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1.6
Maintenance and Inspection
In order to keep the machine operating safely, it must be inspected daily.
Maintenance requirements and procedures are to be found in the Maintenance
Manual. Details of machine warm up and spindle maintenance can be found in
the Operating Manual.
Always turn the power OFF before performing maintenance work.
1.7 Replacing Door Windows and Covers
The majority of windows fitted to Bridgeport Machining Centres are
manufactured from the GE Plastics LEXAN® range of polycarbonate sheet, with
a hardened surface coating called Margard®. The hard coating gives protection
against minor scratching. Testing over the past few years has resulted in
confirmation that the impact resistance of polycarbonate degrades over time
after exposure to the metalworking fluids and lubricants used in the
metalworking process. Although the Margard® coating provides some
protection against the cutting fluids, the polycarbonate still degrades.
For up to 10,000 rpm spindle speed, with 130mm diameter cutter.
Energy Containment - 8 mm Polycarbonate
0
100
200
300
400
500
600
700
800
0
2
4
6
8
10
Years
Jo
u
les
The diagram above is typical for an 8mm thick polycarbonate window, as fitted
to a Bridgeport Machining Centre. Given that a Bridgeport Machining Centre has
a possible maximum cutter of Ø130mm (with adjacent tool pockets empty) and
that the maximum projectile energy that the window is likely to see will be a
fractured piece from the periphery of the cutter, then using the projectile mass
of 0.1kg (as used in the Safety Standard EN12417), then the impact energy
and potential window useable life will be:
Maximum Spindle Speed
(rpm)
Projectile Energy
(Joules)
Window replacement period
(years)
8000 148
8
10000 232 6.1/2
