Claims:I/We Claim

1. An aqua-air fixture for WEDM wherein the aqua-air fixture is used to machine work piece(s) in water and air atmospheric medium and comprises of
i. A base plate (1) with a thickness of 10 to 20 mm.
ii. A plurality of guide plate (2) used to provide the rest to the work piece(s).
iii. A plurality of Spacer (4) used to maintain inter layer gap between stack of work
pieces with a thickness of 0.5 mm to 5 mm.
iv. Locking nut (6) and washer (5), used to hold the spacer (4) and work pieces (3) firmly on the fixture.
v. Clamping rod (7), used to hold the guide plate (2), spacer (4), work pieces (3), locking nut (6) and washer (5).

2. The aqua-air fixture for WEDM as claimed in claim 1, wherein the guide plate (2), spacer (4), locking nut (6) and washer (5) and clamping rods (3) are mounted on the base plate (1).

3. The system as claimed in claim 1, characterizes to provision with clamping technique on a stack of work pieces during WEDM process.

4. The method as claimed in claim 2, characterizes to provide a clamping procedure of the aqua-air fixture for a stack of work pieces for material removal during WEDM process.

5. The method as claimed in claim 2, characterizes to accommodate the stack of work pieces with different thickness for WEDM process ranging from 5 mm to 200 mm.

6. The system as claimed in claim 1, characterizes to accommodate the stack of work pieces with different inter layer gaps for WEDM process ranging from 0.5 mm to 5 mm.

7. The system as claimed in claim 1, characterizes to use for eliminating the marking outs, measuring and other setting methods on the work pieces in WEDM process.

8. The system as claimed in claim 1, characterizes to:
a) Reduce the handling time and setup time of the work piece in WEDM
b) Increase material removal rate, efficiency, effectiveness, availability
c) Increase productivity, overall equipment effectiveness and profit of WEDM
, Description:Complete Specification

