Tooling fabrication: Once an injection molding design is finalized the first step in the manufacturing process is to mill the tooling, which is typically fabricated from steel or aluminum. In most cases, the metal block of material is placed in a CNC mill, which then carves out a negative of the final plastic part. Additional treatments like polishing or laser etching can then be applied to the tooling to achieve specific surface finishes.
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Part production: The actual production of plastic parts begins by loading resin pellets into a barrel. The temperature of the barrel is raised until the resin pellets reach a molten state and are then compressed. Next, the molten plastic is injected into the metal tool through a runner system, which then feed into the mold cavity through gates. The part then cools down, solidifies, and is ejected from the tool with ejector pins.
The term injection molding encompasses a handful of processes that inject liquid resin into a tool to form plastic parts. Here are four common types:
Thermoplastic injection molding: Thermoplastic injection molding is the most common type of molding. It injects thermoplastic resin into the mold where the material cools to form the final part.
Liquid silicone rubber molding: Liquid silicone rubber uses thermoset materials and a chemical reaction creates the plastic part.
Overmolding: Overmolding is a process used to manufacturing plastic parts with two or more materials. You&#;ll often find this on parts to improve grip by adding rubber to the handle.
Insert Molding: Insert molding is process that begins with an insert component placed into the mold before resin enters. The material is then injected and flows around the insert, typically metal, to form the final part. This is frequently used for parts that require metal threads.
Tolerances
With our injection molding process, we can hold about ±0.003 in. machining accuracy. Shrink tolerance depends mainly on part design and resin choice. It varies from 0.002 in./in. for stable resins like ABS and polycarbonate to 0.025 in./in. for unstable resins like TPE.
Wall Thickness
Wall thickness is important because it can lead to defects such as sink and warp. It is best practice to maintain a uniform thickness throughout an injection-molded part. We recommend walls to be no less than 40 to 60 percent of adjacent wall thickness, and all should fit within recommended thickness ranges for the selected resin.
Core Geometry
Core out parts to eliminate thick walls. You get the same functionality in a good molded part. Unnecessary thickness can alter part dimensions, reduce strength, and necessitate post-process machining.
Draft
Applying draft to molded parts is critical to ensure parts do not warp during the cool down process and it helps the part easily eject from the mold. Applying 1 to 2 degrees works well in most scenarios. If there are vertical faces, we advise incorporating .5 degrees of draft.
Side Actions
A portion of the mold that is pushed into place as the mold closes, using a cam-actuated slide. Typically, side-actions are used to resolve an undercut, or sometimes to allow an undrafted outside wall. As the mold opens, the side action pulls away from the part, allowing the part to be ejected. Also called a &#;cam.&#;
Undercuts
A portion of the part that shadows another portion of the part, creating an interlock between the part and one or both of the mold halves. An example is a hole perpendicular to the mold opening direction bored into the side of a part. An undercut prevents the part from being ejected, or the mold from opening, or both.
Bosses
A raised stud feature that is used to engage fasteners or support features of other parts passing through them. There can be a tendency to design thick bosses which will increase the likelihood of sink and voids in a part. Consider reinforcing bosses with ribs or gussets for extra strength
Gates
A gate is an opening in the injection mold tool that allows resin to enter and fill the cavity. There are three common types of injection molding gates.
Ribs
A rib is a thin, wall-like feature parallel to the mold opening direction, its used to add strength and support to features like bosses and walls. To prevent sink, ribs should be no more than 60% of the wall&#;s thickness.
Ejector Pins
Ejector pins are installed in the B-side of the mold and help to release the plastic part from the tool after the part has cooled sufficiently. Designing in sufficient draft can help reduce the need for ejector pins on a part.
Logos and Text
Sans serif fonts will be the easiest to mill into a mold with text. We recommend font larger than 20 pt. and no deeper than 0.010 in to 0.015 in.
Injection molding machine is an important production machine for many daily necessities. The quality of injection molding machine affects the subsequent production and operation.
Purchasing an injection molding machine is a considerable investment. It is a waste of money to buy a machine that is too big, and it is not appropriate to buy a machine that is too small. Therefore, choosing the right machine for the product is the most important thing for the buyer. The supplier recommending suitable machines and suggesting how to choose a machine is the first lesson the supplier provides to the buyer.
This guide answers common injection molding machine questions for you, including basic knowledge, types, specification calculations and selection guidelines, hoping to help you.
1. What is an injection molding machine?
An injection molding machine is a machine that is used for manufacturing plastic products by the injection molding process. It comprises of two main parts: an injection unit and a clamping unit. The injection unit melts the plastic material and injects it into the mold, while the clamping unit holds the mold and applies pressure to ensure the plastic solidifies in the desired shape. Injection molding machines come in various sizes and can be used to create a wide range of products, from small plastic parts to large automotive components.
