Injection molding helps in making toys to car body parts, phone cases, water bottles, and containers. Lastly, many of the plastic products we use in our daily lives are molded under pressure. This is a quick process of creating identical plastic parts.

Ability to perform different shapes and sizes, achieved by using injection molding. The boundaries of design are consistently expanding, which allows the use of significant alternatives to traditional materials due to the large variety of products and their lightweight.

What is the function of an automatic injection molding machine?

The automatic injection molding machine produces polymeric products by injection molding and consists of three main components – the loading bunker, the screw, and the cylinder.

The plastic that is placed in the hopper usually has a powder or granular shape. Then the material melts due to the frictional action of the piston auger and the operation of the ring or semi-ring electric heaters.

Molten plastic vs Injection molding

Molten plastic may seem like a fairly simple process, but injection molding is a very complex type of production. While for injection molding in the cavity of the mold, the material is cooled and solidifies to the configuration of the cavity. When the part hardens, the movable half on which the form is established opens.

The dimensions of the injection molding machine can vary from 5 tons of clamping force to more than 6000. The larger the tonnage, the larger the molding machine.

Classification of injection molding

Injection molding machines are classified based on tonnage, or, more precisely, clamping force or pressure. The automatic molding machine is easy to equip with a hot runner system.

The most complex and high-quality products for injection molding are easy to make using hot-runner systems. Let’s talk about the nuances of working with them. The temperature at which the processing of polymers in the gutters affects the quality of the final product.

Thermal component role in injection molding

Also, the thermal component in the molds during molding will affect the temperature of the molten polymer raw material in the cavity of the mold. This subsequently at the time of curing and the appearance of the finished product.

If the temperature regime of injection molding is violated, a plug of hardened material may form in the intake manifold. Which will stop production. It is important to consider the thermal regime. Heat distribution on the pouring channels, the method of temperature control and regulation when choosing the design of GCS parts, and the temperature control system.

Thermoplastics role in injection molding

Thermoplastics are thermally unstable materials, so increasing the thermal values ​​during production, is necessary to reduce the residence time of the melt in such conditions. But here there can be a second problem in the form of a decrease in stability of process and quality of finished goods.

The uneven effect of the temperature of injection molding is on the molten polymer increases the risk of destruction of the material. Especially often such problem arises in the conditions of a long cast cycle which is characteristic of the production of details with thick walls.

Drawbacks of injection molding

Some of the problems of injection molding and temperature control of pouring channels of TEN 24 is the subject matter ahead. Overheating of the molten polymer, which occurs due to too high a temperature effect.

Or increased residence time in the heating zones leads to changes in the characteristics of the polymer product. Overheating may be accompanied by an unpleasant odor, and the product will show dark spots, strokes. For injection molding, you can also see the destruction and inconsistency with the stated size.

Drawbacks for injection holding

Considerable problems can arise when changing the color of polymer raw materials. On the walls of the channels of the spout can form fixed layers of polymer of another color. The polymer is easy to deposit on some types of nozzles.

What affects the temperature of the polymer in the gutters?

The most important source of heat in the processing of polymers is the dissipation of temperature in the melt. This heat arises from two mechanisms: flow shifts and compression of the material. The rate at which heat q is released in the molten polymer mass in shear flow per unit volume is:

   1-q = η ŷ²  

For injection molding, first, η effective viscosity (depending on the shear rate, temperature, and pressure)

   2- ŷ – shear rate.  

The temperature rise ∆T of the polymer mass under adiabatic compression of indeterminate volume with a simultaneous increase in pressure by the value of P is easy to calculate by the following formula:

   3-∆ T = ∆ P / (Cp)

P is the average density of the molten polymer; Cp is the average specific heat of the molten polymer under constant pressure. Dissipation in the polymer comes by shear flow is a major contribution to the overall heat balance during casting.

The greatest amount of heat for injection molding is released during plasticization and injection because the shear rate is very high. The dissipation that comes by compression will differ in different areas of the ACS. Due to changes in the pressure of the polymer mass during the casting cycle, dissipation will change over time.

How does injection molding work?

Through the channels of the spout and in the cavity of the mold, the melt at the loading stage proceeds due to the increase in pressure drops throughout the system. The dissipation that comes by compression at these stages has almost no effect on the temperature of the polymer.

In injection molding because of the pressure in the flow areas close to atmospheric values. Moving away from the flow front, the effect of dissipation increases. The temperature of the polymer in the ACS affects by the temperatures of the material.

An overview of heat balance

The total heat balance includes the heat produced by the heating elements placed in the GCS and the collector. Electric heaters are common for hot-channel casting in modern equipment. Heat losses in the forms of hot-channel casting can occur for various reasons.

• Firstly, thermal conductivity
• Secondly, convection
• Thirdly, heat radiation

 Cooling of the molten mass can occur due to its expansion due to reduced pressure.

