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Finishing Techniques 

Guillotine Trimming
When trimming on a guillotine, minimum back bar pressure and a sharp blade are required to minimize compression of the lift and maximize accuracy. Lifts no greater than 1.5 inches in height are recommended. Edge fusion from the back side of the blade is much less than from the beveled edge side. A blade angle of 22-24° is recommended. Frequent application of a light coating of silicone release spray to the blade may help to reduce edge fusion in the cut stack. Fanning of the cut edge of the stack is usually sufficient to break edge fusion.

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Slitting
Shear slitting with sharp blades, close tolerance of the anvil to the blade, and good alignment is recommended to produce smooth edges and minimize dust. Score cutting of Teslin substrate is not recommended because it creates dust and fibers on cut edges. As with any web processing of Teslin substrate, low tensions (0.5-1.0 lb./linear in. width) are needed to minimize distortions to the web.

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Die Cutting
Several types of die cutting have been demonstrated with Teslin substrates and laminates: steel rule dies, forged or "high" dies, rotary dies, and blanking dies. The first three require sharp cutting edges to produce clean cuts in Teslin substrate, because plastics do not burst like paper but must be completely penetrated. Cutting blade angle and provision for relief in the waste stock of a lift can also play an important role in controlling edge fusion within a lift. Best results (cleanest edges) are obtained when Teslin substrate has been varnished or top-coated. Smaller lifts may be required to minimize stack deflection.

Rotary die cutting has been done on web speeds of 275 to 300 ft./min. with Roto-Die Co.’s MU100 die on a metal anvil. (Rotometrics Group, phone: 800-325-3851 or 314-587-5600) After 50,000 cuts, a slight polishing of the die blade was seen, but no measurable wear was detected. A slight (about 15%) increase in pressure was required during the 50,000 cut run, which is comparable to the requirements of film rotary die cutting. Accurate adjustment of die to anvil contact is important for success. A gap, as small as 0.0002 inch between the blade and anvil, will prevent clean cuts.

Blanking die cuts are typically used on laminated Teslin substrate applications such as identification cards. A single laminated sheet is punched to yield individual cards. Best results are obtained with tight tolerances between the male and female die parts. A slight angle of the male die to provide shearing action to cutting is helpful in some cases. Spartanics has automatic blanking die cutting equipment that has been used successfully to efficiently die cut Teslin substrate laminated cards. (Spartanics, phone: 847-394-5700)

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Hole Punching / Drilling
Due to the composition and compressible nature of Teslin substrate, it is necessary to varnish the area that will be punched by solid pin punches for plastic coil or comb binding. Varnish should be applied on both sides and should have a coat weight of 2-3 lbs./ream/side. This surface coat greatly reduces the tendency for Teslin substrate to fuse or block when punching. Sharp dies, tight male/female tolerances and limited lifts (4-8 sheets) will also improve punching performance.

When drilling holes in Teslin substrate, some edge sealing may be experienced. This effect can be reduced by using one or more of the following methods:
– using sharp drill bits with drill wax and a rapid delivery,
– press varnishing or top coating the sheets when printing,
– drilling in short lifts with a wax paper or carbon paper on top of the lifts to lubricate the drill bit.

Line hole punching can be done using sharp, hardened dies such as Schrober dies. Cleaner holes have been obtained using a serrated punch design rather than a simple circle punch design. As with other web processes using Teslin substrate, control of web tension <0.5 - 1.0 lb./linear inch of width is important for maintaining registration of line holes.

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Perforation
Teslin substrate has a greater tendency to tear in the machine direction (MD). With the common 0.030 inch tie width, perforations in the MD should be made with 18 - 25 ties/inch. To provide approximately equal ease of tear in the cross direction (CD), 4 - 10 ties/inch are required. Microperfing (0.006 inch tie width) with 72 teeth/inch in the MD and 50 teeth/inch in the CD will provide approximately equal tear in both directions. Sharp perforation wheels and bars will provide the cleanest job. Litho perforation is not recommended with Teslin substrate.

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Folding
Teslin substrate folds well in either direction. Scoring is recommended to obtain a tight fold on Teslin substrate 10 mil and thicker, as well as on laminated pieces. To minimize stretching, the ridge of the score should be on the inside of the fold.

The grain direction of Teslin substrate is similar to that of paper; therefore, the direction can affect the tear characteristic of the sheet. The best way to determine the optimum configuration of a fold in a design is to test the effect of the sheet direction on the final product. A menu fold, for example, should be evaluated for tightness of fold versus tear-resistance and stiffness. For optimum fold performance, the machine direction of Teslin substrate should be oriented perpendicular to the direction of the fold line.

