What Is Injection Mold, How To Make Best Injection Mold 2013

What is injection mold?

Injection mold is a tool used in the injection molding process to produce parts by injecting material into a mold cavity. It is typically made of steel (H13, P20, 1.2312, 1.2344, S136H, etc.) or aluminum and is carefully designed to match the shape and specifications of the final product.

The injection mold is divided into two halves which are cavity half and core half, there are clamped together during the molding process, with the material being injected through a sprue into the mold cavity where it cools and solidifies into the desired shape. Once the part is formed, the mold opens and the part is ejected. The mold can be reused to produce multiple parts.

What is Injection Mold

Types of Injection Molds

Among the many varieties of injection molds, you may find:

Cavity-specific mold

Each cycle of the injection molding process can only generate one part when using a single-cavity mold. The process of making a part with this mold is as simple as injecting plastic resin into it, waiting for it to cool, and then removing the finished product.

When comparing the production costs of multi-shot molds to single-cavity molds, the former is usually more affordable. When making a small number of components at once would be too expensive, these are the go-to for prototyping and low-volume manufacturing runs.

Single cavity mold

The advantages of single-shot molds include:

Effective in terms of cost: the production of a single-shot mold is often less expensive than the production of a multi-shot mold.
Simple design: Ease of production and maintenance due to design simplicity: Single-shot molds are often less complex in layout than multi-shot molds.
Flexibility: A wide variety of applications, such as prototyping and low-volume production runs, are suitable for the utilization of single-cavity molds.

The disadvantages of single-shot molds include:

Limited production: This limitation renders single-cavity molds unsuitable for high-volume molding production runs because they are only capable of producing a single part during each cycle.
Complex parts: Single-cavity molds aren’t good for making complicated parts with many parts; for those, you’ll need a multiple cavity mold or a family mold.
Inefficiency: In comparison to multi-cavity molds, single-shot molds are less efficient because they can only create a single part during each cycle due to their limited capacity.

Multi-cavity molds:

Multi-cavity molds are a type of injection mold that has more than one cavity. This lets the injection molding process make more than one part during each turn. Depending on the need of the application, these molds can be made with holes that are the same or different.

As a result of its ability to create many parts in one cycle, multi-cavity molds are typically utilized for high-volume injection molding production runs. This feature allows them to increase production efficiency while also lowering the cost per part.

multiple cavity mold

The advantages of multi-cavity molds include:

High-volume production: Multi-cavity molds are made for large-scale production runs, which makes it easy to make a lot of parts.
Cost-effective: multi-cavity molds are usually cheaper than single-cavity molds because they can make more parts in a single run.
Complex parts: Multi-cavity molds can be used to make parts that are complicated and have many parts.

The disadvantages of multi-cavity molds include:

Complex design: Multi-cavity molds are more difficult to make and keep up than single-cavity molds because their designs are more complicated.
increased the mold cost: Multi-cavity molds can be more expensive than single cavity molds because different cavities may be put under different amounts of stress and wear during the injection casting process. This could lead to less efficient production and higher costs for repairs.

Hot runner mold:

Hot runner mold is a type of injection mold that uses a hot runner system to deliver the melted plastic material into the mold cavities. The hot runner system consists of a heated manifold that distributes the melted plastic to individual nozzle tips, which are then directed into the mold cavities.

Hot runner mold

The advantages of hot runner molds include:

Improved part quality: Hot runner molds can produce parts with improved quality, as they minimize the amount of plastic that is left over in the runners, reducing the risk of defects such as flash, short shots, and sink marks.
Increased production efficiency: Hot runner molds can increase production efficiency, as they eliminate the need for manual intervention to remove the runners from the molded parts, reducing cycle time and improving overall production speed.
Energy efficiency: Hot runner molds are more energy-efficient compared to traditional cold runner molds, as they minimize the amount of plastic that is wasted in the runners.

The disadvantages of hot runner molds include:

Complex design: Hot runner molds are more complex in design compared to traditional cold runner molds, making them more expensive to produce and maintain.
Increased maintenance: Hot runner molds typically require more maintenance compared to cold runner molds, as they have a more complex heating system that needs to be kept in good working order.
Vulnerability to clogging: Hot runner molds can be vulnerable to clogging, particularly when processing materials with high viscosity or with long flow lengths, as these can cause the melted plastic to solidify in the runners. This can result in reduced production efficiency and increased maintenance costs.

Stack molds:

Stack mold is a type of injection mold that allows for multiple cavities to be molded simultaneously in a single machine cycle. Stack molds are essentially two or more molds that are stacked on top of each other, with each mold producing a single part.

