Design of plastic injection parts

Design of plastic injection parts



طراحی قطعات تزریق پلاستیک

There are currently several ways to create objects to create production. 
If these products are made of plastic, there are many approaches that we can use to build them.
 One of these methods is plastic injection, which requires the implementation of plastic injection
 mold. However, there is currently no conventional injection molding. Engaging in such a process
 requires a great deal of knowledge about the devices and their process.
 In this scientific paper, we show you some of the aspects that we consider in the implementation of
 plastic parts for plastic injection molds, so that we can save our customers' time and money in the
 long run.
Table of Contents

What is injection molding?
What points should we take into account when implementing plastic injection molding?
Radial margins
Solid vs. hollow
Hollow symbols
Hafiz beams / joints
Connect parts normally
Separation lines
Location of fly pins
Condition of pores and material flow
Material and thickness
Recommended wall thickness according to the type of material:
What is injection molding?
Injection molding
It is a method in which plastic is melted and plastic is injected into a metal mold.
This mold consists of two parts, the "A" and "B" sides of the halves become independent of 
each other and allow the plastic piece to come out of the mold after receiving it and produce 
plastic parts.

What should we consider when implementing plastic injection molding?

Draft Angle Draft Angles are shown to the plastic to exit the mold. 
Apart from the suggested angles, this part shows significant resistance to friction when exiting
 the mold. Suggested angles should be both inside and outside the piece.

Radial sides

Having the sides and radial sides (inside and out) of the piece is a special advantage.

This property results in a looser protrusion of the part when the plastic is injected – in connection with the projecting

sides – and a more relaxed lubrication of the material. Most importantly, it prevents gaps from being concentrated by the

stress intensity in the construction part.

Example of radial edges in the implementation of a plastic part

Note that the radial sides must, in other words, protect the wall thickness, 
in the sense that if the inner thickness is r = ½ then the outer thickness must be R = 3 *..


Undercuts are times when both halves of the mold are removed. These cuts can appear anywhere in 
the depilation. These are unacceptable in the depilation as much as not choosing the right angle. 
However, for now, some undercuts are necessary or unavoidable. In these cases, the necessary undercuts
 are produced by sliding or by shaking the piece in the mold. Keep in mind that the construction of 
undercuts when creating a plastic injection mold is very It is expensive and should be at least as 

Solid vs. hollow

As the plastic cools in the mold, it shrinks; This is a common feature for most materials. 
The construction of a hollow (porous) component in front of the solid part helps to reduce the
 amount of shrinkage or twist that occurs during the cooling process of the accident. It also helps
 reduce the cost of materials needed to use the part. There are many ways to make a hollow (porous)
Hollow symbols

In plastic injection, the recess marks, as they appear, appear at a point or part of a plastic
 surface / or feel as if they have sunk inside the part.

These signs are constructed by a number of cases:

• The wall thickness will be uncoordinated (may cause cavities);

• Improper radius on the sides;

• Thickness of protective beams (will be followed by the fight option);

• Sharp edges;

• Non-porous parts

Displacement of improperly constructed parts shows that they are prone to depression and cavity
Hafiz beams / joints

Protective beams and joints are used to further support the product walls. They are mainly used in 
two item situations:

(1) Where the part holds walls that interact with each other at a 90-degree angle.
(2) where a section may be too long or too large and the wall thickness of that section too loose 
or too weak. Hafiz poles tend to make the most worthy effort in the necessary parts, such as entering 
the movement at the time of a long piece.

When laying retaining beams, the main thing is that the angle is predicted and do not consider
 the thickness of the foundation to be more than 2/3 of the wall thickness attached to it.
Design of plastic injection parts
تزریق پلاستیک

Design of plastic injection parts


Connecting parts to each other

Products generally consist of two or more connected parts. These parts can be fastened together with base protrusions, hooks, fasteners, screws, etc. A common way to do one of the two installments is to use screws from the foundation ridges method. Having sides / grooves in which the parts react with each other and mix is ​​one of the common characteristics in integrating parts. When designing how to connect the parts, consider the past points during this presentation, such as prefabricated angles, porous parts, guardrails, and so on.

Separation lines are lines in which the two parts of the mold are matched and matched.
 These lines lead to the entry of a physical line on the piece that is both visible and tangible. 
However, these lines can be hidden in the shape of the edges of the piece, or at least reach. When
 making a plastic injection piece, keep in mind its separation lines.

