Beam Protection Ducting Page - Renishaw HS20 Installation Manual

Beam protection ducting
Fundamental to the reliability of position feedback is that a stable, accurate laser alignment needs to
be maintained along the full axis length. Alignment stability can be affected by temperature gradients
formed through the beam; these are usually caused by rapidly changing environmental conditions.
Temperature gradients across the beam cause fractional changes in wavelength through the cross
section of the beam, with the warmer side of the beam having a fractionally longer wavelength than
the colder side. The resultant effect is "beam bending" and, ultimately, misalignment.
These gradients can vary slowly or quickly as a machine's environment changes in response to a
change, such as a door opening, a heater switching on, or sunlight shining on the machine.
The HS20 beam protection ducting system protects against the formation of thermal gradients by
including an "air feed" system that stirs the air over the entire axis length. It also acts as an effective
protection from swarf, oil and other contaminants usually found in machine tool applications.
For full details please refer to the HS20 beam protection ducting manual, a summary is given below.
The HS20 beam protection ducting system is based upon a standard extrusion supplied in 3 m
lengths. To provide application flexibility, this extrusion can be mounted by either of two methods: with
standard brackets, a cross section of 155 mm x 121 mm is required along the axis whereas, with low
profile brackets, the required section is reduced to 118 mm x 121 mm. The extrusion was designed
primarily for use with long-range optics, but is also suitable for standard optics.
Note: Do not fit any ducting to the machine before aligning the HS20 laser heads
M-8003-4073 Support bracket
M-8003-4071 Main body
A-8003-4288 Air connector
Figure 14 – HS20 beam protection ducting assembly drawing
A-8003-4289 Joint cover assembly
M-8003-4397 Duct alignment slide
M-8003-4098 End cover plate
M-8003-4069 Cover extrusion
P-TL50-0015 Brush strip
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