2. What is the working principle of injection molding machine?
The working principle of an injection molding machine is based on the "injection molding process". The process begins by melting plastic pellets in the hopper, which is then fed into the barrel of the injection molding machine by a screw. The screw then pushes the molten plastic into the mold cavity where it cools and solidifies into the desired shape.
The machine consists of the following main components:
The process begins with the loading of plastic pellets into the hopper, and then the screw is used to melt the plastic and inject it into the mold. Once the plastic has been injected, the mold is cooled to solidify the plastic into the desired shape. Finally, the mold is opened and the finished product is removed.
The whole process is controlled by an injection molding machine controller, which controls the speed of the screw, the temperature, and pressure, and the timing of the mold opening and closing.
3. What is Injection Molding?
Injection molding is a manufacturing process used to produce parts by injecting molten material into a mold. It is typically used to create plastic parts, but can also be used to create parts from other materials, such as metal or glass.
The process begins by melting plastic pellets in an injection molding machine and injecting the molten plastic into a mold. The mold is a hollowed-out block that is designed to give the plastic parts the desired shape. Once the plastic has cooled and solidified, the mold is opened, and the finished parts are removed. The parts are then usually inspected for quality and any defects are removed.
The injection molding process is highly versatile and can be used to create a wide range of parts, from small, intricate parts like gears and electrical connectors, to larger parts like car body panels and household appliances.
It is also highly efficient and can produce large numbers of parts quickly and at a low cost.
4. What are the applications of injection molding&#;
Injection molding is a versatile manufacturing process that can be used to create a wide range of parts and products. Some common of injection molding include:
Automotive
Injection molding is used to create a wide range of parts for the automotive industry, such as car body panels, dashboards, door handles, and mirrors.
Medical
Injection molding is used to create a wide range of medical devices, such as syringes, surgical instruments, and prosthetics.
Packaging
Injection molding is used to create a wide range of packaging products, such as plastic bottles, containers, and caps.
Consumer goods
Injection molding is used to create a wide range of consumer goods, such as toys, small appliances, and household items.
Industrial and electronics
Injection molding is used to create a wide range of industrial and electronic components, such as gears, connectors, and housings.
Food service
Injection molding is used to create food service items such as plates, cups, and utensils.
Construction
Injection molding is used to create construction materials such as pipes, window frames and door frames.
Aerospace
Injection molding is used to create a wide range of aerospace components, such as fuel tanks, ducts, and housings.
The above are just a few examples of the many applications of injection molding. The process is highly versatile and can be used to create a wide range of parts and products for a variety of industries.
5. What kind of knowledge should be possessed in injection molding machine and injection molding process?
In order to work effectively with injection molding machines and the injection molding process, one should possess a good understanding of the following areas:
Plastic materials
A good understanding of different types of plastic materials, their properties, and how they behave under different conditions is important. This includes knowledge of the different grades of plastic, their melting points, and how they react to different temperatures and pressures.
Injection molding machine mechanics
Knowledge of how injection molding machines work, including the different components and how they interact with one another, is essential. This includes an understanding of the injection unit, the clamping unit, and the control systems.
Mold design
Knowledge of how to design molds that are suitable for injection molding, including the different types of molds and the principles of mold design.
Process control
Knowledge of how to control the injection molding process, including how to set the correct temperature, pressure, and speed settings, and how to troubleshoot and optimize the process.
Quality control
Knowledge of how to inspect and test the quality of the finished parts, including knowledge of the different quality control methods and how to interpret the results.
Safety
Knowledge of the safety procedures and regulations related to injection molding, including knowledge of the potential hazards and how to prevent accidents.
Industry Standards
Knowledge of industry standards, such as ISO, ASTM, UL and RoHS and how to apply them in the production process.
Computer Aided Design and Manufacturing (CAD/CAM)
Knowledge of how to use computer-aided design and manufacturing software to design, program and simulate the injection molding process.
In addition to these specific areas of knowledge, it's also important for those working with injection molding machines and the injection molding process to have strong problem-solving and analytical skills, as well as the ability to work well under pressure and in a team environment.
6. What are the types of injection molding machines?
There are several types of injection molding machines, each with its own set of features and capabilities. Some of the main types of injection molding machines include:
Hydraulic injection molding machines
These are the most traditional type of injection molding machine, and they use a hydraulic system to generate the clamping force needed to hold the mold shut during the injection process. They are generally slower and less precise than other types of machines, but they are also less expensive.
Electric injection molding machines
Electric machines use an electric motor to drive the injection unit and the clamping unit. They are more precise and faster than hydraulic machines, and they are also more energy-efficient.
