Die Casting- Report

STUDY OF DIE CASTING MOULD BASEMANUFACTURING PROCESSA project report submitted to

Jawaharlal Nehru Technological University,

Hyderabad

In the partial fulfillment for the award of Degree of

BACHELOR OF TECHNOLOGY IN

MECHANICAL ENGINEERING

Submitted by

SHAIK ABDUL LATHUEF

A. SHO BAB K. NARASIMHA KASYAP SAI

R. ANAND BABU S. VENKATA REDDY

Under the esteemed guidance ofMrs. S. C. SHIRISHA (M.Tech) Mr. RAVI KUMAR

(Associate Professor) (Managing Director)

BATCH: 2005-09DEPARTMENT OF MECHANICAL ENGINEERING

QIS COLLEGE OF ENGINEERING & TECHNOLOGY

An ISO: 9001 – 2000 Certified Institution

(Affiliated to Jawaharlal Nehru Technological University, Hyd.)

VENGAMUKKA PALEM – 523 272, A.P.

QIS COLLEGE OF ENGINEERING & TECHNOLOGY

An ISO: 9001 – 2000 Certified Institution

(Affiliated to Jawaharlal Nehru Technological University, Hyd.)

VENGAMUKKA PALEM – 523 272, A.P.

DEPARTMENT OF MECHANICAL ENGINEERINGCERTIFICATE

This is to certify that the project entitled

“STUDY OF DIE CASTING MOULD BASE MANUFACTURING PROCESS” is a bonafied

work of the following final B.Tech., students in the partial fulfillment of the

requirement for the award of the degree of Bachelor of Technology in

MECHANICAL ENGINEERING

for the academic year 2008-09.

SHAIK ABDUL LATHUEF

A. SHO BAB K. NARASIMHA KASYAP SAIR. ANAND BABU S. VENKATA REDDY

Signature of guide Signature of Head of Department S.C.SHIRISHA Prof.C.V.SUBBA RAO

Associate professor M.E., MISTE.,

Signature of PrincipalDr.G.JAGAN MOHAN RAO Signature of External

Examiner B.E.,(Mech), DBM, (IMDR), M.Sc.(Engg.), Ph.D., (IISC)

A

MINI PROJECT

On

STUDY OF DIE CASTING MOULD BASE

MANUFACTURING PROCESS

At

Hyderabad

By

SHAIK ABDUL LATHUEF (06495A0307) A. SHO BAB (05491A0319) K. NARASIMHA KASYAP SAI (05491A0341) R. ANAND BABU (05491A0334) S. VENKATA REDDY (05491A0325)

DEPARTMENT OF MECHANICAL ENGINEERING

QIS COLLEGE OF ENGINEERING & TECHNOLOGY VENGAMUKKAPALEM, (Village)

ONGOLE, (Prakasham Dist., A.P)

CONTENTS

S. No Description Page No.

1. Introduction

2. Latest Developments in Mould Engineering

3. MOULD DESIGN

a) Introduction on Mould Design & Flow chart

b) Principle of mould Design

c) Mould Design Parameters

d) Material Selection of Mould Design

4. Guide pillars and guide bushes

5. Ejection pins

6. Manufacturing Processes of

a) Cavity Plate

b) Core Plate

c) Ejector Plate

d) Ejector Back Plate

e) Spacer Blocks

f) Guide Pillar

g) Ejector Guide Pillar

h) Ejected Guide Bush

I) Return Pin

j) Ejector Guide Bush

k) Guide Bush

7. Aspects of Heat Treatment

ABOUT THE COMPANY

PRE MOULD ENGINEERS the mould base company born out of a passion for

excellence in 1994. This young name has earned a reputation for meeting the

most challenging mould requirements. It has retained clients with quality,

workmanship and cordial customer service. Started as a one room production

centre, today Pre-Mould is a front runner in the scene. For the future, we are

planning expansion to 50 Mould Bases (Size up to 2000mm X 1600mm) per

monthfromexisting30MouldBasespermonth.

We will continue to go ahead as a technically strong manufacturer of Mould

Bases. We can deliver to you quality and timely delivery at the right price,

Reason why clients come back to us with bigger challenging orders.

Quality Mission

Our attitude towards quality rules all our activities from the selecting the raw

materials to export packaging as per international standards. Product testing

procedures ensure highest standards. The shop floor employs industry

standard benchmarks. Innovative customer expectations guide our designer

teams all the time. Buyers can expect high precision products delivered in time

at the best price possible always.

