Profile member and method for manufacturing thereof

Abstract

A method for manufacturing a profile member for a suspended ceiling system, comprising forming a sheet metal material into an elongate T-shaped profile member with a web having two web side walls and a pair of oppositely disposed flanges projecting from a bottom portion of the web, and laser welding the elongate T-shaped profile member for providing a laser weld joint extending in a longitudinal direction of the T-shaped profile member and joining the two web side walls to each other. The step of laser welding comprises alternatingly performing a first operation and a second operation, the second operation being different from the first operation, whereby a laser weld joint is provided comprising along its extension alternating welded first sections associated to the first operation and second sections associated to the second operation. The present invention also relates to an elongate profile member provided with a laser weld joint.

Claims

1. A method for manufacturing a profile member for a suspended ceiling system, comprising forming a sheet metal material into an elongate T-shaped profile member with a web having two web side walls and a pair of oppositely disposed flanges projecting from a bottom portion of the web, and laser welding the elongate T-shaped profile member for providing a laser weld joint extending straight in a longitudinal direction of the T-shaped profile member and joining the two web side walls to each other, characterized in that the step of laser welding comprises alternatingly performing a first operation and a second operation, whereby a laser weld joint is provided comprising a plurality of welded first sections associated to the first operation and a plurality of welded second sections associated to the second operation, wherein the welded first sections and welded second sections are alternatingly arranged along the extension of the laser weld joint, wherein laser welding is applied continuously in the first operation and not continuously in the second operation, wherein an energy level that each application of laser welding reaches during the second operation is below an energy level that each application of laser welding reaches during the first operation.

2. The method according to claim 1, wherein each first section is formed as a point weld.

3. The method according to claim 1, wherein each first section is given a length L2 in the range of 2-15 mm.

4. The method according to claim 1, wherein each second section in given a length L3 in the range of 1-60 mm.

5. The method according to claim 1, wherein the laser welding is performed at a feeding rate in the range of 20-120 m/min.

6. The method according to claim 1, wherein the laser weld joint is applied at the bottom portion of the web.

7. The method according to claim 6, wherein the laser weld joint is applied in a gap extending in the longitudinal direction of the T-shaped profile member and formed in the bottom portion where the flanges meet the web side walls.

8. The method according to claim 1, wherein the step of forming the sheet metal material into the elongate T-shaped profile is performed in a roll forming operation.

9. The method according to claim 1, wherein the sheet metal material has a thickness in the range of 0.1-0.6 mm.

10. The method according to claim 1, wherein the step of forming the sheet metal material into the elongate T-shaped profile member further comprises forming a bulb adjoining a top portion of the web.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

(2) FIG. 1 is a perspective view of a profile member according to the present invention.

(3) FIG. 2 is a perspective view of an embodiment of a profile member according to the present invention.

(4) FIG. 3 is a perspective view of an alternative embodiment of a profile member according to the present invention.

(5) FIG. 4 is a perspective view illustrating a step of a method for manufacturing a profile member in accordance with the present invention.

(6) FIG. 5 is a perspective view illustrating an alternative method for manufacturing a profile member in accordance with the present invention.

DESCRIPTION OF EMBODIMENTS

(7) The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

(8) An embodiment of a profile member 1 according to the present invention is shown in FIG. 1, to which reference now is made.

(9) The profile member 1 is formed of sheet metal material of for example steel, such as galvanized steel, aluminum, or stainless steel. The profile member 1 has an elongated T-shape and comprises a web 2 and a pair of oppositely disposed flanges 3 projecting from a bottom portion. In the shown embodiment, the flanges 3 are horizontally disposed and project at right angles from the bottom portion 4 of the web 2.

(10) The profile member 1 may also, as shown in the figure, be formed with a bulb 5 adjoining a top portion 6 of the web 2.

(11) The sheet metal material from which the profile member 1 is made may have a thickness in the range of 0.1-0.6 mm.

(12) The web 2 has a two-layered structure and comprises two web side walls 7a, 7b. The two web side walls 7a, 7b are joined to each other by means of a laser weld joint 8 extending in a longitudinal direction of the T-shaped profile member 1 indicated by axis L1. The laser weld joint 8 will be described more in detail below.

