Abstract: A method for manufacturing a broadband cholesteric polarizer includes positioning a layer of reactive material; irradiating the layer of reactive material; directing, at a first side of the layer, a monochromatic beam of light of a given wavelength toward the layer; and detecting, at a second side of said layer, a detected intensity of light of the given wavelength coming from the layer.

Abstract: A method of forming a resin composite part utilizing a mold surface for mitigating post-cure machining of the resin composite part. The method provides for forming a resin preform having a peripheral geometry similarly sized and configured as a configuration of the mold surface. The mold surface is sized and configured to receive the resin preform. The resin preform is then cured to form the resin composite part with the resin composite part being confirmed to the configuration of the mold surface for mitigating post-cure machining of the resin composite part.

Abstract: An apparatus and method for controlling the surface level of a liquid residing within a relatively vertically stationary workpiece support platform disposed within a reservoir for use in stereolithographic processes wherein a layered object or structure is formed by selectively curing portions of the liquid to at least a semisolid state in multiple, at least partially superimposed layers. Providing precise control of liquid depth over the vertically stationary platform as well as focusing of a laser beam for curing the liquid at the varying surface levels thereof relative to the vertically stationary platform is effected using a laser range finder system controlled by a computer used to control the stereolithographic process in a closed loop fashion.

Abstract: A hollow fiber microfiltration (MF) membrane is provided. The casting solution used to make this membrane includes a fiber-forming polymer having a degree of polymerization greater than about 1000, a water-soluble polymer, an anhydride with about 2 to 12 carbon atoms, and a solvent. The membrane is formed by mixing and heating these components to form a viscous dope and then extruding the dope through an annular orifice to form a hollow fiber MF membrane. The hollow fiber membrane is then fed through a coagulation bath and two leaching baths. The membrane is especially useful for filtering liquids, such as wine and juice, so as to remove bacteria, gel, and solid particles from the liquids.

Abstract: The present invention provides a tubing assembly having a sidewall having a first layer. The first layer is fabricated from a first polymer blend comprising a first component of a material not thermally responsive to laser beam and selected from the group consisting of polyolefins, ethylene and lower alkyl acrylate copolymers, ethylene and lower alkyl substituted alkyl acrylate copolymers, ethylene vinyl acetate copolymers, polybutadienes, polyesters, polyamides, and styrene and hydrocarbon copolymers. A second component of the blend is a laser responsive material having low solubility in aqueous medium; and the blend being sufficiently thermally responsive to exposure to a laser beam having a wavelength within a range of wavelengths from about 700 nm to about 1500 nm to melt upon exposure to the laser beam for a short period of time. The assembly also has an end cap film covering the fluid outlet.

Abstract: A Method of manufacturing a sintered structure on a substrate is provided. To this end, a particle-charged liquid is provided on the substrate by means of a (multiple print head) ink jet printer. Subsequently, the liquid is evaporated and the particles contained therein are sintered layer by layer. Said layer-by-layer laser sintering enables 3-dimensional products having a relatively high dimensional accuracy to be manufactured. Preferably, evaporation of the liquid also takes place by means of (the same or) a laser. The liquid preferably comprises particles of glass, ceramics or metal compounds in the form of a sol-gel solution or a colloidal sol.

Abstract: The object of the invention is a process for the production of holes, particularly of micro-perforations, in a composite material, constituted by fibers embedded in a resinous matrix, characterized in that it consists in a preliminary step of carrying out on a specimen of the composite material, with the help of a laser beam, tests consisting in adjusting the duration of illumination at a predetermined place on the specimen, as well as the focusing and power of said laser beam, so as to confine the temperature in the mass of the material to a range of temperatures both greater than the thermal decomposition temperature of the matrix resin and below the temperature of altering the physical properties of the fibers, so as to carry out the elimination of the resin without affecting the physical integrity of the fibers, then in reproducing on the material (8) to be treated, at each position of a perforation to be made, the operating conditions of the laser (10, 12) so as to constitute in said material a through p

Abstract: A method and apparatus are provided for forming a sheet of polymeric material, such as polycarbonate. A forming mold is provided having halves that engage for forming a heated sheet therebetween. Each of the halves defines an interior cavity having a peripheral edge. The sheet is retained between the peripheral edges of the halves and a vacuum is generated within one of the cavities for drawing the sheet therein, whereby a sensing mechanism detects a draw depth for initiating a cooling mechanism to cool the sheet to a temperature below a glass transition temperature of the material. A series of retention mechanisms are provided about the peripheral edge of one of the halves, for biasing the sheet into engagement with the peripheral edge of the opposing half. A trimming mechanism is further provided for trimming the perimeter of the sheet to a desired form.