Our design and manufacturing engineers are trained in NTTF and our

manufacturing operating systems are globally integrated. This allows us to

leverage on the latest technology as well as provides a strategic platform to

serve our customers globally

Machinery

“BMV-80” CNC Milling Machine-2400 X 810 X 810 2 MACHINES

“BMV-60 CNC Milling Machine-1250 X 610 X 610

“BMV-50” CNC Milling Machine-1200 X 510 X 710

“WALDRICH COBURG” (GERMAN) Surface Grinding Machine-3000 X 1000 X 750

“PERFRCT” Thaiwan Make Two Column Surface Grinding Machine-2000 X 1600

“BURKHARDT”(GERMAN) Jig Boring Machine with D.R.O- 1 1000X750

“STANCOFORD” (RUSSIAN) Jig Boring Machine With DRO-700 X 4006.

“MAS” Two Column Jig Boring Machine With DRO-1500 X 1000

“WMW” H-Boring Machine Dia. 80mm Spindle

“GRAFFENSTADEN” (FRANCE) Milling Machines-1350 X 500 X 530 – 2 MACHINES

“HMT” Milling Machine FN-3 – 2 MACHINES

“AVRO” Surface Grinding Machine-1000 X 350

“PRAGA” Surface Grinding Machine

“MICRO MATIC” Cylindrical Grinding Machine- ø265 X 800

“HMT” Radial Drilling Machines RM-63 – 4 MACHINES

Precision Lathe-6 Feet- 3 MACHINES

Precision Lathe-4 Feet- 2 MACHINES

INSPECTION EQUIPMENT

Surface Plate-2000 X 1000

Micrometers up to 400 MM

Bore Gauges up to 400 MM

Vernier Calipers up to 1000 mm

Hardness Tester Dial Indicators with various contact points

Combination squares

Tool Bank:

 Tool Bank 

Cutting tools

 Tool Holders

 Presetting Equipment

 Storage facility for raw material, semi-finished and

finished products

Proper identification system

Proper documentation system

 Highly qualified, skilled & trained personnel

formanagement,  programming and machine

operation

 MAKE :   BFW    

  MODEL :   BMV60TC24    

  CONTROL PANEL :  SINUMERIK 810D

CNC   

  SPINDLE SPEED :   80-10000 rpm    

  MACHINE SIZE :   X - 1050mm    

      Y - 600mm    

      Z - 600mm    

  MAXIMUM SAFE

LOAD:   1000 Kgs.    

  ACCURACY :   Positioning :   ± 5 Microns

      Repeatability :   ± 3 Microns

  NO. OF TOOLS :   24    

  RESOLUTION :   0.001mm    

`  Max. Drilling dia

:  50mm

  Distance between spindle Axis &    

Column

   1600 mm (Max)

  350 mm (Min)

  Taper in Spindle (Morse)

:  5 # (MT)

  Spindle Travel

:  315 mm

  Range of Spindle Speeds

:  25-2000 rpm

  Number of Spindle Speeds

:  16

  Range of Spindle Feeds

:  0.04-3.20

mm/Rotation

  Diameter of Outer Column

:  350mm

  Length of the Arm

:  2140 mm

  Table Size

:  500 x 630mm

  Power of Main Drive Motor

:  4 KW

  Net weight Approx.

:  3500 Kgs.

INTRODUCTION

Mould:

It is a structural assembly of plates, bolestors and other ancillary

items such as guide pillars, guide bushes, inserts, ejector pins fabricated

accordingly and incorporating an impression by the conjugation of core and

cavity which when injected with molten plastic material produces plastic

component of the shape of the impression in due cycle time. Hollow

components can be produced by inserting core into the cavity in the mould.

The type moulding material used has an important influence on the ease of

making the mould and its cost, the permanency of mould, the speed of

production, the rate of cooling of molten metal, surface roughness,

dimensional tolerances and the mechanical strength of the casting.

The metal used for mould should have such a composition as to

withstand high temperatures, dimensional tolerances and mechanical

strength. Moulds are generally made of cast iron, steel, alloy steels and non

ferrous alloys, which are not destroyed or rebuilt after every casting since

these moulds last for long periods, thus the process is called Permanent Mould

casting.

Mould must be designed with parting lines gates, vents etc. so that

molten metal can enter gravity without turbulence. Fine Vents should be so

arranged, that the air in the mould is pushed ahead of the gradually rising level

of molten metal.

The assembly of moulded parts and integration of the assemblies

into the final product contributes significantly to the cost of the product. The

design stage of the product provides the greatest opportunity not only for

cost savings in assembly but also for the potential for automation.

It demonstrates that 70% of the total production cost of a product is

influenced by design and developments, through these areas consume only

10% of the total production costs.

DIE CASTING:

Die casting utilizes two blocks of heat resistant metal machined

to meet along the plane of the parting line and having cavities machined

accurately and smoothly into each to form opposite halves of the shape to

be cast around the edges of the mould.