Stack Mold

The advantages of stack molds include:

Increased production efficiency: Stack molds allow for multiple parts to be molded simultaneously, increasing production efficiency and reducing cycle time.
Reduced material waste: Stack molds minimize material waste, as they allow for the production of multiple parts using a single shot of plastic material.
Lower costs: Stack molds can be more cost-effective compared to single-cavity molds, as they allow for the production of multiple parts with a single machine cycle.

The disadvantages of stack molds include:

Complex design: Stack molds can be more complex in design compared to single-cavity molds, making them more expensive to produce and maintain.
Reduced part quality: Stack molds can produce parts with reduced quality, as the presence of multiple cavities can result in increased risk of defects such as flash, short shots, and sink marks.
Increased maintenance: Stack molds typically require more maintenance compared to single-cavity molds, as they have a more complex design that needs to be kept in good working order.

Family molds:

Family molds, also known as multi-impression molds which is similar to multiple cavity mold, are a type of injection molding that allows for multiple parts with slightly different designs to be molded simultaneously in a single machine cycle. This is achieved by having multiple cavities in the mold that can produce different parts with different shapes and sizes.

family mold

The advantages of family molds include:

Increased production efficiency: Family molds allow for multiple parts with different designs to be molded simultaneously, increasing production efficiency and reducing cycle time.
Reduced costs: Family molds can be more cost-effective compared to producing multiple single-cavity molds for each part, as they allow for the production of multiple parts with a single machine cycle.
Flexibility: Family molds allow for the production of different parts with varying designs, making them a versatile option for manufacturers that need to produce a range of products.

The disadvantages of family molds include:

Complex design: Family molds can be more complex in design compared to single-cavity molds, making them more expensive to produce and maintain.
Reduced part quality: Family molds can produce parts with reduced quality, as the presence of multiple cavities can result in increased risk of defects such as flash, short shots, and sink marks.

Two-shot molds:

Two-shot mold (2 shot injection molding), also known as overmolding or multi-shot molds or 2K mold, are a type of injection molding that allows for two different materials to be molded together in a single machine cycle. This process involves molding a first material (base material) into a mold and then molding a second material (overmold material) onto the first material.

Two shot mold

The advantages of two-shot molds include:

Increased functionality: Two-shot molds allow for the combination of two different materials with different properties to create parts with increased functionality.
Improved aesthetics: Two-shot molds allow for the integration of different colors or textures into a single part, creating a more visually appealing product.
Reduced assembly time: By combining two materials into a single part, two-shot molds can reduce the need for additional assembly steps, reducing production time and costs.

The disadvantages of two-shot molds include:

Complex design: Two-shot molds are more complex in design compared to single-shot molds, making them more expensive to produce and maintain.
Increased cycle time: Two-shot molds typically have a longer cycle time compared to single-shot molds, as the process involves molding two materials in a single machine cycle.
Compatibility issues: Two-shot molds require that the two materials being molded are compatible with each other and will adhere properly, making it important to carefully select the materials being used.

Unscrewing molds:

Unscrewing molds are a type of injection molding specifically designed to produce parts with screw threads, such as caps, lids, and containers. These molds are unique in that they have a mechanism that allows the core of the mold to rotate while the cavity remains stationary, allowing the molded part to be unscrewed from the mold after it has cooled and solidified.

unscrewing mold

Advantages of unscrewing molds include:

High efficiency: Unscrewing molds allow for the efficient production of threaded parts in a single machine cycle, reducing production time and costs.
Improved accuracy: Unscrewing molds allow for the precise production of threaded parts with consistent pitch and thread depth, improving the quality and performance of the final product.
Versatility: Unscrewing molds can be used to produce a variety of different parts with different thread types and sizes, making them a versatile option for many different applications.

Disadvantages of unscrewing molds include:

Complex design: Unscrewing molds are more complex in design compared to other types of molds, making them more expensive to produce and maintain.
Increased cycle time: Unscrewing molds typically have a longer cycle time compared to other types of molds, as the process involves the rotation of the core of the mold.
Wear and tear: The rotating mechanism of unscrewing molds can be prone to wear and tear over time, requiring regular maintenance to keep the mold functioning properly.

Collapsible-core mold:

Collapsible-core molds are a type of injection molding that are used to produce hollow parts with internal cavities, such as tubes, pipes, and other complex-shaped parts. These molds use a unique design that allows the core of the mold to collapse into itself, creating the internal cavity of the part.

Collapsible-core mold component

Advantages of collapsible-core molds include:

Improved efficiency: Collapsible-core molds allow for the production of hollow parts in a single machine cycle, reducing production time and costs.
Improved part quality: Collapsible-core molds provide a more precise and consistent internal cavity, improving the overall quality of the final part.
Versatility: Collapsible-core molds can be used to produce a wide range of different parts with different shapes and sizes, making them a versatile option for many different applications.

