Apparatus and process for automatically cutting textile web with reduced wrinkling

The present invention generally relates to an apparatus and process for automatically cutting a textile web with reduced wrinkling. The process includes passing the textile web across a first guide roller having a first guide surface directing the textile web to the tension roller, passing the textile web across a let-off roller on the let-off roller surface to compensate for web tension fluctuations as the web textile is passed, moving the textile web from the let-off roller surface in tension around a portion of the tension roller and in contact with the exterior surface of the tension roller, passing the textile web across a conveyor guide surface directing the textile web from the tension roller to an automatic laser cutting apparatus, and cutting the textile web in a predetermined pattern in an automatic laser cutting apparatus comprising a cutting table, a movable laser cutting tool, and a vacuum system, wherein the cutting table comprises a perforated conveyor belt having a conveyor guide surface for directing the textile web from the tension roller and wherein the textile web is held by suction to the conveyor by the vacuum system. The angle formed from the let-off roller surface normal to the ground and the textile web from the let-off roller to the tension roller is from about 2 to 25 degrees. The tension roller holds the textile web in 0.2 to 0.6 pounds per linear inch. The apparatus for automatically cutting a textile web with reduced wrinkling is also disclosed.

TECHNICAL FIELD

The present invention generally relates to an apparatus and process for automatically cutting a textile web with reduced wrinkling.

BACKGROUND

A well known method of cutting out pieces from a flexible sheet material consists in bringing the sheet material onto a table in a cutting-out zone, either as a single ply or as a plurality of superposed plies forming a lay-up, and in cutting out pieces in compliance with a pre-established layout by means of a tool which penetrates into the material or laser cuts the material while the sheet material is held against the table by suction. The suction is obtained by sucking through the surface of the table. It has been known for a long time to use a laser as cutting tool more particularly for materials in sheet form. To that end, a laser source is available, generating a light beam, which is directed by means of mirrors towards the zone of cut. Before it reaches the plane of cut, there is interposed on its path a focusing lens whose role is to concentrate the light beam into a spot of very small diameter, which furnishes a very high density of energy. Very different materials may thus be cut out provided that the thicknesses are not too great.

In many systems, the fabric to be cut is pulled onto the laser cutting table with wrinkles. This causes off quality pieces and inaccurate cuts. In the case of air bags, these miss-cuts cause lost time, money, and a safety risk.

Therefore, there is a need for a process and an apparatus to automatically laser cut a textile web with reduced wrinkling and more accurate cutting.

DETAILED DESCRIPTION

Referring toFIG. 1, there is shown an installation10for automatically cutting textile webs with reduced wrinkling incorporating a tension roller300. As illustrated, the tension roller300is located after the unwind roller750the first guide roller100, and the let-off roller500, but before the automatic laser cutting apparatus700. Having the tension roller300with specific placement relative to the let-off roller500and tension parameters incorporated into the installation10reduces wrinkles in the fabric leading to more accurate cutting by the automatic laser cutting apparatus700.

The tension roller300in one embodiment is attached to the installation10by a tension arm310and a tensioning device320. An air compression spring is shown inFIG. 1as the tensioning device, but the tensioning device may also be, but is not limited to a mechanical spring, an electronic load cell, a hydraulic pressure cylinder, or an oil based cylinder. The tension roller moves up and down relative to the installation applying pressure to the textile web400to maintain tension in the textile web400and reduce wrinkling of the textile web400. The tension roller applies 0.2 to 0.6 pounds per linear inch pressure to the textile web, more preferably about 0.35 to 0.50 pounds per linear inch. When the pressure is too high, the tension roller300bottoms out, meaning that the tensioning device320is fully extended and the tension roller300can not longer adjust to provide constant pressure to the textile web400and the textile web may have too much tension and therefore slip as the conveyor belt710attempts to advance the textile web. If the pressure is too low, the textile web may not be held in high enough tension and the textile web400may wrinkle as it enters the laser cutting apparatus700causing miss-cuts. Preferably, the tension in the textile web400is maintained at a substantially constant tension.

FIG. 1also shows optional unwind system750and windup system760. Although rollers are shown for the unwind system and windup system, other known unwind and windup systems may also be used including additional dancer bars and safety equipment. For example, the windup system760may be where the cut pieces are stacked together and the waste is collected to be discarded.

Referring now toFIG. 2, a section of the installation10containing the tension roller300is shown enlarged. Also shown is the first guide roller100, the let-off roller500and the conveyor guide surface200. The first guide roller100has a first guide surface110that guides the textile web400from the first guide100, past the let-off roller surface510to the tension roller300. The conveyor guide surface200guides the textile web400from the tension roller300to the conveyor of the automatic laser cutting apparatus700(not fully shown). The let-off surface510of the let-off roller500is the last surface that the textile web400contacts before the tension roller300. The conveyor guide surface200is the first surface that the textile web400contacts after the textile web400leaves the tension roller300. The first guide roller100and conveyor guide surface200may be of any form that guides the textile web400to and from the tension roller300, including, but not limited to a drive roller, an idle roller, a stationary roller, a cylinder, the textile, a bar, or a wire.