Casting is one of the most versatile form of mechanical process for

producing components because there is no limit to the size, shape and

intricacy of the articles that can be produced by casting. It offers one of the

cheapest method and gives high strength and rigidity even to intricate parts,

which are difficult to produce other products of manufacturing. Casting can also

be in wide range of dimensional tolerances and surface finish. It depends upon

design of mould base and accuracy of mould.

Die casting is used for mass production and is most suitable for

non-ferrous metals and alloys of low fusion temperature.It depends upon the

means for molten metal supply to the die. There are two types of die casting

machines.

1). Hot chamber die casting machine: In hot-chamder die-casting machines, the metal melting unit

forms an integral part of the machine. It mainly consists of a hot-chamber

and a goose-neck type metal container made of cast iron. This machine is

mainly used for low melting point alloys and metals like zinc,lead etc.

a) Submerged plunger type casting machine.

b) Direct air pressure die-casting machine.

2). Cold chamber die casting machine: This machine is used for casting alloys which require high

pressures and have high melting temperatures such as brass, aluminum and

magnesium. In this process of casting mainly consist of four steps

a) Pouring the molten metal below the plunger and placing the moveable

platen and cores in position;

b) Forcing the molten metal into the dies by means of plunger;

c) Withdrawing of cores and opening dies;

d) Ejection the casting from moveable dies platen.

Description of die used in die casting machines:

Generally it is made into halves so that the casting can be

easily removed from it after solidification. One part of die is stationary

(ejector die) and other ids movable. The two halves, when closed have a

vertical parting surface and form a cavity similar to the casting desired. The

die is so designed that after pouring in of casting desired. The die is so

designed that after pouring in of metal and its solidification, the casting will

always cling to the ejector die. In order to keep the two halves in proper

alignment, dies are equipped with heavy dowel pins. The die is then opened

and casting from the moveable die is removed by advancing the ejector

plate in the moveable half of the die, so that the ejector pins project through

the die half and force the casting out. A separate mechanism, which

synchronises the movements of ejector plate, moveable die and moveable

cores, is also provided with the dies.

DIE CASTING MOULD BASE ASSEMBLY

The mould base assembly for die casting process generally consists the

following components.

1. Cavity plate and core plate

2. Ejector plate

3. Ejector back plate

4. Spacer blocks

5. Guide pillars and guide bushes

6. Ejection pins

7. Ejector guide pillars and ejected guide bushes

1. a) CAVITY AND CORE PLATES:

1. The cavity, which is female portion of the mould, gives the moulding

its external form.

2. The core, which is the male portion of the mould, forms the internal

shape of the moulding.

The basic mould in this case consists of two plates. Into one plate is

sunk the cavity which shapes the outside form of the moulding and is therefore

known as the cavity plate. Similarly, the core which projects from the core plate

forms the inside shape of the moulding. When the mould is closed, the two

plates come together forming a space between the cavity and core which is the

impression.

Two types of core and cavities are there. They are:

1. Integer type

2. Insert type

According to our mould design insert type is advantageous because

1. Easy machining

2. Low mold cost

A Plate of block of steel which contains the cavity is called cavity

plate. A plate or block of steel which incorporates the core is called core plate.

Core plate and cavity plates are made with MS and core and cavity

inserts are made with EN 24.

FIXED HALF AND MOVING HALF:

The half attached to the stationary plates of the machine is termed

as the fixed half, which consist of cavity plate. The other half of the mould

attached to the moving platen of the machine is known as moving half, which

consists of core plate, ejector plate, ejector back plate, spacer blocks and

bottom plate.

Generally the core plate is situated in the moving half because the

moulding, as it cools, will shrink on to the core and remain with it as the one

mould opens. This will occur irrespective of whether the core is a fixed half or

moving half. However this shrinkage on to the core means that some form of

ejection system is almost certainly necessary. Motivation for this ejector

system is easily provided if the core is in the moving half.

1. b) EJECTOR PLATE:

The purpose of this member is to transmit the ejector force from

the actuating system of the machine to the moulding via an ejector element.

Generally ejector plate is made up of mild steel.

1. c) EJECTOR BACK PLATE:

This member is securely attached to the ejector plate by screws.

Its purpose is to retain the ejector element. For moulds, the retaining plate is

made to the same general dimensions as the ejector plate. Retaining plates are

normally made from a mild steel.

EJECTOR AND EJECTOR PLATE ASSEMBLY

1. d) SPACER BLOCKS:

Generally spacer blocks are made up of mild steel. The

purpose of spacer blocks is to provide the movement of ejector plate assembly.

It also serves as a support for the core housing.

2. GUIDE PILLARS AND GUIDE BUSHES

To mould an even-walled article it is necessary to ensure that the cavity

and core are kept in alignment. This is done by incorporating guide pillars on

one mould plate which then enter corresponding guide bushes, in the other

mould plate as the mould closes. Guide pillars are usually necessary to ensure

that both halves of the mould are kept in alignment while the mould is closing.