List of factors to be considered for plastic injection molding

Following are some important factors to be considered for plastic injection molding:

1. High productivity/efficiency – fast production

There are several basic reasons why injection molding of plastic parts is considered the most acceptable and effective type of injection molding. The process itself is quite fast compared to other methods, and high productivity makes it even more efficient and cost-effective.

The speed of the process of course depends on the complexity and size of the mold, but the interval between each cycle is only about 15-120 seconds. By reducing the duration of the molding process cycles, this method allows the production of more molds in a short period of time, while increasing profits.

2. An integrated approach to the design of plastic parts

The method of plastic injection molding under pressure can be common to produce both complex parts and uniform. This method also allows you to make millions of identical parts. To optimize and increase the efficiency of high-quality injection molding and maximize the accuracy and quality of the parts themselves, it is necessary to consider the basic design elements and design requirements of the part.

3. Design element in injection molding

The design of the part must be as precise as possible to increase the efficiency of the process. The properly designed part allows you to make the element smoothly and with high accuracy. At the same time, without a detailed and calculated drawing of the part.

You may make big and expensive mistakes to the company regarding plastic injection molding. Industry experts unanimously believe that in any part drawing and mold making, there are basic design/drawing elements that must be considered for the injection molding process to take place correctly.

4. Elements of plastic injection molding

These elements include:

1. Wall thickness
2. Design of the sides of the mold
3. The structural round protrusion on the surface of the part
4. Corner transitions
5. Welding lines
6. Placement of entrances
7. Properly placed vents

5. Power in plastic injection molding

The increase in capacity is one of the important factors that must be considered when designing a mold for the manufacture of parts by injection molding. The designer needs to have information on whether the part should be flexible or rigid.

Power in plastic injection molding is to adjust the integrating fasteners/mold plugs or corner fasteners. Understanding the purpose of the part, as well as the environment in which it will be common is also an important nuance.

6. How to maintain balance for mold strength

Finding the balance between the elements of the drawing form will determine the required strength (load, endurance, resistance of the material) and stability (hardness, strength, margin of safety). Another important element is the choice of material.

7. The function of flexibility in injection molding Products

The choice of the appropriate material and color of the product are the two main factors in the manufacture of plastic parts. Given the great variety of both components of plastic injection molding. There are many variations of their combination. Advances in polymers have contributed to the development and invention of new polymers/resins.

8. Polymer selection and working

To ensure the correct choice of polymer, the following elements are important:

• impact strength (resistance)
• tensile strength (tensile load)
• modulus of elasticity/flexibility
• heat absorption and water absorption

Polymers are easy to obtain using a variety of coloring systems, each of which has its own characteristics, advantages, and disadvantages. It is important to use a molding machine that has already been common to produce plastic products from various polymers, especially those that meet FDA, RoHS, and REACH, and NSF standards.

9. How to reduce waste in plastic injection molding?

When choosing a partner for plastic injection molding, you should choose those companies that use green technology in their activities. The latter allows to obtain the highest quality, ensure sustainability, and optimal safety.

During the molding process, there will be excess plastic. When choosing partners, you should focus on those companies that use technologies for processing excess plastic. The most environmentally friendly manufacturers of plastic products use state-of-the-art machines and machines to reduce waste, reduce transportation and packaging costs.

10. Reducing labor costs

In the production of plastic products, labor costs are usually low compared to other ways. Foundry equipment usually works with a stand-alone, automatic tool that allows you to optimize processes and establish uninterrupted production.

In plastic injection molding which it requires minimal control. And the ability to produce parts at a fairly high level with a high volume of production contributes to the economy and efficiency of the process.

11. The Relationship of plastic injection molding with 3d printing

Injection molding and 3D printing are popular manufacturing processes for the manufacture of plastic parts of varying complexity. Although there is a large selection of plastics and thermoplastic materials on the market that are perfect for any part in any process.

There are situations of plastic injection molding where we choose either injection molding or 3D printing. This is what our article is about. To determine which technology to choose for your production, it is necessary to understand the advantages and disadvantages of both methods.

12. Molding of plastic parts under pressure

Injection molding is a rapid process that is based on the injection of molten plastic or other molding material into a prefabricated mold.

List of reasons to choose plastic injection molding

Following are some of the points regarding plastic injection molding based on which you can choose plastic injection molding

1. The Importance of cost in plastic injection molding

After the manufacturing of the mold, the production of the part is simple. The molten material comes into the mold under high pressure.

Injection molding of plastics allows the most efficient use of raw materials, so it leaves virtually no waste.

2. Production quality aspect in plastic injection molding

Every millimeter of the mold fills with material as much as possible to prevent air bubbles or other design defects.

Moreover, it does not require additional actions, e.g., suturing or assembly. The work quality is very high, and the result is durable.

So you can get more than one part in one press. This, in turn, speeds up the production of plastic injection molding. Thus, in a day you can make hundreds of thousands of parts and easily sort your products by batches.

