DD143145A2 - METHOD AND DEVICES FOR CENTERING AN ENERGY CHARGE CARRIER BEAM - Google Patents

Abstract

The invention relates to a method and devices for adjusting and controlling the centering of a high-energy charged carrier beam according to patent 139,104. Under the respective conditions of the technological process, measurable information on the interaction between the charged carrier beam and the material involved in the process is to be obtained throughout the entire process and used for monitoring and process-dependent regulation. According to the invention, the ion back current is measured in electron beam processes and the electron backscatter current in ion beam processes, with their direct current component and/or amplitude and/or frequency and/or pulse length of the alternating current component and/or their mean value being used for centering. The method and devices, in extension of the main patent, serve in particular to ensure adjustment and control accuracy, even in processes with high beam power.

Description

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Method and devices for centering a high-energy carrier beam

Field of application of the invention

The invention relates to a method and means for adjusting and Eontrolle the centering of a high-energy carrier beam within the gun according to patent 459-4OV- , in particular for welding, cutting, melting, spraying, sputtering, evaporation and material processing »

Characteristic, the known technical solutions

ITach Patent 439ϊοφ is already known that for obtaining process information on the effect of the high-energy carrier beam on the material for control and controlled variables only certain charge carriers and / or energy spectra and / or frequency spectra

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the backscatter and / or workpiece flow can be selected. In the case of electron beam welding using the electron current as a process measuring variable, the method has proved successful up to beam powers of approximately 10 kW.

Object of the invention

It is the object of the invention to provide a method and associated arrangements for adjusting and controlling the centering of a high-energy carrier beam within the gun which ensure a high degree of reproducibility in order to increase the reliability of the equipment and the productivity of high-energy Increase the charge carrier beams operating technological processes, especially in processes with high beam power ·

The essence of the invention

The invention has for its object to provide a method and means by which the centering of a high-energy carrier beam can be set and controlled within the beam gun under the respective conditions of the technological process at a high degree of reproducibility, the method an automatic process flow allow and be guaranteed throughout the beam power range *

According to the invention the object is achieved in that in electron beam method of the ion backscattering and in the ion beam method of preferably electron backscattering is measured, wherein the direct current

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component and / or amplitude and / or frequency and / or pulse length of the Wechselbromkomponenfce and / or the average, which according to the invention, depending on the current strength of Zentrierungsspulen for the X and Y direction have a typical characteristic and the centering state of the high-energy carrier beam within a Accurately reflecting the beam gun, used to set and control the beam centering »

The means for carrying out the method according to the invention are determined by the recovery of the backscattering stream. It is necessary that the own time constant of the Meßsignalerfassungssystems is negligible.

In electron beam method receives the flat, sufficiently large circular collector with the lowest possible bore diameter to ground a certain negative potential, so that depending on the Poten Jiialhöhe electrons largely repelled by the interceptor, but ions are attracted. In ion beam method, the collector receives a certain positive potential to ground, so that depending on the potential level ions largely repelled by the interceptor, but electrons are attracted.

For this purpose, it is expedient to connect the catcher via a low-impedance DC voltage source and a low-impedance, low-inductance resistor with appropriate polarity and negligible interference voltage of the voltage source to ground, the low, dropping at the resistor Prozeßmeßspannung a sufficiently high-impedance broadband amplifier, preferably designed as an integrated circuit Operational amplifier, supply and pay particular attention to low-capacitance construction and switching,

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embodiment

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing there is shown a schematic representation of the collector and its possible arrangement in electron beam welding, as well as the principle for obtaining and processing the process measurement signal.

The beam beam strength I _{g produced} by the beam gun produces an impact on the surface of the workpiece 2 of the thickness s arranged at the working distance a, which moves relative to the electron beam at the welding speed ν. By appropriate adjustment of the individual process parameters while a weld is generated. Above the workpiece 2 at a distance 1 _R, a planar circular ring catcher 3 for the backscattering stream Itj is arranged such that the electron-optical axis of the beam gun 1 extends perpendicular to the catcher plane through the center thereof. The outer diameter of the catcher 3 is 200 mm and the bore diameter is approximately twice the beam diameter. The catcher 3 fastened with insulators 4 is connected to ground via a low-resistance voltage source SQR and a resistance Rp of approximately 10 to 100 SZ . The adjustable with the potentiometer PD negative potential height for the catcher 3 is dependent on the process conditions and is on average 300 V. At the resistor Rp, a voltage drop is measured, which is directly proportional to the ion backflow Lr ** · This measuring voltage is from an operational amplifier OV with 10 kSB input resistance and a bandwidth of 0 to 0.5 MHz amplified and directly or via 'a low-pass filter (EPF, BPF BPF or high pass filter HPF an amplitude-voltage converter ASW, frequency-voltage converter FSV /, pulse width voltage converter LSW and / or an averaging MWB supplied,

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whose Zeifckonstante is only a few milliseconds.

The voltage corresponding to the respective DC current and / or the amplitude, frequency and / or pulse length of the AC component and / or the mean value is displayed by an analog or digitally operating voltmeter SM for checking and / or preferably processed by a process computer PE during automatic operation as in manual mode affects the Elektronenstrahlzentrierung «.

Claims (2)

212 9 0 7 Invention claim 1 _# Procedure for setting and. Controlling the centering of a high- energy carrier beam within the beam gun after p & e.times.139-fOfy , preferably using a higher beam power, in particular for welding, cutting, melting, spraying, sputtering, evaporation and material processing, characterized in that in electron beam methods, the ion backscattering (Ig) and ion beam method, preferably the electron backscattering is measured, wherein the DC component and / or amplitude and / or frequency and / or pulse length of the AC component and / or their average value are used for centering _o 2 · Device for adjusting and controlling the centering of a high-energy carrier beam within the gun according to item 1, characterized in that the catcher (3) in each case via a low-impedance DC voltage source (SQ _R ) and a low-resistance, low-inductance resistor (Rd) "with appropriate polarity and at negligibly small interference voltage of the DC voltage source (SQtO) is connected to ground, wherein the small drop across the resistor (Rr) Prozeßmeßspannung each with a high-impedance broadband amplifier, preferably an executed as an integrated circuit operational amplifier (OV) is coupled. For this purpose-1 page drawings