ARRANGEMENT OF GUIDE PILLARS AND GUIDE BUSHES TYPES: There are four types of guide pillars. They are designated as:

1. Leader pin 2.Standard 3. Spigotted 4. Surface fitting.

2. a) LEADER PIN:

The early evolutionary period of the mould design, the mould consisted

simply of two plates, a cavity plate and a core plate. The alignment between

the two plates was achieved by incorporating shoulder pins in one half and by

machining accommodating holes the other is the other half. These pins were

subsequently called leader pins.

2. b) STANDARD PILLAR AND GUIDE BUSH:

2. c) SPIGOTTED GUIDE PILLAR AND GUIDE BUSH:

It is similar to standard pillar and guide bush but a spigot is

incorporated on both component parts. The guide pillar spigot 1 is fitted into an

accommodating hole in the backing plate 2 while the guide bush spigot 3 is

fitted in to a complementary hole in the second backing plate 4. Thus this

system proving the basic guidance between the two mould halves, additionally

provides an alternative to the use of dowels for the alignment as the respective

mould plate assemblies.

2. d) SURFACE FITTING GUIDE PILLAR AND GUIDE BUSH:

An alternative method of fitted the guide pillar and guide bush is to fit

both of these components from the parting surface side of the mould plate. The

surface fitting guide bush normally incorporates a flange as shown in figure.

This permits the guide bush to be secured in position by a circlip.

3. EJECTION PINS:

Ejection pins are used to eject the solidified component

from the core housing. There are five types of ejection pins, which are

explained below.

3. a) D-SHAPED EJECTOR PIN:-

This is the name given to a flat-shaded ejector pin. It is made quite

simply by machining a flat on to a standard ejector pin. It is used primarily for

the ejection of thin-walled box-type mouldings.

The main advantage of this irregular-shaped ejector pin over the

standard parting surface pin is that, size for size, the former has a greatly

increased effective ejection area.

3. b) SLEEVE EJECTION:- With this method the moulding is ejected by means of a

hollow ejector pin, termed a sleeve. It is used for ejection of certain types of

circular mouldings. Used for the following cases.

I. For the ejection of certain types of circular mouldings.

II. For the ejection (usually local) of circular bosses on a moulding of any

shape.

III. To provide positive ejection around a local core pin forming a round

hole in moulding.

3. c) BLADE EJECTION:-

BLADE EJECTION

The main purpose of the blade ejector is for the ejection of very

slender parts, such as ribs and other projections, which cannot satisfactory, be

ejected by the standard type of ejector pin.

3. D) PIN EJECTION:-

This is most common type of ejection as; in general, it

is the simplest to incorporate in a mould. With this particular technique the moulding is ejected by the application of a force by a circular steel rod, called an ejector pin. The ejector pin is headed to facilitate its attachment to the ejector plate assembly.

3. E) STEPPED EJECTOR PINS:-

The small-diameter ejector pins (under 3mm diameter) are required for a particular design. Slender, long length-to-diameter ratio ejector pins have the tendency to concertina in use. It is desirable therefore to keep the working length of such ejector pins to a minimum. This is

achieved by designing the ejector pin as shown in figure. This is known as a stepped ejector pin.

FLOW CHART OF MANUFACTURING PROCESS

Suitable Raw

Material

Vertical Milling machine for Rough machining

Marking operationas per Drawing

Radial Drilling Machine

Surface Grinding Machine

Cutting or Casting to suitable dimensions

Milling Machine

Jig Boring Machine

CNC Machine

Bench Operation

Mould Assembly

Dispatch

6. MANUFACTURING PROCESSES OF

A) CAVITY PLATEB) CORE PLATEC) EJECTOR PLATED) EJECTOR BACK PLATE

The manufacturing process of cavity plate is done in two stages. In first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below.

Cut off a suitable length, width and thickness plate from the raw material by using gas cutting. After gas cutting by using T-max cutter on horizontal and vertical milling machine clean up the all surfaces. By using vernier height gauge, vernier caliper, divider, chalk piece, center punch etc. mark on the top and bottom surfaces of the cavity plate (guide pillar holes for rough drilling, pockets and slots for rough machining) as per the drawing.

The above marked guide pillar holes are drilled by using series of various drill bits on radial drilling machine. In the same way pockets and slots are machined roughly by using rough end mills T-max cutters, end mills on milling machine.

After completion of rough operation grind the top and bottom surfaces of the cavity plate to the specified size by using abrasive grinding wheel on surface grinding machine. This completes the First stage of machining operation.

