Abstract: An imaging system for sensing light in an area of high optical contrast is disclosed. In some implementations, the imaging system is for monitoring a welding operation, whereby a photochromic filter is used to reduce the intensity of the light observed from the welding arc. The imaging system includes a light source whereby light from the light source activates the photochromic filter. Thus, the opacity of the photochromic filter depends on the intensity of the light from the light source.

Abstract: A process (and apparatus for performing the process) for layer manufacturing a three-dimensional work piece comprising the steps of: feeding raw material in a solid state to a first predetermined location; exposing the raw material to an electron beam to liquefy the raw material; depositing the raw material onto a substrate as a molten pool deposit, the deposit having a forward edge region in an x-y plane with a forward edge region width and a trailing edge region in the x-y plane with a trailing edge region width, under at least one first processing condition; monitoring the molten pool deposit for at least one preselected condition using detecting of scatter from a scanning electron beam contemporaneously with the depositing step; solidifying the molten pool deposit; automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step; and repeating steps at one or more second locations for building up layer by layer, generally alo

Abstract: A process (and apparatus for performing the process) for layer manufacturing a three-dimensional work piece comprising the steps of: feeding raw material in a solid state to a first predetermined location; exposing the raw material to an electron beam to liquefy the raw material; depositing the raw material onto a substrate as a molten pool deposit, the deposit having a forward edge region in an x-y plane with a forward edge region width and a trailing edge region in the x-y plane with a trailing edge region width, under at least one first processing condition; monitoring the molten pool deposit for at least one preselected condition using detecting of scatter from a scanning electron beam contemporaneously with the depositing step; solidifying the molten pool deposit; automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step; and repeating steps at one or more second locations for building up layer by layer, generally alo

Abstract: A process and apparatus for free form fabrication of a three-dimensional work piece comprising (a) feeding raw material in a solid state to a first predetermined location; (b) depositing the raw material onto a substrate as a molten pool deposit under a first processing condition; (c) monitoring the molten pool deposit for a preselected condition; (d) comparing information about the preselected condition of the monitored molten pool deposit with a predetermined desired value for the preselected condition of the monitored molten pool deposit; (e) solidifying the molten pool deposit; (f) automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step (d); and repeating steps (a) through (f) at one or more second locations for building up layer by layer a three-dimensional work piece.

Abstract: A temperature control method for a heating apparatus including a chamber which can be evacuated and has a conductive portion, a filament which is positioned in the chamber, a first power supply which supplies a current to the filament, a second power supply which applies, to the filament, a voltage for acceleration to the chamber, an ammeter which measures a current of the filament, and a voltmeter which measures the acceleration voltage, the method comprises a first step of evacuating an interior of the chamber; a second step of supplying the filament current from the first power supply to the filament after the first step; a third step of applying the acceleration voltage to the filament after the second step; and a fourth step of controlling the acceleration voltage to keep a surface temperature of the chamber to be lower than a temperature of the filament after the third step while keeping constant the filament current from the first power supply.

Abstract: In a partial-vacuum-type, electron-beam irradiation system having a construction such that a static-pressure floating pad is connected to a vacuum chamber incorporating an electron-beam column, and an electron-beam passes through an electron-beam passage of the static-pressure floating pad to impinge on a body to be irradiated in the condition where the static-pressure floating pad is contactlessly attracted to the body to be irradiated, a vacuum-seal valve for opening and closing the electron-beam passage is provided inside the static-pressure floating pad, and when the static-pressure floating pad is separated away from the body to be irradiated, the vacuum-seal valve is actuated to close the electron-beam passage, whereby the atmospheric air is prevented from flowing into the vacuum chamber.