Claims
- 1. A welding method comprising the steps of:
- continuously feeding a first sheet of a first polyethylene material past a weld station;
- continuously feeding a second polyethylene material comprising EVA past a weld station to contact a first side of said polyethylene sheet at the weld station; and
- projecting a laser beam to the weld station from a second side of said polyethylene sheet opposite said first side thereof to weld said materials together, wherein said projecting step comprises focusing the laser beam through a lens system into a generally elliptical shape, as seen in a focal plane substantially coincident with a contact point between said first and second materials,
- said elliptical shape elongated in the feed direction of said first and second materials.
- 2. The welding method of claim 1, wherein said contacting step comprises relatively guiding said first and second materials past a groove in a grooved member.
- 3. The welding method of claim 1, wherein said contacting step comprises leading said first and second materials past a support plate and a guide wheel that are offset from one another in a direction longitudinally along a feed direction of said first and second materials in such a manner as to bring the materials into close contact with one another.
- 4. The welding method of claim 1, further comprising the step the step of laterally adjusting the position of said first material relative to the position of said second material.
- 5. The welding method of claim 1, wherein the second EVA polyethylene material is provided with between 0% and 20%, by weight, of EVA.
- 6. The welding method of claim 1, wherein the second EVA polyethylene material is provided with approximately 10%, by weight, of EVA.
- 7. The welding method of claim 1, wherein said first material is U-shaped, and said second material is an interlocking zipper strip, wherein said method further comprises the step of inserting said zipper strip between the legs of said U-shaped first material.
- 8. The welding method of claim 7, further comprising the step of projecting a plurality of laser beams through both legs of said U-shaped sheet of said first material.
- 9. The welding method of claim 7, wherein the weld station is offset toward the open end of said U-shaped first material.
Parent Case Info
This application is a continuation of application Ser. No. 07/521,037, filed May 9, 1990, now abandoned.
US Referenced Citations (16)
Non-Patent Literature Citations (2)
Entry |
Handbook of Common Polymers, CRC Press, 1973, pp. 25, 51. |
Webster's II New Riverside Dictionary, Riverside Publishing, 1984, p. 425. |
Continuations (1)
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Number |
Date |
Country |
Parent |
521037 |
May 1990 |
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