After completion of grinding operation the cavity plate is passes to the jig boring machine operations. In jig boring machine by using different

types of boring bars, the guide pillar holes are semi-finished by maintaining 0.5mm stock for further finishing operation on CNC(Computer Numerical Control) milling machines.

After completion of jig boring operation, the cavity plate is passes to the surface grinding machine for final grinding where the actual thickness of the cavity plate is maintained. Then by using precision boring bars, guide pillar holes are finished on CNC milling machine. By using facing T-max cutters, carbide end mills, the pockets and slots of the cavity plate are to be finished to final size as per the diagram with the tolerances on CNC milling machine.

By using carbide end mill pillar hole counters are also finished on CNC milling machine. This completes the second stage of machining operation.

The cavity plate now passes to the bench fitter who does a certain amount of hand finishing(bur removing)are to be carried out.

A) CAVITY PLATE:

INSPECTION REPORTS:

Plate length: 520.2 mmPlate width: 400.3 mmPlate thickness: 190.01mmPocket depth: 144.71mmPocket length: 290.025 mmPocket width: 220.03 mmPillar holes diameter: 60.025 mmSprue hole diameter: 170.03 mm

B) CORE PLATE:

INSPECTION REPORTS:

Plate length: 520.2 mmPlate width: 400.3 mmPlate thickness: 140.02 mmPocket length: 290.025 mmPocket width: 220.03 mmPocket depth: 59.71 mmPillar holes diameter: 60.025 mm

C) EJECTOR PLATE:

EJECTOR PLATE

INSPECTION REPORTS:

Plate length: 400.3 mmPlate width: 196.1 mm Plate thickness: 28.01 mmEjector guide pillar: 34.02 mmCounter diameter: 39.06 mmCounter depth: 5.01 mm

D) EJECTOR BACK PLATE:

EJECTOR BACK PLATE

INSPECTION REPORTS:

Plate length: 400.3 mm Plate width: 196.1 mm Plate thickness: 30.01 mmEjector guide pillar: 34.02 mm

8. MANUFACTURING PROCESS OF SPACER BLOCKS:

The manufacturing process of spacer blocks is explained below. Cut off a suitable length, width and thickness plate from the raw material by using gas cutting. After gas cutting by using T-max cutter on horizontal and vertical milling machine clean up the all surfaces. By using vernier height gauge, vernier caliper, divider, chalk piece, center punch etc. mark on the top and bottom surfaces of the ejector back plate (slots and holes) as per the drawing.

The above holes are drilled by using series of various drill bits on radial drilling machine. The slots are machined by using end mills on milling machine. After completion of rough operation Grind the top and bottom surfaces of the spacer blocks to the specified size by using abrasive grinding wheel on surface grinding machine. This completes the finishing of spacer blocks The spacer blocks now passes to the bench fitter who does a certain amount of hand finishing (bur removing) are to be carried out.

SPACER BLOCK (2 NOS)

INSPECTION REPORTS:

Plate length: 520.3 mmPlate width: 115.1 mmPlate thickness: 135.01 mm

9. MANUFACTURING PROCESS OF GUIDE PILLAR:

The manufacturing process of guide pillar is done in two stages. In

first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below.

Cut off a suitable length and diameter of rod from a raw material by using the power saw. One end of the rod is fixed on spindle and other end of the rod is centered to tail stock on turning. Make a step turning by using turning tool.

Further make another step turning as per required size.

Further make another step turning as per required size as shown in operation 4. Now the tail stock is moved away from the end of the rod. Make a chamfer at the end of the rod as shown in operation 5. By using parting tool make a parting operation as shown in figure 6. By using radius turning tool, grooves are produced for the purpose of lubrication. This completes the first stage as operation.

After getting required size of guide pillar, is moved to heat

treatment, to improve the hardness and wear resistance .Then by using cylindrical grinding finishing operation is done, on guide pillar as per final size. This completes the second stage of operation .The final shape and size of the guide pillar is shown figure.

INSPECTION REPORTS:

1. Collar diameter: 65.05 mm2. Collar thickness: 9.82 mm3. Pillar diameter 1: 60.52 mm4. Pillar diameter 2: 44.51 mm

MANUFACTURING PROCESS OF GUIDE PILLAR:

FINISHED GUIDE PILLAR

10. MANUFACTURING PROCESS OF EJECTER GUIDE PILLAR:

The manufacturing process of ejected guide pillar is done in two stages. In first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below.

Cut off a suitable length and diameter of rod from a raw material by using the power saw. After that one end of the rod is fixed on spindle and other end of the rod is centered on tail stock on turning as shown in operation1. Make a step turning by using turning tool as shown in operation 2. Now the tail stock is moved away from the end of the rod.

Make a drilling operation by using drill bits as shown in operation 3. Further make a counter bore operation as per required size as shown in operation 4. By using paring tool make a parting operation as shown in operation 5. By using radius turning tool grooves are produced for the purpose of lubrication. This completes the first stage as operation.

