Full Report Fujitsu Print

8/13/2019 Full Report Fujitsu Print

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BDA 30502 MANUFACTURING ENGINEERING

FACULTY MECHANICAL AND MANUFACTURING ENGINEERING Page 1

1.0 INTRODUCTION1.1 FUJITSU COMPONENT (M) SDN.BHD

Figure 1: Logo Fujitsu

FUJITSU COMPONENT (MALAYSIA) SDN BHD is the electronic company that hasbeen operates since1980 at Parit Raja Batu Pahat, Johor. This company was established to

produce coils for electromagnetic relays that assembled by Fujitsu Singapore Private Limited(FSL). Date of this company incorporation is on 9 October 1980 with authorized capital

RM200000000.00. This company wholly owned by Fujitsu Takamisawa Component Limited,Japan. Before July1986, assembled process by Fujitsu Singapore Limited, but after July 1986,

the assembly process was transferred from FSL to Fujitsu Component Malaysia (FCM), where

various kinds of electromagnetic relays are manufactured for a wide range of applications suchas electrical equipment and computers, etc. In 1987, FCM started producing keyboards and

connectors too, and from 1987 to 1989, the molding, stamping and plating process were

transferred to FCM to support the assemble process.

Fujitsu Companies has 1508 staff working under Fujitsu Component (Malaysia)

which also includes foreign worker, Indonesian 197 worker and Vietnamese 32 worker. Theirbasic salaries are RM900 per month. All Fujitsu Component staff is given uniform of company

and need to wear every time come for working. All uniform are same for all staff except

general manager. The color of scarf and hat gives a different post. White color for operator,

orange color for quality control, blue color for technician, green for new operator, pink forinspection and white for line leader. All staff also is given two pairs of shoes and need to wear

inside production line. For visitors, they are given shoes cover to cover their shoes. All

operator work with three shifts, which is morning 7am until 3pm, afternoon 3pm until 11pmand night shift 11pm until 7am.

Since establishment, Fujitsu Component Malaysia production scale has progressed

rapidly and makes Fujitsu Component Malaysia a major overseas electronics componentproduction base for Fujitsu Limited, Japan. All design for Fujitsu component come from

Research and Development department at Japan and assembled at Fujitsu Component

Malaysia. Fujitsu Component Malaysia use high level production technology to produces theircomponent that is greatly valued for their high reliability and good quality.


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2.0 OBJECTIVE

These projects of Manufacturing Engineering conducted with several objectives. These

project determine so the goal of POPBL achievements.

The objective of this project:-

1. To investigate the problem occur during the process of injection molding.2. To investigate how and why the problem happened during injection molding process.3. To determine optimum parameter and how to solve the problem.4. To know the process to produce the product by injection molding.

3.0 EXPLANATION OF THE PROCESS INJECTION MOLDING

3.1 Injection Molding

Figure 2 : Injection Molding

Injection molding is the most commonly used manufacturing process for the fabrication of

plastic parts. A wide variety of products are manufactured using injection molding, which

vary greatly in their size, complexity, and application. The injection molding process

requires the use of an injection molding machine, raw plastic material, and a mold. The

plastic is melted in the injection molding machine and then injected into the mold, where it

cools and solidifies into the final part.

Injection molding is used to produce thin-walled plastic parts for a wide variety of

applications, one of the most common being plastic housings. Plastic housing is a thin-

walled enclosure, often requiring many ribs and bosses on the interior. These housings areused in a variety of products including household appliances, consumer electronics, power

tools, and as automotive dashboards.


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Other common thin-walled products include different types of open containers, such as

buckets. Injection molding is also used to produce several everyday items such astoothbrushes or small plastic toys. Many medical devices, including valves and syringes, are

manufactured using injection molding as well.

The process cycle for injection molding is very short, typically between 2 seconds and 2

minutes, and consists of the following five stages:

1)Mold Close and Clamping

Figure 3 : Clamping

Prior to the injection of the material into the mold, the two halves of the mold must first besecurely closed by the clamping unit. Each half of the mold is attached to the injection

molding machine and one half is allowed to slide. The hydraulically powered clamping unit

pushes the mold halves together and exerts sufficient force to keep the mold securelyclosed while the material is injected. The time required to close and clamp the mold is

dependent upon the machine - larger machines (those with greater clamping forces) will

require more time. This time can be estimated from the dry cycle time of the machine.

