absorbs and draws off heat form a hot object, thereby neutralizing the extreme temperature.
Hot mirror: A dichroic reflector having a higher reflectance to IR than to visible or UV. See dichroic.
Humidity (Absolute): The amount of moisture present in the atmosphere expressed in grams per cubic meter.
Humidity (Relative): The ratio of the amount of moisture contained in the atmosphere to the amount of moisture that can be carried in the atmosphere at a given temperature. Relative humidity is expressed in percent, e.g., 75% R.H. at a given temperature means that the air is 75% saturated with moisture.

I

Illuminance: luminous flux (energy of visible light) incident per unit area, and measured in Lx (lux) or Lumen/cm2.
Integrated Circuit: A microcircuit that consists of interconnected elements inseparably associated and formed in-situ on or within a single substrate, usually silicon, to perform an electronic circuit function.
Intensity: Measure of light energy over the unit of surface area (usually surface at the specified working distance from the bottom of reflector housing) in W/cm2 or mW/cm2. For the UV portion of light, this measure is often called in literature “irradiance”, i.e. radiant energy arriving at a point on a surface per unit area. View our intensity conversion table.
Intensity: A generic term, with a variety of meanings; undefined, but sometimes used to mean irradiance. Generally mis-applied in UV curing. Its precise optical meaning is flux/steradian (W/sr), applied to emission of light; not useful in UV curing. [Compare irradiance or peak irradiance or effective irradiance].
Irradiance profile: The irradiance pattern a lamp; or, in the case of dynamic exposure, the varying irradiance at a point on a surface that passes through the field of illumination of a lamp or lamps; irradiance vs time.
Irradiance: Radiant power arriving at a surface from all forward angles, per unit area. It is expressed in watts per square centimeter or milliwatts per square centimeter (W/cm2 or mW/cm2). Compare effective irradiance, spectral irradiance and fluence rate.

J

Joule (millijoule): A unit of work or energy (a newton-meter). The time-integral of power. Abbreviated J or mJ. (Although derived from a proper name, the term joule is not capitalized, while its abbreviation is capitalized).

K

L

Lap Shear Tensile Strength: This is the maximum measured strength, in pounds per square inch (psi), of two strips of aluminum bonded together forming an overlapping joint.
Light Weld®: DYMAX adhesives that cure with UV light.
Light: Radiant energy in the visible range of the electromagnetic spectrum.
Line emission: Narrow lines of emission from an atom in an excited state. These are the “spikes” observed in spectrometry. Low-pressure sources exhibit finely distinguished line emission; higher pressure sources generally exhibit more continuous spectra.
Lumen: When making catheters, lumen = tubing. Catheters can have a single lumen = 1 tube with 1 hole in the center. Catheters can have multi-lumen = 1 tube with 3,4,6,or ? holes in the center. Catheter balloons are bonded to the outside of the lumen. Steerable catheters can run guidewires up 4 of the holes in the lumen, bonded to the end, which allow the tip to be moved like a kite (pull one string and the kite turns in that direction). Some lumen holes will contain instruments, or air, or medicine, or be used to suck debris out during the operation, or cameras. The catheter has two ends: Proximal end and Distal end. Distal end (think "distant" or farthest away) is the end in the patient. The Proximal end (think "proximity" or closest) is the end the Doctor holds. There are 8-10 different applications that could fall within "lumen adhesive". Basically it covers any adhesive that can be used to bond onto or into the catheter shaft.

M

Measurement: Measurement of specific ranges may be defined by the responsivity of a radiometer. It should be made clear, when referring to these ranges, exactly what wavelengths they represent. Specific manufacturers of radiometers will use uniquely specified ranges.
Modifier: Any ingredient added to an epoxy formulation that changes its properties.
Moisture Resistance: Having some resistance to high humidity. A moisture resistance adhesive will not be easily affected by moisture. Will not easily change its chemical and physical properties due to moisture.
Monochromatic: Light or UV radiated from a source that is concentrated in only a very narrow wavelength range (bandwidth). This may be accomplished either by filters or by narrow-band emission.
Monochromator: An instrument that separates incoming radiant energy into its component wavelengths for measurement. Two methods are used for dispersing the radiation: diffraction grating or prism. The typical resolution may be 1 nanometer or less.
Multi-Cure® adhesives: DYMAX adhesives that cure with UV/Visible light, activator, or heat.

