JPH0626764B2 - Machining fluid supply device for electrical discharge machining - Google Patents

Description

TECHNICAL FIELD The present invention relates to a machining fluid supply device for wire cutting or die-sinking electric discharge machining, which contains water as a main component (including the case where water is the only component).

(Prior Art) Generally, in wire-cut electric discharge machining, pure water is used as a working fluid, and also in die-sinking electric discharge machining, pure water or a water-based machining fluid whose main component is water is used as a working fluid. However, because it is necessary to reduce machining by electrolytic current at each machining stage of rough machining, medium machining, and finishing machining (super finishing machining if necessary) to improve machining accuracy,
When finishing after finishing roughing, a working fluid having a higher specific resistance than that of the working fluid used in the conventional roughing must be used. Conventionally, since the machining liquids having different specific resistances are supplied to the machining section, the specific resistances of the machining liquids stored in one machining liquid tank progress to rough machining, medium machining, finishing machining and machining. The processing liquid is passed through an ion-exchange resin to perform ion-exchange processing so that it increases every time.
A working fluid having a specific resistance suitable for the purpose of working is sequentially generated and used.

In addition, electric discharge machining in recent years has become faster and more accurate,
In particular, along with the progress of electronics, it is being utilized for ultra-precision die making, and it is usual to use cemented carbide for the punch and die of this seed die. When machining is performed by electric discharge machining using a machining fluid, the electrolytic corrosion of the binder Co of the cemented carbide progresses, the machining accuracy is low, the quality of the machined product is poor, and the strength of the part that becomes the cutting edge decreases, There is a problem of shortening metal life due to chipping and the like. As a solution to this problem, such as modifying the power supply from capacitor discharge type to transistor type,
Measures to prevent electrolytic action have been taken, but it is known that electrolytic corrosion decreases, especially when the resistivity of the working fluid is raised, and it is known to be effective. In the case of shifting to the above processing, a working fluid having a specific resistance suitable for the processing of the cemented carbide was sequentially generated and used.

(Problems to be solved by the invention) Since it takes a long time to process a working fluid using the ion exchange resin, in the case of progressive processing such as rough processing, intermediate processing and finishing processing, the processing steps are performed between the respective processing steps. Therefore, it takes time to process the working fluid by ion exchange, which causes a problem that the conventional apparatus takes a long working time and the working cannot be performed efficiently. In the above, the processing liquid treatment time by ion exchange requires a longer time in the region where the specific resistance is higher, so that it takes time to set up the finishing process.

Further, the working fluid, for example, a working fluid for ordinary workpieces such as machining tool steel, that is, a working fluid with a relatively low specific resistance to a working fluid with a high specific resistance for cemented carbide machining,
In the case of a normal processing liquid supply tank, as preparation before starting processing,
The adjustment operation for 1 to 5 hours or more was required to adjust the working fluid, and the work efficiency was extremely poor.

(Means for Solving Problems) The present invention aims to solve the above problems. In order to achieve this object, the present invention comprises a plurality of zones in a machining fluid supply device that circulates an aqueous machining fluid used for die-sinking EDM or wire-cut EDM to a machining section. A machining fluid tank, a machining fluid recovery conduit that collects used machining fluid from the machining section, filters it with a filter, and collects it in a predetermined area of the machining fluid tank, and ion-exchanges each machining fluid in the multiple areas. A processing liquid circulation purifying device that makes contact with a resin to adjust the resistance value to a predetermined specific resistance value, and a pipe that connects each of the areas to a processing portion via a valve, and a desired one of the plurality of areas. A supply device for pumping the working fluid in the zone to the working part is provided, and further, the openings are communicated with the side walls of the respective zones so that the working fluid flows between the zones. Opening and closing means for opening and closing the communication part Characterized by comprising Te.

(Operation) Depending on the required specific resistance value of the working fluid, the communication part between the adjacent areas is appropriately opened by the opening / closing means, and the working fluid in the storage tank of the used working fluid is flowed to sequentially communicate with each other. Mix with the working fluid whose specific resistance value is adjusted to a higher value in the latter area, and supply the working fluid mixed and adjusted to the specified specific resistance value to the working part from the last area in the communicating state. By doing so, the adjustment and generation of the working fluid having the specific resistance value required depending on the progressing stage of processing or the type of the work piece can be performed quickly, and the processing liquid adjusted to the predetermined specific resistance value can be processed. The liquid is supplied to the processed portion in a stable state in which the specific resistance value does not fluctuate.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings by taking an example of die-sinking electric discharge machining. In the drawings, 1 is a processing table having an X, Y positioning mechanism, 2 is a processing tank installed on the processing table, 3 is a workpiece fixed in the processing tank 2, and 5 is a processing electrode, The processing part where the work piece 3 and the processing electrode 5 face each other with a very small gap therebetween is immersed in the water-based processing liquid 4 in the processing tank 2, and a voltage pulse is applied between the both 3 and 5 to repeatedly generate electric discharge. At the same time, electric discharge machining is performed by giving a machining feed in the opposite direction.

Reference numeral 6 denotes a working liquid tank, and the working liquid tank 6 is divided into a plurality (four in this example) of areas A1 to A4 by a partition member 7. The used working fluid is introduced by the pump 9 via the recovery pipe 10 having the filter 8 or by overflow. There may be a case in which a used processing liquid receiving tank is provided between the processing liquid tank 6 and the processing tank 2, and the used processing liquid is pumped up from the receiving tank and circulated to the processing liquid tank through a filter. .

