US 4,229,639 AGranted

Energy beam welding method

AssigneeSteigerwald Strahltechnik GmbH

InventorsJohannes Koy, Franz Rappold, Erwin Kappelsberger

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Abstract

Disclosed is a method for producing an elongated weld seam in a workpiece by the use of a beam of charged particles, in particular an electron beam. According to the disclosed method, a beam of charged particles is directed to impinge on a workpiece and has a selected beam current, a selected accelerating voltage and is focused by a focusing field of a selected field strength. In order to produce a weld seam there is provided a relative motion between the charged particle beam and the workpiece, to move the point of impingement along the workpiece. The relative motion has a predetermined selected instantaneous velocity. The depth of penetration of the charged particle beam into the workpiece is varied by changing a parameter selected from the group consisting of the beam current and the velocity of relative motion. According to the improvement of the invention, simultaneous with the changing of the depth of penetration, there is provided an active control to change at least one parameter selected from a second group consisting of the strength of the focusing field, the amplitude of periodic beam deflection in a direction parallel or transverse to the path of the relative motion and the frequency of periodic beam deflection in a direction parallel or transverse to the relative motion.

Claims17

Dependent claims

A method for producing an elongated weld seam in a workpiece by means of a beam of charged particles, said method comprising the steps:

(a) producing a beam of charged particles directed to a point of impingement on said workpiece;
said beam having a selected beam current and a selected accelerating voltage and being focused by a focussing field of selected field strength;
(b) producing a relative motion of said beam with respect to said workpiece to move said point of impingement along said workpiece, said relative motion having a selected instantaneous velocity;
(c) changing at least one parameter selected from a first group consisting of
(c1) beam current, and
(c2) velocity of relative motion to change the depth penetration of the beam into said workpiece;
said method further characterized by the step
(d) changing, by active direct control, concurrent with said first parameter group change, at least one parameter selected from a second group consisting of:
(d1) strength of focussing field;
(d2) amplitude of periodic beam deflection in a direction parallel to said relative motion;
(d3) amplitude of periodic beam deflection in a direction transverse to said relative motion;
(d4) frequency of periodic beam deflection in a direction parallel to said relative motion;
(d5) frequency of periodic beam deflection in a direction transverse to said relative motion.

10 more elements

Dependencies are inferred from the claim text.