Thinwall Molding Plastic

Molding parts with thinner wall sections has been prevalent in the packaging industry for many years, but the know how developed in packaging items is limited to the polyolefins and styrenics used in that product area.The benefits of thinwall molding are now sought in technical applications such as cellular phones and notebook computer housings.

When I was a worker at PT Nagai Plastic Indonesia, we produce printer part for PT Epson Indonesia. We are specialize in big part such as housing, coverprinter, paper support and stacker paper. Our facility has 80 Ton till 960 Ton injection machine and as a Maintenance Supervisor, I have to keep that facility work well everytime.
These parts has thinner wall section almost every section. Especially on the rib. Many rib for wall part support. Off course many problem appear. But many merit too. Lighter, smaller parts molded with less resin and fastercycle times are being produced which translate into lower unit costs for themolder. However, these products require higher viscosity engineering polymers such as PC, ABS, and PC/ABS blends, which raises new challenges. Part design,resins, processing, and molding equipment are all impactedand there is a need for boosting performance requirements to meet the high speeds and pressuresdemanded. New hot runner designs play a key role.
Thinwall molding can be defined as either wall sections of less than 1.5 mmor flow length over wall thickness ratios (L/T) of greater than 100. By eithermeasure, thinwall molding pushes conventional molding equipment to the limitby its effect on the flow area as shown in the following example.

Flow path for thinwall molding is 1/10th that of conventional molding

The nominal wall thickness of conventional vs. a thinnwall design are 3.0 mm and 0.75 mm, respectively.In both cases as the molten resin travels throughthe mold, a skin layer is formed approximately 0.25 mm thick immediately atthe mold wall. The resulting flow paths are cut to 2.5 mm for the conventionalmolding and 0.25 mm for thinwall. Reducing the thinwall flow area to just one-tenth that of conventional molding can push standard molding equipment beyond its limits.
The high injection speeds and pressures employed in thin wall molding to overcome this reduced flow path narrow the process window, but higher performance equipment widens the window sufficiantly to produce precision parts. In order to produce thinwall parts, an injection molding must be able to meet these three requirements :

• High injection speeds and pressures;
• Rugged large clamp/small injection unit combination;
• High performance controls and hydraulics.
  

Fill times of less than 0.5 s are typical in thinwall molding in order to fillthe mold before the skin layer builds up and blocks the flow channel.An injection unit equipped with an accumulator can achieve such rapid fill times. The accumulator allows for near instantaneous delivery of a largevolume of oil to the injection cylinder during fill. The accumulator shouldbe located as close as possible to the injection cylinder in order to minimize pressure drop and maximize responsiveness. This also reduces the amount of fittings and hoses which are a potential source of leakage.

Filled resins are used in some thinwall applications to impart necessary performance characteristics. Glass and graphite fillers of up to 20% by weight are used which results in excessive wear to the runner system, particularlyat the gate area where the resin experiences high shear rates and often makes a 90 deg. turn to enter the cavity. Standard beryllium copper tips should be replaced with more wear resistant materials that also provide high conductivity, easy access, and replaceability.Thinwall molding with engineering resins places new demands on injection molding equipment. High pressure, precision molding requires higher performance machines and hot runners that are specially suited to meet these rquirements.

Machine Tool

First month after graduation in 1995, I am a Sales Engineer of Machine Tool at PT. Super Adi Teknik. We sell many brand of machine tool such as Kitamura for CNC Milling Machine

A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by the selective removal of metal. The term machine tool is usually reserved for tools that used a power source other than human movement, but they can be powered by people if appropriately set up. Many historians of technology consider that the true machine tools were born when direct human involvement was removed from the shaping or stamping process of the different kinds of tools. For instance, they consider that lathe machine tools were invented around 1751 by Jacques de Vaucanson because he was the first to mount the cutting instrument on a mechanically adjustable head, taking it out of the hands of the operator.
Machine tools can be powered from a variety of sources. Human and animal power are options, as is energy captured through the use of waterwheels. However, machine tools really began to develop after the development of the steam engine, leading to the Industrial Revolution. Today, most are powered by electricity.
Machine tools can be operated manually, or under automatic control. Early machines used flywheels to stabilize their motion and had complex systems of gears and levers to control the machine and the piece being worked on. Soon after World War II, the NC, or numerical control, machine was developed. NC machines used a series of numbers punched on paper tape or punch cards to control their motion. In the 1960s, computers were added to give even more flexibility to the process. Such machines became known as CNC, or computer numerical control, machines. NC and CNC machines could precisely repeat sequences over and over, and could produce much more complex pieces than even the most skilled tool operators.
Before long, the machines could automatically change the specific cutting and shaping tools that were being used.

