Wire electric discharge machine having estimation function for filter replacement timing

Patent metadata

Field	Value
Publication number	US-10179368-B2
Application number	US-201514874727-A
Country	US
Kind code	B2
Filing date	Oct 5, 2015
Priority date	Oct 6, 2014
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

A wire electric discharge machine has a function of estimating the time for replacement of a filter based on a use situation for the machine. A time Tr during which the filter is serviceable is calculated according to an equation, Tr=|(Pd−Pn)/ΔP|, based on a fluid pressure variation amount ΔP, a current filter fluid pressure Pn, and a filter life pressure. A remaining available time Td for the filter which takes into account the operation rate of the machine is calculated according to an equation, Td=Tr/W.

First claim

The invention claimed is:

1. A wire electric discharge machine configured to perform electric discharge machining while jetting a machining fluid, the wire electric discharge machine comprising:
a filtration device having a filter configured to filter machining chips discharged by the electric discharge machining;
a fluid pressure detection unit disposed in a filter pipe through which the machining fluid is supplied to the filter, and configured to detect a fluid pressure of the machining fluid;
a database storing fluid pressure variation amounts of the filter per unit time together with correlated machining conditions, machining material, machining thickness, wire diameter, wire material, and machining fluid quality;
a fluid pressure variation amount acquisition unit configured to acquire a current fluid pressure variation amount per unit time from the database, based on a current machining condition, machining material, machining thickness, wire diameter, wire material, and machining fluid quality;
a remaining available time calculation unit configured to calculate a remaining available time during which the filter is serviceable, based on the acquired current fluid pressure variation amount per unit time acquired from the database, the current fluid pressure detected by the fluid pressure detection unit, and an upper limit value of the fluid pressure at which the filter is serviceable;
a remaining day/hour calculation unit configured to calculate the number of remaining days and hours before the life of the filter is expired, based on the operation rate of the wire electric discharge machine, the remaining available time acquired by the remaining available time calculation unit, and a current date/time; and
a display unit configured to display the calculated number of remaining days and hours.

2. The wire electric discharge machine according to claim 1 , wherein
the database includes coefficients for the fluid pressure variation amount per unit time for each combination of the machining conditions, machining material, machining thickness, wire diameter, wire material, and machining fluid quality, and
the wire electric discharge machine further comprises a fluid pressure variation amount calculation unit configured, in response to a change of any of the data including the machining conditions, machining material, machining thickness, wire diameter, wire material, and machining fluid quality, to calculate the fluid pressure variation amount of the changed data per unit time, based on a ratio between the coefficients for the fluid pressure variation amount per unit time before and after the change and the fluid pressure variation amount per unit time before the change.

3. The wire electric discharge machine according to claim 1 , wherein the fluid pressure variation amount of the filter per unit time is changed based on the current fluid pressure.

4. The wire electric discharge machine according to claim 1 , wherein the fluid pressure variation amount of the filter per unit time is changed based on a flow rate of the machining fluid which passes through the filter.

5. The wire electric discharge machine according to claim 1 , wherein the machining conditions include at least one of an electric discharge condition, a jet condition, and a number of machining cycles.

6. The wire electric discharge machine according to claim 1 , wherein the fluid pressure variation amount per unit time, obtained when the machining condition is changed from A1 to A2, is
α1×(ε2/ε1),

where A1 is a first machining condition;
A2 is a second machining condition;
ε1 is a first coefficient for the first machining condition A1;
ε2 is a second coefficient for the second machining condition A2; and
α1 is a fluid pressure variation amount per unit time for the first machining condition A1.

7. The wire electric discharge machine according to claim 1 , wherein the remaining available time Tr during which the filter is serviceable is calculated according to an equation,
Tr =|( Pd−Pn )/Δ P|,

where
ΔP is the current fluid pressure variation amount per unit time,
Pn is the current fluid pressure, and
Pd is the upper limit value of the fluid pressure at which the filter is serviceable.

8. The wire electric discharge machine according to claim 1 , wherein
the calculations and the display are performed periodically or when machining situations, fluid pressure, and flow rate are changed so that the calculations and the display correspond to changes of the machining situations, fluid pressure, and flow rate.

Assignees

• Fanuc Corp

Inventors

• Nishikawa Ryou
• Takahashi Shouji

Classifications

• C02F1/008

  Control or steering systems not provided for elsewhere in subclass C02F · CPC title

• B23H1/10 Primary

  Supply or regeneration of working media · CPC title

• B23H1/00 Primary

  Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric · CPC title

• C02F2209/445

  Filter life · CPC title

• B01D35/143

  Filter condition indicators · CPC title