Injection molding is the best way to get custom molding products. Larger machines can cast car parts under pressure.

Smaller machines can produce very precise plastic parts for surgical use. The injection molding process increases the flexibility of the process for designers and engineers.

Significance of custom molding

The low cost of the manufactured part, along with polymers and processing options. All this has contributed to the popularization of injection molding in the modern manufacturing sector. Individual injection custom molding with small tolerances is an ideal solution for many industries. That seek to produce many parts of high quality and precision.

Food Industry as an application of custom molding

To ensure optimal human health safety, food and beverage industry standards require that the manufacture of parts meet many specifications and clear standards: they do not contain BPA and other toxic ingredients and meet.

For example, the standards of the FDA (Office of Health Supervision). quality of food and medicine, USA). Various food materials are common for injection molding of plastics in the food industry: safe for both the end-user and for professionals who work directly with the equipment.

Material required for custom molding

At the same time, the materials common for custom molding can provoke faster wear of the mold, contamination of equipment, blocking of fasteners, and, consequently, reducing production efficiency. That is why professionals advise using special oils and tools to protect and preserve equipment, molds, and tools.

The variety of plastic parts that we encounter every day – is very large, and every day they become more and more. Plastic products are common by more than 90% of the world’s population, in this regard, the processing of plastics is developing very rapidly, there are new technologies for plastic casting.

List of steps to find custom molding

A large niche in this area is occupied by injection molding of plastics with the help of a tool called – a mold. There are several steps to getting a finished plastic product.

 

1. Detail design
2. Construction of the mold according to the drawings
3. Also, making a mold.
4. Checking the efficiency of the forming equipment
5. Product casting
6. Product design

All stages of mold part development are done using software (CAD). The use of CAD for custom molding reduces the time spent on development, reduces the percentage of design errors in the design of the mold. Furthermore, the designer of equipment (molds) makes a mathematical design of the 3-d model on the information given to it from the customer.

Factors for creating a 3D model

To create a 3-d model, such important factors as:

1. Product Individuality
2. Material Characteristics
3. Product Part Optimization

The result will be a model and a drawing of the product. At this stage, an important role will be played by the correct creation of a 3-d model of the part. Also, custom molding can be common to evaluate the product and its forming equipment.

Design of custom molding

When the development of the part is completed, the design engineer begins cooking to design the mold. The choice of components for molds is of great importance. Moreover, the stability of the form, quality of a forming surface of the form, ability to give of processing of working parts, and quality of the future plastic product depends on the material.

Steels with a hardness of 30… 32 HRC are important for the correct operation of the mold. In addition, they can be common for the manufacture of molding parts of the mold without heat treatment; these factors will significantly reduce the time for the manufacture of equipment.

Why you should use a hot runner system?

Nowadays, for custom molding more and more often molds are made of hot runner systems, and there are reasons for this. The use of the hot runner systems has many advantages. It includes:

1. Casting time costs are reduced.
2. Reduced pressure in the mold.
3. Improved product quality.
4. Reducing the cooling time and obtaining the finished product.
5. Lower the cost of the product.

Disadvantages of custom molding

There are also disadvantages of using hot runner systems

1. They are expensive.
2. Difficulty in servicing
3. There are problems if you work on secondary material.

You can read more about hot runner systems and their use in our articles regarding custom molding further aspects.

Role of thermostatic structure in custom molding

The general information about hot channel systems. Res-forms with a hot runner system for processing thermoplastics. Secondly, the thermostatic structure of the mold must create the correct distribution of the thermal sides of the molding levels of the mold and be separate to reduce the time spent on the manufacture of the part.

Working process of 3D machines

The final work of the designer to develop a mold will be a 3-d model of the form, and a set of technical documentation. Moreover, the 3-D example of the forming planes made by the designer is common for the writing of programs and processing of surfaces of metal on the ChPU machine.

At the end of the creation of products of the custom molding in accordance with the design documentation is assembled, also prepared for testing the mold. In addition, after installing the mold on the mold, testing the mold, the task of testing. To collect information for future changes and corrections of surfaces, gutter, and ventilation systems, after these actions, the mold comes into operation.

Injection molding- last stage of custom molding

The final stage of manufacturing the part – Injection molding. Also, at this stage, it is important to adjust the process of casting plastic parts under pressure. Here you will find a special guide for plastics processing.

Setting up the process of casting plastic parts under pressure. Also, the preparation of the process of casting plastic parts under pressure involves a sequence of certain actions, as we wrote earlier in the article.

How is custom molding use in medicine and pharmaceuticals?

In the medical and pharmaceutical industries, the quality of equipment of custom molding is paramount. Moreover, it gives the health and safety, responsibility, and full traceability of the parts production process – from design to final inspection.

It is critical to choose the manufacturer of medical equipment parts and components: standardized parts for molds and dies, as well as tools care and efficiency of the equipment.