After getting required size of guide pillar, is moved to heat treatment, to improve the hardness and wear resistance .Then by using cylindrical grinding finishing operation is done on ejector guide pillar as per final size. This completes the second stage of operation .The final shape and size of the ejector guide pillar is shown figure.

INSPECTION REPORTS:

1. Ejector guide pillar diameter: 26.51 mm 2. Guide pillar length: 120.52 mm

MANUFACTURING PROCESS OF EJECTER GUIDE PILLAR:

FINISHED EJECTOR GUIDE PILLAR

11. MANUFACTURING PROCESS OF RETURN PIN:

The manufacturing process of return pillar is done in two stages. In first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below

Cut off a suitable length and diameter of rod from a raw material by using the power saw. After that one end of the rod is fixed on spindle and other end of the rod is centered on tail stock on turning as shown in operation1. Make a step turning by using turning tool as shown in operation 2.

Further make another step turning as per required size as shown in operation 3. By using paring tool make a parting operation as shown in operation 4. By using radius turning tool grooves are produced for the purpose of lubrication. This completes the first stage as operation.

After getting required size of guide pillar, is moved to heat treatment, to improve the hardness and wear resistance .Then by using cylindrical grinding finishing operation is done on return pin as per final size. This completes the second stage of operation .The final shape and size of the return pin is shown figure.

INSPECTION REPORTS:

1. Collar diameter: 24.03 mm2. Collar thickness: 7.52 mm3. Pin diameter: 20.63 mm4. Pin length: 242.02 mm

MANUFACTURING PROCESS OF RETURN PIN:

FINISHED RETURN PIN

12. MANUFACTURING PROCESS OF EJECTED GUIDE BUSH:

The manufacturing process of ejected guide bush is done in two stages. In first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below.

Cut off a suitable length and diameter of rod from a raw material by using the power saw. After that one end of the rod is fixed on spindle and other end of the rod is centered on tail stock on turning as shown in operation1. Make a step turning by using turning tool as shown in operation 2.

Make a drilling operation as per required size as shown in operation 3 make a internal semi finishing on turning machine. By using paring tool make a parting operation as shown in operation 4. By using radius turning tool grooves are produced for the purpose of lubrication. This completes the first stage as operation.

After getting required size of guide pillar, is moved to heat treatment, to improve the hardness and wear resistance .Then by using cylindrical grinding finishing operation is done on ejected guide bush as per final size. This completes the second stage of operation .The final shape and size of the ejected guide bush as shown figure.

INSPECTION REPORTS:

1. Collar diameter: 38.05 mm2. Collar thickness: 4.82 mm3. Internal diameter: 25.50 mm4. Outer diameter: 34.53 mm

13. MANUFACTURING PROCESS OF EJECTER GUIDE BUSH:

FNISHED EJECTED GUIDE BUSH

14. MAUFACTURING PROCESS OF GUIDE BUSH:

The manufacturing process of guide bush is done in two stages. In first stage roughing operation is completed .In second stage finishing operation is completed, which is explained below.

Cut off a suitable length and diameter of rod from a raw material by using the power saw. After that one end of the rod is fixed on spindle and other end of the rod is centered on tail stock on turning as shown in operation1. Make a step turning by using turning tool as shown in operation 2.

Further make another step turning as per required size as shown in operation 3.By using drill bit and turning tool internal diameter of guide bush is produced as per drawing on turning machine as shown in operation 4. By using paring tool make a parting operation as shown in operation 4. By using radius turning tool grooves are produced for the purpose of lubrication. This completes the first stage as operation.

After getting required size of guide pillar, is moved to heat treatment, to improve the hardness and wear resistance .Then by using cylindrical grinding finishing operation is done on guide pillar as per final size. This completes the second stage of operation .The final shape and size of the guide pillar is shown figure.

INSPECTION REPORTS:

1. Collar diameter: 65.05 mm2. Collar thickness: 9.82 mm3. Internal diameter: 44.515 mm4. Outer diameter: 60.51 mm

MANUFACTURING PROCESS OF GUIDE BUSH:

FINISHED GUIDE BUSH

ASPECTS OF HEAT TREATMENT

Development in Mould Engineering:

Precision Engineering and Development Center (PEDEC) has development a wide range of software programs including precision molding CAD/CAM/CAE program. The intelligent plastic system and can reduce mould lead time by up to 70% the system is able to design a complete drawing including the details of sliders, lifters, cooling channels, runners, ejectors and mould bases from 3-D model.

Pro- Engineering is CAD/CAM/CAE software developed by Parametric Technology Corporation, USA, widely used in modeling, Machining and Analysis areas in Injection Mould Design.

