Method and device for the mask welding of moving plastic films by lasers

• US 7,297,222 B2
• Filed: 05/03/2004
• Issued: 11/20/2007
• Est. Priority Date: 05/22/2003
• Status: Expired due to Fees

• Current Assignee: Leister Technologies AG
• Original Assignee: Leister Process Technologies
• Inventors: Chen, Jie-Wei
• Primary Examiner(s): Aftergut; Jeff H.
• Assistant Examiner(s): McNally; Daniel
• Application Number:
  US10/838,056
• Publication Number:
  US 20040231787A1
• Time in Patent Office: 1,296 Days
• Field of Search: 156/272.8, 156/272.2, 156/275.1, 156/290, 219/121.6
• US Class Current: 156/272.8
• CPC Class Codes: B23K 2101/16 Bands or sheets of indefinite length
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: B23K 26/0846 for moving elongated workpieces longitudinally, e.g. wire or strip material
• CPC Class Codes: B29C 65/1635 at least passing through one of the parts to be joined, i.e. laser transmission welding
• CPC Class Codes: B29C 65/1658 scanning once, e.g. contour laser welding
• CPC Class Codes: B29C 65/1677 making use of an absorber or impact modifier
• CPC Class Codes: B29C 65/1696 making use of masks
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/21 said joint lines being formed by a single dot or dash or by several dots or dashes, i.e. spot joining or spot welding
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/81267 Transparent to electromagnetic radiation, e.g. to visible light
• CPC Class Codes: B29C 66/8242 Pneumatic or hydraulic drives using fluid pressure directly acting on the parts to be joined B29C66/8266
• CPC Class Codes: B29C 66/83413 cooperating rollers, cylinders or drums
• CPC Class Codes: B29C 66/83417 said rollers, cylinders or drums being hollow
• CPC Class Codes: B29C 66/932 by measuring the speed
• CPC Class Codes: B29C 66/93451 by controlling or regulating the rotational speed, i.e. the speed of revolution
• CPC Class Codes: B29C 66/939 characterised by specific speed values or ranges
• CPC Class Codes: B29C 66/961 involving a feedback loop mechanism, e.g. comparison with a desired value
• CPC Class Codes: B29C 66/98 Determining the joining area by using markings on at least one of the parts to be joined
• CPC Class Codes: B29K 2995/0027 : for light outside the visible spectrum

Abstract

A method and device allows dynamic mask welding with online position adjustment in the high-speed welding of structured and endless plastic films. By a transparent driven mask roller provided with masks being arranged in a passive pressure roller surrounding the mask roller, detection can take place optically, and the mask roller and consequently the mask are synchronized with the film speed. Adjustment is detached from a film transport mechanism and does not influence the welding process and in this case, above all, the speed. High film transport speeds in the range of up to 1000 mm per second can be employed.

Claims

1. A method for welding plastic films together comprising:

providing a transparent endless film;

providing an absorbent endless film;

providing a lower pressure roller;

providing an upper pressure roller;

providing a mask roller carrying a mask;

providing a laser beam;

providing means for driving the mask roller independently from the pressure rollers;

rotating the mask and pressing the endless films together by the pressure rollers within a welding zone,

moving the endless films in synchronism with the rotating mask through the welding zone; and

penetrating the rotating mask and the endless transparent film with the laser beam when the films are in the welding zone, wherein the transparent film is connected to the absorbent film at locations defined by the mask.

2. The method as claimed in claim 1, including arranging the mask roller so as to be spaced apart from the transparent film wherein moving speed of the mask roller is set by separate drive means.

3. The method as claimed in claim 2, including providing recognition marks on the absorbent film and on the mask roller, wherein the movement of the mask roller is synchronized with the movement of the films prior to a defined location reaching the welding zone.

4. The method as claimed in claim 3, wherein the synchronization of the mask roller speed is carried out by a comparison of the recognition marks of the absorbent film and the mask roller and by regulation of rotation speed of the mask.

5. The method as claimed in claim 1, wherein the lower pressure roller is transparent and arranging the mask roller inside the transparent pressure roller, wherein the laser beam is applied to the films through the mask of the mask roller and the transparent pressure roller.