Servo injection molding machines
Hybrid machines combine the best features of hydraulic and electric machines. They use an electric motor to drive the injection unit and a hydraulic system to generate the clamping force. They are faster and more precise than hydraulic machines and more energy-efficient than electric machines.
Two-shot or multi-shot injection molding machines
These machines are able to inject two or more different materials into the same mold, allowing for the creation of multi-material parts.
Micro-injection molding machines
These machines are specially designed for the production of small and precise parts, typically less than 5 grams.
Vertical injection molding machines
These machines have the mold clamping and injection unit on a vertical axis, allowing for a vertical injection of the molten plastic into the mold. They are best suited for insert molding and are commonly used for applications that require the production of small parts with precision.
Rotary injection molding machines
Rotary machines have a horizontal mold clamping and rotating injection unit. They are best suited for producing large parts, such as automotive parts, and are commonly used in the production of large plastic products.
The type of machine you choose will depend on the specific requirements of your application, such as the size, complexity, and material of the parts you want to produce.
7. What is a hydraulic injection molding machine?
Hydraulic injection molding machine is a type of injection molding machine that uses a hydraulic system to generate the clamping force needed to hold the mold shut during the injection process. The hydraulic system uses a combination of oil and high-pressure pumps to create the force required to close the mold.
Hydraulic injection molding machines are known for their durability and reliability, and they are capable of producing high-quality parts. They are also relatively simple to operate and maintain, which makes them a popular choice for many manufacturers.
However, hydraulic machines are generally slower and less precise than electric or hybrid machines. They are also less energy-efficient and tend to be more expensive to run. They are also less precise and repeatable in comparison to electric machines.
Hydraulic injection molding machines are a good choice for manufacturers who are looking for a reliable, durable, and cost-effective option for producing high-quality plastic parts.
8. What is an all-electric plastic molding machine?
An all-electric plastic injection molding machine is a type of injection molding machine that uses electric motors to drive all of its mechanical movements, rather than using a hydraulic system.
All-electric injection molding machines are known for their high precision, repeatability and accuracy, as well as their energy efficiency, as they don't require oil or other hydraulic fluids to operate. They are also faster and quieter than hydraulic machines. They are ideal for producing small and precise parts, they have a high degree of control over the process parameters, which results in a high-quality part.
All-electric machines are also easy to maintain, they have fewer moving parts and less complex systems, making them less prone to breakdowns and malfunctions.
On the other hand, all-electric machines tend to be more expensive than hydraulic machines, and they may require more technical expertise to operate and maintain. They also may not be suitable for certain applications that require high clamping force and large parts.
All-electric injection molding machines are a good choice for manufacturers who are looking for a precise, energy-efficient, and low-maintenance option for producing high-quality plastic parts.
9. What is a servo motor injection molding machine?
A servo motor injection molding machine is a type of injection molding machine that uses servo motors to drive the mechanical movements of the machine, rather than using a hydraulic system or traditional electric motors.
Servo motors are highly precise and accurate, and they can provide a high level of control over the injection molding process. This results in a high-quality part with minimal defects and less material waste. They also can provide energy savings by only using the energy required for the specific process and not wasting energy like traditional electric motors.
Servo motor injection molding machines are also more adaptable to changes in the production process, they can easily adjust to changes in product design and production volume, providing more flexibility.
However, servo motor injection molding machines tend to be more expensive than traditional hydraulic or electric machines. They also may require more technical expertise to operate and maintain.
10. What is a fixed pump injection molding machine?
A fixed pump injection molding machine is a type of injection molding machine that uses a fixed displacement pump to provide the hydraulic power for the injection and clamping mechanisms. The pump is pre-set to a specific, fixed amount of flow and pressure and it is not adjustable during the machine operation.
Fixed pump injection molding machines are known for their simplicity, durability, and low maintenance costs. They are also relatively low in cost, making them a popular choice for manufacturers who are looking for a cost-effective solution.
However, fixed pump machines have some limitations, such as lower energy efficiency and less precise and repeatable production, compared to other types of machines like servo motor or variable pump machines. They also have a lower injection pressure and speed, which makes them less suitable for production of large or complex parts.
11. What is a PET injection molding machine?
PET (polyethylene terephthalate) injection molding machine is a type of injection molding machine that is specifically designed to process PET plastic. PET is a thermoplastic material that is commonly used to make bottles, containers, and other products that require transparency, high strength, and resistance to heat and chemicals.
PET injection molding machines are designed to handle the high viscosity and high melting point of PET plastic. They typically use a specialized screw design, called a preform screw, which is specifically designed to process PET plastic and ensure that the material is properly melted and homogenized before it is injected into the mold.