The mould is closed within the platen arrangement and clamped using necessary force to

hold the mould shut during the plastic injection cycle, thus preventing plastic leakage overthe face of the mould. Present day moulding machines range from around 15 to 4,000

metric tonnes available clamping force (150 to 4000 kN).Many systems are available for

opening/closing and clamping of mould tools, although usually they are of two generaltypes.

Direct Hydraulic Lock is a system where the moving machine platen is driven by a

hydraulic piston arrangement which also generates the required force to keep the mouldshut during the injection operation. Alternatively, smaller auxiliary pistons may be used to

carry out the main movement of the platen and a mechanical blocking arrangement is usedto transfer locking pressure from a pressure intensifier at the rear of the machine, whichmoves only by a few millimeters, through to the platen and tool. The second type of general

clamping arrangement is referred to as the Toggle Lock.


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2) Injection

Figure 2 : Reciprocating Screw Injection Moulding Unit

At this stage in the machine cycle the helical form injection screw (Figure 1) is in a

'screwed back' position with a charge of molten thermoplastic material in front of thescrew tip roughly equivalent to or slightly larger than that amount of molten material

required to fill the mould cavity. Injection moulding screws are generally designed withlength to diameter ratios in the region of 15:1 to 20:1, and compression ratios from rear to

front of around 2 : 1 to 4 : 1 in order to allow for the gradual densification of the

thermoplastic material as it melts. A check valve is fitted to the front of the screw such asto let material pass through in front of the screw tip on metering (material dosing), but not

allow material to flow back over the screw flights on injection. The screw is contained

within a barrel which has a hardened abrasion resistant inner surface.

The raw plastic material, usually in the form of pellets, is fed into the injection molding

machine, and advanced towards the mold by the injection unit. During this process, thematerial is melted by heat and pressure. The molten plastic is then injected into the moldvery quickly and the buildup of pressure packs and holds the material. The amount of

material that is injected is referred to as the shot. The injection time is difficult to calculate

accurately due to the complex and changing flow of the molten plastic into the mold.However, the injection time can be estimated by the shot volume, injection pressure, and

injection power.

Normally, ceramic resistance heaters are fitted around the barrel wall, these are used to

primarily heat the thermoplastic material in the barrel to the required processing

temperature and make up for heat loss through the barrel wall, due to the fact that, during

processing most of the heat required for processing is generated through shear imparted bythe screw. Thermocouple pockets are machined deep into the barrel wall so as to provide a

reasonable indication of melt temperature. Heat input can therefore be closed loop

controlled with a Proportional Integral and Derivative (PID) system. The screw (non-rotating) is driven forward under hydraulic pressure to discharge the thermoplastic material

out of the injection barrel through the injection nozzle, which forms an interface between

barrel and mould, and into the moulding tool itself.


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3)Holding Pressure and Cooling

The screw is held in the forward position for a set period of time, usually with a molten

'cushion' of thermoplastic material in front of the screw tip such that a 'holding' pressure

may be maintained on the solidifying material within the mould, thus allowingcompensating material to enter the mould as the moulded part solidifies and shrinks.Holding pressure may be initiated by one of three methods: by a set time in seconds from

the start of the injection fill phase; by the position of the screw in millimeters from the end

of injection stroke; or by the rise in hydraulic pressure as measured by a pressuretransducer in the mould itself or in the injection hydraulic system.

As the material solidifies to a point where hold pressure no longer has an effect on the

mould packing, the hold pressure may be decayed to zero, this will help minimize residualstresses in the resultant moulding. Once the hold pressure phase has been terminated the

mould must be held shut for a set period of cooling time. This time allows the heat in the

moulding to dissipate into the mould tool such that the moulding temperature falls to alevel where the moulding can be ejected from the mould without excessive distortion or

shrinkage. This usually requires the moulding to fall to a temperature below the rubbery

transition temperature of the thermoplastic or Tg (glass transition temperature). Depending

on the type of plastic this can be within a few degrees or over a temperature range. Mouldtemperature control is incorporated into the tool usually via channels for pressurized water

flow. The mould may be connected to a cooling unit or water heater depending on the

material being processed, type of component and production rate required.