Abstract: A system for molding optical attenuators that have a lens portion and a supporting portion includes a molding machine containing a mold, an extractor robot and optical inspection portion, and a controller that assesses the inspection information and send control signals to the molding machine and mold. The mold includes a cavity and a core which define a space in which the supporting portion and the attenuator are formed. The cavity and core are separable from each other by an actuating motor of the molding machine subsequent to each injection cycle to permit removal of each molded optical attenuator. The mold also includes a core pin, movably located in the core element. The core pin has a proximal end defining a surface of the lens portion and a distal end remote from the molding space. A core pin motor is coupled to the core pin, through a number of intermediate elements, so that the core pin can be moved relative to the core element to adjust a thickness of the lens portion.

Abstract: The disclosed methods and systems for inspecting and repairing vessels include a laser used to project a laser beam into a hot furnace or vessel, a laser reader to measure a point cloud formed when the laser light reflects from the wall of the furnace, means for selecting those points in the cloud that are more relevant, and using the points to produce a 3D image that corresponds to the geometry of the interior of the furnace or vessel. The disclosed systems and methods further include means for comparing the 3D geometric data corresponding to the interior of the vessel with 3D geometric data provided as a reference, generating a 3D repair trace based on the comparison, and controlling a spray gun for applying refractory material according to the trace by taking into account a set of physical variables related to the vessel and the refractory material.

Abstract: The invention pertains to a technique for determining the dye uptake or measuring one or more structural parameters or mechanical properties of polymeric fibres. This technique entails measuring the Raman spectrum of the fibres during or after a spinning process. After the Raman spectrum has been treated, a model is applied to it which is derived from the Raman spectra of fibres having the same chemical composition as the fibres to be examined.

Abstract: A process for marking which enables a colored pattern formed by at least two different and contrasting colors to be created on a dark or black surface of a rubber article, which process includes preparing a light-colored rubber composition having at least one elastomer and at least two coloring agents of different light colors, giving the said composition its initial color, and then incorporating a dark or black masking agent into this colored composition in a limited proportion to darken or mask the initial color of the rubber composition. The process further includes causing a first laser beam of appropriate characteristics to interact in a first stage in order to reveal a first colored pattern part, followed in a second stage by a second laser beam of appropriate characteristics in order to reveal a second colored pattern part.

Abstract: Heating and extruding a polymeric sheet having a predetermined thickness and introducing it into and through a gap between cooling rolls, measuring directly by laser beam and without reflection the gap between the cooling rolls, and controlling the gap to control minimal pressure on the softened and heat-plastified sheet.

Abstract: Heating and extruding a polymeric sheet having a predetermined thickness and introducing it into and through a gap between cooling rolls, measuring directly by laser beam and without reflection the gap between the cooling rolls, and controlling the gap to control minimal pressure on the softened and heat-plastified sheet.

Abstract: Methods for reproducing a 3D object surface are provided. A preferred method according to this invention includes (1) identifying a real object surface, (2) acquiring at least a 3D data set with a 3D surface imaging device, (3) acquiring at least a 2D data set using a 2D surface imaging device with a surface resolution of at least about 0.1 mm2, (4) synthesizing a 3D composite data set by orienting a first virtual image of the first data set and a second virtual image of the second data set to form a composite virtual image that corresponds to the composite data set, and (5) making a reproduction of the object surface with the composite data set. Orientation of the virtual images is relative to each other and without substantial loss of surface resolution.

Abstract: A method and apparatus for controlling the diameter of a clear extruded molten tube wherein the extruded tube contains a volume of a clear liquid and the level of the liquid is indicative of the tube diameter so the level rises as the tube diameter decreases. A light beam passing through the tube is refracted from a straight line path when the liquid level rises above the level of the beam. The refracting of the beam in turn triggers the introduction of air into the extruded tube to increase the diameter of the extruded, molten tube.

Abstract: The Application describes a method and devices for manufacturing a broadband cholesteric polarizer having a well-defined bandwidth and edge position. To this end, a liquid-crystalline cholesterically ordered layer comprising reactive chiral monomers and reactive nematogenic monomers having a different reactivity is polymerized by exposure to radiation. The invention is characterized in that the intensity of the radiation is increased substantially, preferably by a factor of 10 or more, when a desired edge position of the band is reached. As a result, the bandwidth and edge position of the reflection band reached at that moment are frozen as it were. A monochromatic sensor can be used to determine whether said edge position has been reached, the wavelength used by the sensor corresponding to the wavelength of the desired edge position of the band. Broadband, cholesteric polarizers having a well-defined bandwidth and edge position can very advantageously be used in a display.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making three-dimensional objects with enhanced control of the temperature of the build environment. A modulated control signal is supplied to a heating element based on a difference between a desired build temperature and a detected temperature. The modulated signal result in the heater supplying, on average, more energy to the build chamber when the temperature difference is large and supplying, on average, less energy to the build chamber when the difference is small. The detection of the build chamber temperature may occur at one or more locations. If multiple locations are used, the detected temperatures may be averaged, or otherwise combined, to derive a single difference value that will be used to control the heater.

