Varnishing, Flocking, Laminating, Numbering, Stamping - Finishing Printed Materials
VARNISHING
After an image has been transferred to a substrate, it is sometimes coated or varnished. The coating becomes a clear protective surface. Usually, the coating makes the surface resistant to moisture and scuffing.
Glossy restaurant menus, annual report covers, and similar products are typical examples of varnishing. The coating materials vary but some of the latest coatings are epoxies that give excellent wear qualities.
Total area coverage can be accomplished by various processes but a planographic press can be used when the dampeners are removed. Letterpress and screen processes can also be used for specific varnishing jobs.
FLOCKING
Whenever the surface of a printed package, T-shirt, or greeting card is fuzzy, the inked surface has been covered with cloth fibers. This called flocking.
The fibers are attached into the ink while the ink is still wet. For example, some wall coverings use this technique to give an unusual texture.
This is a highly specialized finishing process. It is NOT commonly found in the graphic communications industry.
LAMINATING
Laminating is the bonding of two or more material together to become one common unit. If you have attended a conference or convention where graphic communications suppliers have booths, the suppliers of laminators might ask you for your business card. The card will be laminated in plastic. In this case, the card often becomes the identification tag for luggage.
Many of today's restaurant menus also use this process as a protective surface to prevent rapid wear and destruction of the paper.
NUMBERING
The process of consecutively placing a number or skip placing of figures (numbers) in forward or backward order is called numbering.
The figures are transferred from the inked relief image onto the stock, usually paper. The plunger is automatically depressed by the press to ratchet the numbering head. This permits forward or backward numbering, each impression changes to a different figure or digit. See Figure 6-31.
Often, the numbering machine is set to start on the maximum amount. When printed, the last figure will be number one. This prevents an overrun and places the tickets, forms, or other numbered materials in the right order. Numbered tickets or gate passes would be good example of sequential numbering. See Figure 6-32.
STAMPING
Goldstamping is the term commonly used for stamping foil onto a substrate. Gold or simulated gold is commonly used as a stamping material. However, silver and some other colors are also available as hot stamping materials.
Stamping is an image transfer process closely associated with the relief process. Letterpress images, are placed between two jaws which tighten, Figure 6-33, and hold the type characters. The clamping device is heated. Before the image comes in contact with the substrate, a coated foil is placed between the type characters and the substrate. The heated type characters are then depressed. The heat and pressure transfers the image to the substrate. The proper image transfer depends on the amount of heat, the pressure applied, and the dwell time the type characters are in contact with the foil and substrate.
Usually, the relief images are brass or a service type. Service type is more durable and will withstand the heat and pressure longer.
In a production situation, the stamping unit is automated but it can also be a hand-operated process. Some production facilities have platen presses which have been modified for the hot stamping process.
| 0 Comments |
|---|