PET injection molding machines also typically include special features to handle the unique properties of PET plastic, such as faster cooling rates and higher clamping forces. They also may have specialized temperature controls and cooling systems to maintain the proper temperature and cooling rate for the PET plastic.
12. What is a high-speed injection molding machine?
A high-speed injection molding machine is a type of injection molding machine that is designed to operate at a faster cycle time compared to traditional injection molding machines. This allows for the production of more parts in a shorter amount of time.
High-speed injection molding machines are designed to handle the high injection speeds and fast cycle times required for high-volume production. They often use advanced features such as servo motors, high-speed injection units, and fast-acting clamping mechanisms to achieve faster cycle times. Some high-speed injection molding machines can achieve cycle times as fast as 0.5 seconds or less.
High-speed injection molding machines are typically more expensive than traditional injection molding machines, and they may require more technical expertise to operate and maintain. They are also more demanding on the molds and tooling, as they require a high level of precision and accuracy.
13. What is a variable pump injection molding machine?
Variable pump injection molding machine is a type of injection molding machine that uses a variable displacement pump to provide the hydraulic power for the injection and clamping mechanisms. The pump's flow and pressure can be adjusted during the machine operation, allowing for more precise and efficient control of the injection process.
Variable pump injection molding machines are known for their energy efficiency and precise control over the injection process. They can adjust the amount of oil flow and pressure according to the actual needs of the process, which results in energy savings and a reduction of the machine's noise level. They also have a higher injection pressure and speed, which makes them suitable for the production of large or complex parts.
Variable pump injection molding machines are more versatile and adaptable to changes in the production process, they can easily adjust to changes in product design and production volume, providing more flexibility. They also tend to be more expensive than fixed pump machines.
14. What is a two-platen injection molding machine?
A two-platen injection molding machine is a type of injection molding machine that uses two platens (horizontal plates) to support the mold during the injection process. The two platens, one fixed and one movable, work together to clamp the mold and hold it in place during the injection process.
Two-platen injection molding machines are known for their durability and reliability, and they are capable of producing high-quality parts. They also tend to be more compact and less expensive than three-platen machines. They are also more versatile and adaptable to changes in the production process, they can easily adjust to changes in product design and production volume, providing more flexibility.
Two-platen injection molding machines are typically used for a wide range of applications, including the production of small and medium-sized parts, such as household appliances, automotive parts, and packaging materials.
15. What is a three-platen injection molding machine?
A three-platen injection molding machine is a type of injection molding machine that uses three platens (horizontal plates) to support the mold during the injection process, rather than the traditional two platens.
Three-platen injection molding machines have a larger platen size and increased clamping force, which allows them to handle larger and heavier molds. They also have a longer mold opening stroke, which allows for easy removal of the molded parts, as well as easy cleaning and maintenance of the machine.
Three-platen injection molding machines are typically used for large-scale production of large and heavy parts, such as automotive parts and household appliances. They are also suitable for producing large parts with deep cavities or undercuts.
However, three-platen injection molding machines tend to be more expensive than traditional two-platen machines, and they may require more technical expertise to operate and maintain. They also tend to be larger and take up more space in the factory.
16. Can one injection molding machine produce three products?
It is possible for one injection molding machine to produce multiple products, but it depends on the design of the molds and the complexity of the parts being produced.
Multi-cavity molds
One way to produce multiple products on one machine is to use multi-cavity molds. These molds have multiple impressions or cavities that can produce multiple parts at the same time.
Stack molds
Another way is to use stack molds, where multiple molds are stacked on top of each other and are all connected to the same injection molding machine. Each mold produces a different part, and the machine cycles through the molds to produce all the different parts.
Indexing molds
With indexing molds, the machine rotates the mold to produce different parts. This is done by having a rotating table that holds multiple cavities that can produce different parts.
Multi-component molds
Some parts require more than one type of plastic to be molded together, this is called multi-component molding. In this case, one machine is used to inject different types of plastics into the same mold, resulting in a finished part.
It's worth noting that the production rate will be affected depending on the design of the mold, the complexity of the parts, and the number of cavities or impressions. It's important to consult with experienced injection molding professionals to ensure that the production rate is sufficient and that the machine selected meets the specific requirements of the application.
17. What does tonnage mean in injection molding?
In the context of injection molding, tonnage refers to the clamping force that the machine can exert on the mold to hold it shut during the injection process. It is usually measured in U.S. tons (short ton) or metric tons (tonne).
The clamping force is generated by the machine's clamping unit and is necessary to keep the mold shut while the molten plastic is injected into it. The tonnage required for a specific application will depend on the size and complexity of the part, as well as the type of plastic being used.