For example, a drill machine might contain a magazine with a variety of drill bits for producing holes of various sizes. Previously, either machine operators would usually have to manually change the bit or move the work piece to another station to perform these different operations. The next logical step was to combine several different machine tools together, all under computer control. These are known as machine centers, and have dramatically changed the way parts are made.

Today, it is possible to design a complex part on a computer, put a bar or rod into a machine center, and have a finished part within a matter of minutes.

Examples of machine tools are:

- Broach

• - Drill (like mill, but optimized to make holes)
• - Gear shaper
• - Hobbing machine
• - Lathe (work rotates, single-edge cutter is fixed)
• - Milling machine (work is fixed, multi-edge cutter rotates)
• - Shaper Stewart platform mills
• - Grinders

When fabricating or shaping parts, several techniques are used to remove unwanted metal. Among these are:

• EDM (electrical discharge machining)
• Grinding
• Multiple edge cutting tools
• Single edge cutting tools

Other techniques are used to add desired material. Devices that fabricate components by selective addition of material are called rapid prototyping machines.

Workshop with various Machine Tool

High Tech 5 Axis Machine

Bench Work Practice

When i am accepted as a student on Swiss Project on Politechnic for Mechanic ITB, in first year we are trained how to use manual tool such as handsaw, chisel and file. We have to make some shape as drawing to make sure the dimension tolerance is not run out. Whatever the shape is we don't allow to use machine tool. For example my name is Patrisisus Iwan, so i have to make first letter of my name that is 'P' letter. From unshape raw material must be shaped like P with tight dimension tolerance. For some student is a boring practice. You imagine that from 7 am till 2 pm frommonday to thursday in one year. On friday and saturday we study theoritical matter. Actually that practice build your sense of benchwork and machine tool. Because we are dealing with very tight tolerance you can say 50micron till 10micron so we must have enough skill for that job.

One case my customer Ishikawa corp want their mold to be modified. Their customerwant a 0,4mm round shape in their part. I make a electrode from copper.I cut it using lathe machine then i am finishing with file to shape it about 0,4mm. Because i think maybe is just for aesthetic matter,i just use manual tool. A file.The electrode i make then put it in EDM (Electro Discharge Machine) as cutting tool to cut the mold.

Using High Technology such as CNC EDM we just simply choose the parameter we want speed, surface finish and dimension tolerance etc.

With this machine you do not have to finishing like polishing this machine can achieve 0,1micron surface finish.

After finish i send the mold already modified for trial in plastic injection machine.

That surprise me is they cut the injection part in four section then they check it with Visual Projector. The result is good with plus minus 0,05mm. Wow... close enough.

Thanks to the 1 year practice.

Leak Test Machine

Leak Test Machine is used for showing any leaking on the component or sub assy component.Leakage is a process in which material is lost, intentionally or accidentally, gradually through the holes or defects of their containers. The material lost is usually fluid, usually liquid or powder and sometimes gas, from an imperfectly sealed container Many industries use this equipment for their component;
1. Chemical plant

2. Petrochemical plant: hydrocracker, vapocracker, catalytic reforming, steam reforming are all Hydrogen based processes were Hydrogen leak testing will be very appropriate,

3. Semiconductor industry; all processes taking place in a process chamber at atmospheric pressure or under vacuum; Diffusion, Oxidation, LPCVD, PECVD, PVD, Etch, Ion Implant, typically the later that implies vacuum will require Helium leak testing, while the other will make good use of Hydrogen leak testing,

4. Automotive: with airbag being the most demanding leak testing application (small gas tank, very high pressure, long shelf life) and air conditioning system (for best efficiency), fuel system (for low emission), exhaust system (for lowest pollution), engine and transmission (for no oil dripage), rims to keep tyre safe,

5. Medical: to ensure safe and long life implant (pacemaker) or a safe catheter

6. Airplane: to quickly and safely locate fuel leaks , to check oxygen distribution devices and cabin pressurization systems

7. Refrigeration and air conditioning systems-residential, commercial or industrial- in order to deliver best efficiency at the lowest loss rate of refrigerant gases (ozone depletion)

8. Power distribution for high voltage circuit breaker using SF6 as a dielectric

9. Drinking water distribution grid as today average leakage rate or efficiency is above 25%, wasting precious resources, water and power.

