Hot Foil Stamping

 

Hot foil stamping is the process used to bind foil to paper or board using heat and pressure. Its purpose is to create a “Wow” factor by giving a shiny and shimmering look to the design.

 

Hot foil stamping happens after the printing process has been completed and basically involves a “heated” metal die pressing a thin foil onto the substrate.The foil is attached to a thin carrier film that is removed after the foil has been stamped onto the substrate.

The operation is a complicated one that has four variables: die temperature, dwell time, pressure and stripping time.

Die Temperature is generally controlled by a thermostat or temperature controller within a range of 100 – 170 degrees Celsius and should be set just high enough to transfer the foil to the substrate.

Dwell Time refers to the time the die is pressing the foil onto the substrate. A longer dwell time ensures a stronger bond but canalso slow down the production speed. If the temperature is increased slightly, the dwell time can be reduced and providing they are both balanced correctly, the production speed can increase.

 

Pressure determines the depth of penetration of the stamp below the surface of the substrate.

 

Stripping Time refers to the time required to allow the transferred foil to cool and harden on the substrate. When the carrier is stripped away from the substrate, the transfer is complete.

 

Hot foil stamping requires the die to have a reversed image on it that looks correct on the substrate after the process is complete. The die itself is usually made from magnesium, brass, copper or steel depending on the job requirements. The longer the run, the harder the die needs to be and naturally the more expensive.

 

The process itself normally occurs on a letterpress or a platen which is a time consuming process, however there are small desktop machines available for shorter runs.

 

Hot foil stamping is a skilled type of work and the companies that perform this kind of work specialise in it. Most printers would not even attempt to do this kind of work in house and as a result outsource it to the experts.

 

As the work requires actual printed sheets to set up the machine, printers have to supply “setters” for the foil machine operator to “set up” the machine. This usually results in increased expenses as the printer will forward on the costs of the job, plus the freight costs plus a margin.