For example, a small, simple part made of a relatively soft plastic may require only a few tons of clamping force, while a larger, more complex part made of a harder plastic may require several tens of tons of clamping force.
When selecting an injection molding machine, it is important to choose one that has a clamping force that is appropriate for the specific application. Choosing a machine with too low of a tonnage may result in the mold not being held shut properly, leading to defects in the finished parts. On the other hand, choosing a machine with too high of a tonnage can result in excessive wear and tear on the machine and the mold, as well as increased energy consumption.
18. How to calculate the tonnage of injection molding machine?
Calculating the tonnage of an injection molding machine requires taking into account several factors, including the size and complexity of the part being produced, the type of plastic being used, and the desired cycle time of the machine.
One way to estimate the tonnage required for a specific application is to use the "rule of thumb" of 2 to 3 tons per square inch of the projected area of the part. This means that for a part with a projected area of 100 square inches, a machine with a tonnage of 200 to 300 tons would be appropriate. However, this is just a general guideline and the actual tonnage required can vary depending on the specific application.
Another way to estimate the tonnage of an injection molding machine is to use a clamp force calculator. These calculators take into account a variety of factors such as the projected area of the part, the type of plastic being used, the size and complexity of the part, and the desired cycle time. These calculators are available online and can give a more accurate estimate of the tonnage required for a specific application.
However, it is important to note that the tonnage calculation alone is not enough to determine the suitability of a machine for a specific application. Other factors such as the machine's injection rate, injection pressure, and cooling rate are also important.
19. How long does injection molding take?
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The length of time it takes for an injection molding process to complete can vary depending on a number of factors, including the size and complexity of the part, the type of plastic being used, and the machine's cycle time.
A simple and small part made with a thermoplastic material can take as little as a few seconds to be injected, cooled and ejected from the mold. While a larger and more complex part made with a thermosetting material can take several minutes to complete the process.
The cycle time of an injection molding machine is the total time it takes to complete one injection molding cycle, which includes the time for filling the mold, cooling the part, opening the mold, and ejecting the finished part. The cycle time can vary from a few seconds for simple parts to several minutes for larger and more complex parts.
However, it's also worth noting that the injection molding process is not limited to only the time that the machine is actively working on making the parts. It also includes the time for preparing the machine, loading the mold, and removing the finished parts from the machine. Additionally, the time for inspection, packaging, and shipping of the finished parts also have to be taken into account.
In summary, the time it takes for an injection molding process to complete can vary widely depending on the specific application, but it is typically measured in terms of the machine's cycle time, which can range from a few seconds to several minutes.
20. Can the injection molding machine work 24 hours a day?
Injection molding machines can work 24 hours a day, but it depends on the specific machine and its maintenance schedule. Some machines are designed to run continuously for long periods of time, while others may require more frequent maintenance and downtime.
It's important to note that even if the machine is able to run for 24 hours, it doesn't necessarily mean that it should. Operating an injection molding machine for extended periods of time can lead to wear and tear on the machine, as well as the mold. This can result in increased maintenance costs, reduced efficiency, and decreased quality of the finished parts.
To avoid these issues, it's important to have a regular maintenance schedule in place to keep the machine in good working order. This can include regular cleaning and oiling, as well as more extensive maintenance such as replacing worn parts and calibrating the machine.
Additionally, it's also important to consider the availability of the raw materials, the personnel, and the demand of the product. Without enough raw materials, the machine can't produce parts and without personnel, the machine can't be operated. Also, without the demand of the product, it would be pointless to run the machine 24/7.
While injection molding machines can work 24 hours a day, it's important to have a regular maintenance schedule in place and to consider the availability of the raw materials, the personnel and the demand of the product. It's also important to consider the wear and tear on the machine and the mold, and to balance the need for continuous production with the need for maintenance and downtime.
21. How to reduce the weight of parts in injection molding?
There are several ways to reduce the weight of parts in injection molding:
Reduce the thickness of the walls
Thin-walled parts are typically lighter than thick-walled parts. By reducing the thickness of the walls, it's possible to reduce the weight of the part without compromising its structural integrity.
Use a lightweight plastic material
Substituting a lightweight plastic material for a heavier one can also help to reduce the weight of the part. Some plastics have a lower density than others and are therefore lighter.
Optimize the design
Changing the design of the part to eliminate unnecessary features or to use less material can also help to reduce its weight. For example, using ribs or hollow sections in the design can provide additional strength while reducing weight.
Use of foaming agents
Some materials can be blended with foaming agents to create a cellular structure in the part, which can reduce weight while maintaining strength.
Gas-assisted injection molding
This process involves injecting a small amount of gas into the mold during the injection process. This helps to displace the plastic and create hollow sections within the part, which can help to reduce its weight.