N

Nanometer: Unit of length. Abbreviated nm Equals 10-9 meter, = 10-3 micron, = 10 A (angstrom). Commonly used unit to define wavelength of light, particularly in the UV and visible ranges of the electromagnetic spectrum. An older equivalent term, millimicron, is rarely used today.

O

OHM Unit: Unit of electrical resistance. Resistance of a circuit in which a potential difference of one volt produces a current of one ampere.
One-Component
(Room Temperature or Heat Cured):
Adhesives (including epoxy, urethane, and silicone) have the catalyst or hardener as an integral part of the system and require no mixing. These adhesives may have limited shelf life and/or special storage conditions such as refrigeration may be required. Curing can be activated by introducing heat (epoxies), oxygen (anaerobic, or moisture) silicones)). Such adhesives can be desirable when eliminating measuring or mixing errors is required or when dispensing equipment cannot handle multi-component systems.
One-Component
(Ultra-Violet Cured):
Adhesives require UV light to cure. High-power, UV light sources can cure these adhesives very quickly when needed for high speed assembly work or applications that require a fast cure. In most cases, it is desirable to have substrates that can pass light or open bond lines where the light source can reach. Blind or closed applications are usually difficult applications for this type of adhesives. Common applications are found in the medical device industry.
Opaque: A material that no light can be transmitted through.
Optical density: The logarithm of the reciprocal of reflectance or transmittance. A dimensionless number. In printing and color, it is the log of the ratio of visible light absorbed by an “absolute white” to the light absorbed by the measured ink.
Outgassing: The slow release of gas trapped within a material.
Ozone: Oxidizing agent (O3) produced by the action of Ultraviolet radiant energy (below 185 nm) or electrical corona discharge of oxygen on air.

P

P.S.I.: Pounds per square inch; a unit of measure of pressure.
PCB: Printed Circuit Board - A substrate of glass fabric impregnated with a resin and cured, and clad in metal upon which a pattern of conductive traces is formed to interconnect components.
Peak irradiance: The intense, peak of focused power directly under a lamp. The maximum point of the irradiance profile. Measured in irradiance units, W/cm2.
Peel Strength: The peeling force necessary to break a bond, divided by its cross-sectional area.
Photometer: An instrument for measuring visible light, usually filtered or corrected to match the human eye response.
PLC: Programmable Logic Controller
Polychromatic, or polychromic: Consisting of many wavelengths.
Polymerization: A chemical reaction in which the molecules of a monomer are linked together to form large molecules whose molecular weight is a multiple of that of the original substance. A polymer is a material formed by polymerization.
Polymerize: To chemically unite two or more polymers or monomers of the same kind to form a molecule with a higher molecular weight.
Pot Life: The length of working time of a two-component reactive system from the time of the addition of the curing agent in a specific mass (i.e., 100 grams). It is expressed in minutes.
Potting: Similar to encapsulating, except that steps are taken to insure complete penetration of all the voids in the object before the resin polymerizes.
Power (radiant) see radiant power: The rate of radiant energy or total radiant power (W) emitted in all directions by a source.
Power (UV lamp): Tubular UV lamps are commonly described by their operating power in “watts per inch” or “watts per centimeter.” This is derived simply from the electrical power input divided by the effective length of the bulb. (It does not have a direct meaning to the output efficiency of a lamp system, to the spectral conversion efficiency, to the curing performance, not to the UV irradiance delivered to a work surface).
Pull Strength: A measure of the quality of a solder joint formed between a component lead and a bonding pad on a substrate.

Q

Quantum yield: A measurement of the photon efficiency of a photochemical reaction. The ratio of the number of chemical events per unit time to the number of photons absorbed per unit time. It is a unitless measure. Note that it is based on the absorbed and not the incident photon flow.