Disadvantages of collapsible-core molds include:

Complex design: Collapsible-core molds are more complex in design compared to other types of molds, making them more expensive to produce and maintain.
Increased cycle time: Collapsible-core molds typically have a longer cycle time compared to other types of molds, as the process involves the collapsing of the core of the mold.
Wear and tear: The collapsible mechanism of the core can be prone to wear and tear over time, requiring regular maintenance to keep the mold functioning properly.

Advantages and Disadvantages of Plastic Injection Mold

Advantages of Injection Molding:

High Volume Production: Injection molding is a highly efficient method for producing high volumes of identical parts. This makes it ideal for mass-production of consumer goods, automotive parts, and other products that require large quantities of similar parts.
Precision: The process allows for very precise control of dimensional accuracy and part consistency. This is due to the use of tightly controlled processing conditions and the rigidity of the molding machine and mold.
Speed: Injection molding is a fast process, with cycle times as low as a few seconds for small parts. This allows manufacturers to produce large quantities of parts in a relatively short amount of time.
Cost-effective: The cost of producing parts through injection molding becomes more economical as the volume of production increases. This is due to the fact that the mold can be used to produce many parts over its lifespan, and the per-part cost decreases as the volume increases.
Versatility: Injection molding can be used to produce parts from a wide range of materials, including plastics, metals, and elastomers. This versatility makes it a popular choice for manufacturers who need to produce parts from different materials depending on the specific requirements of the product.
Automation: Injection molding machines can be automated, which makes the process more efficient and reduces the need for manual labor. This can also improve part consistency and quality.
Complex Shapes: Injection molding can be used to produce complex shapes and designs, including parts with intricate details and tight tolerances. This is possible due to the precise control of the molding process and the ability to design highly detailed molds.
Material Selection: Injection molding allows manufacturers to choose from a wide range of materials, each with its own unique properties, such as strength, flexibility, and resistance to heat, chemicals, and wear. This makes it possible to choose the best material for each application and produce parts with the desired properties.

Disadvantages of Injection Molding:

High Initial Cost: The initial cost of creating the mold can be high, especially for complex shapes and designs. This can make the process less cost-effective for small quantities of parts or for prototypes.
Limited Design Flexibility: Once the mold is made, changing the design can be difficult and expensive. This can limit the ability to make design changes or improvements once the mold has been created.
Material Waste: Injection molding generates a significant amount of scrap material, which can be costly to dispose of and environmentally harmful. This can also add to the cost of production and decrease the overall efficiency of the process.
Lead Time: The lead time for creating the mold and setting up the injection molding process can be long, especially for complex parts. This can slow down the product development process and limit the ability to quickly bring products to market.
Surface Finish Limitations: Injection molding may not produce a high-quality surface finish on some parts, especially those with intricate details or tight tolerances. This can limit the ability to produce parts with a high-quality aesthetic appearance.
Material Compatibility: Compatibility between the material and mold can be a challenge, as some materials may not work well with certain types of molds or require special processing conditions. This can limit the ability to produce parts from certain materials and increase the cost of production.
Limited Part Size: Injection molding is limited by the size of the mold and the clamping force of the molding machine. This can limit the size of parts that can be produced and increase the cost of producing larger parts.
Secondary Operations: Some parts may require secondary operations, such as trimming or finishing, after being molded. This can add to the cost of production and limit the overall efficiency of the process, of course some time those issues can be solved by improving the injection mold

Common Issues faced with an Injection Mold

Once you are working in plastic injection molding field, there will be always some issue that you need to solve every day, Here are some common challenges faced in injection molding:

Warping issues:

Warping is a common issue faced in injection molding and refers to a deformation or distortion of the molded part that occurs after it has been removed from the mold. This can happen due to a variety of factors, including:

Warp Distortion

Improper cooling: If the part cools too quickly or unevenly, it can cause warping as the material shrinks and contracts at different rates.
Residual stress: Injection molding creates residual stress in the part due to the high pressure used during the molding process. This stress can cause warping if it is not properly relieved.
Material selection: Some materials are more prone to warping than others. For example, materials with low heat resistance or low dimensional stability are more likely to warp.
Mold design: The design of the mold can also contribute to warping, especially if the mold does not allow for proper cooling or material flow.
Processing conditions: Inconsistent processing conditions, such as varying injection speeds, mold temperatures, and pressure levels, can cause warping.