10.Sewage water collecting network as leaks can contaminate drinking water collection process;

Once ago we build a Leak Test Machine for Suzuki Motor Corp, for testing leakageon theirs part Cylinder Head Motor (combustion chamber and exhaust system).We make machine base,jig and mechanic parts.

For electric parts we use branded part as Fuji,Mitsubishi for PLC, Cosmo for Leakage Main Control,etc.

For pneumatic parts we use Festo Indonesia's parts. After we assemble all together, the system doesn't work. We doing check the control system or the cylinder head part is not good. Finally we find error in the control system. We change the pneumatic parts from Festo to SMC especially the micro valve then the system work well. But this cut US$ 3000 my profit.

Knuckle Washing Machine

I'm not realize how important cascade method to solve pneumatic problem untill i have a case . While ago i'm just ordinary student on Swiss Project in Politechnic for Mechanicin Bandung. I like technic but for study theoritically that a part i'm too lazy for. When i follow pneumatic lesson i like it but theoritically i don't catch it too much.

Eleven years later i must open my pneumatic book again.

My customer Tsuzuki Asama need a washing machine to wash off the car's component name is knuckle.After pass several cnc machine process that part must be washed through water contain anti rust agent. The part put in tray and that tray is moving up and down actionmoved by pneumatic cylinder.They want that machine is fully pneumatic without electric component.

Here is the challenge.

The action can be controlled, timing, how many times up and down action how deep is down level and other thing without use PLC.That is easy for professional but for me..feuwww.I try to design pneumatical scheme for that and try and try again. But stillcan not work. Then i open my lesson book about automation. I read again because already 11 years ago that i never read it well. And then i found about cascade method but still i can't understand it. After read well in a hour i found usage of motion diagram and control diagram are solve my problem.

Ceramic Component

Ceramic is made of clay then expose to heat reach up to 1300 degree C

or about 4000 degree F. Before heating process must lay on open air to

drop offwater contain from mold part.
My friend need component made by ceramic, because he try many

component made by many material like steel, alloy steel, carbide, etc.

The component use for carry something that must through heating

process by conveyor system.

He found that Ceramic more useful.

Ceramic mold is simple has three part body, top plate and bottom plate.

Material is put on the body part assy with bottom plate then put on top

plate then press it by press machine.

Thats it.

3D Design Interior and Animate It

Build a house or a construction site need good planning if not after finish it

we realize that is not our want.And if we want some modification or rebuilt

is not as simple as we make something like make castle from sand in the

beach.It need high investment. We can build it first in 3D design so we can

look around observe our design then we can make some modification or

redesign again if we don't want it.We can try various texture for our wall,

roof or furniture inside it.After we satisfy with our design , then the

construction company do the rest.

This design request by Indofood Corp to make meeting room in their office.

We can explore every detail of our room's design.

With 3D design software we can build everything in virtual dimension.

Try it!Its fun.

Palm Oil Processing Machine

Research and development work in many disciplines -biochemistry, chemical and mechanical engineering - and the establishment of plantations, which provided the opportunity for large-scale fully mechanised processing, resulted in the evolution of a sequence of processing steps designed to extract, from a harvested oil palm bunch, a high yield of a product of acceptable quality for the international edible oil trade. The oil winning process, in summary, involves the reception of fresh fruit bunches from the plantations, sterilizing and threshing of the bunches to free the palm fruit, mashing the fruit and pressing out the crude palm oil. The crude oil is further treated to purify and dry it for storage and export.
Large-scale plants, featuring all stages required to produce palm oil to international standards, are generally handling from 3 to 60 tonnes of FFB/hr. The large installations have mechanical handling systems (bucket and screw conveyers, pumps and pipelines) and operate continuously, depending on the availability of FFB. Boilers, fuelled by fibre and shell, produce superheated steam, used to generate electricity through turbine generators. The lower pressure steam from the turbine is used for heating purposes throughout the factory. Most processing operations are