The let-off roller500serves to control the amount of textile and when the textile web400is advanced from the unwind system through the installation10acting as a dancer roller moving forward to back (as shown inFIG. 1). The tension roller installation must not interfere with the function of the let-off roller500. The angle θ shown inFIG. 2is formed between a first line running from the let-off roller surface510to the ground such that the line is perpendicular or normal to the ground and the line formed by the textile web400traveling between the let-off roller surface510and the tension roller300. This angle θ is between about 2 and 25 degrees, more preferably between about 5 and 15 degrees. It has been found this range produces an installation10with reduced wrinkling from the addition of the tension roller and correct and accurate feeding of the textile web400through the installation10.

Referring back toFIG. 1, there is shown the laser cutting apparatus700. The laser cutting apparatus700generally cuts the textile web400based on a predetermined electronic input. The laser cutting apparatus700generally includes a perforated conveyor belt710that includes the conveyor belt surface200and a laser cutting system720with a laser cutter730. The textile web400is held by suction to the conveyor belt710by a vacuum system for example discussed in U.S. Pat. No. 5,626,066, which is herein incorporated by reference.

The laser cutting system700is typically based on a printed or woven pattern or location marker on the textile web400. In one embodiment, it is a grid pattern woven into the textile web. The laser cutting apparatus has a sensing system, such as an optical camera (not shown) that aligns the textile web correctly. The laser cutting tool730uses laser energy to cut the textile web in the preprogrammed pattern. More detailed information on the laser cutting system700may be found in U.S. Pat. Nos. 6,737,607, 6,521,074, 5,975,743, and 5,867,392.

Preferably, the tension roller300is rigid, meaning that it does not deform or bend in any significant amount in use with the textile web400in the installation10.

FIG. 2illustrates a method of threading the textile web400onto one embodiment of the installation10. The textile web400has a first side401and a second side402. In the embodiment shown inFIG. 2, the first side401of the textile web400passes across the first guide roller100in contact with the external surface of the first guide100. Next, the second side402of the textile web400passes by, in contact with, a portion of the let-off roller surface510of the let-off roller500. Next, the second side402of the textile web400passes around a portion of the tension roller300in contact with the exterior surface of the tension roller300. Then, the first side401of the textile web400then passes across the conveyor guide surface200and into the laser cutting apparatus700. In other embodiments the textile web may be threaded through the treatment apparatus10such that different sides of the textile web400passes across the first guide roller100, let-off roller500, conveyor guide surface200and tension roller300.

The first guide surface110, the let-off roller surface500, the conveyor guide surface200, and the tension roller300are substantially parallel and the textile web400passes across each in contact in a direction substantially perpendicular to the axis of the rollers and surfaces. Preferably, the tension roller300is at least as wide as the textile web400.

The textile web400may be any textile, including, but not limited to woven, nonwoven, or knit textiles. Woven fabrics are preferred and may be plain weaves, twills or other well-known constructions. Examples of knit fabrics include double knits, jerseys, interlock knits, tricots, warp knit fabrics, weft insertion fabrics, etc. Such fabrics may be constructed from spun or filament yarns or may be constructed by using both types of yarns in the same fabric. The textile may be of any suitable material, including, but not limited to, polyamide, polyester, polypropylene, aramid. In one embodiment, a woven, nylon textile is used which is a commonly used textile for airbags.

The process for automatically cutting a textile web with reduced wrinkling comprising in order:

1) passing the textile web across a first guide roller having a first guide surface directing the textile web to the tension roller;

2) passing the textile web across a let-off roller on the let-off roller surface to compensate for web tension fluctuations as the web textile is passed;

3) moving the textile web from the let-off roller surface in tension around a portion of the tension roller and in contact with the exterior surface of the tension roller;

4) passing the textile web across a conveyor guide surface directing the textile web from the tension roller to an automatic laser cutting apparatus;

5) cutting the textile web in a predetermined pattern in an automatic laser cutting apparatus comprising a cutting table, a movable laser cutting tool, and a vacuum system, wherein the cutting table comprises a perforated conveyor belt having a conveyor guide surface for directing the textile web from the tension roller and wherein the textile web is held by suction to the conveyor by the vacuum system.

The angle formed from the let-off roller surface normal to the ground and the textile web from the let-off roller to the tension roller is from about 2 to 25 degrees and the tension roller holds the textile web in about 0.2 to 0.6 pounds per linear inch.