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 The design process is relatively simple for bridge laser technology. (Image courtesy Hirsch Solutions)

The Ins and Outs of Bridge Lasers

by: 

Ed Levy

Ed Levy is an industry veteran and director of software technologies at Hirsch Solutions.

This article appears in the latest issue of Printwear magazine. To ensure that you can access this and other industry focused pieces, subscribe today!

Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Laser technology has many benefits in the textile industry.

The bridge laser is an enterprise-level industrial workhorse, designed to integrate cutting and etching processes into apparel decorating. The concept of the bridge is simple. The laser head travels over the embroidery machines or workstations, stops at each head or station to perform the work, and then returns to a designated starting/stopping position.

Inside the head, there are two mirrors moved by two galvanometric motors that operate the bridge laser. The ray enters in the head, is reflected by the first mirror (X-axis), reflected to the second (Y-axis), and is then reflected to the cutting area.

Depending on the focalization needs and the maximum surface area we want to use, there are two different technologies available, referred to as “2-axis” or “3-axis”.

- The 2-axis head is always the same distance from the cutting area to keep the ray focused. For this reason, it allows work on a defined area only.

- The 3-axis head can operate at different heights and with different field, and spot, sizes.

The bridge laser is capable of precisely cutting different materials. A burn test occurs the first time a specific material is being utilized. The burn test performs a series of cuts with different power and velocity. The goal is to find the shape that achieves the perfect cut, which would be deep enough to cut the top material but not enough to affect the layer below it. Once the desired result is achieved, the settings should be logged for future use of the same or similar material.

anatomy of a bridge laser

This is an example of a traditional bridge laser workstation layout. 

ANATOMY OF A BRIDGE

Beam. The beam forms the bridge structure. It is the overhead cross-section that the laser head travels across to run production. Beams are configured in a single beam or double beam depending on the equipment required under the bridge.

Laser head. The laser head travels across the bridge and stops at each point it needs to cut or etch.

Machine configuration. The machine configuration is dependent upon the type of work required. Typically, a bridge laser will have a combination of embroidery machines and workstations to allow for a flexible production flow.

Workstations. The workstation is utilized when the laser does not require embroidery. Etching is commonly performed on the workstation. An object is simply placed on the workstation, and then the laser performs its work.

Computer software. The laser has a software component that adds laser commands to an embroidery file. While the best method of creating designs is through a laser tool within the digitizing software, the bridge laser software can add the laser commands to designs created on any software.

THE BENEFITS OF A BRIDGE LASER 

Cut on demand. A bridge laser lets you simply keep fabric on hand and cut it as needed. The need for precutting appliqué pieces is eliminated. This allows for greater flexibility for just-in-time delivery, without having to worry about stocking precut components.

Expanded materials. The process for bridge lasering is different than traditional appliqué. With a bridge laser, the material is secured to the garment before it is cut. Typically, appliqué material — such as twill — is rigid to allow for easy handling of the cut pieces, as well as to make it easier to position the cut pieces in place. Since the material is secured first with a bridge laser, delicate materials and flimsy materials such as T-shirt material can be used for a soft look. 

Reduced stitch count. Another significant advantage of a bridge laser is the ability to significantly reduce or eliminate stitches, which in turn considerably increases output and reduces labor. 

Etching. Laser etching is a process by which the laser does not cut all the way through the fabric. This is controlled by laser power and velocity. The faster the laser travels, the less it will cut. Laser etching creates a unique effect, which is also very profitable. There is no cost of materials with laser etching: no thread, no backing, no bobbin, and no appliqué material is needed. 

Reverse appliqué. Another benefit of the bridge laser is its ability to cut more than just appliqué material. The laser can easily cut through fabric which makes it very useful for doing reverse appliqué. Reverse appliqué is a process where the appliqué material is sandwiched between the backing and the garment, and the laser cuts the garment, allowing for the appliqué material behind it to show. This creates a very distinctive look.

Caps. Recent technological advancements in bridge laser and embroidery machines have allowed for the introduction of caps to bridge laser production. Special algorithms and machine movements are required to compensate for the fact that a cap has a curved surface. The curve can affect the focal point of the laser and cause distortion and other production challenges. Recent technology makes it possible to manage the curved surface, creating beautiful appliqué and etched designs on caps. 

BRIDGE LASER DESIGN PROCESS

The design process is relatively simple for bridge laser technology. Vector lines of the objects are created, and the vector objects are designated to be laser line or laser fill. The laser fill is utilized for the etching process. Each laser object is coded with a power setting and a velocity. The combination of these settings determines if the laser cuts or etches.

Figure 1

Figure 1 is a traditional embroidery piece comprised of 38,000 stitches, no laser, and a 45-minute run time.

The design in Figure 1 is comprised of 100 percent embroidery. It is made of 38,000 stitches, no laser, and a 45-minute run time. This is a traditional embroidery piece. This creates a fashion-oriented look rather than a rigid, sports-based look. 

Figure 2

Figure 2 is the same design utilizing appliqué. This creates a fashion-oriented look rather than a rigid, sports-based look.

Let’s look at the same design utilizing appliqué in Figure 2. Notice the soft layer of T-shirt material that was used as the appliqué itself. This creates a fashion-oriented look rather than a rigid, sports-based look. The stitch count on this design is 4,200 and the run time is five minutes, with the laser cut time at 10 seconds.

Figure 3

Figure 3 takes the same design and incorporates laser etching. The etching process in Figure 3 does not require any stitches and the run time is only 20 seconds. As previously mentioned, there are no consumables required to create the laser etching which makes it a high-profit revenue stream.

There are considerations that need to be made when determining the material for specific applications. When it comes to cutting, just about any material will suffice. The laser can cut through single or multiple layers of material. With etching, the material needs to be something that will not burn. Most synthetic materials such as polyester or fleece work well with etching. The thicker the material, the easier it is to do a nice, deep etch. Polyester performance shirts also etch well, but the etching is more subtle. If the etching goes too deep, it can compromise the integrity of the material. Etching is also at the mercy of the color that is revealed once the material is etched. Thus, different materials and colors should be tested prior to determining good candidates for etching. 

While textile lasers are designed to cut and etch textiles, the laser is capable of working in many different scenarios. Wood, acrylic, leather, and a host of other materials can be utilized with a bridge laser.

In conclusion, the bridge laser provides the cutting-edge technology necessary to take enterprise-level organizations to new depths.