(13) A capping 9 in the form of strip of folded sheet metal may be provided enclosing the pair of oppositely disposed flanges 3. The capping 9 may thus cover the laser weld joint 8.

(14) In FIG. 2, the profile member 1 shown in FIG. 1 is disclosed without the capping 9 thus exposing the laser weld joint 8.

(15) The laser weld joint 8 extends in the longitudinal direction L1 of the profile member 1. In the shown embodiment, the laser weld joint 8 is arranged in the bottom portion 4 of the web 2. More specifically, the laser weld joint 8 is applied in a gap 10 extending in the longitudinal direction L1 of the profile member 1 and formed in the bottom portion 4 of the web 2 where the horizontal flanges 3 meet the web side walls 7a, 7b.

(16) It is understood that the laser weld joint 8 may be arranged in a different portion of the web 2. It is also understood that the profile member 1 may be provided with two or more laser weld joints 8 extending in parallel at a distance from each other. In FIG. 3, alternative locations of the laser weld joint 8 are disclosed.

(17) According to the present invention, the laser weld joint 8 comprises along its extension alternating first sections 11 and second sections 12. The first sections 11 are welded and different from the second sections 12.

(18) Each first section 11 is a welded section and may be a point weld or may have a length L2 in the range of 2-15 mm.

(19) Each first section 11 may be a laser weld of conduction/penetration mode type or penetration mode type.

(20) Each second section 12 may be a welded section comprising a laser weld of conduction mode type. Alternatively, each second section 12 may be a non-welded section.

(21) Each second section 12 may have a length L3 in the range of 1-60 mm.

(22) The length L2 of each first section 11 may be equal to the length L3 of each second section 12.

(23) The length L2 of the first sections 11 and the length L3 of the second sections 12 may be chosen dependent on the desired properties of the profile member.

(24) If the profile member is to be used as a main runner in a suspended ceiling system, a high torsional stiffness may be desirable, and the first section 11 may be a point weld or have a length L2 2-15 mm, and the second sections 12 may have a length L3 in the range of 1-15 mm.

(25) On the other hand, if the profile member is to be used as a cross runner in a suspended ceiling system, a lower torsional stiffness may be acceptable, and in such a case, each first section 11 may be a point weld of have a length L2 in the range of 2-15 mm, while each second section 12 may have a length L3 in the range of 15-60 mm.

(26) In FIG. 4, to which reference now is made, a step of a method in accordance with the present invention for manufacturing a profile member 1 of the type described above is shown.

(27) In a first step, not disclosed in FIG. 4, a sheet metal material is formed into a T-shaped profile member with a web having two web side walls, and a pair of oppositely disposed flanges projecting from a bottom portion of the web. The flanges may project at right angle from the web and thus form essentially horizontally disposed flanged.

(28) The forming of the sheet metal material into the T-shaped profile member may be performed in a conventional roll forming operation.

(29) The method step illustrated in FIG. 4 relates to the step of laser welding the elongated T-shaped profile member 1 by means of a laser welding apparatus 13 for providing a laser weld joint 8 extending in the longitudinal direction L1 of the profile member 1 and joining the two web side walls 7a, 7b of the profile member 1 to each other.

(30) The profile member 1 is moved relative the laser welding apparatus in a direction indicated by arrow P1 during the laser welding. The relative movement, which also may be referred to as a feeding rate, may be in the range of 20-120 m/min.

(31) In the figure, the laser weld joint 8 is applied from a bottom side of the profile member 1, in a gap 10 extending in the longitudinal direction L1 of the profile member 1. The gap 10 is formed in the bottom portion 4 of the web 2 where the flanges 3 meet the web side walls 7a, 7b.

(32) It is understood that the laser weld joint 8 may be applied at other locations of the web 2 and that more than one laser weld joint 8 may be applied to the profile member 1. As a non-limiting example, FIG. 5 discloses the application of two laser weld joints 8 to the web 2 from a lateral side of the profile member 1.

(33) The step of laser welding comprises alternatingly performing a first and a second operation.

(34) The first operation is different from the second operation.