The molten plastic that is inside the mold begins to cool as soon as it makes contact with

the interior mold surfaces. As the plastic cools, it will solidify into the shape of thedesired part. However, during cooling some shrinkage of the part may occur. The packing

of material in the injection stage allows additional material to flow into the mold and

reduce the amount of visible shrinkage. The mold cannot be opened until the requiredcooling time has elapsed. The cooling time can be estimated from several thermodynamic

properties of the plastic and the maximum wall thickness of the part.

4) Material Dosing or MeteringDuring the cooling phase, the barrel is recharged with material for the next moulding

cycle. The injection screw rotates and, due to its helical nature, material in granule or

powder form is drawn into the rear end of the barrel from a hopper feed. The throatconnecting the hopper to the injection barrel is usually water cooled to prevent early

melting and subsequent material bridging giving a disruption of feed. The screw rotation

speed is usually set in rpm which is measured using a proximity switch at the rear of thescrew. Screw rotation may be set as one constant speed throughout metering or as several

speed stages.


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The material is gradually transferred forward over the screw flights and progressively

melted such that when it arrives in front of the screw tip it should be fully molten and

homogenised. The molten material transferred in front of the tip progressively pushes thescrew back until the required shot size is reached. Increased shear is imparted to the

material by restricting the backward movement of the screw, this is done by restricting the

flow of hydraulic fluid leaving the injection cylinder. This is referred to as `back pressure'and it helps to homogenise the material and reduce the possibility of unmelted materialtransferring to the front of the screw.

5) EjectionAfter sufficient time has passed, the cooled part may be ejected from the mold by the

ejection system, which is attached to the rear half of the mold. When the mold is opened,

a mechanism is used to push the part out of the mold. Force must be applied to eject thepart because during cooling the part shrinks and adheres to the mold. In order to facilitate

the ejection of the part, a mold release agent can be sprayed onto the surfaces of the mold

cavity prior to injection of the material. The time that is required to open the mold andeject the part can be estimated from the dry cycle time of the machine and should include

time for the part to fall free of the mold. Once the part is ejected, the mold can be clamped

shut for the next shot to be injected.

After the injection molding cycle, some post processing is typically required. During

cooling, the material in the channels of the mold will solidify attached to the part. Thisexcess material, along with any flash that has occurred, must be trimmed from the part,

typically by using cutters. For some types of material, such as thermoplastics, the scrap

material that results from this trimming can be recycled by being placed into a plastic

grinder, also called regrind machines or granulators, which regrinds the scrap materialinto pellets. Due to some degradation of the material properties, the regrind must be

mixed with raw material in the proper regrind ratio to be reused in the injection molding

process.

Figure 6 : Injection Molded Part


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4.0 THE PROBLEM AND SOLUTION THAT OCCURRED DURING THE PROCESS,

THE POSSIBLE CAUSES THAT EFFECT THE PROCESS OR PRODUCT

1) Flash Defect

Figure 7: Flash Defect

The injection molded part defect known as Flash is that thin layer of plastic that flowsoutside of the cavity where the two halves of the injection mold meet. If the flash has to be

manually trimmed off by an operator or some other employee, it becomes a labor-intensive,

high cost problem. Plastic parts with flash are usually put in the scrap grinder or just

thrown away, depending on the plastic material and company guidelines.

Causes Solution

Material is too hot.

The injection pressure is too high.The clamping pressure is too low.

Worn or poorly fitting cavity/mold

plates, including, mold plate

deformations and obstructions

(grease, dirt, debris)

Overpacked sections cause increased

localized pressure.

An improperly designed venting

system, a very poor venting system,

or a venting system that is too deep.

Reduce the temperature

Lower the injection pressure.Reface the parting line.

Increase the clamping pressure.

Select machine with higher

clamp force.

Reduce pressures and shot size

to the minimum required.

Use the material supplier

recommended venting size.


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2) Short Shot

Figure 8 : Short Shot

As the name suggests, "short shot" means that not enough resin has flowed into the mold to

fill it adequately. The main causes for short shot are the mold condition or flow ability

problems with the resin. The problem is alleviated when a greater volume of resin flowsmore easily. This is done by raising temperature and pressure as well as enlarging the gate

to reduce resin resistance.

Cause Solution

Injection pressure is too low. Increase injection pressure.

Resin flows too slowly. Increase temperature in the cylinder.

Increase injection speed.

Mold temperature is too low andresin viscosity is too high. Increase the mold temperature.

Resin supply is insufficient. Increase the resin volume.

Too much flow resistance is at the

sprue, runner and gate.

