Abstract

The objective of this project is to design creating a 3D model & analyze a WIRE CUT JIG used for production of Turbine Parts using CAD & CAE.

Initially the turbine parts are formed in press tool in two stages. After that the parts moved to wire cut to achieve required shape by cutting excess material.

In our organization, the fixture was used to wire cut for the turbine parts. But the fixture consumes lots of time for wire cutting, so the fixture is replaced by Jig to improve productivity & quality in minimum time.

Now the turbine parts are wire cut by using the Jig in production. Further some of operations like milling, grinding, buffing & engraving are done as per the requirement to produce the final part & that can be dispatched to customer.

The concept design & project drawing in project will be done using Auto CAD. The modeling of Assembly & Details of the jig is done by using Solidworks & the analysis of the jig is done by using Ansys.

Introduction to Wire Cut Jig

JIGS & FIXTURES:-

A fixture is a special tool used for locating and firmly holding a work piece in the proper position during a manufacturing operation. As general rule it is provided with devices for supporting & clamping the work piece. In addition, it may also contain devices for guiding the tool prior to or during its actual operation. Thus, a JIG is a type of fixture with means for positively locating, guiding and supporting tools for drilling, boring and related operations.

What is wire cut machining? :-

In wire-cut machining also known as wire electrical discharge machining (Wire EDM) thin single-strand metal wire, usually brass, is fed through the workpiece, submerged in flowing dielectric fluid, typically deionized water. Wire-cut EDM is typically used to cut plates as thick as 300mm and to make punches, tools, and dies from hard metals that are difficult to machine with other methods. The wire, which is constantly fed from a spool, is held between upper and lower diamond guides which is centered in a water nozzle head. The wire EDM usually CNC-controlled, move in the x–y plane.

Component details (workpiece) :-

In our organization Turbine parts are manufactures. These parts are used as holders in turbines.

What is Wire Cut Fixture :-

Wire cut fixture is a component holding device which holds the component on wire EDM. First the wire cut fixture is placed on machine bed & clamped at required position.

What is Wire Cut Jig :-

Wire cut jig is component holding device but it also guides the component & locate the component in required position as per cutting tool movement. Jig also clamped to the wire cut machine bed but we change its cutting position without de-clamping the jig.

The component detail shown below

Before wire cut component:-

This component initially formed in two stages of press tools & moved to wire cut process.

After wire cut component:-

In wire cutting process both ends radii to be cut i.e. R25.00 & slots to be cut at both ends shown in detail B. Refer below drawing.

Wire EDM using Fixture

In wire cutting process there are four settings to complete one component.

Wire EDM process using fixture showing in below pictures

First setting (Right side R25.00):-

In this process first clamp the component to the fixture. Component should be clamp at the center of fixture by using vernier caliper. Then clamp the fixture by using oblong slot clamp on wire cut machine bed. After that take the reference of fixture & start the program to wire cut at end.

Second setting (Left end R25.00):-

In this process de-clamp the fixture from first setting position & again clamp at another side of bed as shown in below. Then start wire cutting at another end by taking reference of fixture.

Third setting (Left end slot):-

In this process de-clamp the fixture and rotate the fixture in 90° for slot cutting and again clamp at same side of the bed as shown in pic. Then take the reference of fixture & start the wire cut for end slot.

Fourth setting (Right end slot):-

In this process de-clamp the fixture from third setting & clamp the fixture at another side as shown in pic to cut another end slot of component. Take the reference of fixture & start the wire cut program to cu end slot.

Purpose to design JIG

Now, we can observe the wire cut process using fixture is time taking due to again & again clamping and de-clamping actions, fixture reference taking in every settings individually. Handling of fixture is hard to move one side to another side.

Because of this type of complicated process the fixture can not use for mass production.

Based on this points we decided that the process should be simplify by modifying the process or design some other device to handle the component on machine bed easily i.e. WIRE CUT JIG

The fixture is to be designed for below given objectives:-

Main objective of the jig is to improve the productivity with high quality.
To minimize the cycle time in mass production.
To avoid the repetitive clamping and de-clamping actions.
To avoid individually reference taking for individual component.
Handling or moving of the component should be easily done.
To control position of component easily for every component.
No need to change the program again & again.
Initial clamping of component to center of the holder (jig) should be done easily.
To minimize human fatigue factor in work.

Concept of WIRE CUT JIG

Wire cut machine details:-

Before going to estimation drawing of wire cut jig we have to study about the wire cut machine bed & we have to prepare the estimate design of machine bed.

So, EZEE CUT HNXG machine is used for this component. In this process Wire movement in X direction is 300mm & in Y direction is 400mm.

Machine bed details are given in below drawing-

Estimation drawing of JIG:-

Now, we are going to design the jig by considering the wire cut machine bed.

In this jig the guiding block is designed as per the bed resting block.

The jig movement must be in between 650mm in Y direction.

The component ends must be locate in between 300mm in X direction & 400mm in Y direction.

