plastic industry development.pdf

Plastic industry problem
& development.
Automatic Control project 12/27/22 Dr. Tamer Khalaf

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Team members
Nu. Project member name B. N
1 Mohamed hassan Mohamed Abdelhamid 704533
2 Mohamed Kamal Mohamed Ebrahem 704540
3 Esmail Ahmed Maamoun Nada 704512
4 Magdy Mohamed Naguib Abd Alaaty 704527
5 Muhammad Ibrahim Abdullah Haggag 704528
6 Abdullah Elsaid Muhammad Noaman 704522
7 Mohamed El-Sayed Ahmed Mohamed Salem 704531
8 Mustafa Muhammad Shaaban Attia
(Power Section)
704056
9
10

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Content
Nu subject Page Nu.
1 preface 3
2 introduction 5
3 Problem definition 6
4 Project Objective 7
5 Problem 1 Background 9-12
6 Alternative solution 13-15
7 Problem 2 Background 16-18
8 Methodology planning problem 1 20-25
9 Methodology planning problem 2 26-27
10 Implementation problem 1 29-34
11 Implementation problem 2 35
12 Discussion 37
13 conclusion 37
14 Other problems with plastic products 38-48
15 Acknowledgements 49
16 Contact 49
17 Reference 49
18 The End 50

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preface
− At first, we offer our apologies for the number of pages over
conditional.
− the project team is made up of five members, but when we met
more than one problem, we pushed the enthusiasm to increase
the project's personnel, increase the search for problems and
more solutions
− so that this report will help everyone who reads it and faces a
problem of plastic products. The number of project team
members is 10.
− We depend on this block diagram to finding and solving
problem:

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CHAPTER (1)
Introduction, Problem Definition and Project Objective

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Introduction
Every day, the industry faces many problems and disturbance that affect the
performance of the industrial system, but some are more complex and difficult than
others. In both cases, you must have special skills to ensure you have access to the
right solutions in a timely manner. This is what's known as problem-solving skills.
Problem-solving skills as their name refers to reflect the ability to find effective
solutions to the various problems facing us in working or private life, and in a timely
manner that ensures that losses are avoided or minimized as much as possible. Hence
this skill was essentially for the engineer as the main driver of the process of
development and organization within the industrial organizations.
During the search stage for some problems. We found that the most problems that
occur within industrial organizations come from the production departments. So, all
our efforts focused on solving the problems facing factories and divisions of
production within companies.
We have suffered a lot in determining the type of plants targeted. The diversity of
industries resulting from technological development has been a source of delay in
choosing the type of industry. So, we had to choose very carefully from one type of
different industry. Fortunately, based on the results of the research, plastic industries
were selected.
The plastics industry has entered almost every home, factory, and office. Seats, tables,
cutlery, wall paint, cars, airplanes, space garages, TVs, audio-visual recorders,
lampposts, and clothes are not without plastic parts in their manufacture, making them
difficult to do without because plastic industries are today's industry in which billions
of dollars are invested in various countries.
Plastic has become something that is acceptable in the society in which we live, a
whole civilization, with new designs and shapes that make us say with great certainty
that we are living through the age of plastic. The plastics industry is closely linked to
some of the modern core industries such as petroleum distillation and chemical
industries and is also directly involved in other countless industries: metallurgical,
medical, electrical cable, electronics, household appliances and packaging industries.
etc.
Egypt's plastics industry has evolved rapidly in the last decade and the number of
factories has increased to 7120 registered factories in the Chamber of Chemical
Industries according to 2022 data as well as informal sector companies due to the
community's need for plastic products that are included in most used tools in our daily
lives.

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Problem definition
• Maintenance of production problems.
• Developing the production process.
1- Maintenance of production problems.
• The production department contains many different problems in the
production process that involve the performance and quality of the
products.
• For plastics factories there are many problems that arise in products that
cause a decline in production levels resulting in loss of funds and raw
materials and a waste of available capabilities.
• Some problems found during our visits to different factories
1. Flashing in product.
2. Weld lines.
3. Burn Marks.
4. Short Shot.
5. Sink Marks.
6. Splay.
7. Vacuum voids.
8. Jetting.
9. Warpage.
• The problem of Flashing in product is one of the most common problems
facing the production sector in plastics factories, which has caused
damage to the product and waste of raw materials and requires more
workers to clean the product and sometimes resort to maintenance of the
mold.
• Because it was the problem experienced by the plant during the visit, it
was chosen to be the subject of study, solution, and implementation.

