Laser welding system and method using cooling mask to control the width of the weld

Patent metadata

Field	Value
Publication number	US-2018071990-A1
Application number	US-201615266182-A
Country	US
Kind code	A1
Filing date	Sep 15, 2016
Priority date	Sep 15, 2016
Publication date	Mar 15, 2018
Grant date	—

Abstract

A laser welding method and system for joining portions of first and second workpieces of thermoplastic material that is partially permeable to a laser beam but absorbs radiation from the laser beam. The first and second workpieces, which are made of material that absorbs radiation from a laser beam, are clamped together. A mask is placed on a first surface of the first workpiece, the first surface being opposite the surface engaging the second workpiece. The mask is impermeable to a laser beam and forms a slot for passing a laser beam to the portion of the first surface of the upper workpiece exposed by the slot, so that heating and melting of the material of the workpieces is limited to the width of the slot. A laser beam is directed onto the slot and moved in a manner to illuminate the slot to melt and join the workpieces.

First claim

1 . A laser welding method for joining portions of first and second workpieces of thermoplastic material that is partially permeable to a laser beam, said method comprising
clamping together the portions of said first and second workpieces to be joined, said first and second workpieces being made of material that absorbs radiation from a laser beam, placing a mask on a first surface of the first workpiece, said first surface being opposite the surface engaging the second workpiece, said mask being impermeable to a laser beam and forming a slot for passing a laser beam to the portion of the first surface of the upper workpiece exposed by said slot, so that heating and melting of the material of said workpieces is limited to the width of said slot, directing a laser beam onto said slot and moving said laser beam in a manner to illuminate the slot to melt and join said first and second workpieces along said slot while said workpieces remain clamped together, and cooling the molten portions of said first and second workpieces to solidify the joined portions of said workpieces to form a weld seam while said workpieces remain clamped together.

2 . The laser welding method of claim 1 in which said first and second workpieces both absorb portions of said laser beam to heat and melt the portions of said first and second workpieces exposed to said laser beam.

3 . The laser welding method of claim 1 in which said mask absorbs heat from said first workpiece to cool the portions of said first workpiece not exposed to said laser beam.

4 . The laser welding method of claim 1 in which said laser beam has a wavelength of about 2 microns.

5 . The laser welding method of claim 1 in which said laser beam is an optical fiber beam.

6 . The laser welding method of claim 1 in which said laser beam is substantially perpendicular to said mask.

7 . The laser welding method of claim 1 in which said mask is chrome plated on glass.

8 . The laser welding method of claim 1 in which each of said first and second workpieces is an unfilled polymer that can be optically transparent, and said laser beam is partially absorbed by said polymer.

9 . A laser welding system for joining portions of first and second workpieces made of thermoplastic material that is partially permeable to a laser beam but absorbs radiation from said laser beam, said system comprising
a pair of clamping plates positioned to engage opposite sides of said first and second workpieces when said workpieces are adjoining each other with contacting surfaces, an actuator urging at least one of said clamping plates toward the other clamping plate to press said workpieces together, a mask on the opposite side of said first workpiece from said second workpiece, said mask being impermeable to said laser beam and forming a slot for passing said laser beam to the portion of said first workpiece exposed by said slot, so that heating and melting of the material of said workpieces is limited to the width of said slot, a laser beam source directing a laser beam into said slot, and a drive unit moving said laser beam in a manner to illuminate said slot to melt and join said first and second workpieces while said workpieces remain clamped together.

10 . The laser welding system of claim 9 in which the absorption of radiation from the laser beam by said first and second workpieces melt the portions of said first and second workpieces exposed to said laser beam.

11 . The laser welding system of claim 9 in which said mask absorbs heat from said first workpiece to cool the portions of said first workpiece not exposed to said laser beam.

12 . The laser welding system of claim 9 in which said laser beam has a wavelength of about 2 microns.

13 . The laser welding system of claim 9 in which said laser beam has an optical fiber beam.

14 . The laser welding system of claim 9 in which said laser beam is substantially perpendicular to said mask.

15 . The laser welding system of claim 9 in which said mask is chrome plated on glass.

16 . The laser welding system of claim 9 in which each of said first and second workpieces is an unfilled polymer that can be optically transparent, and said laser beam is partially absorbed by said polymer.

Assignees

• Dukane Ias Llc

Inventors

• Savitski Alexander
• Bugaj Grzegorz Zdzislaw
• Klinstein Leo

Classifications

• B29C66/71

  characterised by the composition of the plastics material of the parts to be joined (welding bar compositions B29C65/125) · CPC title

• B29C66/41

  Joining substantially flat articles (B29C66/47 and subgroups take precedence); Making flat seams in tubular or hollow articles (B29C66/51 and subgroups take precedence) · CPC title

• B29C66/836

  Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table (B29C66/65 takes precedence) · CPC title

• B29C66/81267

  Transparent to electromagnetic radiation, e.g. to visible light · CPC title

• B29C65/1629

  characterised by the way of heating the interface · CPC title