Multi-component molding
This process involves using two or more materials with different properties in the same part. This can reduce weight by using a lightweight material in sections of the part where strength is not a critical factor.
It's important to note that the weight reduction should not compromise the part's function and strength. It's also important to consider the cost, the material properties and the process requirements for any weight reduction methods.
22. What is the L/D ratio of an injection molding machine?
The L/D ratio (L/D stands for "length to diameter") of an injection molding machine refers to the ratio of the length of the screw to its diameter. The screw is the part of the machine that melts the plastic and injects it into the mold.
The L/D ratio is used to determine the compression ratio of the screw, which is the ratio of the volume of the plastic in the feed section of the screw to the volume in the metering section of the screw. A higher L/D ratio results in a higher compression ratio, which can improve the mixing and homogenization of the plastic and can help to reduce the residence time of the plastic in the machine, resulting in a faster cycle time.
The standard L/D ratio for an injection molding machine is typically around 20:1 or 24:1. However, depending on the specific application and the type of plastic being used, a different L/D ratio may be more appropriate. For example, a higher L/D ratio may be more suitable for processing highly filled or abrasive plastics, while a lower L/D ratio may be more appropriate for processing more delicate or heat-sensitive plastics.
23. How to determine the injection weight?
Injection weight is an important parameter of an injection molding machine, and it is the most useful and critical parameter for selecting an injection molding machine. Expressed in gram or ounce, although this parameter is simple and easy to understand, it can also be easily misunderstood. the reason is simple. When the plastic material is determined, the weight of the plastic part can be determined. Therefore, it is easy for them to use the injection weight to select an injection molding machine. In fact, the definition of injection weight refers to the maximum plastic injection weight that the injection device can reach when the screw performs the maximum injection stroke under the screw. Air shot state (not injected into the mold); this parameter reflects the processing capacity of the injection molding machine to a certain extent; it can be measured or calculated theoretically (theoretical value and measured value may be different). The material used in the test is usually ordinary PS with a density of 1.05.
Steps to determine the injection weight
Calculate the product weight first: W = product weight + gate system weight, where: W is the weight required for injection. In actual situations, there are two situations to consider.
When the injection molded product is polystyrene (PS), the injection volume of the injection molding machine should be Wps; Wps = (1.3 ~ 1.1) × W (product weight + total gate system weight), when the product requirements are high, The coefficient in the above formula should take a large value, otherwise, it can take a small value.
When the product is the imitation method of other plastics (named X plastic), first calculate the theoretical injection volume of the plastic should have Wx; Wx = (1.3 ~ 1.1) × (product weight + total weight of the gate system); then according to the plastic The density (X) is converted into the actual weight of the PS material Wps, the conversion formula is: Wps=Wx×1.05/Vx
According to the calculation results of the Wps and LOG manuals, select the appropriate injection molding machine.
Remarks: The relationship between injection weight and injection volume
The injection weight is more than just the injection volume multiplied by the density of PS. Measure the injection weight, and the injection volume is a theoretical value. Because the plastic material will flow into the gap between the barrel and the screw during injection, and the non-return ring needs to move backwards to reach the closed position, the injection volume is doubled because the density of PS is greater than the injection weight.
Products with low requirements, such as toy dolls: the total weight should be 85% of the injection weight; in high-demand injection molding; such as crystal products, 75%.
Do not use an injection molding machine with an excessive injection weight
The total weight of plastic and runner plastic should be between 35% and 85% of the injected weight. The lower limit is due to the following three considerations: the bending of the plate; the residence time of the plastic in the barrel and the power consumption per kilogram of injection molded parts. The use of small molds for small injection molded parts will cause excessive bending of the pressure plate, resulting in warping (affecting product quality), and even cracking of the pressure plate. Use an oversized injection molding machine to inject small plastic parts. If the residence time of the molten material is too long, it may cause the melted plastic in the barrel to decompose.
Injection speed
For ultra-thin-walled products, high fluidity materials are used to make the molten plastic flow at an ultra-high speed to ensure that the thickness l of the surface layer formed by cooling and solidification after the molten material contacts the mold wall is as thin as possible, which is to delay the generation time of the solidified skin as much as possible. So it involves the issue of injection speed. In terms of experience, the injection speed can be 1 to 1.5 times the flow length ratio.
24. How to calculate the clamping force of the injection molding machine?
Calculating the clamping force of an injection molding machine is important for ensuring that the machine is capable of producing high-quality parts and holding the mold shut during the injection process.
