ZX10 Zoom Beamreducer
The model ZX10 zoom beamreducer is designed to allow a variable focal length CO2 laser focusing
system to be constructed. This enables the optimum cutting parameters to be easily established for
any laser power, beam diameter and divergence. The ZX10 is for use in conjunction with CO2 lasers
of up to 20mm full beam diameter. It may be mounted directly into a standard 1.5″ x 12TPI threaded
bulk head, or via the model ‘WMA’ water cooled mount, (with or without any of the internal
beamexpanders – depending on laser beam dia. Section 20.4). When used with a focusing lens of
focal length F, the model ZX10 allows zoom over a focal length range of F to 4F, at a fixed focal plane.
The ZX10 is a 3-element assembly in which the axial locations of two elements are changed by
operation of the zoom control ring. The ZnSe elements are made from laser grade material and
treated with ultra-low absorption anti-reflection coatings. The lenses are mounted in a rugged, black
anodised aluminium housing. At the input side of the ZX10 unit there is a male 1.5″ dia. x 12TPI
fixing thread, which enables the unit to be placed into the same location as M11-type cells, or into
FF25 or CFF25 focusing heads (Section 63.0). The ZX10 also fits directly into model WMA mount
(Section 20.3). At the output side of the ZX10 there is a female 1.5″ x 12TPI thread which accepts
M11-type cells or any of the TF or XF range of lenses.
Input aperture : 25.4mm.
Output aperture : 25.4mm (at 1:1 zoom). 6.35mm (at 1:4 zoom).
Other dimensions : Figure 20.51.
Maximum beam deviation on zoom : Within 5 minutes of arc.
Model ZX10 allows conversion of a parallel input beam of diameter ‘d’, into a parallel output beam
of diameter in the range ‘d’ to ‘d/4’. Note that the power density incident on the internal lenses can
be as high as x16 of the input power density. It is for this reason that the ZX10 plus focusing lens
arrangement is not recommended for continuous cutting use above 1000 Watts laser power. Rather,
it should be regarded as an instrument for establishing ideal cutting parameters, and replaced in
permanent use by a simpler system giving the same cutting conditions, for lasers of 1kW power or
greater. The effect of the ZX10 zoom action is the equivalent of changing the focal length of the
focusing lens, except at the same focal plane. Table 20.51 shows a range of conditions at the focus
achieved with a laser beam of 15mm diameter, 2 milliradians divergence and the ZX10 used with
a TF50 lens. The ZX10 plus the TF50 focusing lens are considered as a ‘system’ with an effective
focal length as detailed.
In addition to use as a setting-tool in high power cutting applications, the ZX10 has innumerable
applications for continuous use in lower power systems. Examples include the drilling of variable
size holes in babies rubber teats, and in plastic devices used in beer cans. The ZX10 is invaluable
in setting-up small laser systems (employing 10W and 25W waveguide CO2 lasers for example) for
processing paper, rubber, plastics, with the optimum compromise between energy density and depthof-
focus readily found at the turn of the zoom control ring.
Assist gas/nozzle fitting
The output side of the ZX10 accepts a mounted focusing lens, as detailed above, and the appropriate
GNA gas nozzle. The ZX10 does not have to withstand excess gas pressure, as it is shielded by the