Assembly Drawing of Wire Cut Jig

Details of WIRE CUT JIG

Component holder:-

This element holds the component therefore it is called as component holder. Two slots are present in this element to slide in linear direction on guiding block. This two slots are in 90° to each other. One of this is for component end radii cutting & another is for end slot cutting. There are also two guide holes present on this element. These holes are for guiding of locating pins. Some tap holes & relief holes are also present in this element for clamping purpose.

Manufacturing process of the component holder is given below:-

First we got the raw material size of 210mm length, 95mm width & 90mm thick.

This raw material block go for milling & grinding to achieve finished block size. Then it moves to jig boring process to drill & bore the tap holes or relief holes which present in the element. After that it moves to CNC machining. For CNC machining the model is to be created & convert into IGES file format by this file CNC program can be created in MasterCAM or UGCAM & apply for machining. Then we got the complete manufactured element of the JIG i.e. component holder.

Material selection:-

Component holder is continuously slide on guiding block so frictional force is continuously applying on this element. And the pins also continuously acting in holes. To prevent from this type of frictional forces the material should be hard for this element. So, we are using EN353 material (medium carbon steel) for this element.

Heat treatment is to be done for this element to increase its life. Heat treatment is done at 50-52 HRC.

Guiding block:-

This element guides the component holder, therefore it is called as guiding block. In this element two counter bored oblong slots are provided at both extreme ends. These slots are provided to clamp the guiding block to machine bed. A slot is provided at center of the guiding block on its edge for X-Y reference taking purpose before machining. The slot size is 6mm X 6mm as shown in fig. another for slots are there in guiding block to lock the component holder with the help of locating pin. Two slots which are on opposite side of reference slot edge is for control the first setting & second setting location And remaining two slots which are on same edge of reference slot is to control the third setting & fourth setting location. There are four tap holes are in guiding block to clamp the component holder while machining.

Manufacturing process of guiding block:-

First we got the raw material size of 660mm length, 50mm width & 50mm thick.

This raw material block go for milling & grinding to achieve finished block size. Then it moves to jig boring process to drill & bore the tap holes or relief holes which present in the element. After that it moves to CNC machining. For CNC machining the model is to be created & convert into IGES file format by this file CNC program can be created in MasterCAM or UGCAM & apply for machining. Then we got the complete manufactured element of the JIG i.e. guiding block.

Material selection:-

Guiding block is used for mass production so it is in continuous use that means the component holder is continuously sliding on this element so wear & tear can happen due to frictional force & the weight of the component holder is more so the guiding block tends to bend due to component holders weight. While selecting material for guiding block we have to consider all factors to prevent above problems. So, D3 (high carbon high chromium tool steel) material is used for the guiding block. Heat treatment is to be done to increase its life & function ability. Heat treatment is done at 56-58 HRC.

Locating pin 1 & 2:-

This element is used for controlling the location of component, therefore it is called as locating pin. This element is in cylindrical shape shown in pic. This pin is inserted in component holder. A spring is inserted into the pin & rested on the bigger cylindrical portion of pin for self-locking purpose and this subassembly is hold by collar & the collar is clamped to the component holder. Top portion of the pin is for pulling the pin by hand. Bigger cylindrical portion is for guiding the pin in hole present in component holder. Bottom portion of the pin is to lock the linear movement of the component holder by falling in the slot of guiding block.

Working of the pin:-

Initially the pin is locked in one of the slot present in the guiding block. Pull & hold the pin & move the component holder in then leave the pin after little distance to unlock the linear movement of the component holder. In this condition the pin is placed on guiding block surface & slides with component holder until the pin get slot of guiding block which is at another side. Locating pin 1 & locating pin 2 both of the functions are same. Only the difference is locating pin works in end slot cutting condition & locating pin 2 works in end radii cutting condition.

Manufacturing process of locating pins:-

First we get the raw material for this element size of cylindrical diameter is 22mm & length is 110mm for locating pin 1 & diameter is 22mm & length is 90mm for locating pin 2. These raw materials are moved to cylindrical grinding process, in this process facing & turning operation are done. First we achieve finishing sizes of the pins i.e. Ø17mmX104mm (locating pin 1) & Ø17mmX88mm (locating pin 2). Then start the step turning as per the final element shown in pic.

Material selection:-

This elements tends to break due to spring force on bigger cylindrical portion & also tends to wear tear due frictional force at the bottom surface of the pin & it reciprocate in component holder. We have to select suitable material to prevent above problems. So EN353 (medium carbon steel) material is used for these elements. Heat treatment is to be done at 45-50 HRC for these elements to increase the life.

Pivot pin:-

This is a smallest element in this jig. It is used to pivot the stopper at the corner of component holder, therefore it is called as pivot pin. It is simple cylindrical element placed at corner hole of the component holder though stopper. It allows to rotate the stopper to fix the component at center. Then stopper is closed by rotating through pivot pin while machining.

Manufacturing process:-

First we get the raw material size of 10mm in diameter & 30mm in length. It moves cylindrical grinding process to achieve final element. Or we can use the standard size of dowel for this function.