Treatment Methods for Tool Surfaces:

Molders are always looking for that extra edge to give them a competitive advantage one that will lead to smoother operation and higher profits from their injection moulds as the technology of mould surface enrichment and coating continues to evolve, processor have increasingly turned to these treatment in the hope of gaining these advantages.

What capabilities are needed from coating hear is a look at some the results that are often desired.

Hardness:

Longer mould life can often be achieved by increasing the hardness of the tool surface increased wear properties are especially critical with abrasive glass and mineral and reinforced resin.

Corrosion Resistance:

Untreated surface may rust from water in the resin and humidity in the air. Lubricity improved released characters are commonly advertised advantage of mould coating and surface treating this can be critical in application with long cores, low draft angles or resins that tend to stick and hot steel in hard to cool areas.

Reduced Cycle Time:

Many suppliers advertise reduced cycle time with coatings due to reduced flow resistance and better release from the tool thus faster ejection.

Metallic Coating:

These are the original mould surface coatings. Chrome and electrolysis nickel steel still sees wide use injection mould the primary benefits of these coatings are increased hardness and chemical resistance. Chrome plating generally contains micro cracks. Because of this it is common to backup hard chrome plating with electrolysis nickel- plating for environments that prove to be really harsh.

Surface Hardening Treatment:

The hardness of the surface falls between 55 and 70 HRC, depending on the treatment parameters.

PRINCIPLES OF MOULD DESIGN

Mould:

It is a structural assembly of plates, bolestors and other ancillary items such as guide pillars, guide bushes, inserts fabricated accordingly and incorporating an impression by the conjugation of core and cavity which when injected with molten plastic material produces plastic component of the shape of the impression in due cycle time.

I mpression:

Impression is formed by conjugation of core and cavity which gives the shape and size of the required component.

Core and Cavity:

The core which is the male portion of the mould, gives the moulding its internal form.

The cavity which is the female portion of the mould gives the moulding its external form.

Locating Ring:

The locating ring or registered ring is a circular member fitted on to the front face of the mould, Its purpose is to locate the mould with respect to the moulding machine axis. Locating Ring is made with MS

Sprue Bush:

Sprue bush is a hardened steel bush which incorporates the tapered sprue passage way. In practice the sprue bush is the connecting member between the machine nozzle and the mould face and provides a suitable aperture through which the material can travel on its way to the impression or the start of the runner system in "multi impression molds". The internal aperture of the sprue bush has between 2 - 4° included taper, which facilitates removal of the sprue from the mold at the end of the molding cycle. Sprue bush is made with EN24

Guide Piller and Guide Bush:

To mold an even walled .article it is necessary to ensure that the cavity and core are kept in alignment. This is done by in corporating guide pillars on one mold plate which then enter corresponding guide bush on the other mold plate as the mold closes. Guide bush and Guide pillar has sliding fit. These are made with EN36

Feed System:

An internal passage way in the mold which provides a flow path for the plastic material from the machine's nozzle to the impression. The feed system normally comprise; sprue, runner and gate.

Sprue is the plastic material in the tapered passage which connects the nozzle to the molds parting surface.

Runner is a channel machined into the mold plate to connect the sprue with the entrance (Gate) to the impression. The cross-sectional area of the runner used in a mold is usually one of the four terms, full round, Trapezoidal, Modified trapezoidal and Hexagonal. The criteria of efficient runner design is that the runner should provide a maximum cross-sectional area from the stand point of pressure transfer and minimum contact on the periphery from the standpoint of the heat transfer.

Gate is a channel or orifice connecting the runner with impressions. It prevents backflow. It maintains constant pressure. The types of Gates commonly used are Sprue gate, Edge gate. Overlap gate, Diaphragm gate, Ring gate, Film gate, Pin gate, Submarine gate.

According to our project work pin gate is advantageous because after degating only a small witness mark remains and easy ejection.

Mold Cooling:

Principle of injection molding is that the material enters the mold, where it cools rapidly to a temperature at which it solidifies sufficiently, to retain the shape of the impression. The temperature of the mold is therefore important as it governs a portion of the overall molding cycle. To maintain the required temperature different between the mold and plastic material, water is circulated thought holes or channels within the mold. These holes or channels or termed as flow ways or water ways and complete system or flow ways is termed as cooling system.

Ejection System:

When a molding cools, it contracts by an amount depending on the material being processed for a molding which has no internal form for example solid rectangular block, the molding will shrink away from the cavity wall, thereby permitting a simple ejection technique to be adapted.

The ejector system consists of Ejector grid, Ejector plate 3ssembly. The basic method of ejection is Pin ejection, Bar ejection, Blade ejection, Air ejection, Stripper plate ejection.

