Hot printing

An important target reached by Cielle technology

The topic will be addressed in two parts: the first regarding the general introduction of the process, and the second the types of surface and the working techniques Hot printing is a technique used above all in the paper, bookbinding and hide industries to transfer an image from a relief matrix to the print support, such as a card, label, etc.

The procedure for creating the matrices used in hot printing is quite specialised, and is the result of the combination of a number of factors, with some of the more important being the characteristics of the machines used and the experience of the engravers. As a result of its partnership with leading engraving workshops, Cielle can exploit a specific background of information and technology, allowing us to effectively face the problems involved in hot printing,

resolving many of the difficulties that arise when working with hot relief matrices, such as the expansion of the material used in the matrix (above all brass) due to thermal deformation at temperatures above 100°C, and the presence in the matrix of internal stress caused by local overheating during the cutting phase to produce the raised image. The hot printing procedure can be divided as follows:

• creation of the metal matrix (dollies are also required for some applications);

• the matrix is heated to 100°-120°C;

• the matrix is pressed against the foils (metal or dyed sheets), which in turn are in contact with the item being printed, or is pressed directly against the print support (dry relief printing).

It should be stressed that the hot printing technique exploits, in the pressing operations, the combined action of temperature and pressure, applied for a precise period of contact time, with the consequent transfer of the image, logo or text onto the item being produced. It should also be remembered that the engraving of the metal is a predominant factor in the production of hot printing work; in fact, it determines the quality of the relief, as do the printing pressure and temperature.

The knowledge of the technique required to produce the matrix is a decisive factor for precise and simple production; for this purpose, our company offers a new software package created by a group of experts, which allows engraving operations to be performed effortlessly and simply.

The technology provided by a company such as ours, specialising in the manufacture of computerised pantographs, can be used for the construction, by engraving, of the components (matrices) in the hot printing process; the specialist study of this process has allowed us to establish a procedure for this process, through the provision of specific knowledge for the various applications.

(following - In the second part we will look at the types of surface and the hot printing techniques).