DESCRIPTION / STATEMENT OF INVENTION
The present invention relates with the development of an aqua-air fixture for stack cutting (i.e., cutting number of work pieces simultaneously), for wire electrical discharge machining (WEDM). This fixture accommodates the work pieces of different thickness and different inter layer gaps of stack. Through stack cutting, several technical issues must be solved to improve the material removal rate (MRR), efficiency, productivity and overall equipment effectiveness of WEDM.
FIELD OF INVENTION
Wire Electrical Discharge Machining (WEDM) is a non-conventional machining method. This method is used for machining difficult to machine materials like titanium, nimonics, zirconium, etc. This machining process is extensively used for critical manufacturing of components for aerospace, nuclear, missile, and turbine, etc. WEDM process offers an effective solution over the conventional machining method for machining complex, precise and accurate contours with intricate shapes in low volume and greater variety. WEDM process can achieve high dimensional accuracy, repeatability and high surface finish as compared to mechanical machining but at the cost of very slow machining rate. WEDM has brought a lot of research effort to increase its production rate since the inception of this technology in the year 1960. When the WEDM is applied for massive mass production, a large economic benefit can be expected but for that it is the machining rate which needs to be improved.
BACKGROUND OF INVENTION (PRIOR ART)
WEDM, in fact, is a thermal process. The high power density results in the erosion of a part of material from both the electrodes by local melting and vaporization. WEDM process is controlled by several process factors such as pulse duration, pulse interval, current, wire tension, wire feed, voltage, and many other factors that play a dynamic role on response parameters such as MRR, surface finish, hardness, and wear resistance.
Generally, a single work piece is used to cut through WEDM at a time. The present invention relates to a fixture which is used to control and ease of the machining process during stack cutting, to cut numbers of work pieces at a time (call stack cutting), so that the maximum cutting capacity of WEDM can be utilized. Through stack cutting, several technical issues must be solved to improve the MRR and efficiency of WEDM.
Fixture is a device which holds and locates a work piece on a machine. Various attempts have been made in this area of WEDM and these are discussed below.
In the prior art, U.S. Patent No. 5019219 discloses a work piece holding system that comprises opposed vises that exert a downward force on to the work piece, and the vises include dovetail recesses for holding tall or elongate work piece.
In other prior art, U.S. Patent No. 5487538 discloses a work piece holding assembly for holding a work piece that includes a rail clamp, a beveled head and a beveled rail that adjustably interconnect for mounting with machine table to hold the work piece.
In other prior art, U.S. Patent No. 5095635 discloses a positioning block for wire of NC WEDM that includes a block that is used to determine the position of the discharge wire in the coordinate system in which the table and the work piece move.
In other prior art, U.S. Patent No. 5595377 discloses a work piece presetting assembly that comprises a subassembly for precisely aligning a work piece to be worked on along predetermined axes.
In other prior art, U.S. Patent No. 6103987 discloses a retaining plate for a machine tool work piece that comprises of one opening for receiving the work piece and sections that allow for the transference of the retaining plate.
In other prior art, U.S. Patent No. 6179279B1 discloses a gripping device for holding a work piece that comprises a movable block between fixed blocks with the movable block and at least one fixed block capable of holding irregular-shaped work pieces.
Raouthor (2014) evaluate that the MRR is increasing with increasing the thickness of work piece. At the same time the surface roughness is also increasing with increase in thickness. For a thick work piece more amount of material is to be melted which requires high power. Moreover, at higher power levels the spark will jump longer causing wider cut at the cost of cutting speed. At the same time, the wire wear will be higher at higher power levels that may break the wire during machining process. The wire breakage would make a negative impact upon the machining accuracy, productivity, and stability of WEDM process. This is the main reason for limiting the work piece thickness, cutting speed and MRR of WEDM.
More particularly, the present invention relates to an aqua-air fixture for stack cutting on WEDM to cut the stack of work pieces with different thicknesses and different inter layer gaps between stack of work pieces. Several types of fixtures are known but there is no provision yet available to accommodate stack cutting with different work piece thicknesses and different inter layer gaps between stack of work pieces in water and air atmospheric medium. The limitations of the existing technologies in relation to such fixtures are more handling time due to marking, measuring and other setting methods to be applied on a work piece before WEDM cutting process and hence, the production capacity also decreases. The present invention provides an aqua-air fixture for WEDM which can be used for stack cutting either in air medium or in aqua medium and is capable to overcome the afore-discussed limitations of existing technologies in relation to such fixtures. As a result of this, the setup time associated with WEDM also reduces and this increases the MRR and production time of WEDM. The present invention will reduce the setup time and at the same time increases the efficiency, effectiveness, availability, productivity, overall equipment effectiveness and profit in a novel way.
OBJECTIVES OF INVENTION
The prime objective of the present invention is to provide an aqua-air fixture for WEDM for cutting a stack of work pieces in water and without water.
Yet another objective of the present invention is to provide the aqua-air fixture for material removal provisioned with clamping technique on a stack of work pieces during WEDM process.
Yet another objective of the present invention is to provide a clamping procedure of the aqua-air fixture for a stack of work pieces for material removal during WEDM process.
Yet another objective of the present invention is to provide the aqua-air fixture which accommodates the stack of work pieces with different thicknesses for WEDM process.
Yet another objective of the present invention is to provide the aqua-air fixture which accommodate the stack of work pieces with different inter layer gaps for WEDM process.
Yet another objective of the present invention is to provide the aqua-air fixture for stack cutting on WEDM which is used to eliminate the marking outs, measuring and other setting methods.
Yet another objective of the present invention is to provide the aqua-air fixture for stack cutting on WEDM which is capable to increase the production capacity by reducing the handling time due to quick setting and locating the work pieces.
Yet another objective of the present invention is to provide an aqua-air fixture for stack cutting on WEDM which is portable, non-expensive, manually operated and reduced labour cost.
Yet another objective of the present invention is to provide an aqua-air fixture for stack cutting on WEDM which is able to increase the MRR, productivity, overall equipment effectiveness and profit by cutting the numbers of work pieces at a time in a stack.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following drawings described herein are the features of the present invention and are illustrative for the purposes of the present disclosure, and in which:
Figure-1 illustrates the schematic diagram of the proposed aqua-air fixture for stack cutting on WEDM.
Figure-2 shows the schematic diagram of the base plate used in the proposed aqua-air fixture for stack cutting on WEDM.
Figure-3 shows the schematic diagram of the guide plate used in the proposed aqua-air fixture for stack cutting on WEDM.
Figure-4 shows the schematic diagram of the spacer used in the proposed aqua-air fixture for stack cutting on WEDM.
Figure-5 shows the schematic diagram of the washer used in the proposed aqua-air fixture for stack cutting on WEDM.
Figure-6 shows the schematic diagram of the locking nut used in the proposed aqua-air fixture for stack cutting on WEDM.
Figure-7 shows the schematic diagram of the clamping rod used in the proposed aqua-air fixture for stack cutting on WEDM.

