Hypertherm LR2075 - Manual (Page 34)

OPERATION
LR 2075 Laser Head Instruction Manual 4-9
Focal position locations
Effective focal lengths listed in the table are for Hypertherm lenses only. The formulas in the table will help determine the
focal position for each lens and lens-bay if Hypertherm lenses are not being used.
Definitions
Lens bay location (LBL) = Location of the lens bay relative to the nozzle exit
Edge thickness (ET) =
Back focal length (BFL) = The distance from the lower edge of the lens to the focal point
Lens position (LP) = The number read off the indicator on the laser head
Effective focal
length
(Hypertherm
lenses)
Lens bay location
(LBL)
relative to nozzle
Edge
thickness
(ET)
Back focal
length
(BFL)
Lens
position
(LP)
read by
indicator
Formula
LBL - ET - BFL + = FP
Focal
position
(FP)
relative to
nozzle
5.0"
P/N 021086
114.7 mm
(4.515")
8.0 mm
(0.315")
123.4 mm
(4.858")
17.0 mm
(0.669") 114.7 - 8.0 - 123.4 + 17.0 = 0.279 mm
4.515 - 0.315 - 4.858 + 0.669 = 0.011 in
0.279 mm
(0.011")
7.5"
P/N 021087
178.2 mm
(7.015")
8.0 mm
(0.315")
187.3 mm
(7.374")
17.0 mm
(0.669") 178.2 - 8.0 - 187.3 + 17.0 = -0.127 mm
7.015 - 0.315 - 7.374 + 0.669 = -0.005 in
-0.127 mm
(-0.005")
Beam
BFL
Note: Hypertherm 1.5" lenses are rated for 20 bar (290 psi). 2.0" lenses are rated for 20.7 bar (300 psi)
Effective focal
length
(Hypertherm
lenses)
Lens bay location
(LBL)
relative to nozzle
Edge
thickness
(ET)
Back focal
length
(BFL)
Lens
position
(LP)
read by
indicator
Formula
LBL - ET - BFL + LP = FP
Focal
position
(FP)
relative to
nozzle
5.0"
P/N 021088
114.7 mm
(4.515")
8.0 mm
(0.315")
122.4 mm
(4.819")
16.0 mm
(0.63")
114.7 - 8.0 - 122.4 + 16.0 = 0.279 mm
4.515 - 0.315 - 4.819 + 0.63 = 0.011 in
0.279 mm
(0.011")
7.5"
P/N 021006
178.2 mm
(7.015")
7.9 mm
(0.310")
185.3 mm
(7.295")
15.0 mm
(0.59")
178.2 - 7.9 - 185.3 + 15.0 = 0.025 mm
7.015 - 0.310 - 7.295 + 0.59 = 0.001 in
0.025 mm
(0.001")
1.5" diameter lenses
2.0" diameter lenses