R

Radiachromic: Exhibiting a change of color or optical density with exposure to light or UV. A character of films whose color or density change can be correlated to exposure to UV energy.
Radiance: Generally refers to the radiant output of a source. It is radiant flux per unit area per steradian (W/cm2/sr). In UV curing, it is used in a generic sense rather than as a precise optical term.
Radiant energy: Energy transfer, expressed in joules or watt-seconds (J = Wxsec).
Radiant exposure: See exposure.
Radiant intensity: Power per unit of solid angle from a source, expressed in watts/steradian (W/sr).
Radiant power: Rate of energy transfer, expressed in watts or joules/second (W = J/sec).
Radiochromic: Preferred term is radiachromic.
Radiometer: A device that senses irradiance incident or its sensor element. Its construction may incorporate either a thermal detector or a photonic detector. This instantaneous signal output will usually have a linear proportionality to radiant flux, and will depend on incident wavelength(s). The resulting characteristic response to irradiance versus wavelength is called responsivity.
REACH: Acronym for Registrations, Evaluation, Authorization, and restriction of Chemical substances. Read more abour REACH.
Resin: An organic material that has an indefinite and often high-molecular weight. Resins tend to flow when subjected to stress, usually have a softening or melting range, and usually fracture conchoidally.
Resistivity: The ability of a material to resist passage of electrical current either through its bulk or on a surface. The unit of volume resistivity is the ohm-cm, of surface resistivity, the ohm.
Responsivity (spectral sensitivity): The response or sensitivity of any system in terms of incident wavelength. In radiometry, it is the relative output of a device versus wavelength. In photochemistry, it may also be applied to the spectral response of photoinitiators.
Rework: A manufacturing operation that restores a part or an assembly to an operable condition. The reworked part/assembly should meet or surpass specifications.
Rheology: The study of the change in the form and flow of matter, including elasticity, viscosity, and plasticity.
RoHS: Acronym for Restriction of Hazardous Substances. All DYMAX adheisves are RoHS compliant. Read more abour RoHS.
RTV: An acronym for room-temperature vulcanizing. An RTV adhesive vulcanizes without the application of heat.

S

See-Cure: Color transition and cure indicator technology incorporated into DYMAX adhesives that changes from blue to clear when exposed to UV light indicating an adhesive is cured
Set: To convert into a fixed or hardened state by chemical or physical action through polymerization.
Shadowing: The failure of molten solder to wet the leads of surface mount components due to their location on a board during wave soldering.
Shear Strength: The sliding force required to break a bond, divided by its cross-sectional area.
Shore A Hardness: The reading of a material's hardness on a durometer, the scale of which is 0-100, used on elastomers and other flexible materials. Consists of a pin point depression into the material, the material being at least 100 mils thick. A Shore A reading of 80 equal a Shore D reading of 30. View our comparison chart.
Shore D Hardness: The reading of a material's hardness on a durometer, the scale of which is 0-100, used on rigid and semi-rigid materials. Consists of a pin point depression into the material. Both the Shore A and Shore D instruments are made by the Shore Instrument Manufacturing Company, Inc. Jamaica, NY. View our comparison chart.
Shrinkage: The decrease in volume, or contraction, of a material by the escape of any volatile substance, or by a chemical or physical change in the material.
SMT: Surface Mount Technology - a method of assembling PCBs where components are mounted onto a surface of the board rather than being inserted into holes.
Specific Gravity: The ration of weight of any volume of a mass or substance to the weight of an equal volume of water at given temperature. The specific gravity of a substance times the density of water equals the density of the substance.
Spectral absorbance (absorbance spectrum): Absorbance described as a function of wavelength.
Spectral irradiance: Irradiance at a given wavelength per unit area per unit wavelength interval. Expressed in W/cm2/nm. Usually measured with a spectroradiometer. Compare effective irradiance.
Spectral output: The radiant output of a lamp versus wavelength. It is displayed in a variety of ways, but commonly a graph or chart of output watts plotted against wavelength. The appearance of the plot will vary dramatically, depending on the wavelength resolution used. A technique of normalizing is to integrate spectral power over 10-nanometer bands, (W/10nm), to reduce the difficulty of quantifying the effects of line emission spectra.
Spectroradiometer: An instrument that combines the functions of a radiometer and a monochromator to measure irradiance in finely divided wavelength bands.
SpeedMask®: Line of DYMAX temporary peelable maskants used to protect components during finishing processes.
Static exposure: Exposure to a constant irradiance for a controlled period of time. Contrast with dynamic exposure.
Storage Life: The period of time during which a packaged adhesive or curing agent can be stored under specific temperature conditions and remain stable for use. Sometimes called shelf life.
Stress: An applied force or pressure, as tension or shear, exerted on a body which produces a resultant strain on the material. The ability of material to withstand a stress depends on the strength of its cohesive force or molecular resistance.
Substrate Failure: The failure of the substrate material itself, upon subjecting bonded adhered surfaces to stress.
Substrate Geometry: Substrate dimensions, typically dimensions critical to implement a successful bonding process.
Substrate: A material upon the surface of which an adhesive is spread for any purpose, such as bonding or coating.
Surface Resistivity: The resistance to a current flow along the surface of an insulator material. Measure in ohms-cm.
Surface Tension: The property of a liquid which causes the surface to pull into the smallest area for a maximum volume, hence, drops are spherical. The fact that water drops on a wax surface do not spread out due to surface tension. If a wetting agent were to be added to the water the round droplet would spread out into a film because of the lowered surface tension.