automatically controlled and routine sampling and analysis by process control laboratories ensure smooth, efficient operation. Although such large installations are capital intensive, extraction rates of 23 - 24 percent palm oil per bunch can be achieved from good quality Tenera.
Conversion of crude palm oil to refined oil involves removal of the products of hydrolysis and oxidation, colour and flavour. After refining, the oil may be separated (fractionated) into liquid and solid phases by thermo-mechanical means (controlled cooling, crystallization, and filtering), and the liquid fraction (olein) is used extensively as a liquid cooking oil in tropical climates, competing successfully with the more expensive groundnut, corn, and sunflower oils.
Extraction of oil from the palm kernels is generally separate from palm oil extraction, and will often be carried out in mills that process other oilseeds (such as groundnuts, rapeseed, cottonseed, shea nuts or copra).

The stages in this process comprise grinding the kernels into small particles, heating (cooking), and extracting the oil using an oilseed expeller or petroleum-derived solvent. The oil then requires clarification in a filter press or by sedimentation. Extraction is a well-established industry, with large numbers of international manufacturers able to offer equipment that can process from 10 kg to several tonnes per hour.

Alongside the development of these large-scale fully mechanised oil palm mills and their installation in plantations supplying the international edible oil refining industry, small-scale village and artisanal processing has continued in Africa and Indonesia. Ventures range in throughput from a few hundred kilograms up to 8 tonnes FFB per day and supply crude oil to the domestic market.
Efforts to mechanise and improve traditional manual procedures have been undertaken by research bodies, development agencies, and private sector engineering companies, but these activities have been piecemeal and uncoordinated. They have generally concentrated on removing the tedium and drudgery from the mashing or pounding stage (digestion), and improving the efficiency of oil extraction. Small mechanical, motorised digesters (mainly scaled-down but unheated versions of the large-scale units described above), have been developed in most oil palm cultivating African and Asian countries.
Palm oil processors of all sizes go through these unit operational stages.

They differ in the level of mechanisation of each unit operation and the interconnecting materials transfer mechanisms that make the system batch or continuous. The scale of operations differs at the level of process and product quality control that may be achieved by the method of

mechanisation adopted.

The general flow diagram is as follows:

PALM OIL PROCESSING UNIT OPERATIONS

Harvesting technique and handling effects
In the early stages of fruit formation, the oil content of the fruit is very low.

As the fruit approaches maturity the formation of oil increases rapidly to about 50 percent of mesocarp weigh.

In a fresh ripe, un-bruised fruit the free fatty acid (FFA) content of the oil is below 0.3 percent.

However, in the ripe fruit the exocarp becomes soft and is more easily attacked by lipolytic enzymes, especially at the

base when the fruit becomes detached from the bunch. The enzymatic attack results in an increase in the FFA of the

oil through hydrolysis. Research has shown that if the fruit is bruised, the FFA in the damaged part of the fruit increases rapidly to 60 percent in an hour. There is therefore great variation in the composition and quality

within the bunch, depending on how much the bunch has been bruised.

Harvesting involves the cutting of the bunch from the tree and allowing it to fall to the ground by gravity. Fruits may be damaged in the process of pruning palm fronds to expose the bunch base to facilitate bunch cutting.

As the bunch (weighing about 25 kg) falls to the ground the impact bruises the fruit. During loading and unloading of bunches into and out of transport containers there are further opportunities for the fruit to be bruised.

In Africa most bunches are conveyed to the processing site in baskets carried on the head. In Indonesia some do that but now mostly by truck bring bunches. To dismount the load, the tendency is to dump contents of the basket onto the ground. This results in more bruises. Sometimes trucks and push carts, unable to set bunches down gently, convey the cargo from

the villages to the processing site. Again, tumbling the fruit bunches from the carriers is rough, resulting in bruising of the soft exocarp. In any case care should be exercised in handling the fruit to avoid excessive bruising.