In this project Pin ejection has been used. This is the most common type of ejection. It is simplest to incorporate in the mold. With this particular technique the molding is ejected by the application of a force by a circular steel rod called an ejector pin. The ejector pin is headed to facilitate its attachments to the ejector plate assembly.

Parting Surface:

The part of both mold plates adjacent to the impression which but together to form a seal and prevent a loss of plastic material from the impression.

Push Back Pins:

A hardened circular steel pin incorporated in the design to return the ejector assembly to its rate position as it closes. It is made with silver steels.

MOULD DESIGN PARAMETERS

Mould Design Aspects:

1. Part design

2. Material selection

3. Shrinkage

4. Moulding machine compatibility

5. Strength of material of the mould

6. Fluid flow in mould

7. Venting the mould

8. Heat transfer

9. Thermal conductivity

10. Thermal expansion of the mould

11. Co-efficient of friction

12. Abrasion resistance

13. Corrosion resistance

14. Ejection system

15. Draft and shut off

16. Detail drawing & dimensional stack up

17. Mould and setup

18. Method of construction

Heat treatment aspects of mould materials:-

Heat treatment may be defined as an operation or combination of operations involving heating and cooling of a metal (or) alloy in solid state to obtain desirable conditions and properties.

Purpose of heat treatment:-

Heat treatment process is carried out in order to:

1. Cause relief of internal stresses developed during cold working,

welding, casting, forging etc.

2. Harden and strengthen materials

3. Improve ductility and toughness

4. Change the grain size

5. Soften metals for further working as in wire - drawing or cold rolling

6. Increase heat, wear and corrosion resistance of materials

7. Homogenize structure, to remove coring or segregation

8. Spheroidises particles such as those like Fe, in steel by diffusion.

Heat treating a mould always introduces risks of distortion and cracking. Permanent linear movements in metals during heat treatment are to be expected. It is impossible to predict accurately the extent or direction of movement, since chemical composition, moss, geometry, design and heat treating techniques all affect the final dimensions of a mould.

Mould made from low carbon steel is usually carburized. Moulds made

from the higher carbon and alloy steels have sufficient, carbon to give the desired hardness and tend to harden all the way through.

Care must be taken to protect the mould surface against oxidation. This is

done by packing the mould into spent cast-iron chips or pitch coke, by heating in a controlled atmosphere furnace, or by heating in a vacuum furnace.

After heating the mould to the hardening temp, it is either quenched in a liquid such as oil or it is allowed to cool in air, depending upon the analysis of the steel. High alloy steels harden sufficiently when cooled in air from

hardening temp.

Tempering:

After quenching, the mold is reheated to a definite temperature ranging from 350°- 1150° F to obtain the desired hardness and to relieve the stresses created during the hardening operation. Mold hardness may vary from 30-65 HRC depending upon requirements.

It should be noted that the tempering process while relieving the major stresses caused by quenching, induces minor stresses inherent to the process resulting from crystalline structure changes. Best results are obtained by a second tempering or what is known as double tempering.

Annealing or reducing the hardness of the steel is accomplished by heating the metal to a temp just above the critical point and then permitting it to cool very slowly.

Stress Relieving:

Distortion can be caused by residual stresses. Steel that has been subjected to (severe grinding, hobbing and cutting operations become highly stressed. Stresses induced by those operations must be relieved or distortion may occur during heat treatment.

Another source of distortion is too rapid heating during heat treatment. Rate of heating should be slow enough so that all portions of the mold are at practically the same temperature.

During rapid heating, thin sections expand faster than thick sections. This causes stress in the junctions which, if greater than the yield strength of the steel, will cause the mold to distort. Distortion can also occur during rapid heating when the thin sections reach the critical temperature, first and start contracting while the thick sections are still expanding.

Distortion problems can be prevented by using a pre hardened steel. It is advisable to stress relieve molds made from pre hardened steel if the mold is complicated or has sharp radii and corners.

Hardness Penetration:

Steels must be quenched rapidly to give them proper hardness, will have an outer ell that is hard and inner core that is relatively soft owing to delayed action of the quenching. This outer shell may be 0.8 to 3.2 mm deep in a water- hardening tool steel. The oil hardening steels show greater

hardness penetration than the water hardening steels, while the air hardening penetration that the water hardening steels, while the air hardening steels show the greatest degree of hardness penetration. Molds subjected to large deflection should not have a high degree of penetration.

MANUFACTURE PROCEDURE

Request for quote

Confirmed order

Design mould structure Mould flow analysis

Confirmed design

3D lay out 2D lay out

Confirmed 3d & 2d layouts

Preparing material

Cnc machining

polish

Machines classify

Rough machining Edm machining Wire cutting

Mould assembly

Inspection sample report

Customer approval

Delivery

inspection

Quality control

Improve mould

Quality control

Mould trail