To prevent warping, it is important to choose the appropriate material, optimize the mold design and processing conditions, and implement proper cooling and material handling practices. Additionally, it may be necessary to use post-molding treatments, such as annealing, to relieve residual stress and improve dimensional stability.

Flash issues:

Flash defects are a term used in injection molding to refer to the excess material that is forced out of the mold during the molding process. Flash occurs when the material flows beyond the intended mold cavity and into the parting line, or the space between the two halves of the mold.

Molding Flash or burrs

Flash can be caused by several factors, including:

Improper mold design: A poorly designed mold can cause flash by allowing material to leak into the parting line.
Inconsistent processing conditions: Varying processing conditions, such as injection speed and pressure, can cause flash.
Material compatibility: Some materials may not be compatible with the mold and may cause flash as they flow into the parting line.
Wear and tear on the mold: Over time, the mold may wear and cause flash as the material leaks into the parting line.

Flash can have several negative effects, including reducing the dimensional accuracy of the part, increasing the scrap rate, and making post-molding operations more difficult. To minimize flash, it is important to optimize the mold design, processing conditions, and material selection, and to regularly maintain and repair the mold as needed.

Weld Lines:

Weld lines are a common issue in injection molding and refer to visible marks on the surface of the molded part where two streams of melted plastic material meet and solidify. Weld lines occur when the material does not fully fuse together as it flows into the plastic mold cavity, leaving a visible line on the surface of the part.

Welding line

Weld lines can be caused by several factors, including:

Insufficient melt flow: If the material does not have enough time to flow and fully fuse together, a weld line may form.
Improper gate design: A poorly designed gate, which is the point where the melted material enters the mold cavity, can cause a weld line.
Inconsistent processing conditions: Varying processing conditions, such as injection speed and pressure, can cause a weld line.
Material compatibility: Some materials may not be compatible with the mold and may cause a weld line as they flow into the mold cavity.

Weld lines can weaken the strength of the part and reduce its overall quality. To minimize weld lines, it is important to optimize the mold design, processing conditions, and material selection, and to implement proper material handling practices. Additionally, it may be necessary to use special processing techniques, such as multi-cavity molds or hot runner systems, to reduce the formation of weld lines.

Sink marks:

Sink marks, also known as “sink,” “vacuum sink,” or “skin,” are sunken or depressed areas on the surface of an injection-molded plastic part. They are usually caused by a number of factors, including:

Resin shrinkage: As the resin cools and solidifies, it may shrink unevenly, leading to sink marks.
Poor material flow: If the resin does not flow evenly into all areas of the mold, it may create voids or sunken areas.
Inadequate packing pressure: If the injection pressure is not high enough, the resin may not fill the mold completely, leading to sink marks.
Mold design issues: The mold design, including gate placement and size, runner system, and venting, can all impact the quality of the molded part and may contribute to sink marks.

Sink marks can affect the aesthetic quality and functionality of a molded part and can be a source of frustration for manufacturers and end-users. To minimize sink marks, it is important to carefully consider the factors that contribute to them, such as material selection, mold design, processing parameters, and part design, and make adjustments as needed to optimize the injection molding process.

Flow marks:

Flow marks are a common issue in injection molding and refer to visible marks or streaks on the surface of the molded part that are caused by the flow of the melted plastic material as it fills the mold cavity. Flow marks occur when the material flows unevenly, leaving behind a visible mark on the surface of the part.

Flow marks can be caused by several factors, including:

Insufficient melt flow: If the material does not have enough time to flow and fill the mold cavity, flow marks may form.
Improper gate design: A poorly designed gate, which is the point where the melted material enters the mold cavity, can cause flow marks.
Inconsistent processing conditions: Varying processing conditions, such as injection speed and pressure, can cause flow marks.
Material compatibility: Some materials may not be compatible with the mold and may cause flow marks as they flow into the mold cavity.

Flow marks can reduce the overall quality and cosmetic appearance of the part. To minimize flow marks, it is important to optimize the mold design, processing conditions, and material selection, and to implement proper material handling practices. Additionally, it may be necessary to use special processing techniques, such as multi-cavity molds or hot runner systems, to reduce the formation of flow marks.

Scratch issues:

Scratch issues refer to visible marks or scratches on the surface of an injection-molded part that are caused by physical contact between the part and the mold or other foreign objects during the molding process. Scratch issues can occur for several reasons, including:

Poor mold design: Improperly designed molds or mold components can cause scratches on the surface of the part.
Insufficient lubrication: If the mold and mold components are not properly lubricated, they can cause scratches on the surface of the part.
Poor material handling: Poor handling of the raw material or finished parts can cause scratches on the surface of the part.
Debris in the mold: Foreign objects or debris in the mold cavity can cause scratches on the surface of the part.