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2- Developing the production process.
It was one of the most difficult requirements that we were directed during
our visit to some factories the customer requested to design handling robot
arm to:
− Utilization of its characteristic Add a permanent stick to the
product by direct injection on the stick
− handling the plastic parts after molding.
Project Objective
1- Develop problem solving skills engineered by project members.
2- Linking theoretical and practical content to solve industrial problems.
3- Develop scientific research skills and apply it to solve industrial
problems.
4- Solving some of the problems of industrial enterprises which increases
performance and saves time and profit.
5- Identify the most common problems in plastic products in factories and
find solutions to them.
6- Combining problems and solutions into a source of easy access for non-
project members.
7- Assist some engineers and technicians in plastic factories in finding
appropriate scientific solutions for the most common problem in the
plastic injection industry.
8- Recognize one of the most important methods of manufacturing plastic in
the present time.
9- Helping some factories to automate plastic injection machines.
10- Increase the skills of the project team in CAD software.
11- In our view, one of the most important objectives of the project is
to solve one of the most important problems of plastic injection, saving
time, saving money, reducing workers and increasing the engineering
awareness of the project team to solve engineering problems.

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CHAPTER (2)
Background and Evaluation of Proposed Alternative Solutions

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1- Maintenance of production problems.
➢ Flashing
What Is Flash In Injection Molding?
• An injection moulding flash occurs
when a thin film of plastic flows out of
the mold cavity during the injection. It
arises from several causes, such as
high injection rate and pressure, and
occurs majorly at the parting line (it
can also emerge from other locations).
• On escaping the mold cavity, the
molten plastic solidifies outside,
resembling flapping which can be
aesthetically displeasing or non-
functional. As a result, there is a need
to remove them in high and low-
volume injection molding or they can
damage the mold.

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What Causes Injection Molding Flash?
There are several reasons why you can experience plastic injection molding
flash. Below are a few you should be wary of during part injection molding:
Parting Line Mismatches
The mold’s parting line is the line where the
two halves of the mold meet. A mismatch in
the parting line due to debris or bad design
can prevent the complete sealing of the
mold. As a result, molten plastic will be
leaked during the injection.
Improper Venting
Improper venting can lead to the inability of air to escape
the mold cavity during the injection. When this occurs, it
can lead to the compressed trapped air increasing the
injection mold pressure and forcing the molten material.
Venting problems can also be due to old/worn-out vents,
which may permit too little or too much air to escape.
Clamping Pressure
Clamping pressure is the force required to keep the mold closed during the
injection process. When there is a problem with the clamping pressure, even
with a perfect parting line, the high injection pressure built up in the mold can
cause it to be forced open. As a result, this can cause an injection molding flash.

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Low Viscosity
Molten plastic with low viscosity flows out of the mold readily. Viscosity is
how easily the molten material flows, depending on the operating temperature
and pressure. Furthermore, the pressure and the temperature of the nozzle and
barrel can increase the viscosity of the molten material and contribute to the
formation of an injection molding flash. As a result, there is a high tendency for
the error defect to occur.
Overfilling the Mold
Overfilling the mold with the material will naturally result in leakage due to
increased injection pressure greater than the clamping pressure. These extra
materials from the cavity will attach to the final product, creating
Photos of plastic injection molds from the factory. An uncommon vertical
injection machine.

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Ways To Fix Flash in Injection Molding Process….
If you have experienced flash injection molding already, there are several ways
to fix the defect. Below are the common solutions you can try:
1. Using Hot Air
In the occurrence of injection molding flash, you can melt the flash into the
formed plastic using hot air. However, this is only suitable for removing thin
and fine flashes. For coarse flashes, it may not be easy to melt back into the
part’s surface, or it can compromise the final product’s appearance. Instead, you
can use hot air as the secondary deflashing method after mechanically removing
the flash.
2. Cryogenic Deflashing
Cryogenic deflashing is the most effective way to fix flashing in injection
molding. It involves cooling down the part using liquid nitrogen to a
temperature where the flash is easily removable. The process does not affect the
finish of the parts. However, commercially available cryogenic deflashing
machines are expensive.
3. Manual Deflashing
Manual deflashing is popular because of its versatility. It involves cutting
the injection mold flash using equipment such as scissors, knives, and
grinders. This removes flashes along the parting line of the final product.
Almost all engineering materials can be subjected to manual deflashing.
Deflashing by hand produces the highest quality (although this depends on
the operator) without putting the material under stress. Furthermore, it
enables quick inspection during the deflashing process.

