Report On Mould and Design Polymer (PST 632) PDF

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FACULTY OF APPLIED SCIENCEBACHELOR OF SCIENCE (HONS ) POLYMERTECHNOLOGYPST 632 Project AssignmentNAME : NUR IMANI BINTI MOHD FAUZIMATRIC ID : 2017..........TEAMMATE (NAME) :1. SHADATUL NISHA BINTI MA’AMOR2. NUR ANISSHAH BINTI AZRIGROUP : AS2434LCOURSE CODE : PSTPROJECT ASSIGNMENT DATE SENT : 27 JUNE...

Description

FACULTY OF APPLIED SCIENCE BACHELOR OF SCIENCE (HONS ) POLYMER TECHNOLOGY PST 632 Project Assignment

NAME : NUR IMANI BINTI MOHD FAUZI MATRIC ID : 2017………. TEAMMATE (NAME) : 1. SHADATUL NISHA BINTI MA’AMOR 2. NUR ANISSHAH BINTI AZRI GROUP : AS2434L COURSE CODE : PST632 PROJECT ASSIGNMENT DATE SENT : 27 JUNE 2019 LECTURER’S NAME : DR. RAJA ROSLAN BIN RAJA MOHAMED

1

TABLE OF CONTENT

No

Contents

pages

1

Executive Summary

4

2

Introduction

5-7

3

Product design and description

8-12

4

Machine selection

13-15

5

Material selection

16

6

Mould description

17-19

7

Mould design

20-31

8

Recommended parameter

9

Conclusion

36

10

Reference

37

11

Appendix

38-41

EXECUTIVE SUMMARY

2

processing 32-35

Injection molding is a cyclic process of forming plastic into a desired shape by forcing the material under pressure into a cavity. The shaping is achieved by cooling (thermoplastics) or by a chemical reaction (thermosets). It is one of the most common and versatile operations for mass production of complex plastics parts with excellent dimensional tolerance. It requires minimal or no finishing or assembly operations. In addition to thermoplastics and thermosets, the process is being extended to such materials as fibers, ceramics, and powdered metals, with polymers as binders.

Based on the project that i and my friend carried out, we can observed the most important thing while doing this project is after designing the product and the mould. The cavity and core also need to add-in the feature such, cooling channel, (with or without buffle), venting on cavity, ejection hole in core, logo insert, sprue insert, and so much more to serves it as a complete mould with function. Each feature serves a crucial function that will determine the success of the polymer melt to become the desired product. The detail will be discussed later in this report.

First of all, before we start design the component and mould base, it a must to know the standard measurement for each component and mould base. The standard such as LKM, PME and DME . The significant of this method is to ensure the designing is based on the mould company for ease manufacturing and fabrication and to familiar the student about the real mould

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design in industry, because in order things to become valid is must follow the standard. There has a lot of benefits that we can get by doing this project such as this project of designing product and mould will surely provide a basic knowledge of designing and processing of plastic product especially in injection moulding and also teach and improve student IT skill which is using a solidwork software. For the conclusion, I would like to give some opinion or comment towards the method used in this project which is injection moulding method to produce product.From my opinion, injection molding machine has undergone significant modifications and improvements. In particular, the invention of the reciprocating screw machine has revolutionized the versatility and productivity of the thermoplastic injection molding process. This show that injection moulding such a great and high quality method to produce product.

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INTRODUCTION

1.Objective

The objective for this project is the student from (PST632 Mould and Die Design course) are required to design a simple injection moulded plastic product and its mould by using SOLIDWORK software as well to enhance the skill of using the software. This is to ensure that all student fulfil the requirement in PST632 Mould and Die Design course. Therefore the next objective for this project is to produce a locally made product and to produce a cheap and affordable product

The next objective for this project is student should make a single cavity layout mould by following the standard measurement such as LKM and DME (standard mould with component part. By doing this project, the student should know how to design a convenient product with embossed logo, how to make a two-plate mould.