The clamping force can be calculated using the following formula:
Clamping force (kN) = (projected area of the part (cm²)) x (maximum injection pressure (bar)) / (2 x safety factor)
The projected area of the part is the total surface area of the part that is in contact with the mold. The maximum injection pressure is the highest pressure at which the plastic is injected into the mold. The safety factor is a value that accounts for any discrepancies in the measurements or unexpected variations in the process. A typical safety factor is 2, but this can vary depending on the specific application.
It's important to note that this formula is an approximation, and the actual clamping force required may vary depending on the specific application, the part's design and the type of plastic being used. Additionally, the clamping force required for a specific application also depends on factors such as part size, weight, and complexity, and the type of material and molding process.
It's also worth noting that the clamping force required for a specific application can vary depending on the size of the machine, the design of the mold and the type of clamping system used. Some machines have a fixed clamping force, while others can be adjusted to suit the specific application.
25. How much does an injection molding machine cost?
The cost of an injection molding machine can vary widely depending on the type, size, and features of the machine.
A small, benchtop injection molding machine can cost as little as $10,000 to $20,000. These machines are typically used for prototyping or for small-scale production of low-volume parts.
A standard, full-sized injection molding machine can cost anywhere from $50,000 to $500,000 or more. These machines are typically used for high-volume production of medium to large parts and can have a wide range of features including:
All-electric injection molding machines are generally more expensive than hydraulic machines, but they are more energy-efficient and have a longer lifespan. The cost of an all-electric machine can range from $100,000 to $1,000,000 or more.
It's also worth noting that the cost of an injection molding machine is just one component of the total cost of ownership. Other costs such as the cost of the mold, the cost of raw materials, the cost of labor, and the cost of maintenance and repairs also have to be taken into account.
In summary, the cost of an injection molding machine can vary widely depending on the type, size, and features of the machine. Benchtop machines can cost as little as $10,000 to $20,000, standard machines can range from $50,000 to $500,000 or more, and all-electric machines can range from $100,000 to $1,000,000 or more. It's important to consider all the cost associated with the injection molding process in order to have a realistic view of the investment.
26. How much does injection molding cost?
The cost of injection molding can vary widely depending on several factors, such as the size and complexity of the part, the type of plastic material being used, the quantity of parts being produced, the type of mold being used, and the location and capacity of the injection molding facility.
To calculate the cost of injection molding, you can use the following formula:
Cost = (Mold cost + Material cost + Labor cost + Maintenance and repairs + energy cost) / Number of parts produced
It's important to note that this formula is an approximation, and the actual cost of injection molding can vary depending on the specific application and the factors mentioned above. Additionally, the cost can vary depending on the production volume, the complexity of the parts, the material and the location.
27. How to maintain the injection molding machine?
Proper maintenance is crucial for ensuring the efficient and reliable operation of an injection molding machine. Here are some general guidelines for maintaining an injection molding machine:
Regular cleaning
Keep the machine, molds, and surrounding areas clean to prevent dust and debris from accumulating and causing damage or wear.
Lubrication
Lubricate the moving parts of the machine according to the manufacturer's recommendations. This can include the screw, barrel, mold, and other mechanical components.
Inspection
Regularly inspect the machine for any signs of wear or damage, and replace any worn or damaged parts as necessary.
Cooling system
Keep the machine's cooling system clean and free of debris to ensure efficient cooling of the molds and the machine.
Electrical
Regularly check and maintain the electrical components of the machine, such as the wiring and control systems.
Machine calibration
Calibrate the machine according to the manufacturer's recommendations to ensure accurate and consistent production.
Machine operation
Follow the manufacturer's instructions for operating the machine, and ensure that the machine is not overloaded or run for excessive periods of time.
Training
Keep the machine operators and maintenance personnel trained on the proper operation and maintenance of the machine, as well as on safety procedures.
It's important to follow a regular maintenance schedule, and to keep accurate records of all maintenance activities, to ensure that all necessary maintenance is carried out on time.
28. How to clean the screw of injection molding machine?
Cleaning the screw of an injection molding machine is an important part of regular maintenance. Here are some general guidelines for cleaning the screw of an injection molding machine:
It's important to follow the manufacturer's recommendations for cleaning and lubricating the screw, and to keep accurate records of all maintenance activities.
29. How often should an injection molding machine be replaced?
The frequency of replacing an injection molding machine will depend on several factors including the usage, maintenance, and the type of the machine.
A well-maintained machine that is used in a low-volume, low-stress application may last for many years. On the other hand, a poorly maintained machine that is used in high-volume, high-stress applications may need to be replaced after just a few years.
For machines that are used in high-volume production, it's common to replace them every 7 to 10 years. The reason for this is that over time, the machine will experience wear and tear, and the technology is constantly improving, making new machines more efficient, faster, and more accurate.