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Thermal Lamination
Teslin substrate laminates much better than conventional synthetic printing sheets, films and foils. Peel strength of Teslin substrate laminates is two to six times that of coated papers or other synthetic stocks.

Teslin substrate does not require an edge seal to produce a durable, laminated piece. Press sheets can be laminated and then guillotine cut or die-cut without fear of delaminating in service. Moreover, because no edge seal is required, generally a thinner laminating film can be used. This use of thinner laminating films can significantly offset the cost of the synthetic sheet.

For optimum peel strength of laminations, the moisture content of Teslin substrate should be between two to six weight percent. Very low moisture contents give poor adhesion, while excessively high moisture contents can create bubbles between Teslin substrate and the laminating film. Control of lamination temperature is important for maximum adhesion of the film to Teslin substrate. Your laminating film supplier can provide guidance in the minimum substrate temperature required for optimum adhesion. Paper thermometers (Paper Thermo Company Inc., phone: 603-547-2034) are useful in checking that these minimum temperature requirements have been met in your equipment.

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Gluing and Bonding
There are several end uses which require gluing or bonding of Teslin substrate to other materials, surfaces or parts: adhesive application of labels, padding, creating case bound book covers, perfect binding, and fusion bonding to other plastics. While Teslin substrate is a polyolefin-based material, it does not readily fusion bond to itself by impulse sealing. RF welding and ultrasonic welding are generally unsuccessful in creating self-bonds. Some adhesive or fusible material is required to create a bond between two pieces of Teslin substrate. Hot melt adhesives or films/coatings of LDPE, LLDPE and co-polymers can be used to create such bonds. Water-based glues and adhesives (e.g., animal glues, casein or polyvinyl alcohol resin glues) can be used to affix labels made of Teslin substrate to surfaces and book covers made of Teslin substrate to chipboard (gray board), and to perfect bind covers made of Teslin substrate to publications.

Care should be taken in choosing a glue or adhesive to avoid components that might migrate from the adhesive and stain or discolor the Teslin substrate material. Many rubber-based adhesives contain stabilizers that can migrate and cause color changes in the Teslin substrate that they contact. For best results, request adhesives based on high molecular weight polymers containing non-staining antioxidants or stabilizers.

In printed or unprinted form, Teslin substrate can be fusion bonded to various thermoplastics and certain thermosets. Best results are obtained in moldings where there is little flow of resin over the bonding surface of the item bonded with Teslin substrate. Excessive shear created by resin flow can lead to fracture of the item bonded with Teslin substrate. Fusion bonds have been made between Teslin substrate and flat panel samples of polyethylene, polypropylene, polymethyl methacrylate, ABS, polystyrene, rigid PVC, polycarbonate, and epoxy resin. Every plastic fusion bonding application using Teslin substrate should be evaluated for molding compatibility, laminate appearance, and bond integrity.

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Sewing and Grommeting
In general, Teslin substrate fabricates much like polyethylene film and should be handled as such.

Sewing: Teslin substrate can be sewn with conventional equipment. Banner hems should be sewn with 4 - 6 stitches per inch. Thread tension must be controlled to avoid tear initiation in the machine direction, which can occur with excessive thread tension. Extra support and strength in the hems can be obtained by reinforcing these areas with sewn-in webbing (twill tape), rope, or "O" rings.

"Pole" or rod pockets for hanging a banner can be produced by creating a hem large enough to fit the pole through. "Snap hooks" can be sewn into or onto the top hem of the banner to slip over a rope or wire stretched to support the banner.

Grommeting: Standard #2 grommets have been used to provide support holes large enough for common rope (#2) attachment.

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Foil Stamping
When properly applied, foil can adhere to Teslin substrate extremely well. Temperatures in the range of 190-220° F may be required. Temperature setting will be a function of the foil, the pattern and the hardware. It is recommended that some experimental work be conducted to determine the best set of conditions for the contemplated design.

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Embossing
Teslin substrate has truly unique embossing characteristics. The high porosity of the film allows for both one-sided (recessed or raised surfaces on only one side) and two-sided (raised on one side, recessed on the other) embossing. The strong adhesion of inks helps prevent offsetting during the embossing of printed pieces.

With a male and female die system, Teslin substrate will emboss similar to most papers and plastics. The effects of embossing will be most pronounced with thicker grades of the product.

Temperatures in the range of 200-270° F may be required. Cold embossing is not generally as effective as thermal embossing. Dwell times and pressure requirements will be a function of the graphics, the degree of embossing desired, and the hardware.

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