One answer to the many ways in which harvesting, transportation and handling of bunches can cause fruit to be damaged is to process the fruit as early as possible after harvest, say within 48 hours. However the author believes it is better to leave the fruit to ferment for a few days before

processing. Connoisseurs of good edible palm oil know that the increased FFA only adds ‘bite’ to the oil flavour. At worst, the high FFA content oil has good laxative effects. The free fatty acid content is not a quality issue for those who consume the crude oil directly, although it is for oil

refiners, who have a problem with neutralization of high FFA content palm oil.

The main point of clarification is to separate the oil from its entrained impurities. The fluid coming out of the press is a mixture of palm oil, water, cell debris, fibrous material and ‘non-oily solids’. Because of the non-oily solids the mixture is very thick (viscous). Hot water is therefore added to the press output mixture to thin it. The dilution (addition of water) provides a barrier causing the heavy solids to fall to the bottom of the container while the lighter oil droplets flow through the watery mixture to the top when heat is applied to break the emulsion (oil suspended in water with the aid of gums and resins). Water is added in a ratio of 3:1.
The diluted mixture is passed through a screen to remove coarse fibre.

The screened mixture is boiled from one or two hours and then allowed to settle by gravity in the large tank so that the palm oil, being lighter than water, will separate and rise to the top. The clear oil is decanted into a reception tank. This clarified oil still contains traces of water and dirt.

To prevent increasing FFA through autocatalytic hydrolysis of the oil, the moisture content of the oil must be reduced to 0.15 to 0.25 percent.

Re-heating the decanted oil in a cooking pot and carefully skimming off the dried oil from any engrained dirt removes any residual moisture. Continuous clarifiers consist of three compartments to treat the crude mixture, dry decanted oil and hold finished oil in an outer shell as a heat exchanger.

In next year our team will plan to build small scale CPO (5 tonnes FFB/day) processing for remotes area of Indonesia especially Sumatra island for first priority.

We make machine processing from FFB to CPO and CPO to cooking oil and bar soap. For oil that are produced from kernel is used for medical industry.

Many farmer could not process their bunches because of CPO price is too low or already decompose on the way to the factory. With this small scale machine process, they can process by themself for their welfare.

So we prepare for all technic manufacturing and make improvement on machine so can used by unskill man(the farmer itself).

Food Processing Plastic Component

Indofood Corp has conveyor system is used for carry away wheat flour

from bottom site to hopper on top of food processing machine.Conveyor

has some bucket rotate on railway system. Material made of plastic

PA6 (nylon) or PP.

They need bucket replacement and they give me sample.Before that they

already search the available plastic maker to make it.Many maker give a

quotation US$ 10,000.00-20,000.00 for 400x700x350mm mold size

with 1 cavity investment and US$ 8.00 for production cost of that part.

I just give price 40% from that above price for mold and US$ 7.00 for

production cost. Because they just need only 200pcs of bucket. So the

mold doesn't have to use mold steel and the tolerance isn't too precisely.

Deal!

I take the sample to reverse engineering it just with ruler and

pocket caliper. Go to mold design process within many consideration,

machine ability, dead line,cost and handling.Our machine ability only

400x600mm process stroke.Whoala! design ok get ready to machine

process. To speed up i divide the process one part on our machine one

part to subcontractor.

Subcon A(Stalion)give a quotation US$ 600.

Subcon B(Coppal) give US$ 2000.

I give it to Stalion.

After mold is finish we deliver to AA Plastic Corp to make plastic part

using injection machine 550Ton.And then i send that part to Indofood.

They happy we are happy too.

How to Think Design then Create

How to think design and create something stage by stage :

First of all of course think about something and create it in mind.
Then make a sketch about it.













For make it more realistic design it by 3D software like UG,ProE,Catia
or SolidWorks



















If that request from second party must has approval or next discuss
about it.
We can share it with face to face and if this is far distance bussiness we
can share by mail. We can save the design as application file or
presentation file like eDrawings format. So the second party can see
our design even they don't have 3D software. The file can be eDrw ,
exe or html file that still the second party can use the file as 3D format
when they receive it. They can rotate it or display manipulate it as 3D.















If there is modification they can put a mark or information on the
design then send it back to us. If they approve after that we can use
the design for marketing purpose like advertise it, we can use software
rendering like 3DMax atau Vray SketchUp.




















For create it we can use several method by machining, mold or hand
making.
By machining example are used by CNC router or CNC milling for
precision reason.

