Embossing is the production process of post-print finishing, applying images to printed or souvenir products using or without foil, under pressure and high temperature.
Stamping
Embossing is used for the manufacture of cards, business cards, labels and other souvenir products. The most impressive is foil stamping; the finished material has a presentable and colorful look.
Types of embossing:
- Blind (blind) embossing - extruding an impression below the surface of the material used without the use of foil;
- relief stamping - compressing the material between a special cliche, matrix and patricia, to make the image bulge; may be blind or foil;
- hot foil stamping - the process of thermal transfer to a cramped material of a metallized powder from a film by means of a cliche. Various types of foil are used - metallized, textured, pigmented, holographic, etc.
Hot stamping is widely used for finishing covers of daily logs, as well as card holders, purses and other products made of artificial and genuine leather.
There are photopolymer and metal cliches for stamping (zinc, magnesium, copper, brass, sometimes steel):
- photopolymer cliches are used for small runs (up to 1000 prints) - business cards and souvenir products. This is the most economical option;
- zinc cliches are used in the manufacture of products up to 10,000 prints;
- Magnesium cliches have their advantages: the ability to print on any material, quick production, print run resistance (up to 50,000 prints). Has an imprint depth of 0.7-2.5 mm (depending on the material);
- brass cliches are made on special engraving machines by machining. Advantages - the ability to give cliches several levels of depth, giving embossed elements a greater height. They are used on soft materials with multi-level hot stamping. The print run depends on the thickness of the cliche (more than 50,000 prints).
Photopolymer plates are a photopolymer deposited on a metal substrate and protected by a film from light exposure.
Metal plates are made in two ways - etching (chemical) and milling (mechanical). Hot stamping and other types of hot stamping are mainly carried out by cliches made by chemical means.
The stamping foil has the following composition:
1) lavsan base;
2) a thermally degradable wax resin layer that breaks down when heated, freeing the lower layers of the foil;
3) a paint layer (a layer of varnish or paint) with a binder;
4) a thin layer of aluminum, present only on holographic and metallized foils;
5) an adhesive layer designed to adhere the layers to the material.
A cliche warmed to the required temperature frees the colorful layers from the lavsan base and sticks them to the embossing material. The heating temperature is selected depending on the type of foil, type of cliché, cramped material, impression pattern, equipment used and many other factors.