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Alternative solution
How To Prevent Flash in Injection Molding?
Instead of fixing flash in injection molding, the better approach is to prevent its
occurrence. Below are a few ways to prevent injection mold flash:
Proper Cleaning and Maintenance of Mold
Cleaning up mold is necessary to prevent injection molding flash. To do this,
you can use a clean rag, mold cleanser, and compressed air to clean the surface
of molds. Before the molding process, ensure to remove debris, plastic, and
other contaminants that can prevent the mold from fully closing. Furthermore,
examine the mold carefully for plastic fragments hiding behind slides and deep
into the leader pins’ pockets.
Apply Enough Clamp Tonnage
The success of a molding process depends on the tonnage, point of force
exertion, and the clamping mechanism. However, you should be careful because
using too much force can damage the mold and the final part. To prevent flash
and other damages, apply the correct clamp tonnage.
Design for Manufacturability (DFM)
DfM is an effective way of preventing flash injection molding. It is a set of
design rules advocated by the industry so that you can manufacture parts at a
low cost in the shortest time with the highest quality. With a properly done
DfM, you can get various parameters such as ideal injection mold gate design,
wall thickness, hole design, and mold parting line design to produce a flash-free
part.

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This is very important in prototype injection molding. However, note that the
more the complexity, the need for features such as undercuts are used
in undercut injection molding which can increase the injection mold cost.
Use a Flash-free Mold
Avoid flash in your molded parts by using a flash-free mold. The mold has
high injection molding tolerance and is perfect where aesthetics and
functionality are important. Though they guarantee the best results, many
businesses may be unable to afford them.
Slow Down the Injection Rate
A high injection rate increases the pressure of injecting molten plastic. As a
result, there is an increasing tendency for injection molding. Slowing down the
injection rate will reduce the injection pressure. However, reducing the injection
rate will also lengthen the cycle time.
Photos of some of the moulds and machines in the factory.

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• matrix for the proposed alternative solutions
• After experimenting with all previous solutions on the machine control unit,
the solutions were unsatisfactory as the previous solutions showed a
temporary solution to the problem, but after a very short period the problem
reappears again Not only one solution is mold maintenance.
• Mold maintenance is the ultimate solution to this problem, but it is the most
expensive solution due to the interruption of the production process until the
mold maintenance as well as the cost of maintenance and transportation, but
all things require mold maintenance so we will clarify the maintenance
plan in the next chapter.
Maintenance
of the Mold
ApplyEnough
Clamping
force
DFM
changing
design
Slow Down
the Injection
Rate
Use a Flash-
free Mold
changing raw
material

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2- Developing the production process.
It was one of the most difficult requirements that we were directed during
our visit to some factories the customer requested to design handling robot
arm to:
− Utilization of its characteristic Add a permanent stick to the product
by direct injection on the stick
− handling the plastic parts after molding.
The importance of automation in production processes
• Robotic technology plays a significant role for plastic injection moulding
post processing. A robotic trimming cell provides superior repeatability
when compared with a human performing the same task, and it increases
flexibility by performing multiple operations. A robot will consistently
dispense the same amount of sealant or adhesives following a highly
repeatable pattern, offering greater shot accuracy, improving cycle times and
reducing waste.
• With or without vision, robots can pick and place plastic moulded parts for
further operations such as inspection, testing and hot stamping.
• In the assembly of injection moulded parts, robots can perform complex
welding operations using laser, ultrasonic and infrared, increasing precision
and driving down cycle times.
• Robots also meet the needs of automated finishing, ranging from PAD
printing to polishing.
• Further, automating the end of plastic production line can make a big
difference to production rates and cost effectiveness. Robots can liberate
workers from strenuous and repetitive manual work such as wrapping,
labelling, palletising, and provide flexibility for quality packing,
storage, and logistics.