Increase the sectional area of the gate,

sprue and runner, and shorten the length.

Make the sprue, runner and gate surfacesmore slippery.

Too much flow resistance is at the

sprue, runner and gate. Too muchflow resistance is in the cavity.

Change the gate position; increase the

thickness of the mold cavity; modifydesign to improve flow.


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3) Jetting

Figure 9 : Jetting

Figure 10 : Jetting Formation

"Jetting"is marks on the product surface that look like a worm has crawled across it.

When molds have a small cold slug well, the cool resign that comes out of the nozzle

will harden first on the mold surface. Subsequent hot resin that enters the mold will not

blend well with the cooler layer and will pile up, forming noticeable lines. This

problem can be addressed by changing the gate position or enlarging the gate to slow

the flow speed. Another method is to install a tap gate.


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Appearance

Plastic at a relatively low temperature is injected

from the nozzle during the initial stage of molding,

upon coming into contact with the mold wall, thisplast ic becomes hi gh ly viscous an d swir ling takes

place; fu rthermore, as hot te r plas ti c is cont inuall yinjected into the die, the original material is pusheddeeper into the die and leaves flow marks.

Cause

When the plastic temperature is low, the viscosity of

the molten material is high, and this become higher inthe case of plastic which has been injected into the

die; consequently, the resistance to flow is large and

je tt ing occurs .

When the die temperature is low, the material injectedinto it will be rapidly cooled, and the corresponding

increase in viscosity leads to the occurrence of thisprob lem.

When gates are small, the speed of plastic injectedinto the cavity will be relatively fast, and this leads to

the occurrence of jetting in many cases.

(Gate sectional area x flow speed = Fixed injectionamount )

Countermeasures

Molding conditions:

Increase the temperature of the plastic to lower its

viscosity.In the case of amorphous plastics, the id ealtemperature of the die is between 20deg.C and

30deg.C lower than the plastic's thermal deformation

temperature.

It is also beneficial to reduce the injection speed.Dies.


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4) Weld Line

Figure 11 : Weld Line

The weld line is the place where the resin flow contacts the two halves of the mold.

The line appears when the resin temperature is not high enough for the molted polyme to

completely blend together. Eliminating the weld line altogether is difficult, so molds are

designed to position the weld line where it will not show on the finished product and whereit will not weaken the product.

5) Sink Mark

Figure 12 : Sink Marks

Figure 13 : Sink Mark Occur


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A sink mark is a depression in the molded product surface. This is one of the greatest

causes for defects and most often occurs on thick ribs or other projecting parts. Sink marks

happen when cooling resin loses some of its volume, and this shrinkage is not replenished.

This volume reduction can also cause voids inside the plastic.

It is important to supply sufficient packing pressure to fill in areas where volume has been

reduced during resin cooling. Be sure that the wall thickness of the mold is uniform during

the mold design stage.

Cause Solution

Injection pressure is low. Increase injection pressure and time.

Cooling time is short. Lower the mold temperature and lengthen the

cooling time.

Resin shrinks excessivelyduring cooling.

Lower the cylinder temperature. Blend in aninorganic additive to the material to reduce

shrinkage.

The mold temperature is

high.

Lower the mold temperature.

Resin volume per shot is

insufficient.

Increase the resin measurement slightly.

*Be careful not to induce flashing

Molded products are too

thick.

If the thickness occurs at the reinforced parts

of the product, reduce the thickness and

design ribs instead. Design the productthickness to be as uniform as possible and do

not allow abrupt changes in thickness. Designthe rib and boss to be as small and thin as

possible.

The gate, sprue or runner

are small.

Increase the size so that pressure is delivered

evenly throughout the mold.

The gate position is

improper.

Position the gate where the mold is thick.

The gate is too big(when

the resin flows back out of

the cavity).

Reduce the gate size. Increase the packing

time.


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5.0 DETERMINE THE COST SOLUTION

As we know that cost is the most important role in any industrial machining. Injection

molding that is the main process we discuss is highly cost in every industrial because of the mass

usage of electrical supply and also human workers. So all the cost that have the factory store has

spent is equivalent to half million per year. Including tax for the government, maintenance andetc.

