Page 27
2
DOOR INTERLOCK FUNCTION
The door interlock function is developed to ensure the operator’s safety during
machine operation.
Before starting the machine operation, make sure that the door interlock
function is valid. When the door interlock function is made valid, machine
operation is enabled or disabled in response to the closing or opening of the
machine door. Spindle rotation and all automatic operations (including ATC
operations) are inhibited when and whilst the door is open. Axes feedrate is
limited when the door is open.
Anticipated danger and possible accidents, which exist or will likely occur, are
described below. Access to the rotating cutter however, can only be possible if
the door interlock is defeated.
The following cases describe possible accident occurring in general vertical
machining centers. However, similar accidents will occur in horizontal
machining center’s or other type of machining centers.
The operator will become entangled with the spindle if the spindle starts while
the operator is touching the cutting tool.
The operator will become entangled with the spindle if the operator touches the
cutting tool while the spindle is rotating.
The accidents described above, in which the operator becomes entangled with
the rotating parts of the machine, will result in serious injury or death.
A workpiece and/or cutting tool will fly out if the cutting tool is hit against the
workpiece due to a programming error.
A workpiece will fly out if the machining (automatic operation) is started while
the workpiece is not clamped properly.
A workpiece will fly out due to excessively heavy cutting force.
The hazards described above can cause accidents in which the operator or a
person near the machine is struck by a flying workpiece or a cutting tool,
resulting in serious injury or death.
The operator or person standing near the machine will be splashed with chips
and coolant during machining, resulting in injury or health problems
(particularly if chips or coolant get into the eyes).
The operator will be caught by the table or the column during axis feed,
resulting in serious injury or death.
The operator will be injured by touching the cutting tool or tool magazine while
the ATC is operating.
The accidents described above, in which the operator is caught by or becomes
entangled with the moving parts of the machine, will result in serious injury or
death.