All-electric injection molding machines are generally considered to have a longer lifespan than hydraulic machines, due to their lack of mechanical components that are subject to wear and tear.
It's also worth noting that the cost of repairs and maintenance should also be taken into account when considering whether to replace a machine. If the cost of repairs and maintenance becomes too high, it may be more cost-effective to replace the machine instead.
30. How to choose an injection molding machine?
Choosing an injection molding machine can be a complex process as it depends on several factors including the type of part to be produced, the material to be used, the production volume, and the budget. Here are some general guidelines to help you choose the right injection molding machine for your application:
Part and material
Consider the size, shape, and complexity of the part, as well as the type of plastic material that will be used. This will help determine the clamping force, shot size, and other machine specifications that are required.
Production volume
Consider the number of parts that will be produced on a daily, weekly, or monthly basis. This will help determine the cycle time, machine size, and other production-related specifications.
Budget
Consider the budget for the machine and the overall cost of ownership, which includes the cost of the machine, the cost of the mold, the cost of raw materials, and the cost of labor, maintenance and energy.
Type of machine
Consider the type of machine that best suits your application, such as a hydraulic, all-electric, or servo motor machine.
Additional features
Consider the additional features that you may need, such as automation, robotics, or in-mold labeling.
Brand and supplier
Consider the reputation and experience of the brand and supplier, as well as their ability to provide support and service.
Maintenance and repair
Consider the cost and ease of maintenance and repair of the machine.
Energy efficiency
Consider the energy efficiency of the machine, as this can significantly impact the cost of operation over time.
31. How can I expand my injection molding business?
Expanding an injection molding business can be achieved through several strategies, here are some general guidelines:
Increase production capacity
Consider investing in new or upgraded injection molding machines, molds, and automation equipment to increase production capacity.
Diversify product offerings
Consider diversifying the product offerings to attract new customers and enter new markets. This can include producing different types of parts, using different types of plastics, or offering additional services such as assembly, packaging, or logistics.
Improve efficiency and quality
Invest in training and technology to improve the efficiency and quality of the production process. This can include implementing lean manufacturing principles, investing in quality control equipment, and investing in software to improve data analysis and management.
Marketing and Sales
Focus on expanding your customer base through marketing and sales efforts. This can include developing a strong online presence, attending trade shows, or creating a referral program to attract new customers.
Networking and Partnership
Building relationships with other businesses, suppliers, and customers can help expand your business by creating new opportunities for collaboration and partnerships.
Innovation
Constantly seeking new and innovative ways to improve the business will help to stay ahead of the competition and offer new products and services to attract new customers.
Scalability
Make sure that the business has the capacity to scale up quickly if the demand increases. This includes having the necessary resources, staff, and equipment to handle an increase in volume.
32. What is the most important thing in plastic injection molding?
There are several important factors to consider in plastic injection molding, but the most important thing is to ensure that the finished product meets the required specifications in terms of quality, performance and cost-effectiveness.
Quality
Quality control is crucial in plastic injection molding, as it ensures that the parts produced meet the required specifications and tolerances. This includes monitoring the process, inspecting the parts, and implementing quality control measures such as Statistical Process Control (SPC) to detect and correct any issues.
Design
The design of the mold and the part is also important. A well-designed mold can improve the efficiency and quality of the injection molding process, while a poorly designed mold can lead to defects and increased production costs.
Material selection
Choosing the right type of plastic material is also crucial in plastic injection molding. Different materials have different properties, and it's important to select a material that is suitable for the application and meets the required specifications.
Machine maintenance
Proper maintenance of the injection molding machine is also crucial to ensure that it runs smoothly and efficiently. Regular cleaning, lubrication, and inspection of the machine can help prevent downtime and prolong the life of the machine.
Process control
Controlling the various parameters of the injection molding process is also important to ensure that the finished parts meet the required specifications. This includes controlling the temperature, pressure, and speed of the injection molding process.
Cost-effectiveness
The cost-effectiveness of the plastic injection molding process is also important, as it can help to reduce production costs and increase profitability. This includes minimizing waste, using energy-efficient equipment, and automating the process.
33. Do you need an injection machine?
Purchasing an injection molding machine is a big investment, and it is very important to choose the right one. Through the above steps, you can get the injection molding machine specifications you need and the injection molding machine manufacturers that suit you. Every manufacturer offers a different solution. Please ask the injection molding machine supplier for all details carefully to ensure you get the product you want. Please choose the most suitable manufacturer after horizontal comparison. Hope this guide helps you.
Finally, we recommend Log Injection Molding Machine, a top injection molding machine manufacturer. We provide high quality injection molding machines and low prices. Log Injection Molding Machine will be your ideal partner.
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