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From year to year, many companies change the products they make, or begin producing new product lines in niche areas that require new and different finishing methods. In some shops, the steps taken to finish products are done with inappropriate tools. Furthermore, many shops keep their laminators, cutters and other finishing tools too long and put off new purchases or upgrades, which negatively affects productivity and quality.

This article examines tools used in the finishing marketplace and will address opportunities for better and more efficient production for the future.

Finishing Solutions for Banners and Textiles

Sewing Machines
A variety of industrial sewing machines are available to finish items made of varying vinyl grades such as banners. Finishing banners by sewing pole pockets and hems is standard work for many imaging businesses. Some companies try to use consumer-grade sewing machines, but they stitch too slowly to work efficiently. Consumer-grade units generally stitch 1,000 stitches per minute, while industrial units can move material in thousands of stitches per minute. This higher productivity is necessary for sewing products in a reliable and repeatable manner. Consumer-grade sewing machines are not made just for the imagers’ purposes.

The feed movement on a consumer-grade sewing machine utilizes a set of toothed, metal walking plates that move under the material, pressing it up onto the machine’s presser foot. In contrast, a dual (or unison feed) commercial sewing machine is a better investment. Also known as “walking foot machines,” these units have a presser foot with its own set of gripping teeth that walks in unison with the bottom feed to facilitate double feeding of the material. The end result is a larger, more consistent stitch. These machines typically are used by upholsterers and people who need to sew heavy-grade industrial fabrics.

The one-needle, unison-feed lockstitch is the most common type of industrial sewing machine in use. Double-needle, chain-stitch machines also are used. They use four thread spools that feed from the unit’s top and do not require the bottom bobbin thread to be changed. These are a better choice for companies producing large volumes of work without interruption. Given the many variations and options found on industrial machines, talking to a manufacturer may be the best way to narrow down the possibilities.

Sticky Alternatives to Stitching
Instead of sewing hems and pockets onto banner or textile pieces, you can use double-sided adhesive tapes. These tapes — known as “banner hem tape” or “double-sided hem tape” — are useful for creating quick hems in lightweight banner materials. If you are using tape for heavier materials or pole pockets, look for “very-high-bond” (VBH) tape.

VHB tapes have enormous gripping power and are used when material stress is of concern, there is no access to a sewing machine or the project requires tape for the intended product life. Hem tapes also can be used in a one-sided application as a reinforcing material when inserting grommets. Vinyl that is not reinforced is a soft material in which grommets have a tendency of tearing out under stress. Using reinforced hem material, a high-strength plastic that has an adhesive on one side, solves this problem. It is applied to the banner’s back before grommeting.

Banner Welding
Vinyl welding, a strong improvement to stitching, is the only way to seam together really large vinyl projects. Vinyl welders come in a number of different designs, depending on a facility’s size and usage requirements. Units can be portable tools or industrial, non-movable equipment.

Hot Air or Hot Wedge
Vinyl welders all work via heat and pressure. Heat sources are electrically produced, high-temperature air or electronically heated, high-temperature wedge — which is precisely controlled and injected between two or more layers of thermoplastic material. Heating the thermoplastic material prepares the two surfaces to be joined for molecular bonding.

Hot air rotary heat sealing is used to join thermoplastic industrial fabrics and films using precise heat, speed and pressure settings. Hot air temperatures for these units can range from 537.8oC (1,000oF) to as high as 732.2oC (1,350oF). On these systems, a heated wedge is positioned precisely at the weld point, providing the required heat. The fabric or film is then pulled across the heated wedge.

There are strong advantages to both rotary welder types. Wedge welders can use less power than their hot air counterparts and do not have the noise associated with hot air blower systems. However, hot air systems can provide a better, more dependable bond. Also, for substrates that are not always produced perfectly, hot air systems seem better suited in dealing with these variations.

Radio Frequency Welding
Radio frequency (RF) welders are another vinyl seaming technology that have been around for a long time, predating rotary and hot air systems. In RF welding, electrical energy in a radio frequency field is conducted to the surfaces that will be joined together. This stimulates the material’s molecules to move at a speed of tens of millions of times per second. The friction (heat) arising between the molecules is what fuses the material together. A weld seam is created, which has the same strength as the surrounding material.

For grand-format RF welding, the seaming head is on a traversing rail that runs the length of a long, narrow table. Companies such as Zemat and Forsstrom High Frequency AB have units for seaming together billboards. Of all vinyl seaming technologies, RF units are the most expensive and consume the most energy. They are used from automobiles, swimming pools, tarpaulins and electronics to the food industry, and are widely used in material sealing and welding.

Grommeting
If your facility uses grommets, you know how difficult it is to use a manual “punch-and- anvil” system. If this is the case, it may be time for your company to upgrade to a hand-operated grommeting machine or automated grommeting device. Hand-operated devices can prevent the operator from ruining the printed product because of a mistake in hole-punching or setting.

Automated grommeting devices cut the hole, place it and set the grommet in under a second. Many of these units can handle grommets of varying sizes and set them through many difficult materials, such as Sintra and Durabond. When there is a need for the operator to place one or both parts of the fastener, varying degrees of semi-automation include a pneumatic or electric-powered press for closure.