Furthermore , the objective for this project is to To design and make an injected product using injection moulding machine available at the current market.student should knoe how to follow all rule of plastic product manufacturing . the most important thing is , student have to ensure and determine all possible defect in injection moulding. If student know how to determine the defect, this moulding machine can be operate in excellant operation.

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2.Background Injection Molding is a manufacturing technology that can be used to mass-produce identical plastic parts. In Injection Molding, polymer granules are first melted and then injected under pressure into a mold, where the liquid plastic cools and solidifies. The materials used in Injection Molding are thermoplastic

polymers

that

can

be

colored

or

filled

with

other

additives.Injection Molding is so popular, because of the especially low cost per unit when manufacturing high volumes. Injection molding also offers high repeatability, good design flexibility and produces parts with good tolerances.

Design rules for Injection Molding(a few) is shown below:1. Uniform wall thickness ,use a uniform wall thickness throughout the part (if possible) and avoid thick sections. This is essential as non-uniform walls can lead to warping or the part as the melted material cools down.If sections of different thickness are required, make the transition as smooth as possible using a chamfer or fillet. This way the material will flow more evenly inside the cavity, ensuring that the whole mold will be fully filled.

2. Round all edges,the uniform wall thickness limitation also applies to edges and corners: the transition must be as smooth as possible to ensure good material flow. 3. Hollow out thick sections,thick sections can lead to various defects, including warping and sinking. Limiting the maximum thickness of any section of your design to the recommended values by making them hollow is

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essential.To improve the strength of hollow section, use ribs to design structures of equal strength and stiffness but reduced wall thickness. 4. Add a draft angle,to make the ejection of the part from the mold easier, a draft angle must be added to all vertical walls. Walls without a draft angle will have drag marks on their surface, due to the high friction with the mold during ejection.

Mould designs that have to be considered are given below:-.

1. Angles on the side walls are necessary to ensure the moulding can be removed from the mould. 2. The surface finish of the moulding needs to be decided before the mould is completed. Embossing, etching and other finishes can be added to the moulding to enhance the aesthetic qualities of the moulding. Any imperfection on the finish of the moulding will transfer to every mould made. 3. Weight, surface area and thickness of the moulding directly affect cycle time. Where mouldings have significantly varying thickness, cooling has to be controlled very carefully otherwise depressions form (sink marks) on the outer surface of the moulding caused by excessive shrinkage of the thick section of the moulding. 4.

There are several things that must consider to avoid from defect problems, which is, suitable shot size, good plasticizing rate used,suitable clamping force, suitable maximum area of machine platen for easy assemble to machine and suitable injection pressure.

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PRODUCT DESIGN AND DISCRIPTION

Product specification No 1. 2. 3. 4. 5. 6. 7. 8.

Specifications Material Shaped Maximum width Maximum length Maximum height Draft angle Product weight Wall thickness

Description PP Square 150 mm 150 mm 60 mm 4deg and 5deg 72.23 grams 1.5 mm

9.

Volume

133557.99 mm3

10. 11. 12. 13. 14.

Surface area Surface finish Shrinkage factor Scaling factor = 1/(1−x/100) Product

175542.97 mm2 High polish 1.8% 1.018 Accessories holder

This product Inspired by :-

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Injection moulding component and function:Component Sprue bush

Design

Function A channel to transfer molten ejected

plastics from

the

nozzle Locating ring

To

ensure

alignment

proper between

the nozzle and the sprue bush, Top plate

The outer top of the mould. To hold the fixed side of the mold to attached at the fixed platen of the injection machine

Guide bush

To allocate moving guide

pin

that

function is to ensure the mould is aligned and to get a high quality of product

9

Cavity insert

Consist

of

cooling

channel,baffle,plug,a nd logo insert which is place inside the plate A It is attached to Plate A and to the top plate or the stationary side. Core insert

An impression for the product, where melt take the shape of it. It is attached to the plate B and to the movable plate.

Plate A

Plate a is function to hold cavity side of product together.