The processing liquid in each area is sent to each of the areas A1 to A4 by the pumps 14A, 14B, 14C, 14D to the purification circulation paths 15A, 15B, 15C, 15D, and the ion exchange resins 13A, 13B, 13C, 13D. Provided with a machining fluid circulation purification device that contacts with and adjusts to a predetermined specific resistance value.
Each partition member 7 is provided with opening / closing plates 16A, 16B, 16C that enable the flow of the working fluid between the adjacent areas, and the working fluid supply pipe 11 corresponds to each of the areas A1, A2, A3, A4. Branch pipes 11A, 11B, 11C and 11D having valves 17A, 17B, 17C and 17D, respectively, are provided, and these are collectively connected to the processing tank 2 into one pipe 11 having a pump 12.

In this configuration, in the case of rough machining requiring a relatively low resistivity, the opening / closing plates 16A to 16C are kept closed, only the valve 17A of the valves 17A to 17D is opened, and the pumps 14A to 14D are Operate and pump 9,12
Is operated to feed the processing liquid to the processing tank 2 while purifying the processing liquid in the area A1, while the other areas A2 to A4 are supplied.
The machining fluid of (1) is also purified in advance so as to have a predetermined specific resistance value in accordance with the machining in the next process.

Further, in the case of medium processing or finishing that requires a processing liquid having a higher specific resistance, only the opening / closing plate 16A (or the opening / closing plates 16A and 16B) is opened and the opening / closing plates 16B and 16C (or the opening / closing plate 16C) are closed. Leave it open, valves 17A-17D
Of these, open only 17B (or 17C), pump 1
4A to 14D are operated and pumps 9 and 12 are operated so that the working fluid flows from the zone A1 to A2 (or from the zone A1 to A2 and then to A3), and is mixed. Supply to the processing tank 2 via the valve 17B (or 17C). In this case, since the working fluid in the areas A2 and A3 has already been purified, the specific resistance of the mixed working fluid becomes high, and the working fluid having a desired specific resistance can be immediately obtained. Further, when a working liquid having a higher specific resistance is required as in the case of super finishing, the opening / closing plate 16A to
16C are all opened, and among valves 17A to 17D, 17C
By opening only D, actuating pumps 14A-14D and actuating pumps 9,12, sections A1-A
The processing liquids of No. 4 are mixed and supplied to the processing tank 2. In this case, a working fluid having a higher specific resistance can be obtained, and the waiting time becomes extremely short.

In addition, in the said Example, although one processing liquid tank 6 was divided | segmented by the partition member 7 and the area A1-A4 was formed, each area A1-A4 is formed by each individual container, and each adjacent individual container is formed. As a means for connecting the individual containers by connecting the openings provided on the side wall with a pipe and opening and closing the communication part,
Instead of the opening / closing plates 16A to 16C, a valve may be provided in the connecting pipe to form an openable / closable communicating portion for mixing.

(Effects of the Invention) As described above, according to the present invention, the working fluid tank is composed of a plurality of areas, and the used working fluid collected from the working portion and filtered through the filter is collected in a predetermined area of the working fluid tank. In addition, a machining fluid circulation purification device that adjusts the specific resistance value to each of the machining fluids in each zone by ion exchange treatment is provided, and machining fluids can flow through the side wall openings between zones. Since there is a freely openable and closable communication part, the specific resistance of the working fluid in each area should be adjusted to a predetermined specific resistance value in advance, and the ratio required depending on the progress of the working stage or the type of workpiece. Depending on the resistance value, the openable and closable communication parts provided between the areas are appropriately opened, and the working fluid in the used working fluid storage tank (area A1) is sequentially communicated with the latter-stage area A2.
~ A4 and mixed with the working fluid in which the specific resistance value is adjusted to be higher than that in the relevant area, and the working fluid mixed and adjusted to a predetermined specific resistance value in this manner is fed from the final stage area in the communicating state. By pumping with a pump and supplying it to the machining unit, it is possible to quickly adjust the machining fluid with the required higher specific resistance value in a short waiting time, and at the same time, adjust the machining fluid with a specific resistance value to a specific resistance. The value can be supplied to the processing part in a stable state with little fluctuation, and stable and efficient processing can be performed.

[Brief description of drawings]

 The drawings are device configuration diagrams showing an embodiment of the present invention.

Claims (1)

[Claims] 1. A machining fluid tank comprising a plurality of areas in a machining fluid supply device for circulating and supplying an aqueous machining fluid used for die-sinking electric discharge machining or wire cut electric discharge machining to a machining section,
A working fluid recovery conduit for collecting used working fluid from the processing unit, filtering it with a filter and collecting it in a predetermined area of the working fluid tank, and contacting each working fluid in the plurality of areas with an ion exchange resin. A working fluid circulating and purifying device that adjusts each to a predetermined specific resistance value, and a working fluid in a desired area of the plurality of areas that has a pipe that connects each of the areas to a processing unit via a valve. And a supply device that supplies the processed liquid to the processing unit by pumping it, and further, an opening is provided in the side wall of each of the above-mentioned regions to allow adjacent regions to communicate with each other to allow the flow of the processing liquid between the respective regions. A machining fluid supply device for electric discharge machining, comprising an opening / closing means for opening / closing the communication part.