Cutting and Trimming Solutions

Safety Rulers
If your company still uses flat-steel rulers and yellow utility knives to trim prints and products, now is the time to upgrade for increased efficiency and safety. Safety rulers have been around for years, with more versions and models available than ever before.

Normally, safety rulers are aluminum extrusions with painted inch markings or an applied ruler tape. Aluminum cutting edges eventually become uneven, as they are repeatedly cut into, and become “shaved” through repeated cutting or trimming. Some safety rulers come with stainless steel rods or sheets fastened to or embedded into the ruler. This greatly improves the effective life span of the ruler.

Table/Stand Cutters
For a higher degree of accuracy, table or stand-mounted cutters are available for prints and boards. These tools use straight or roller-type cutting blades, and some units have the addition of a powered cutting assembly. Some of these units have a surprisingly high degree of linear accuracy over their cutting length. For instance, the Keencut Javelin’s accuracy is “within 0.2mm over the 3.1 meter length of the cutter bar,” according to the company.

Perhaps, your company still uses an old-style table saw that kicks up a lot of dust. If dust is a problem, an upgrade to a panel saw with a vacuum system would improve this situation. Panel saws are vertical in orientation, save space and are capable of cross cutting or ripping boards from plywood to aluminum to plastic sheets. All are available with vacuum removal systems for debris and dust.

Hand-Held Cutters
Specialty hand tools can save a lot of time and frustration. The Plast-Kut can be used for scoring and cutting fluted Coroplast® or similar material. The Coro-Claw™ works like the Plast-Kut on 4-mil or 11-mil material. With the Coro-Claw, two square, metal rods fit into the material’s flutes, guiding the knife blade. If your company needs to make shapes or cut in a straight line, check out these tools.

For synthetic or other fabrics, the use of a rotary cutter results in a cleaner cut, without pulling out threads or leaving behind a fuzzy edge. Even better than the rotary knife for use on heavy synthetics is the “hot knife.”

Hot knives come in a variety of models with many different cutting tips to choose from. The advantages of a hot knife include the ability to seal the edges of synthetic material as the cut is made. This also works for webbing, cords, rope and heavy gauge synthetics.

Environmental Controls

Air Cleaners
For a cleaner environment, air-filtration units help reduce airborne dust and dirt. One manufacturer, Island Clean Air, has units with dust filtration and activated charcoal to lower levels of air pollutants (volatile organic compounds or VOCs) emitted from mild-solvent and solvent-based inkjet printers.

These air cleaners may be used with flexible piping — much like the vent hose on a clothes dryer — that connects directly to the exhaust ports found on many printers. Room scrubbers, which clean ambient air, capture fumes only after they have entered a room or space, not at the source. Shops that utilize higher solvent ink volumes or cleaning solvents that are more volatile may benefit from using potassium permanganate grids with activated charcoal to achieve higher VOC capture rates.

Also available for inkjet printing systems are custom hoods, which are made for specific inkjet printers by PAT Technology Systems Inc. PAT is a Canadian corporation that sells portable HEPA air purifiers and humidity solutions to the printing industry. The company’s custom manufactured hoods capture air directly at the source and vent it through flexible piping to a filtration unit. The advantage of these units is that they capture fumes at the source, before the pollution has dispersed into the room.

Dust Removal for Print Finishing
There is nothing worse than laminating or mounting prints only to find dust either under the laminate or under the substrate. Many shops use an air hose to clear dust, but high-speed air blowing over most plastics can cause static to build up on the surface, attracting even more dust. The best approach I’ve found to clear dust immediately prior to lamination is through a polymer roller. These slightly tacky rollers grab any particles from the side of the print and substrate that is to be laminated.

Dirty machines, tables and dusty operators are the first priority for dust removal. Operators can use an air hose to de-dust themselves after using any saw in order to remove wood, plastic or metal particles from their hair and clothing. This should be done far away from the finishing area.

To clean finished prints and substrates, Drytac offers a Dust Removal System (DRS) Roller in a 30.4-cm (12-inch) width. It comes with 50 tear-off adhesive sheets in a pad, which clean the dust and dirt from the roller. One must simply roll the print clean, clean the roller on the pad and roll and repeat as necessary.

SDI Systems Division, Inc. is a premier supplier of industry-specific cleaning systems, supplies and solutions. The company offers a large product line for many industries, including a roller cleaning system similar to the Drytac one. It comes in widths up to 45.7 cm (18 inches), offering medium or high tackiness. These units come with matched adhesive cleaning pad stations.

If your company uses plastics, another solution may help: Ionizing air guns that use electricity discharged across an air stream. This ionized air neutralizes static charges and removes electro-statically bonded particles from the surface material. Many companies make these device types for static control. Simply do an Internet search using the keywords “anti-static air gun.”

Jeff Burton, Digital Printing Analyst for SGIA, has served with the Association since 1998. He provides solutions to digital printing production, computer and work-flow issues as well as digital equipment and vendor recommendations. Burton currently teaches Introduction to Digital Printing and Color Management at SGIA headquarters in Fairfax, Virginia. jburton@sgia.org

This article appeared in the SGIA Journal, 1st Quarter 2009 Issue and is reprinted with permission. Copyright 2009 Specialty Graphic Imaging Association (www.sgia.org). All Rights Reserved.