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Given data
• The client gave us pictures of the machine and some dimensions and images
of the robot arm - like arm will be designed.

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Cad model
• This design is what we got, and we were able to conclude with the
dimensions and specifications available with us.
• We will discuss the implementation plan in the next chapter

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Chapter (3)
Methodology for Implementing Optimal Solution

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Maintenance of production problems
Injection Mold Maintenance
What is mold maintenance?
• Injection mold maintenance, or tool maintenance, refers to the
cleaning and repairs that are needed to keep an injection mold in the
best working order.
• Maintenance is performed routinely over the life of the mold
(preventative maintenance or PM), and when any problems arise.
Why is mold maintenance important?
• Many buyers overlook injection mold maintenance when choosing a
supplier, but it’s a critical aspect of a successful long-term molding
program.
• The condition of the injection mold affects the quality of the plastic
components produced. Performing necessary preventative
maintenance improves tool longevity and part quality by stopping
issues before they happen.

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What problems does mold neglect cause?
• Over time, the molding process can cause wear on a mold. For
example, a fine layer of material gradually builds up on the mold
surfaces; if left unchecked, this vent deposit can dent the tool, causing
flash and other unwanted part defects. It’s like owning a car.
• If you never perform regular injection mold maintenance, like changing
the oil, the mechanical parts will experience wear, reduce running
efficiency, and eventually fail.
• Unfortunately, many molders will avoid doing injection mold
maintenance until these quality problems arise or the tool breaks
down.
• Repairing the mold at this point can be expensive and can jeopardize
your part supply. However, if done regularly and correctly, preventative
maintenance can improve production and lower the overall cost of owning
the tool

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Methodology for Implementing Optimal Solution
1- Winch processing to carry the mold of the machine.
The available winch in the factory is OVER HEAD CRANE so we will prepare the
winch to carry the mold from the machine.
OVER HEAD CRANE
In the simplest of terms, an overhead crane is a machine, or piece of equipment, that
allows you to lift and move heavy materials from one location to another in a precise
manner. There is no “one size fits all” approach to defining an overhead crane, as each
overhead crane is carefully designed and engineered for a specific purpose or
application to suit a business’ material handling needs.
• Loading or unloading materials from a truck
• Moving materials around a facility more efficiently than a tow motor or
manpower can
• Flipping or pulling dies in and out of stamping machines at a manufacturing
facility
• Feeding raw material into a machine at a manufacturing facility
• Moving pieces or parts down an assembly line in a controlled fashion
• Moving containers around a shipyard or railyard

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2- Unwinding the splicing keys from the mold
3- Transfer of mold from machine and production department for
maintenance department
4- Unwinding molding by skilled workers.
5- You should know the main parts of injection molding:

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main cause of the problem
Movable blate and ejector plate always subjected to pressure through the
piston so plate will not be On Her Integrity have deflection.
So stamping It will not close tightly making there a chance to leak molten
plastic from the inner vacuum of the mold.

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6- Loaded it in CNC Milling machine to machining it and make it flat
surface
7- Assembly molding again.
8- Loaded it in overhead cranes to installing it in the injection machine.
9- Verification of maintenance output by inspection of products after
injection process.
10- The implementation process will be discussed in the next chapter.

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Developing the production process.
• This robot arm is about some mechanical parts and power transmission and
conveyer part so we will be manufacturing every part alone then we will
assembly it according to drawing sheets.
1- Base
2- A set of metal plates that
cut with certain dimensions
on the laser machine are
assembled by permanent
connections such as
welding or timed
connections such as screws.
3- Linear Base.
profile of aluminum used as
pillars to carry the liner used in
moving the movement
accurately and often
purchased at the required
dimensions.
4- Linear.
Used to transmit power to
moving head in desired
direction with high level of
accuracy.
5- Servo motor.
Source of power used to high
level of accuracy
6- Other transmission power component.