Design of plastic injection parts

The condition of the orifice is occasionally determined by the following: Where it is less noticeable Where it does not interfere with other parts of the piece How plastic material flows in the piece Or a combination of all of these. The location of the hole in this image is shown where it is independent of the plastic part Material and thickness

A material should be selected depending on 
(1) the way the property is operated,
 (2) the environment in which it is located, and 
(3) the designer's priority. These materials determine what the piece will look like, how it will
 look, and how it will work. Some are flexible, some are hardworking, some are hard-working, and 
some are vulnerable. The type of material selected often has a significant impact on the fabrication
 of the part. We may need to remove or add some guardrails, and the walls may need to be wet-soaked
 or thin-soaked, and so on.

Recommended wall thickness based on material type:

The sum of the concepts presented in the previous slides is only sometimes due to the correct 
engineering methods that you have to consider when applying the parts that are made by plastic
 injection molding.

These paths are also known as DFMs (deployment for capability and capability) and should be used as 
a continuous list analysis throughout the product design and redesign process.

Keep in mind that paying attention to these ways will save on construction costs and ensure 
long-term service for customers.

The process of creating and manufacturing plastic parts

Design of plastic injection parts

As mentioned, making plastic parts requires a delicate knowledge of plastic materials and what kind of plastic material is used to create the part, how much heat will be given to the rubber and how strong this plastic is. In order for a plastic piece to be constructed, it must be specified above what the piece is used for and where it is used. Is there going to be a plastic bowl that can be used in the microwave, or is there a bottle of mineral water, or is there a bottle that holds chemicals?

Once it has been determined that the constructed part has a useful application, the strength of the
property and the type of plastic material can be determined.

Construction of plastic parts

Design of plastic injection parts

Having such information greatly reduces the cost of manufacturing and molding and embroidering the material. As mentioned, engineering impregnation has a very high impact on the impregnation and creation of plastic molds, cooled sections of plastic parts and the like.

Plastics and raw materials are not the first cheap plastic constructions and because of the fact that
plastic parts can be created in one hand and in bulk, they have high demands and applications
compared to metal parts. For this reason, the construction process of plastic parts is of great
importance. You can see the value sheet of plastic mold making and plastic injection for more data.

Design of plastic injection parts

Ghodrat mentioned that one of the most important and common methods of manufacturing plastic parts

is the use of injection machines. By using these machines, the authority can use the plastic
injection mold. The process and method of operation of these machines is as follows: Above, a plastic injection mold is made and installed on the injection machine. After that, uncooked plastic materials enter the machine and after heating and melting, they are
directed to the injection mold by the method of one cylinder. These materials are then injected into the mold at very high pressure and a plastic piece is
produced. After making the plastic parts in this way, we have to cool them and take them out of the mold.

Implementation of plastic parts and their properties

The construction process of plastic parts using injection molding machine is very fast and rare. From injection machines to making plastic parts, the item is used in all industries from car manufacturing to gaming accessories. Another mold that can be used by the authority to make plastic parts is the air mold. Almost all plastic bottles and cans must be made using molds. The process of making plastic parts using injection molds and pneumatic molds.

Closing step In this step, the mold made for the construction of the part must be installed on
 the injection machine or the pneumatic construction machine. This template is made before this and 
based on the proposed design.

Injection stage or sending hot air: In this stage, molten plastic material is injected into the mold
 or it is suspected by using hot air inside the mold.

Cooling stage: In this stage, the formed parts enter the cooling process. At this stage, the part
 may be smaller than the first example due to the contraction interval due to the constructor interval.
 In general, the cooling stage of the piece never leaves the inside of the mold.

Production of plastic parts and their properties

Design of plastic injection parts Importance of manufacturing plastic parts The construction of plastic parts is very important today because of the expansion they have found. As mentioned, plastic parts are used in almost all industries. These parts are very beneficial and cost-effective due to many complications.

The most important construction complications of plastic parts are as follows:
Plastic parts are made in a shorter time.
They have high durability and resistance
They need more common and less raw materials
The speed of creating plastic parts using injection mold is very high
A wide range of plastic parts can be up-to-date construction injection
They cost much less to build
For the consumer, plastic parts are much cheaper than metal parts
They have the ability to be recycled and turned into another piece of plastic
They have the least amount of waste and spoilage during construction.
The first activity force for the construction of plastic parts is very limited and injection 
molding machines require only one operator.

Design of plastic injection parts

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