T

Temperature, Curing: The temperature to which and adhesive or an assembly is subjected to cure the adhesive.
Tensile Strength: The pulling force necessary to break a bond, divided by its cross-sectional area. Tensile strength is the resistance of a material to stretching without rupture. It’s expressed in pounds per square inch.
Thermal Conductivity: A measure of how rapidly heat is conducted through a material.
Thermal Cycling: A method used to induce stresses on electrical components by means of sequential heating and cooling in an oven.
Thermal Shock Resistance: The ability of a cured system to resist cracking or crazing under conditions of rapid and continuous thermal change. The 1/4 inch Olyphant Washer test is cycled over a temperature range of -55°C to +125°C, this temperature is normally used as the test condition unless otherwise stated.
Thermosetting: Describes the property of an epoxy, to set or become rigid and non-meltable when heated with or without pressure.
Thixotropic Ratio: An indication of thixotrophy as a ratio of viscosities at two different shear rates.
Thixotropy: False body. The property of a paste or fluid to thicken or set up to a paste or semi-gel when allowed to stand. Agitation breaks it down but further standing will again permit a viscosity rise.
Two-Component
(High Temperature Cured):
Adhesives (including epoxy urethane, polyester, acrylic and silicone) are systems that require, just prior to application, the addition of a second component which must be measured and thoroughly mixed. The second component is commonly referred to as the curing agent, hardener, catalyst, activator, or accelerator. The two components are also sometimes described as PART A (Resin) and PART B (curing agent). These systems, once mixed, are designed to cure only at elevated temperatures. Generally, a minimum temperature of 80 degrees C is required to fully cure these systems. Various cure temperatures and cure schedules are often provided to offer the user a variety of cured characteristics. In many cases, heat-cured systems can offer unique or extended capabilities such as improved chemical resistance or higher operational temperature ranges.
Two-Component
(Room Temperature Cured):
Adhesives (including epoxy urethane, polyester, acrylic and silicone) are systems that require, just prior to application, the addition of a second component which must be measured and thoroughly mixed. The second component is commonly referred to as the curing agent, hardener, catalyst, activator, or accelerator. The two components are also sometimes described as PART A (Resin) and PART B (curing agent). These systems, once mixed, are designed to cure at room temperature. However, in many cases, the cure time may be accelerated with heat, but this is not required.

