Beam welding method with geometric fixing by a film

Abstract

A method for the gap-free joining of two workpieces is provided. The method comprises the following steps: a. the workpieces to be joined are brought into contact with one another so that a joining point is formed, b. the joining point is geometrically fixed by means of a film, c. the workpieces are joined in a gap-free manner, wherein the step a. and the step b. can be interchanged.

Claims

1. A method for joining two workpieces, comprising; a. bringing the two workpieces to be joined into contact with one another, wherein a point of contact between the workpieces is a joining point, b. geometrically fixing a relative position of the two workpieces with a film so that the joining point of the two workpieces is fixed relative to the two workpieces for a subsequent joining step, said film being disposed on a surface of each of said two workpieces so as to cover and be in contact with a portion of each of said two workpieces without being situated between the two workpieces, said film covering said joining point without being situated in the joining point, c. joining the two workpieces by welding the point of contact using a beam transmitted through said film so that the workpieces are joined at the joining point in a gap-free manner, wherein said joined joining point consists of material limited to either one or both of said two workpieces, and d. during said joining, vaporizing the film with heat from said welding so as to remove all or a portion of the film.

2. The method according to claim 1, wherein the workpieces are brought into contact with one another in an overlapping manner.

3. The method according to claim 1, wherein the workpieces are brought into contact with one another at a joint.

4. The method according to claim 1, wherein said film is a transparent film.

5. The method according to claim 1, wherein said film is an adhesive film.

6. The method according to claim 1, wherein said joining comprises joining the workpieces to one another in a gap-free manner by welding the workpieces to one another with a laser beam.

7. The method according to claim 1, wherein said two workpieces comprise either one or both of a foil and a sheet, each one of said either one or both of said foil and said sheet having a thickness of 0.005 mm to 5 mm.

8. The method according to claim 1, wherein said two workpieces comprise a foil made from aluminum, beryllium or titanium.

9. The method according to claim 1, wherein said two workpieces comprise two ends of one common piece, so that a first workpiece of said two workpieces is formed by a first end of said one common piece and a second workpiece of said two workpieces is formed by a second end of said one common piece, said one common piece being a thin sheet or a foil.

10. The method according to claim 1, wherein said two workpieces comprise a first workpiece and a second workpiece, and wherein the step b. is carried out before the step a., by way of the film being placed onto a section of the first workpiece, wherein the section is intended to form the joining point, and is then brought into contact with the second workpiece and fixed, said first and second workpiece being two ends of a common workpiece or being two separate workpieces.

11. The method according to claim 1, wherein before step a., the workpieces are disposed on a shaping substrate, and wherein the geometric shape of the substrate is transferred to the workpieces conforming to the substrate.

12. The method according to claim 11, wherein a cylindrical shape of the substrate is for producing a tube.

13. The method according to claim 1, wherein the joined workpieces are removed from the substrate.

14. The method according claim 1, wherein energy is input into the joining point, by means of which the workpieces are non-detachably joined to the substrate.

15. The method for joining two workpieces according to claim 1 to form a scintillation tube, in which said joining comprises; joining the workpieces to one another in a gap-free manner to form the scintillation tube made from a thin-walled, metallic foil having a thickness of 0.005 to 5 mm.

16. The method for joining two workpieces according to claim 1, further comprising removing with a solvent any of the film that remains after said welding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: shows an abutting fixation of two workpieces, which have different thicknesses, at a right angle to one another;

(2) FIG. 2: shows an abutting fixation of two workpieces, which have the same thickness, in the same plane;

(3) FIG. 3: shows an abutting fixation of two workpieces, which are made from a single foil, for producing a tube;

(4) FIG. 4: shows a lap fixation of two workpieces, which are made from a single foil, for producing a tube; and

(5) FIG. 5: shows joining of three sheets around the corners thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) FIG. 1 shows a first exemplary embodiment of the joining method according to the invention. The cross section through a hollow body 14 at one of the sides thereof is shown. The hollow body consists of a 3 mm-thick sheet. The workpiece 13, which is a thin foil, has been placed thereon and the joining point 16 has been geometrically fixed around the corner thereof by means of film 12. The thin foil 13 is 0.5 mm thick. The base of the hollow body or the foil is 2.62.9 m. The foil and the hollow body are the workpieces to be joined.

(7) The two workpieces having the reference characters 14 and 13 are brought into contact with one another in a first step. FIG. 1 shows the so-called corner joint, by means of which the two workpieces 13 and 14 have been brought into contact with one another. The workpiece 13 is a thin foil having the following dimensions: widthheightdepth=26000.52900 mm. The hollow body 14 has the following dimensions: widthheightdepth=260032900 mm. The two workpieces 13 and 14 are connected to one another at the joint, around the corner, by means of the film 12, along the entire joining point. The joining point 16 is disposed at the joint of the two workpieces 13 and 14 and is, therefore, geometrically fixed by means of the transparent adhesive film 12 along the entire length thereof. The sheet 14 can be referred to as a lower sheet and the sheet 13 can be referred to as an upper sheet. The two workpieces are fixed at a right angle to one another.

(8) The workpieces are joined by means of a laser welding method or an electron beam method, a plasma-assisted welding method or an arc-assisted welding method, which is indicated here with reference character 11.

