Special Information - ALFRA ROTABEST 80SP Manual De Instrucciones

SPEciAL inFORmATiOn On hAndLing SwiTchABLE
PERmAnEnT mAgnETS
The magnetic surface is located on the underside of the magnetic core drilling machine and generates the
magnetic holding force through magnetic flux when activated. The magnet can be activated independently
from the mains voltage by pressing the lever down. For the magnet to be released, the black safety tab
must be pushed by using the ball of your thumb and pulling the lever upwards. The machine will remain
attached to the workpiece even in the event of a power failure.
material thickness
The magnetic flux of the TML permanent magnet requires a minimum material thickness of 8 mm (appox. 0.315
inches) to flow completely through the workpiece. If this material thickness is not given, the maximum holding
force is reduced in accordance with the material thickness. Conventional electric or permanent magnets have
a deeply penetrating magnetic field similar to a tree ́s tap roots, and require a large material thickness of
more than 25 mm (appox. 0.984 inches) to achieve the maximum holding force. The compact magnetic field
of the TML magnets is similar to a shallow root and achieves maximum holding force even with low material
thicknesses, so that drilling can be done with sufficient holding force even on thin sheets from only 3-4 mm
(appox. 0.118 to 0.157 inches).
material
The load-bearing capacity of the permanent magnets is determined using S235 material. Steel with a high
carbon content or whose structure has been changed by heat treatment has a low holding force. Foamed
or pore-flawed cast parts also have a lower holding force.
material
Unalloyed steel (0.1-0.3% C content)
Unalloyed steel (0.3-0.5% C content)
Cast steel
Grey cast iron
Nickel
Stainless steel, aluminium, brass
Surface quality
If an air gap is created between the magnet and the work piece it reduces the holding force. In the same way,
paint, rust, scale, surface coatings, grease or similar substances all form an air gap between the work piece and
the switchable magnet, reducing the holding force.
Temperature
The high-power permanent magnets installed in the TML-magnet irreversibly lose their magnetic
properties at temperatures preceding 80°C (176°F). The full holding force is never reached again even after
the magnets have cooled down.
magnetic force in %
100
90-95
90
45
11
0
15