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3. Overview, functional description
3.5.3 Automatic illing pump
Drilling operations with increasing bor-
ing depth encounter increasing difficul-
ties transporting the required amount of
lubricant to the edges of the tool because
the increasing borehole depth impedes the
aerosol flow. A declining air flow rate simul-
taneously leads to reduced aerosol generation
due to unfavorable internal pressure condi-
tions.
Active bypass valve control counteracts this
dynamic.
The aerosol flow is divided by a Y-piece at
the end of the aerosol line, as close as pos-
sible to the tool spindle.
The divided aerosol flow is transported
to the tool via a spindle as well as via the
bypass valve either back into the refilling
reservoir or into the customer’s exhaust air
system.
During operation, the bypass valve is
opened and closed according to the prevail-
ing pressure conditions in the MQL system.
The result is uniform aerosol generation and
supply to the tool across the entire drilling
operation.
Lubrication program number 50 is used to
activate the controlled bypass (bypass valve).
The maximum amount of aerosol at the tool
is achieved at the maximum permissible
inlet pressure of 10 bar.
Automatic control of the bypass valve in
machining processes on tools that generate
an unfavorable pressure ratio in the aerosol
reservoir (for example, at a small diameter
of < 5 mm) provides increased aerosol
quantity and consistency.
Pressure sensors (P1/P2) integrated in
the UFD10-X-1XXXX provide the usable
signals.
The MQL systems can be equipped with
self-priming filling pumps.
This pump allows for refilling of the lubricant
supply inside the aerosol generator from a
refilling reservoir supplied by the customer
(SKF reservoir according to customer re-
quirements). The pump is switched on and
off by the control unit of the MQL system.
There are two ways to activate the pump:
Either through a command from the machine
tool via PROFIBUS or PROFINET, or through
the control unit’s automatic mode.
The option to be used is set manually by
means of DIP switches in the MQL control
unit.
See also Chapter 3.6
3.5.4 Automatically controlled bypass valve – bypass control
3.5.4.1 Usage and principle of operation
See Figures 12/13 or 20/21