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other power transmission elements as gear and bearing
will be choices according to types of loading.
7- Holder attachments.
Also used to hold plastic products is used to put the
adhesive on the packaging so that the injection process is
done in an appropriate way. There is another part
assembly with this holder. This part is changeable to many
shapes, his function is to hold plastic parts and to enter label to mold in the
injection machine.
8- Another component
used to carry component A
set of metal plates that cut
with certain dimensions on
the laser machine are
assembled by permanent
connections such as welding
The manufacturing process will be discussed in the next chapter. The
previous discussion was the expression of parts and manufacturing
plans.

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CHAPTER (4)
Implementation and Performance Measurement

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Maintenance of production problems
Some factors after mold maintenance
1- The worker charged with changing the mold must possess great
experience and prior knowledge of the following steps so as not to
cause damage to the mold and restore it again, which means more
downtime and more financial loss.
2- Workers should be very good at machine control.
3- The injector responsible for introducing molten plastic into the mold
must stay away from the mold until the mold is unloaded without any
damage to any part of the injection machine
4- Then mold is ready for uninstalling

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5- Using eye bolt to carry mold in overhead cranes.
6- Clamping removing.
Clamping is used to
clamp mold in the
machine.
7- Loaded mold in
overhead cranes.

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8- Loaded in 3-axis CNC milling machine.
9- Mold machining in cnc milling machine.
10- Mold assembly after maintenance.

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11- Adding piston ring.
12- Loaded it in the overhead cranes.
13- Clamping tighting.

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14- Return injector to desired position.
15- Then check the output of
maintenance mold.
• We've already succeeded. Incredible
superstitious effort. We did it the first
time.
• The maintenance of the plastic
injection mold has been successful
after we have identified the problem
and developed all possible solutions.
We selected the optimal solution, and
the execution plans well.
• The mold maintenance process has
survived and here is the guide is a
plastic product free of annoying flash.

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After Before
By applying control system concept, we can say:

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Developing the production process.
• Our cad design is ready for manufacture in all parts as well as paper
drawing.
• This is an effort that must be fully completed, but the project is now in
the review and decision-making phase by the management department
of the factory.
• We are fully prepared to manufacture this design with ease through
project member.
• In the design process, we took care of the use of standard parts. For easy
purchasing instead of manufacturing especially in power transmission
parts.
• The design was presented to engineers with experience in
manufacturing such machines and was modified based on observations
taken from them.
• We plan with enthusiasm to implement this project to link the
conceptual and practical aspects to maximize its benefit from the
project.

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CHAPTER (5)
Discussion and Conclusion

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Discussion
− Plastic has become something that is acceptable in the society in which we live, a
whole civilization, with new designs and shapes that make us say with great
certainty that we are living through the age of plastic.
− The plastics industry is closely linked to some of the modern core industries such
as petroleum distillation and chemical industries and is also directly involved in
other countless industries: metallurgical, medical, electrical cable, electronics,
household appliances and packaging industries. etc.
− So, after deep research we selected this project plastic industry problem and
development. From the point of view of getting closer to this industry and
developing it because it lacks the scientific aspect.
− By applying the rules derived from this project to all problems in the industrial
sector, the project team is able to solve them on a strictly scientific basis.
Conclusion
− Industrial Sector is of great importance for economic development of country. It is
historical fact that countries with strong industrial sector have showed more
economic growth and development industrial sector have shown improvement in
national income and promoted living standard of population.
− The industry contains many industrial problems that reduce the expected revenues,
affecting the country's development process.
− One of the problems I have noticed through my direct contact with the industry
during the project is not to solve problems using a sound scientific basis.
− The manufacturing process must be followed up, examined from time to time,
problems discovered and solved. Because the production department is the main
part of the production process and is responsible for the financial gains achieved
by the system.
− The process of developing production departments is the fundamental difference
between a successful institution and a late one. So, I learned through the project
that the process of development would always like to continue.
− The best way to teach and benefit from experiences are real projects that link the
practical and theoretical aspect.
− The process of industrial automation of machines is very important and contributes
to saving time, which is the most important work in the industrial process. It also
reduces human error, increases productivity, and performs the tasks required of
them with high accuracy.