5.1 Production Cost (Before improvement)

MODAL DETAILS ESTIMATED COST (RM)

Expenses Modal New Material Manufacturing 90,000,000

Modify the plant layout -

Tools and Equipment

Production equipment 10,000,000

TOTAL 100,000,000

Working Modal (1

month)

Raw material purchase 700,000,000

Workers salary 60,000,000

Factory rental -

Electrical rental 9,000,000

Building / machine maintenance 10,000,000

TOTAL 779,000,00

TOTAL (Expenses + Working) 879,000,000


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An improvement we can made by deducting all the not necessary things and cut the cost of

not available electrical supply. Also, cut the working hours for the works that does not need their

work if most of the time it was doing by a machine. It may have to be monitor by a person but ithas not to be by too many person to monitoring one machine. So, by doing this we can save more

cost per year or per month.

5.2 Production Cost (After improvement)

MODAL DETAILS ESTIMATED COST

(RM)

Expenses Modal New Material Manufacturing 20,000,000

Modify the plant layout -

Tools and equipment -

Production equipment 20,000,000

TOTAL 40,000,000

Working Modal (1 month) Raw material purchase 400,000,000

Workers salary 60,000,000

Factory rental -

Electrical rental 7,000,000

Building / machine maintenance 5,000,000

TOTAL 472,000,000

TOTAL (Expenses +Working) 512,000,000


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5.3 Statement of modal budget

= Total production cost before improvement Total production cost after

improvement

= RM 879,000,000 RM 512,000,000

= RM 367,000,000

5.4 Cost for material or tools condition

Problem Clamping Force Injection Machine

Solving - Adjust the clamp force if the machine capacity does haveenough clamp force. But, if there clamp is damaged, the

clamp need to be replaced.Cost Required - RM318-RM 954 / Set

6.0 CONCLUSION

As a conclusion, after an improvement over the budget cost, we can see that we can save

about half of the actual value before the improvement have been made. All this improvement is

good for some company that has less demand for their product.

Most of the machine that has in this factory is highly cost. Fujitsu also have to use a

workers to complete most of the product and also to monitoring all the machine that does thejob. So, highly recommendation is totally directed to any factory that did not have any big input

and output so that it can reduced the cost of their spent.

Lastly, every company in manufacturing industries having a lot of problem related to theproduct defect from product process. This defect comes from many factors which is material,

manpower, machine maintenance and standard operation process like the above state. So, material

selection is very important to make sure that the material is suitable for that product in order to

avoid any problem or defect to the product.


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7.0 REFERENCE

1) https://www.skchem.com/english/Info/Troubleshoot/ac_sa_02.asp?mode=all&pg=&pc=2) http://www.umgabs.co.jp/en/trouble/molding.html3) http://www.paulsontraining.com/injection-molded-part-problems-and-their-solutions-flash/4) http://www.kenplas.com/service/imtroubleshooting.aspx5) Modul Teknologi Pembuatan.6) http://www.beejaymolding.com/injection-molding-disadvantages.html7) http://www.glstpes.com/resources_im_tr.php8) http://www.umgabs.co.jp/en/trouble/molding.html#t019) http://www.custompartnet.com/wu/InjectionMolding10) http://www.azom.com/article.aspx?ArticleID=265
https://www.skchem.com/english/Info/Troubleshoot/ac_sa_02.asp?mode=all&pg=&pc=http://www.umgabs.co.jp/en/trouble/molding.htmlhttp://www.paulsontraining.com/injection-molded-part-problems-and-their-solutions-flash/http://www.kenplas.com/service/imtroubleshooting.aspxhttp://www.beejaymolding.com/injection-molding-disadvantages.htmlhttp://www.glstpes.com/resources_im_tr.phphttp://www.umgabs.co.jp/en/trouble/molding.html#t01http://www.custompartnet.com/wu/InjectionMoldinghttp://www.azom.com/article.aspx?ArticleID=265http://www.azom.com/article.aspx?ArticleID=265http://www.azom.com/article.aspx?ArticleID=265http://www.custompartnet.com/wu/InjectionMoldinghttp://www.umgabs.co.jp/en/trouble/molding.html#t01http://www.glstpes.com/resources_im_tr.phphttp://www.beejaymolding.com/injection-molding-disadvantages.htmlhttp://www.kenplas.com/service/imtroubleshooting.aspxhttp://www.paulsontraining.com/injection-molded-part-problems-and-their-solutions-flash/http://www.umgabs.co.jp/en/trouble/molding.htmlhttps://www.skchem.com/english/Info/Troubleshoot/ac_sa_02.asp?mode=all&pg=&pc=

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