(9) In the end, a very thin foil 13 is mechanically fixed to the thicker sheet 14 at a right angle by means of the film. The free ends or sides of the sheets 13, 14 can also have been fixed in this way, or can have been mechanically fixed using hold-down devices.

Second Exemplary Embodiment

(10) In one first variant of FIG. 1, the adhesive film 12 is only partially disposed at the joining point, which, in this case, is the corner joint at workpieces 13 and 14. In the cross-sectional view shown in FIG. 1, the two workpieces 13 and 14 are fixed to one another along the entire length thereof by means of a multiplicity of short adhesive strips 12. For the rest, the joining method is identical to the first exemplary embodiment.

Third Exemplary Embodiment

(11) FIG. 2 shows a cross section of one exemplary embodiment of a so-called I-joint. The two thin sheets 23, 24 are identical. The sheets have the following dimensions: widthheightdepth=20000.51500 mm. The two thin sheets 23, 24 are disposed on a steel sheet 25 made from copper, as the substrate. The joining point is present as a so-called I-joint at the point at which the two sheets 23, 24 abut one another. The joining point 26 has been fixed along the entire length by means of a transparent adhesive film 22. Optionally, the non-fixed areas of the sheets 23, 24 can also be fixed by means of foil, a foil, or mechanically by means of hold-down devices. A laser beam method, an electron beam method or a plasma-assisted joining method or an arc-assisted joining method can be used, in turn, as a joining method.

Fourth Exemplary Embodiment

(12) As one variant of this exemplary embodiment, the adhesive film 22 is not disposed on the entire longitudinal side of the I-joint, but rather only sequentially. In this case, a further joining process, such as, for example, an electron beam welding process, a plasma-assisted welding process, or an arc-assisted welding process, can be used in the areas of the joining point which have not been fixed by means of adhesive film 22.

Fifth Exemplary Embodiment

(13) FIG. 3 shows a cross section through a thin foil 33, 34, which has been rolled onto a shaping substrate 35. The thin foil has the following dimensions in the flat plane: widthheight (or thickness)depth=3000.0153 mm. The foil has been wound onto a support cylinder 35 having sufficient stability for supporting the workpieces made from steel, or from a non-metallic material or another metallic material. The two ends 33, 34 form the workpieces to be joined and are disposed with respect to one another at the I-joint. There is no overlapping area. The two ends 33, 34 are also not in direct physical contact with one another or are directly disposed with respect to one another in such a way that the ends just touch one another. The resultant joining point 36 is fixed by means of a transparent adhesive film 32 or, generally speaking, a fixing foil. Instead of a support cylinder, a support tube 35 can also be used. The workpieces 33 and 34 to be joined, which are formed from a single foil in this case, preferably abut one another at the end faces thereof in a seamless manner. This form is referred to as a so-called I-joint.

(14) A laser beam welding method, or an electron beam welding method or a plasma-assisted or arc-assisted welding method is preferably used as the joining method. Complete fusion across the entire thickness of the foil is possible only when a groove is present in the support tube 35 underneath the joining point. In this exemplary embodiment, the groove and the joining point are identical and are labeled with reference character 36. Otherwise, welding-in, which is to say, connecting of the foil to the support tube, occurs.

(15) Ultimately, a very thin tube, preferably made from aluminum foil or beryllium foil, is obtained. This can be used, for example, as a scintillation chamber for particle accelerators.

(16) FIG. 4 shows, as does FIG. 3, one exemplary embodiment for producing thin small tubes, in which, in contrast to FIG. 3, the free ends 43, 44 are disposed in a lap joint. This means that the free end 43 of the foil overlaps the free end 44 at the joining point 46. This joining point 46 is mechanically fixed by means of a fixing foil or an adhesive foil 42, which is transparent, across the entire longitudinal side thereof.

(17) The joining method preferably consists of a laser beam welding method, or an electron beam method, a plasma-assisted welding method, or an arc-assisted welding method.

(18) The thin sheet or the foil 43, 44 is wound onto the support tube or support cylinder 45 as described above, and so the sides 43, 44 to be welded overlap. The complete fusion of the upper part 43 of the foil into the lower foil 42 takes place at the lap joint or at the fillet (special case: fillet weld at the lap joint).

(19) Thin-walled tubes made from aluminum or beryllium foil, which is 0.015 mm to 0.005 mm thick, have already been produced in this way. These small tubes have been successfully tested as scintillation chambers in accelerators.

Sixth Exemplary Embodiment

(20) FIG. 5 shows a cross section of a three-sheet connection formed from the sheets 53, 54 and 58. The three sheets have the following dimensions: widthheightdepth=12000.51200 mm. The material consists of chromium nickel steel.

(21) The sheets are fixed around the corners thereof by means of the film 52. The bracket indicates the joining point 56. The laser 51 is moved over the joining point, as indicated by the dotted line, for an I-seam on the multi-layer joint and, therefore, joins the sheets to one another. The laser can also be moved perpendicular thereto in order to generate an edge weld without edge preparation.

(22) Connections of this type are referred to as a multi-sheet connection formed from at least two sheets in a set-up. The sheets typically have a thickness of 0.1 to 2 mm and are usually joined to one another in up to four layers.

(23) In FIGS. 1-5, the reference characters 16, 26, 36 and 46, 56 respectively indicate the location of the joining point.