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CHAPTER (5)
Other problems with plastic products

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Most common plastic problem
1.Flow Lines
2.Sink Marks
3.Vacuum Voids
4.Surface Delamination
5.Weld Lines
6.Short Shots
7.Warping
8.Burn Marks
9.Jetting
• Most mistakes are caused by nescient personnel without the necessary
experience or the right tools at their disposal.
• Conversely, creative solutions and ingenuity abound in personnel with
the right experience and the correct combination of hardware and
software.
• Finding the right team of people with relevant expertise is the most
important part of the process.

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1- Flow Lines
Description: Flow lines are streaks, patterns, or lines - commonly off-toned
in colour - that show up on the prototype part as a consequence of the
physical path and cooling profile of the molten plastic as it flows into the
injection mold tooling cavity. Injection molded plastic begins its journey
through the part tooling via an entry section called a “gate.” It then flows
through the tool cavity and cools (eventually hardening into a solid).
Causes: Flow line defects are caused by the varying speed at which the
molten plastic flows as it changes direction through the contours and bends
inside the mold tool. They also occur when the plastic flows through
sections with varying wall thickness, or when the injection speed is too low
causing the plastic to solidify at different speeds.
Remedies:
1. Increase injection speeds and pressure to the optimal level, which
will ensure the cavities are filled properly (while not allowing the
molten plastic time to start cooling in the wrong spot). The
temperature of the molten plastic or the mold itself can also be
elevated to ensure the plastic does not cool down sufficiently to
cause the defect.
2. Round corners and locations where the wall thickness changes to
avoid sudden changes in direction and flow rate.
3. Locate the gate at a spot in the tool cavity with thin walls.

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2- Sink Marks
Description: Sink marks are small craters or depressions that develop in
thicker areas of the injection molded prototype when shrinkage occurs in
the inner portions of the finished product. The effect is somewhat similar to
sinkholes in topography, but caused by shrinkage rather than erosion.
Causes: Sink marks are often caused when the cooling time or the cooling
mechanism is insufficient for the plastic to fully cool and cure while in the
mold. They can also be caused by inadequate pressure in the cavity, or by
an excessive temperature at the gate. All else being equal, thick sections of
the injection molded part take longer to cool than thin ones and so are
more likely to be where sink marks are located.
Remedies:
1. Mold temperatures should be lowered, holding pressure increased,
and holding time prolonged to allow for more adequate cooling and
curing.
2. Reducing the thickness of the thickest wall sections will also ensure
faster cooling and help reduce the likelihood of sink marks.

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3- Vacuum Voids
Description: Vacuum voids are pockets of air trapped within or close to the
surface of an injection molded prototype.
Causes: Vacuum voids are often caused by uneven solidification between
the surface and the inner sections of the prototype. This can be aggravated
when the holding pressure is insufficient to condense the molten plastic in
the mold (and thereby force out air that would otherwise get trapped). Voids
can also develop from a part that is cast from a mold with two halves that
are not correctly aligned.
Remedies:
1. Locate the gate at the thickest part of the molding.
2. Switch to a less viscous plastic. This will ensure that less gas is
trapped as air is able to escape more rapidly.
3. Increase holding pressure as well as holding time.
4. Ensure that mold parts are perfectly aligned.

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4- Surface Delamination
Description: Surface delamination is a condition where thin surface layers
appear on the part due to a contaminant material. These layers appear like
coatings and can usually be peeled off (i.e. “delaminate”).
Causes: Foreign materials that find their way into the molten plastic
separate from the finished product because the contaminant and the plastic
cannot bond. The fact that they cannot bond not only has an affect on the
appearance of the prototype, but also on its strength. The contaminant acts
as a localized fault trapped within the plastic. An over-dependence on mold
release agents can also cause delamination.
Remedies:
1. Pre-dry the plastic properly before molding.
2. Increase the mold temperature.
3. Smooth out the corners and sharp turns in the mold design to avoid
sudden changes in melt flow.
4. Focus more on the ejection mechanism in the mold design to reduce
or eliminate the dependence on mold release agents.

