The Lasermet LS-20 Laser Safety Shutter is intended to provide a means of preventing accidental exposure to a potentially harmful laser beam.
It has been designed to form part of a high-integrity safety system and features a gravity-close blade and force-disconnect proving contacts. When closed, the shutter deflects the incoming laser beam onto an internal beam dump where the energy is converted to heat which is dissipated in the aluminium casing of the shutter. When the shutter is open, the laser beam passes through the shutter without interruption.
SIL Rated Version
A ‘SIL3’ version is available which, when correctly wired to a Lasermet Interlock® Control System, can provide a safety Interlock® which meets Safety Integrity Level 3 to EN61508 and Performance Level ‘e’ to EN ISO 13849-1.
Standard operation is by means of the ‘Open’ and ‘Close’ buttons on top of the shutter case. A remote switching station (LS-RS20) is available for remote operation of the shutter. Alternatively the shutter can be set to open as soon as power is applied. In all cases the shutter will close when power is removed.
Connection to Beam Tube System
The LS-20 has 16 mm diameter entry and exit apertures. These are threaded and beam tubes can be supplied to fit to the shutter case and enclose the laser beam.
Beam Shutter for High Power Lasers
The maximum average power for use with the internal beam dump is 20 W. However for higher powers the beam dump can be easily removed by unscrewing it from the side of the shutter case. Beam tubes can be fitted and the beam can be directed to a remote beam dump. This allows the shutter to be used for much higher powers, even for multi-kilowatt lasers.
Shutter Blade Options
The shutter blade is made of stainless steel which is sufficient for most applications. However, standard front silvered or dielectric mirrors can be factory fitted to the blade if required. This is generally recommended for average powers in excess of 20W when the remote beam dump option is being used. It may also be advisable when using Q-switched lasers as these can cause some minor ablation of the blade even when the average power is below 20W.
The LS-20 shutter is equipped with an M6 female thread in the base, located under the beam centreline. An anti-rotation slot is also provided in the base into which a second M6 stud should be located to prevent the shutter turning or coming unscrewed. The slot allows for posts on imperial and metric optical breadboards.
Laser Beam Power Measurement
When fitted with a mirror, the LS-20 facilitates easy laser beam power measurement. The beam dump can be removed and a laser power meter detector head fitted to the side of the shutter. In this way a power or energy reading can be obtained whenever the shutter is in the closed state.
|Max Average Power Using Internal Beam Dump||20 W||20 W|
|Max Average Power Using Separate Beam Dump||Unlimited||Unlimited|
|Aperture Diameter||16 mm||16 mm|
|Operating Voltage||24 V DC||24 V DC|
|Current Closed||30 mA||60 mA|
|Current Open||250 mA||500 mA|
|Internal Beam Dump Cooling||Convection||Convection|
|Size (mm)||98 x 65 x 37||98 x 65 x 73|
|Mass||400 g||800 g|
|Safety Integrity Level (to EN 61508)||TBA||SIL 3|
|Certified to EN ISO 13849-1|
Safety of machinery – Safety-related parts of
control systems. Performance Level as shown
|Lifetime||5 x 105 Operations||5 x 105 Operations|
LS-20 shutters are supplied with a permanently connected, 3 m long lead, terminated with a 15 pin high density D connector (male). If required this can be extended by use of one or more 3 m leads (part no. LEAD-LS20-3M)
Remote Switching Station
A remote switching station is available, allowing the shutter to be opened and closed by pressing buttons remote from the shutter itself. As well as start and stop buttons there is LED indication of ‘power on’, ‘open’ and ‘closed’. These are available in 2 types:
- Fixed (LS-RS20) – Wall mounted with shutter socket and terminals for connecting to ICS
- Floating (LS-RS20-FL) – With shutter socket and 3 m flying lead for plugging into a distribution box
Distribution Box for LS-20 Beam Shutters
These are wall mountable distribution boxes with terminals for connection to a Lasermet ICS Interlock® control system or other shutter power supply. Available with 1, 2 or 4 shutter connections.