3D Design and 3D Machining

WHAT YOU THINK IN YOUR MIND
WE CAN DESIGN IT FOR YOU
WHAT YOU HAVE IN YOUR HAND
WE CAN REVERSE ENGINEERING FOR YOU
WHAT YOU NEED IN YOUR LIFE
WE CAN CREATE IT FOR YOU

With CNC Mill HURCO VMX24 (GERFA Trading Company)we can
create 2D and 3D part/component/equipment/souvenir with
dimension 400x600x400mm. For dimension bigger than that
using 'split technology'. Using cutting tool like Hitachi
(PrimaTigon Trading Company) ASR HighFeed Mill with
insert EPNW and ETM Solid Carbide EndMill will speed up
our process. The price are cheaper than Taegutec Tool or
Sandvick but result higher.

Die Making Optimizing

Die Making Optimization Methodology
1. Identify the best process and flow
2. Implement 3-D design and manufacturing
3. Implement High Performance Machine and Tool

1. Identify the best process and flow

• Analyzing the formability of the material early in the development

cycle to allow for product design optimization.

• Predicting metal flow during the stamping process.
• Determining the final dimensions of the stamped part.
• Preventing flow induced defects such as excessive thinning of

material and wrinkling.

• Reducing amount of scrap material.
• Increasing die life.
• Use software for optimize design like DIESTAMP, FAST BLANK,

FASTFORM etc.

2. Implement 3-D design and manufacturing

































With Curvature radius analysis we can determine cutting tool we used
in machining process so all surfaces can be cut perfectly.

Press Part Example










Modification on dies is needed as drawing
specification. Dies must have additional radii for material spring in.



3. Implement high performance machine and tool

As we can see this graphic, "Processing costs" have highest initial cost

that need cost down.
Usage of machine and tool effectively can achive with the formula below :

After that we can create some simulation from machining software with

various cutting strategy to get quality and machining time as fast as

possible relate to the machining cost effeciency.

Machining time can be observed everytime we run a simulation.
Conclusion :

There are some problem that may appear in case doing the machining
process from a design part.

1. Process translate or converte from customer's drawing file to another
CAD software or CAM software, it can happened format distortion or
interference format on surface part.
CAM software read all surface contour into G-code/cutting movement
on machine, hence many case the result from process machining did not
macth with the original drawing or design.
2. So that all surface can be machined all surface contour must known
by CAM operator to determine tool usage.

If surface contour can not known than surface contour is not cut perfectly
that in conventional technnic depend mostly in die spotting/die setting
machine to cu manually by portable grinding tool or files or another
equipment.
Today mostly CAD/CAM software already adopted all above features.
The difference only in display and familiar icon to access that features.

Plastic Recycle

IT'S PLASTIC!
Americans seem to have a love–hate affair with plastic. We look down

on plastic imitations of natural products and fibers. They are cheap, we

say. We all want real leather, for example, rather than imitation plastic.
Yet we are using plastic products more than ever before. We cover our

food in plastic wrap, drink coffee from Styrofoam® cups, wear clothes

made from man-made fibers like nylon, polyester, and rayon, and even

buy our plastic things with plastic credit cards! We use plastic hundreds

of times every day.
Plastic is a versatile product. Plastic can be flexible or rigid; transparent

or opaque. It can look like leather, wood, or silk. It can be made into toys

or heart valves. Altogether there are more than 10,000 different kinds

of plastics. The basic raw materials for plastic are petroleum and/or

natural gas. These fossil fuels are sometimes combined with other

elements, such as oxygen or chlorine, to make different types of plastic.
Plastics are not the waste and energy culprits that some people think

they are. Plastics are really very energy efficient. It takes 20-40

percent less energy to manufacture plastic grocery bags than paper

ones. And, since plastics are lightweight and take up so little space,

it is much more efficient to transport them. It takes seven trucks to

deliver the same number of paper bags as can be carried in one

truckload of plastic bags.

