Thursday 05 April 2018
How does the laser cutting of a punch work? In this article we will describe all the process necessary to achieve a perfect result.
After explaining how to make a die, we want to deepen the aspect related to the laser cutting of the punch.
The laser cutting of a die is divided into two large branches:
1) cutting flat dies
2) cutting rotary dies
A flat die is made from a birch panel that is usually 18 mm high. The panel must respect tolerances both in terms of thickness and flatness, since otherwise there would be big problems with die-cutting.
The laser cutting is done following strict rules of precision related to the width of the channels cut with the laser, which are precisely 0.71 mm (2 points) or 1.05 mm (3 points).
The latest generation lasers like those of Cutlite Penta are able, thanks to software, to modulate the cuts made in 8 directions with precise off-sets. The precision cut die must have the same precision width both on the upper and on the lower part, so as to guarantee the tightness of the cutting threads.
There are many elements that affect the precision of laser cutting of a die, such as the characteristics of the machine (use of high precision recirculating ball screws or linear motors), focal accuracy and stability of the laser flow.
In addition to laser cutting, the galvanometric marking head is often used, capable of writing a lot of information on the punch in a few seconds, with the guarantee of a saving of time and gas.
A rotary die is generally obtained from a 13 mm poplar panel with diameters ranging from 176 to 800 mm.
As in the case of flat dies, even for rotary ones, compliance with certain rigid rules of planarity and thickness is fundamental. The cut is usually done with a width of 1.42 mm (4 points).
The laser cutting of a rotary die begins with off-line assembly outside the machine, by screwing the wooden supports into the lower cavity of the rotary shell, which will then be housed in the rotary shell.
Then a milling head is mounted with a tool changer, so that special pockets can be milled which are essential for the assembly of additional supports for the die-cutting of the rotary die.
Cutlite Penta produces both flat die and rotary stand-alone dies, but also flat and rotary combined systems that use a single laser source for two cutting systems with power from 750 Watt up to 3000 Watt.