Corresponding to the above reference, the numerals in figure-1, indicates corresponding part of the proposed aqua-air fixture throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The following is a detailed description of embodiments, to illustrate the working principles of the invention. The scope of the invention encompasses numerous alternatives, modifications and is equivalent with dimension variation. For the purpose of understanding, the embodiments in accordance with, the present invention will now be described with reference to the accompanying drawings. In the present invention, an aqua-air fixture for stack cutting on WEDM comprises of a base plate (1), a plurality of guide plates (2), at least two work pieces (3), a plurality of spacers (4), a plurality of washers (5), four locking nuts (6) and four clamping rods (7) such that the aqua-air fixture for stack cutting on WEDM is used to cut number of work pieces simultaneously through stack cutting technique during WEDM process in water or air atmospheric medium.
The figure 1 portrays the schematic drawing of assembly of the aforesaid components accompanying together to make the aqua-air fixture in which the key components define the following functions and features:
i. Base Plate (1): The base plate is that main part of the fixture on which all the parts are mounted to support for clamping the work piece. It is made of stainless steel. The thickness of base plate is used up to 10 to 30 mm.
ii. Guide Plate (2): The guide plates are fitted with the clamping rod and base plate to provide the rest to the work pieces of different size. It is also made of stainless steel
iii. Spacer (4): The spacers are fitted with the clamping rod to hold the work pieces and used to maintain inter layer gap between stack of work pieces. These spacers are completely lifted out, while unloading. It is also made of stainless steel. The thickness of spacer may very as per requirement ranging from 0.5 mm to 5 mm.
iv. Washer (5): The washers are fitted between the locking nut and clamping rod. The washers are completely lifted out, while unloading. It is also made of stainless steel.
v. Locking nut (6): The locking nut is the part of fixture mounted on the clamping rod. Its main function is to hold the spacer and work pieces firmly on the fixture. It is also made of stainless steel.
vi. Clamping rod (7): The clamping rod is the part of fixture mounted on the base plate. Clamping rod is a thread rod, used to hold the spacer to maintain inter layer gap between work pieces with the help of locking nut. It is also made of stainless steel.

In WEDM process, material is removed by electric sparks. There is no direct contact between cutting tool, i.e., wire electrode and work piece. Due to this, the involvement of cutting forces in WEDM process are negligible. Hence, no additional parts are required in the proposed fixture to accommodate the cutting forces. The locking nut and clamping rod of this aqua-air fixture as proposed in the present invention are capable enough to hold the work pieces firmly during WEDM cutting process.
Another embodiment of this invention of the aqua-air fixture is the clamping procedure on WEDM to perform stack cutting process. The method is as follows:
a) Locating and fixing the base plate of this aqua-air fixture on working table of WEDM by means of bolts and nuts.
b) Placing clamping rod at given location on the base plate of this aqua-air fixture and fix it firmly with the help of nuts.
c) Placing guide plate with the help of clamping rod at a given location on the base plate of this aqua-air fixture to hold the work piece on the fixture.
c) Placing a work piece on this aqua-air fixture and placing the spacer in clamping rod between the stack of work pieces to maintain required inter layer gap(s).
d) Fixing the stack of work pieces tightly on this aqua-air fixture maintaining required inter layer gap(s) by means of screw nuts and washers.
e) After completion of setting on this aqua-air fixture, checking the position of the work pieces and level, if required.
This present invention provides an aqua-air fixture for WEDM for cutting a stack of work pieces in water and without water. This fixture accommodates the stack of work pieces with different inter layer gaps. This invention discloses the material removal provisioned with clamping technique and procedures on a stack of work pieces having different thickness. As the present invention accommodates stack of work pieces and hence, reduces the marking, measuring and other setting time, as its offer to cut multiple job at a time. This also helps to increase the production capacity by reducing the handling time due to quick setting, locating the work pieces and cutting multiple jobs at a time. The present aqua-air fixture is portable, non-expensive, and reduces labour cost. This fixture also helps to increase the MRR, productivity, overall equipment effectiveness and profit of WEDM by stack cutting of work pieces in a novel way.