| |
- Information about technological processes
and working systems . Everybody can contribute with documentation,
that must be sended to info@rioweb.it
accompanied with the name of the source, and if possible the link
of the site one where there is the possibility of a deepening.
|
|
|
|
Laser cutting
|
|
- Lasers cut by melting the material in the
beam path. Materials that are heat treatable will get case hardened
at the cut edges. This may be beneficial if the hardened edges
are functionally desirable in the finished parts. However, if
further machining operations such as threading are required, then
hardening is a problem.
• A hole cut with a laser has an entry diameter larger than
the exit diameter, creating a slightly tapered hole.
• The minimum radius for slot corners is 0.75 mm (0.030 in).
Unlike blanking, piercing, and forming, the normal design rules
regarding minimum wall thicknesses, minimum hole size (as a percent
of stock thickness) do not apply. The minimum hole sizes are related
to stock thickness and can be as low as 20% of the stock thickness,
with a minimum of 0.25 mm (0.010 in) for upto 1.9 mm (0.075 in).
Contrast this with normal piercing operations with the recommended
hole size 1.2 times the stock thickness.
• Burrs are quite small compared to blanking and shearing.
They can be almost eliminated when 3D lasers are used and further,
eliminate the need for secondary deburring operations.
• As in blanking and piercing, considerable economies can
be obtained by nesting parts, and cutting along common lines.
In addition, secondary deburring operations can be reduced or
eliminated.
- Whether laser cutting with CO2 or
Nd:YAG lasers, the principles employed are basically the same.
The beam from the laser is focused on to the surface of the material
being cut by means of a lens.
The focused laser beam heats the material surface and a very local
melt capillary is quickly established throughout the depth of
the material. The diameter of this capillary is usually just slightly
greater than the diameter of the focused laser beam.
The great majority of CO2 laser cutting is performed using an
assist gas. The significant feature of gas assisted laser cutting
is that the molten material is ejected from the base of the capillary
by a jet of gas coaxial with the laser beam.
For some materials this gas can further assist the process by
chemical (exothermic) reaction as well as physical work. The cut
is generated by either moving the focused laser beam across the
surface of the stationary material or by keeping the laser beam
stationary and moving the workpiece. Hybrids of these two options
are also possible. In this way simple and complex linear cuts
or two dimensional parts can be produced. More complex systems
are required for three dimensional processing.
Most laser cutting with CO2 lasers is performed in the power range
1 - 1.5kW.
|
|
|
 |