U

UL recognized:
This product is UL recognized.
Denotes an adhesive or coating that has been evaluated by the Underwriters Laboratories Inc. (UL). Comprehensive test results are available at www.ul.com. DYMAX’s file number is QMJU2.E140512.
Ultra Light-Weld®: DYMAX adhesives that cure with UV and/or visible light.
Ultra-Red™: Red fluorescing technology incorporated into DYMAX adhesives that fluoresce bright red under a specific wavelength
Ultraviolet (UV): The invisible region of the spectrum just beyond the violet end of the visible region. Wavelength ranges in general from 1.0 to 400 nm. DYMAX® bulbs (burners) do not radiate energy in deep Ultraviolet; there are very minute amounts below 220 nm and practically nothing can be sensed below 200 nm. This is due to the use of an ozone blocking quartz bulb envelope (See Ozone).
Ultraviolet Radiation: The portion of the electromagnetic spectrum between X-Rays and visible light. Wavelengths range from 40 to 400 nanometers.
UV: Ultraviolet. Radiant energy in the 100 nm to 450 nm range. 100 nm to 200 nm is generally called vacuum UV (VUV), because it does not transmit in air. There is no precisely defined boundary between UV and visible light, and may be considered about 400-450 nm.
UVA: UVA is commonly referred to as long UV wavelengths; while UVC is considered short UV wavelengths. VUV should not be confused with the very long UV range called UVV (400-450 nm).
UVA, UVB, UVC: Designations of UV wavelength ranges, originally for distinction of physiological effects or UV, and establishment of safe exposure limits.
UVCS: Line of UV/Visible light curing conveyor systems used for curing UV inks, coatings, and sealants.
  • Ultraviolet A (UV-A) - UV of long wavelength from within approximately 400 to 320nm of the spectral band (4000 to 3200Å) - predominately produced by DYMAX Flood Lamps.
  • Ultraviolet B (UV-B) - UV of medium wavelength from within approximately 320 to 280nm - DYMAX Flood Lamps produce some amount of their energy within this bandwidth.
  • Ultraviolet C (UV-C) - UV of short wavelength below 280nm (we say from 280 to 200nm) – a large amount of this energy is present in the Sunlight.
  • Visible – Light that can be seen 400-700 nm.

V

Viscosity: How well a fluid flows. It’s usually measured in Centipoise (cps). The lower the number, the thinner or more pourable the liquid. Water has a viscosity of 1 cP, corn syrup has a viscosity of 3,500 cP, and ketchup has a viscosity of 50,000 cP. View our comparison chart.
Volume Resistivity: The ratio of electrical resistance through a cross section A divided by the length through which the current flows. Measured in ohms-cm. Volume Shrinkage (%).

W

Watt (milliwatt): The absolute meter-kilogram-second unit of power equal to the work done at the rate of one joule per second or to the power produced by a current of one ampere across a potential difference of one volt: 1/746 horsepower. Abbreviated W or mW. In optics, a measure of radiant or irradiant power. (Even though the term is derived from a proper name, the term watt is not capitalized, while the abbreviation is capitalized).
Wavelength: A fundamental descriptor of electromagnetic energy, including light. It is the distance between corresponding points of a propagated wave. It is the velocity of light divided by equivalent frequency of oscillation associated with a photon. UV wavelengths are currently measured in nanometers (10-9 meter). An older term, Angstroms (A = 10-10 meter) is rarely today. The typical symbol for wavelength is l (lambda).
WEEE: Acronym for Waste Electrical and Electronic Equipment. Read more about WEEE.
Wetting: The thorough impregnation of a material by a liquid. The more viscous a fluid and the higher its surface tension, the more difficult it is for the liquid to "wet" materials.
Working Life: The period of time during which an epoxy after mixing with a curing agent, remains workable and suitable for use.

X

Y

Yield Strength: The load in pounds per square inch (psi) where the material under test begins to change dimensions and will not completely recover when the load is removed. Yield strength will normally be lower than ultimate strength.

Z

Stay Up-to-Date on Our Latest Products & News

Join our email list and be the first to know about new products, white papers, studies, and more.

 

Resources