Plate B

Plate that hold core nd attached to the 2 pacer block.

10

Guide pin

Accurately

locate

core and cavity side of ,make them match perfectly and move smoothly

Ejector plate

Pushed the retainer plate

that

contain

ejector pin.

Retainer plate

Fixed and guide the ejector plate and hold the ejector pins in position.

Return pin

Pin that aligned and allocate ejector

for

the

plate

and

ejector retainer plate to move

Spring

Attached with return pin

to

ease

the

moving ejector plate and ejector retainer plate.

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Bafflle

To split the drilled waterline

into

two

equal channels and to

prevent

minimize

or

warpage

defect and lower the cooling time

Hose nipple

To grips the interior wall of the tubing and provides

a

surface

sealing without

damaging the tubing wall. Logo insert

Component

that

placed

the

inside

cavity to provide the shape

of

product

logo on the surface of product

plug

Attached to the end of the cooling circuit that had drilled to prevent

the

water

come out from the cooling channel

MACHINE SELECTION

12

A machine tool selection is an important decision-making process for many

manufacturing

companies.

Improperly

selected

machines

can

negatively affect the overall performance of a production system. The speed, quality and cost of manufacturing strongly depend on the type of the machine tool used.To determine a suitable injection moulding based on the product of this project. It should be noted a few points such as clamp force and the distance between tie bars. These factors are crucial in determining the machine selection. Neglecting these factors will serve a possible problem on injection moulding process afterwards. The problems are: 1. Clamp force is too low and will need an extra force to clamp the mold. 2. Mold cannot be inserted to the machine as the size of mold is bigger and cannot fit to the small distance of the tie bars.

Clamping Force, F measurement :F = (Cavity pressure, Pc) x (total projection area, A) Cavity pressure for Polypropylene = 650 bar = 65MPa = 0.065 KN/mm2 Total projection area, A = 150 x 150 = 22500 mm2 Required mould clamping force, F = (Cavity pressure, Pc) x (total projection area, A) F = 0.065 KN/mm2 x 22500mm2 F = 1462.5 KN

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From the above calculation, the product clamping force is 1462.5KN. The injection machine is selected from Arburg which is one of the renowned injection machine supplier and manufacturer in the world. The machine is Arburg Allrounder 420 C. This machine can served a clamping force from 600KN and above. The weight of movable half mould maximum is 500kg but for our weight in average 200 to 300kg. This show that our product are suitable for this machine.

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Injection Molding Process Guidelines for polypropylene The following is given as a potential process starting point. The final molding process may be dependent upon factors like: part and tooling design, wall thickness, flow lengths, gate size, number of cavities, cycle time and desired level of molded part quality, for example. - Melt Temperature: 400 – 470ºF (200 – 250ºC) .Set barrel temperatures, screw speed (60 to 125 rpm) and back pressure (50 to 200 psi) so that the melt temperature coming out of press nozzle is in the above range, temperature of an air shot using a needle thermoprobe. - Barrel Temperature = Rear: 390 - 440 ºF (199 – 227 ºC) Middle: 390 – 450 ºF (199 – 232 ºC) Front: 390 – 470 ºF (199 – 250 ºC) - Screw Speed = 50 – 125 rpm Back Pressure: 50 – 200 psi - Mold Temperatures = 60 – 120 ºF (15 to 50 ºC) - Cushion = 0.25 inch - Maximum Shot Size = 40 – 60 % of barrel capacity Injection

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- Speed = As fast as possible without causing cosmetic defects Pack / Hold - Pressure = 50 – 75 % of injection pressure - Hold Time = Until gate freeze achieved

MATERIAL SELECTION

Polypropylene , is a synthetic resin used in our injection molding for a wide range of applications. Polypropylene is one of the lowest density plastics; the density ranges between 0.895 and 0.92 g/cm. Polyproplyene is safe for use as food containers because polypropylene does not leach chemicals into food products.polypropylene is a tough and rigid, crystalline thermoplastic produced from propene (or propylene) monomer. It is a linear hydrocarbon resin. The chemical formula of polypropylene is (C3H6)n. PP is among the cheapest plastics available today.polypropylene belongs to polyolefin family of polymers and is one of the top 3 most used polymers today. Polypropylene has applications, both as a plastic and as a fiber in automotive Industry , Industrial Applications Consumer Goods, and Furniture