DECODING PLASTICS

PET Polyethylene Terephthalate Two-liter beverage bottles,

mouthwash bottles, boil-in-bag pouches.
HDPE High Density Polyethylene Milk jugs, trash bags, detergent bottles.
PVC Polyvinyl Chloride Cooking oil bottles, packaging around meat.
LDPE Low Density Polyethylene Grocery bags, produce bags, food

wrap, bread bags.
PP Polypropylene Yogurt containers, shampoo bottles, straws,

margarine tubs, diapers.
PS Polystyrene Hot beverage cups, take-home boxes, egg cartons, meat

trays, cd cases.
OTHER All other types of plastics or packaging made from more than

one type of plastic.

DISPOSING OF PLASTIC ANOTHER look PLASTICS RECYCLING IN

AMERICA

Today, Americans recycle only 5 percent of all the plastics produced in

this country. Why aren’t we recycling more? There is no simple answer.
Part of the issue in recycling plastics is the cost. To remain competitive

in the global marketplace, manufacturers usually choose the cheapest

option for making products. New plastic resin, or virgin resin, often costs

less than recycled plastic. Until recently, when the U.S, experienced

massive hurricanes, virgin resin was cheaper than recycled plastic.

After the hurricanes in 2005, supplies of oil and natural gas--the building

blocks of virgin resins--became limited and more expensive. Prices for

virgin resin soared, and the demand for recycled plastics increased.
Another important consideration is human behavior. Surveys conducted

by Proctor & Gamble and other companies show that while most people

expect their plastic to be recycled, they won't go out of their way or pay

a few cents more to buy products made of recycled plastic.
There are success stories in plastics recycling, nonetheless. Soft-drink

bottles made of polyethylene terephthalate (PET) can be melted down

and made into carpet, t-shirts, stuffing for ski jackets, or molded into

bottles again. In 1999, Ford Motor Company used more than 60 million

2-liter plastic soda bottles (7.5 million pounds) to make grille

reinforcements, window frames, engine covers and trunk carpets for

its new vehicles.

In recent years, several plastics recycling companies have closed their

doors. They claimed they could not sell their products at a price that

would allow them to stay in business. Thanks to the relatively low cost

of petroleum today, the price of virgin plastic is so inexpensive that

recycled plastic cannot compete. The price of virgin resin is about 40

percent lower than that of recycled resin.
Because recycled plastic is more expensive, people aren’t exactly lining

up to buy it. Surveys conducted by Procter & Gamble and others show

that while most people expect their plastic to be recycled, they won’t go

out of their way or pay a few cents more to buy a bottle made of recycled

plastic. Recyclers say plastics recycling won’t be profitable until we close

the loop by creating more demand for recycled plastics.
Soft-drink bottles, however, are one success story in plastics recycling.

Made of polyethylene terephthalate (PETE), they can be melted down

and made into carpet, t-shirts, stuffing for ski jackets, or molded into

bottles again. When a soft-drink bottle is recycled into another soft-drink

bottle, the loop is closed.
Is plastic trash choking the Earth with Styrofoam® cups and fast-food

plates? Not really. That’s just another misconception. By weight, plastics

make up about 11 percent of America’s municipal solid waste.

In comparison, paper makes up about 35 percent.
Of course, plastics are generally very lightweight. When plastics are

buried in a landfill, they occupy about 25 percent of the space. Putting

plastics into landfills is not always the best disposal method. There are

two other alternatives: recycling and incineration.
These methods recover some of the value from the plastic. Recycling

recovers the raw material, which can then be used to make new plastic

products. Incineration recovers the chemical energy, which can be used

to produce steam and electricity. Landfilling plastics does neither of

these things. The value of landfilled plastic is buried forever.
RECYCLING PLASTICS
Recycling plastics is easy. First, you should learn what types of plastics

can be recycled and only give your collector those types of plastics.
Resist the temptation to slip plastics that recyclers don’t want into the

recycling bin. Plastics have different formulations and should be sorted

before they are recycled to make new products. Mixed plastics can be

recycled, but they are not as valuable as sorted plastics because the

recycled plastic’s physical properties, such as strength, may vary with

each batch.
Once you know what kinds of plastics your recycler wants, you should

follow the wash and squash rule—rinse the container and squash it.

You may leave the paper labels on the container, but throw away the

plastic caps. Plastic caps are usually made from a different type of plastic

than the container and cannot be easily recycled.