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5- Weld Lines
Description: Weld lines are actually more like a plane than a line that
appears in a part where molten plastics meet each other as they flow from
two different parts of the mold.
Causes: Weld lines are caused by the inadequate bonding of two or more
flow fronts when there is partial solidification of the molten plastic.
Remedies:
1. Raise the temperature of the mold or molten plastic.
2. Increase the injection speed.
3. Adjust the design for the flow pattern to be a single source flow.
4. Switch to a less viscous plastic or one with a lower melting
temperature

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6- Short Shot
Description: As the term implies, short shots can be described as a
situation where a molding shot falls short. This means that the molten
plastic for some reason does not fully occupy the mold cavity or cavities,
resulting in a portion where there is no plastic. The finished product
becomes deficient because it is incomplete.
Causes: Short shots can be caused by a number of things. Incorrect
calibration of the shot or plasticizing capacities can result in the plastic
material being inadequate to fill the cavities. If the plastic is too viscous, it
may solidify before fully occupying all the cavities and result in a short shot.
Inadequate degassing or gas venting techniques can also result in short
shots because air is trapped and has no way to escape; plastic material
cannot occupy the space that air or gas is already occupying.
Remedies:
1. Select a less viscous plastic with higher flowability. This plastic will fill
the hardest-to-reach cavities.
2. Increase mold or melt temperature so as to increase flowability.
3. Account for gas generation by designing the mold so that gas is not
trapped within the mold and is properly vented.
4. Increase the material feed in the molding machine or switch to a
machine that has a higher material feed in the event that the
maximum material feed has been reached.

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7- Warping
Description: Warping (or warpage) is the deformation that occurs when
there is uneven shrinkage in the different parts of the molded component.
The result is a twisted, uneven, or bent shape where one was not intended.
Causes: Warping is usually caused by non-uniform cooling of the mold
material. Different cooling rates in different parts of the mold cause the
plastic to cool differently and thus create internal stresses. These stresses,
when released, lead to warping.
Remedies:
1. Ensure that the cooling time is sufficiently long and that it is slow
enough to avoid the development of residual stresses being locked
into the part.
2. Design the mold with uniform wall thickness and so that the plastic
flows in a single direction.
3. Select plastic materials that are less likely to shrink and deform.
Semi-crystalline materials are generally more prone to warping.

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8- Burn Marks
Description: Burn marks are discolorations, usually rust colored, that
appear on the surface of the injection molded prototypes.
Causes: Burn marks are caused either by the degradation of the plastic
material due to excessive heating or by injection speeds that are too fast.
Burn marks can also be caused by the overheating of trapped air, which
etches the surface of the molded part.
Remedies:
1. Reduce injection speeds.
2. Optimize gas venting and degassing.
3. Reduce mold and melt temperatures.

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9- Jetting
Description: Jetting refers to a situation where molten plastic fails to stick
to the mold surface due to the speed of injection. Being fluid, the molten
plastic solidifies in a state that shows the wavy folds of the jet stream on
the surface of the injection molded part.
Causes: Jetting occurs mostly when the melt temperature is too low and
the viscosity of the molten plastic becomes too high, thereby increasing the
resistance of its flow through the mold. When the plastic comes in contact
with the mold walls, it is rapidly cooled and the viscosity is increased. The
material that flows through behind that viscous plastic pushes the viscous
plastic further, leaving scrape marks on the surface of the finished product.
Remedies:
1. Increase mold and melt temperatures.
2. Increase the size of the gate so that the injection speed becomes
slower.
3. Optimize gate design to ensure adequate contact between the
molten plastic and the mold.

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Acknowledgements
The project team acknowledge support from:
1- Al-Shurbji Plastic Industries Factory.
2- Al BADR plast Factory.
3- Master mold company for mold design and manufacturing.
4- EOMD company for mold design and 3D scanning.
Contact and references
1- Master mold company.
10 th of Ramadan – tabarak complex-factory 66 – 01092449733-
0554492015
Mastermold256@yahoo.com – www.mastermold-hassanfathy.com
2- EOMD company.
Engineering office for mechanical design - 10 th of Ramadan
01026934004 – 01227403098 – mectrmohamed@gmail.com
3- Fine Tools.
Fine Tools for Molds, dies and special Tools
http://finetoolseg.com/?fbclid=IwAR1ZnRoKcGUeRUmBWzR3M_D
bHd7yjXVXEcSWcXiupgX4XvDVpSEHsTAZPg4
055 4365370 - 10 th of Ramadan - info@finetoolseg.com
01005753606 - 01208656862

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