Abstract: The present invention relates to a process for the stereolithographic preparation of a three-dimensional object, wherein the object is built in a container which contains a radiation-curable liquid formulation with fillers by a repeated alternating succession of process steps (a) and (b). In step (a), a layer of the radiation-curable liquid formulation, one limitation of which is the surface of the formulation, is cured using suitable radiation within an surface area which corresponds to the desired cross-section of the three-dimensional object to be formed at the level of this layer. In step (b), said cured layer is coated with a new layer of the radiation-curable liquid formulation. The process comprises homogenizing the radiation-curable liquid formulation continuously or discontinuously to such an extent that there is no noticeable change in the filler content of the radiation-curable liquid formulation in the area of that layer with which the cured layer is coated in step (b).

Abstract: A method for obtaining both light and dark laser marks on a colored plastic article by using a composition with (i) a thermoplastic resin that foams when heated, (ii) about 0.4% to 0.7% by weight of a mica based laser energy absorbing additive and (iii) a coloring agent with one or more colorants selected from the group of pigments, dyes, and mixtures of pigments and dyes. Using a laser at certain settings results in charring of the resin to produce dark laser marks. At other selected laser settings, the resin foams to produce a light mark on a colored background. By varying the laser energy settings, various degrees of both foaming and charring can be achieved on a single plastic article, having a single resin composition, resulting in a multicolored laser image produced by various shades of light and/or dark marks against the background color.

Abstract: A method is described for producing a line-shaped weakening in a flat material by one-sided local removal of the flat material by controllable pulsed laser radiation. The occurring line-shaped weakening is not visible on the surface of the flat material that is not machined and has a reproducible constant breaking resistance.

Abstract: A process for ablation etching through one or more layers of dielectric materials while not etching an underlying conductive material layer comprises selecting parameters whereby the ablation process automatically stops when the conductive material layer is reached, or monitoring the process for end point detection of the desired degree of ablation. Parameters selected are the absorptivity of the dielectric layer versus that of the conductive material layer. End point detection includes monitoring radiant energy reflected from the workpiece or the content of the materials being ablated from the workpiece.

Abstract: A method of continuously draw-molding a fiber reinforced plastic rod formed with a spiral groove includes the steps of arranging in parallel a plurality of reinforcing fibers under tension, impregnating an unhardened thermosetting resin in the reinforcing fibers with tension being applied to the reinforcing fibers, winding a tape having a resin impregnable property and an expandible and contractible property around a fiber bundle composed of the thermosetting resin impregnated reinforcing fibers in a spiral fashion with a winding angle being substantially equal to an angle of the spiral groove with respect to an axial direction of a rod to be molded, passing the fiber bundle with the wound tape in a heating mold provided with a hole having a cross section substantially equal to that of the rod to be molded to heat and harden the thermosetting resin, and taking up the tape thereafter.

Abstract: In a method for quality control during production of concrete blocks by bringing a concrete mortar into an upwardly open hollow mold with a solid peripheral wall for forming at least one molded blank placed on a flat supporting surface, a thickness of a molded blank is determined contact-free for testing the dimensional stability. The volume of the molded blank is determined from the determined thickness and the cross-section of the hollow mold. The density is obtained from the weight and volume, which is a criteria for strength and resistance testing of the molded blank. Finally, the appearance of the molded blank is determined by at least one video camera and compared with the appearance of faulty molded blank to determine the molded blanks with surface errors. All results of the height, density and surface measurements can be used for control of the production arrangement.

Abstract: A process for detecting fine particles includes the steps of forming a sublimable thin film on an essential surface of a wafer on which fine particles are present, irradiating laser beam at the surface of the wafer, receiving a reflected beam from the surface which is scattered by the presence of the fine particles, and detecting the particles from the received scattered beam. The process may further include the step of accomplishing an etchback against the sublimable film to partially retain the sublimable film adjacent the surface of the fine particles. The film can be prepared from one or a mixture of gas including free sulfur generatable gas under discharge-dissociation conditions. Sulfur compounds or polythiazyl are preferable. Alternatively, the film can be made of a condensed film of organic solvent vapor. The sublimable film is sublimed by heating after the step of detecting the fine particles.

Abstract: In a system for the production of solvent-spun cellulose tow, trash and other undesirable material is detected by a device which projects a light beam across the tow and a receiver for the beam which initiates a signal if the beam is obscured beyond a predetermined amount.

Abstract: A method and apparatus for injection molding. The injection molding machine includes a mold formed by a fixed mold half and a movable mold half cooperating with the fixed mold half for defining a mold cavity of the mold and a gate channel leading to the mold cavity. An injection piston is operatively associated with the mold cavity for pressing a melt via the gate channel into the mold cavity. A sensor device detects a melt front of the melt rising upstream of the mold cavity in a conveying direction of the melt at a predetermined detection height. The sensor device includes walls defining a measurement gap disposed at the detection height and extending transversely to the conveying direction of the melt. The measurement gap is at least partially penetrated by a fraction of the melt from the melt front when the melt front rises toward the mold cavity.