HOW PLASTIC IS RECYCLED
A recycling plant uses seven steps to turn plastic trash into recycled

plastic:
1. Inspection Workers inspect the plastic trash for contaminants like rock

and glass, and for plastics that the plant cannot recycle.
2. Chopping and Washing The plastic is washed and chopped into flakes.
3. Flotation Tank If mixed plastics are being recycled, they are sorted in

a flotation tank, where some types of plastic sink and others float.
4. Drying The plastic flakes are dried in a tumble dryer.
5. Melting The dried flakes are fed into an extruder, where heat and

pressure melt the plastic. Different types of plastics melt at different

temperatures.
6. Filtering The molten plastic is forced through a fine screen to remove

any contaminants that slipped through the washing process. The molten

plastic is then formed into strands.
7. Pelletizing The strands are cooled in water, then chopped into uniform

pellets. Manufacturing companies buy the plastic pellets from recyclers

to make new products. Recycled plastics also can be made into flowerpots,

lumber, and carpeting.

ENERGY FROM PLASTIC
Because plastics are made from fossil fuels, you can think of them as

another form of stored energy. Pound for pound, plastics contain as much

energy as petroleum or natural gas, and much more energy than other

types of garbage. This makes plastic an ideal fuel for waste-to-energy

plants.
Waste-to-energy plants burn garbage and use the heat energy released

during combustion to make steam or electricity. They turn garbage into

useful energy. So, should we burn plastics or recycle them? It depends.

Sometimes it takes more energy to make a product from recycled plastics

than it does to make it from all-new materials. If that’s the case, it makes

more sense to burn the plastics at a waste-to-energy plant than to recycle

them. Burning plastics can supply an abundant amount of energy, while

reducing the cost of waste disposal and saving landfill space.
PAPER OR PLASTIC?
A paper cup or a plastic cup? Should you choose paper cups over plastic

cups since the paper cups are made from natural wood products and will

degrade? Not if the plastic cup is polystyrene (another name for Styrofoam®).
A study by Canadian scientist Martin Hocking shows that making a paper cup

uses as much petroleum or natural gas as a polystyrene cup. Plus, the paper

cup uses wood pulp. The Canadian study said, “The paper cup consumes

12 times as much steam, 36 times as much electricity, and twice as much

cooling water as the plastic cup.” And because the paper cup uses more

raw materials and energy, it also costs 2.5 times more than the plastic

cup. But the paper cup will degrade, right? Probably not. Modern landfills

are designed to inhibit degradation so that toxic wastes do not seep into

the surrounding soil and groundwater. The paper cup will still be a paper

cup 20 years from now.

Learn more about how long it takes buried trash to disappear.
DEGRADABLE plastic
Degrade is another word for rot. It’s nature’s way of getting rid of dead

plants and animals or the things made from them. Of course, plastics

are man-made materials, but scientists have figured out two ways to

make plastics degrade: biodegradation and photodegradation.
Biodegradable plastics are made with five percent cornstarch or vegetable

oil. The idea is that hungry bacteria will devour the starch or oil in the

plastic, causing the plastic to disintegrate into a fine dust. That is the idea,

but does it really work? No, say both environmentalists and plastics

manufacturers. Nothing degrades quickly in a modern landfill, not even

organic wastes like paper and food scraps, so there is no reason to think

that the corn starch in biodegradable plastics will disappear overnight

either. Modern landfills are designed to inhibit degradation, not promote

it. The idea is to keep wastes in, so landfill contaminants do not seep into

the surrounding environment. In addition, biodegradable plastics cannot

be recycled because the starch or oil additive compromises the quality

of recycled plastics.
Photodegradable plastics are a different matter. They use no organic

additives. They are made with a special type of plastic that breaks down

and becomes brittle in the presence of sunlight. Of course, that means

photodegradable plastics do not break down when they are covered by

leaves or snow, or when they are buried in a landfill.
The maker of the plastic six-ring carrier that is used to attach six cans of

soda, beer, and other beverages, says its photodegradable carrier loses

75 percent of its strength when exposed to sunlight after just a few days,

and totally disintegrates within a matter of weeks. This means if an animal

were to become entangled in the six-ring carrier, it could rip through the

weakened pack to free itself. Since photodegradable plastics contain no

organic additives, they can also be recycled, unlike their biodegradable cousins.

Last Revised: September 2006Source: National Energy Education

Development Project, Museum of Solid Waste , 2006