(35) By alternatingly performing the first and the second operation, a laser weld joint 8 is obtained comprising alternating first sections 11 associated to the first operation and second sections 12 associated to the second operation. As the first and second operations are different, the first sections 11 will be different from the second sections 12. Thus, the resulting laser weld joint 8 will comprise alternating first and second sections 11, 12 having different properties.

(36) Each first section 11, which thus is obtained by performing the first operation, is a welded section.

(37) Each second section 12 obtained by performing the second operation may be a welded or a non-welded section.

(38) The first operation comprises laser welding at a first energy level as measured at point where the laser beam interacts with the work piece, i.e. the profile member 1.

(39) The second operation may comprise laser welding at a second energy level as measured at a point where the laser beam interacts with the work piece, i.e. the profile member, wherein the second energy level is below the first energy level.

(40) The first energy level may be sufficient for obtaining a laser weld of conduction/penetration mode type (also referred to as transition mode type) or penetration mode type in each first section 11 of the laser weld joint 8.

(41) The second energy level may be sufficient for obtaining a laser weld of conduction mode type in each second section 12 of the laser weld joint 8.

(42) Alternatively, the second energy level may be zero, resulting in each second section 12 of the laser weld joint 8 being a non-welded section.

(43) In order to alternatingly perform the first and second operations during the laser welding of the profile member 1, the laser welding apparatus 13 may be controlled in different ways.

(44) For instance, a rotating screen/reflector (not shown) may be provided arranged to intermittently allowing the laser beam emitted from the laser welding apparatus 13 to pass the rotating screen/reflector and to engage with the profile member. Thus, each time the laser beam is allowed to pass the screen/reflector, the first operation of the laser welding step is performed, and each time the laser beam is screened/reflected, the second step of the laser welding step is performed.

(45) Alternatively, the laser weld apparatus may alternatingly be turned on and off, in which case the turned-on state would represent the first operation and the turned-off state would represent the second operation.

(46) The use of a rotating screen/reflector or by turning the laser welding apparatus 13 on/off results in the second section 12 of the laser weld joint 8 being a non-welded section.

(47) It would also be conceivable to alternatingly vary the power input to the laser welding apparatus 13, resulting in the laser welding apparatus 13 to alternatingly emit a laser beam at the first energy level and a laser beam at the second energy level. Thus, emitting the laser beam at the first energy level would correspond to the first operation of the step of laser welding and emitting the laser beam at the second energy level would correspond to the second operation.

(48) The power input to the laser welding apparatus 8 during the first and if appropriate the second operation may be constant. However, it would also be conceivable to vary the power input during each operation. Thus, during each operation, a power pulse may be utilized for generation of the laser beam, which power pulse may be a square pulse, a spike pulse or an annealing pulse.

(49) The switch between the first operation and the second operation may also involve modification of the focus point of the laser beam emitted from the laser welding apparatus 13.

(50) Thus, according to the present invention, an elongate profile member is manufactured by forming a sheet metal material into a T-shaped profile member and subsequently laser welding the profile member for providing a laser weld joint joining the two web side walls of the web to each other. The step of laser welding comprises alternatingly performing a first operation and a second operation, whereby the laser weld joint obtained comprises along its extension alternating welded first sections associated to the first operation and second sections associated to the second operation.

(51) The second operation comprises laser welding at an energy level which is below the energy level used for performing the first operation, and may in some cases even be zero. Thus, the thermal energy transferred to the profile member may be lowered while a laser weld joint improving the strength and rigidity of the profile member still can be provided. The reduced thermal energy may ensure reduction of thermal induced deformation of the profile member.

(52) In a practical test, laser weld joints comprising alternating welded first sections and non-welded second section was applied to elongate profile members. The switch between the first operation for providing the first sections and the second operation for providing the second sections was made by turning on/off the laser welding apparatus. It was surprisingly found that the feeding rate, i.e. the relative movement between the laser welding apparatus and the profile member, could be increased while still obtaining a high weld quality as compared to a continuous laser welding operation.

(53) It will be appreciated that the present invention is not limited to the embodiments shown. Several modifications and variations are thus conceivable within the scope of the invention which thus is exclusively defined by the appended claims.