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Market. Polypropyleme also has the lowest density among commodity plastics. The melting point of polypropylene occurs in a range, so the melting point is determined by finding the highest temperature of a differential scanning calorimetry chart. Perfectly isotactic PP has a melting point of 171 °C (340 °F). Commercial isotactic PP has a melting point that ranges from 160

to 166 °C (320 to

331 °F),

depending on atactic material

and

crystallinity. Syndiotactic PP with a crystallinity of 30% has a melting point of 130 °C (266 °F).[8] Below 0 °C, PP becomes brittle. MOULD DESCRIPTION Mould Assembly ( Exploded View With Bill Of Material )

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Mould Assembly ( Collapsed View with Bill Of Material)

18

Function of screw

Screw 1

Type of Screw

Diameter

Hex socket head cap M8

Length

Functions

Amount

10mm

s To mount locating 2

screw -Din 912

ring onto the top

2

Hex socket head cap M16

70mm

plate To mount plate A 6

3

screw -Din 912 Hex socket head cap M12

45mm

to the top plate To mount plate A 4

4

screw -Din 912 Hex socket head cap M12

30mm

to the cavity insert To mount plate B 4

5

screw -Din 912 Hex socket head cap M12

30mm

to the core insert To mount ejector 4

screw -Din 912 6

retainer plate onto

Hex socket head cap M16

160mm

screw -Din 912

ejector plate To mount plate B 6 and both spacer block onto bottom

7

Hex socket head cap M12

19

80mm

plate To mount

both 4

screw -Din 912 8

spacer block onto

Hex socket head cap M1.4 screw -Din 912

5mm

bottom plate To mount mould 1 cavity insert

Standard Element : LKM, PME, DME

20

with

logo

MOULD DESIGN Type of this project mould is two plate mould with single cavity. Both of the cavity and core are equipped with cooling channel system, venting at cavity side and ejection system at the core insert. A complete mould cavity must equip with the following parts and components to serve as functional mould. Two plate mold is the easiest injection mold structure and has many advantages. It's consist with A side and B side 2 main parts, when it is load in ejection machine to do molding, A side is fixed and held still, B side is movable. See below figure to get the details of the 2 plate mold. 1. FEEDING SYSTEM The feed system for a mold provides the path for the molten material to flow from the nozzle of the machine to the machined impression. This flowway is called the Feed System. Usually the feed system consists of sprue, runners and gates. Due to the single cavity of the mould, the mould use direct sprue bush for the flow of molten direct to the cavity. The function of sprue is act as a channel trhough which to transfer molten plastic injected from the nozzle of the injection molding machine to the mold. it is a part of sprue of sprue bush,which is a separate part from the mold. Next, the function of runner is a channel that guides molten plastic into the cavity of a mold. For the gate, a gate is an entrance through which melt plastic enters the cavity. the gate has the following functions: restricts the flow and the direction of melt plastic; simplifies cutting of a runner and molding to simplify finishing of parts; quakly cools and solidifies to avoid backflow after molten plastics has filled up in the cavity.

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2. Parting line

Parting line is the line of the product that separate from mould and cavity. Parting line lies along the edge of the moulded part and between the core and the cavity surfaces. The function of the parting line is to create the parting surface and then separate the surface. The parting line in mould making is the place where two or more parts of the mould is meet. P arting lines occur due to minute inherent gaps between two mating faces of halves of the die. The material filling between this gap is call flash. Flash is a wasted of material and need to be trimmed.

3. CAVITY LAYOUT Mould cavity layout for this project is only a single cavity which is it only produce one product for each cycle. The cavity will shape the melt ABS and forming the im...