Material selection:-

We can use Mild steel for this because there are no any heavy forces are applied on this element. Better we use the standard dowel pin.

Strip clamp:-

This element is small strip shaped pieces used for clamp the component on component holder, therefore it is called as strip clamp. It is simple rectangular element contains relief hole to allow the screw to fit the component holder. The only function of this strip clamp is to clamp the component to the component holder. In this jig two clamps are used.

Manufacturing process:-

First we get the raw material size of 35mm in length, 25mm in width & 6mm in thickness. It moves to grinding & milling process for to achieve finished size.

Then it moves to jig boring operation to make a relief hole in the clamp. So, we get the final element.

Material selection:-

This element is not critical & there is no any kind of forces are applied on this element. So we can use any soft material for this like Mild Steel. Heat treatment is not necessary for this.

Collar:-

This element is used to hold the spring which is in locating pin & the locating pin’s neck inserted in this element at its middle slot therefore it is called as collar. This element is used for clamping purpose but it is permanent clamp. It is also a simple rectangular shaped element in which two relief holes are there to clamp this to component holder using screws & one slot is there at middle to insert locating pin. Two collars are used in this jig to hold two locating pins at each side.

Manufacturing process:-

First we got the raw material size of 65mm length, 32mm width & 10mm thick.

This raw material blocks go for milling & grinding to achieve finished block size. Then it moves to jig boring process to drill & bore the relief holes which present in the element. After that it moves to wire cut machining to cut middle slot. For wire cut machining we need to convert the CAD file in DXF. Before machining wire cut path program will be created & the program will be apply for machining. Then we got the complete manufactured element of the JIG i.e. Collar.

Material selection:-

This element is not critical & it is only for holding purpose. There is no any heavy forces are applied on this element. So we can use any soft material for this like Mild Steel. Heat treatment is not necessary for this.

Stopper:-

This element is used stop the component while clamping to fix at center of the component holder, therefore it called as stopper. This is ‘L’ shaped element in cross section. A hole is provided at its end to pivot this to component holder with the help of pivot pin for opening & closing purpose. The stopper opens while clamping the component to align the center & the stopper close while machining. The end surface is semicircle shaped as shown in pic to rotate in slot present in component holder.

Manufacturing process:-

First we got the raw material size of 160mm length, 25mm width & 20mm thick.

This raw material block is moved to milling & grinding to achieve finished block size. Then it moves to jig boring process to drill & bore the hole which present in the element. After that it moves to CNC machining to make ‘L’ shaped cross section. For CNC machining the model is to be created & convert into IGES file format by this file CNC program will be created in MasterCAM or UGCAM & apply for machining. Then we got the complete manufactured element of the JIG i.e. stopper.

Material selection:-

It is one of the critical element in jig because it decides the center of the component. It is overhanging when it is in open condition so it can cause bend in component. It has rotating function in so there is presence of frictional force in between pin & stopper & component holder. To avoid above problems we have to select suitable material to prevent from bends and wear & tear. So, EN353 material used for this element. Heat treatment is to be done at 45-50 HRC to increase its life.

Spring:-

Spring is also important element in this JIG. There are two springs are used for each locating pin. The locating pin reciprocates with due to this spring force to lock the location.

Spring selection:-

Springs are selected form spring manual where we can get standard & suitable size of springs. Our stroke length is 12mm by considering this we have to select the spring. Spring should be light loaded. The gap 43mm where spring is placed so have to select 45mm of free length of the spring to maintain the spring in little compression condition before locking. The wire diameter of the spring is 1.5mm & no. of coils of the spring is 8. Outer diameter of spring should be 16mm then it can be inserted in locating pin from its top & the whole spring & locating pin subassembly will be inserted in diameter 17mm hole.

Wire EDM with JIG

In this process two settings to be done to complete on component. First the guiding block is mounted on the machine bed & the block will be adjust in Y Axis by dialing with the help of dial indicator then clamp the guiding block to the bed. Then mount the assembled component holder with all remaining elements on guiding block. Now the jig & on machine bed is ready take the reference for X-Y direction to start the machining.

First setting left position:-

In first setting, the component is clamped at the center of component holder by using stopper. Move the component holder to the left position until the locating pin fall into slot present in guiding block. After locking the position clamp the component holder to guiding block with screws.

Now, first take the reference of the middle slot of the guiding block to make X-Y direction origin from where the wire start its cutting position. Then will follow the program which given to the machine for this component.

Now start the wire cutting for R25.00mm at right end of the component. After complete cutting of the arc of left end don’t abort the program just halt (pause) the program because the program is not completely performed.

First setting right position:-

Now the program is in halt condition, first de-clamp the so move the component holder by pulling the locating pin & make sure the cutting wire will not be disturbed while moving the component holder. The locating pin falls in slot which at right of the guiding block to lock the another position to cut another end of the component i.e. R25.00mm.

Then continue the program to cu another R25.00mm. After cutting of component in this position again halt the program & don’t abort because program is not completed.

Note - Make sure the stopper is in closed condition before start the machining otherwise the wire will cut the stopper.

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