Scratch issues can reduce the overall quality and cosmetic appearance of the part. To minimize scratch issues, it is important to implement proper mold design, lubrication, material handling, and maintenance practices. Additionally, regular cleaning and inspection of the mold and mold components can help to prevent scratch issues from occurring.

Ejector marks:

Ejector marks are visible marks on the surface of an injection-molded part that are caused by the ejector pins or other ejection mechanisms during the molding process. Ejector marks occur when the ejector pins push the molded part out of the mold cavity and leave behind visible marks on the surface of the part.

Ejector marks can be caused by several factors, including:

Improper ejector pin design: If the ejector pins are not properly designed, they can leave visible marks on the surface of the part.
Excessive force: If the ejector pins are applying excessive force to the part during ejection, they can leave deeper and more noticeable marks on the surface of the part.
Inconsistent ejection force: If the ejection force is not consistent from one ejector pin to another, it can result in uneven ejector marks on the surface of the part.
Poor surface finish: If the surface finish of the mold cavity is not smooth, it can cause ejector marks on the surface of the part.

Ejector marks can reduce the overall quality and cosmetic appearance of the part. To minimize ejector marks, it is important to optimize the design of the ejector pins and the surface finish of the mold cavity, and to implement proper maintenance and inspection practices. Additionally, it may be necessary to use special ejection mechanisms, such as air-assisted ejection or side-action ejection, to minimize ejector marks.

Short shot issues:

A short shot is a common issue in injection molding that occurs when the melted plastic material does not completely fill the mold cavity, resulting in a molded part that is smaller than the desired size. Short shots can occur for several reasons, including:

Insufficient material: If there is not enough material to fill the mold cavity, a short shot can occur.
Improper processing conditions: If the processing conditions, such as the injection speed and pressure, are not set correctly, a short shot can occur.
Poor mold design: A poorly designed mold can cause a short shot, as the material may not be able to flow into all areas of the mold cavity.
Material degradation: If the material has degraded or has not been stored properly, it can cause a short shot.

Short shots can reduce the overall quality and functionality of the part and result in wasted material and processing time. To minimize short shots, it is important to optimize the mold design, processing conditions, and material selection, and to implement proper material handling practices. Additionally, regular monitoring and maintenance of the molding equipment can help to prevent short shots from occurring.

Air trap and burn marks:

Air traps and burn marks are common issues in injection molding that can occur due to improper processing conditions or mold design.

Air traps occur when air becomes trapped in the mold cavity during the injection molding process, causing the material to flow around the air pocket rather than filling it. This can result in visible voids or pockets in the molded part. Air traps can be caused by several factors, including:

Insufficient material flow: If the material is not flowing properly into the mold cavity, air can become trapped.
Improper gate design: If the gate is not designed correctly, air can become trapped in the mold cavity.
Inadequate venting: If the mold is not vented properly, air can become trapped in the mold cavity.

Burn marks occur when the plastic material is exposed to high temperatures for too long, causing it to degrade and produce visible marks or discoloration on the surface of the part. Burn marks can be caused by several factors, including:

Excessive processing temperatures: If the processing temperatures are set too high, the material can degrade and produce burn marks.
Insufficient cooling time: If the part is not cooled properly, the material can degrade and produce burn marks.
Poor mold design: A poorly designed mold can cause the material to be exposed to high temperatures for too long, resulting in burn marks.

To minimize air traps and burn marks, it is important to optimize the processing conditions and mold design, and to implement proper monitoring and maintenance practices. Additionally, it may be necessary to use special processing techniques, such as low-temperature molding or vacuum molding, to minimize air traps and burn marks.

Processing to make an injection mold:

The process of making an injection mold involves several steps:

Mold Design:

Injection mold design is a critical aspect of the injection molding process, as it directly affects the quality, efficiency, and cost of the molded parts.

A well-designed injection mold will produce parts that meet the desired size, shape, and quality requirements, while also being efficient to produce and easy to maintain.

The key factors to consider when designing an injection mold include:

Part geometry: The design of the molded part must take into account the desired size, shape, and features of the part.
Material selection: The material to be used for the mold and the molded part must be selected based on factors such as cost, strength, and thermal stability.
Mold cavities: The number and arrangement of the mold cavities must be selected to meet the production volume requirements.
Gating system: The design of the gating system is critical, as it determines how the plastic material flows into the mold cavity.
Ejection system: The ejection system must be designed to ensure that the molded parts can be removed from the mold without damage.
Cooling system: The cooling system must be designed to ensure that the molded parts cool evenly and quickly, reducing cycle time and improving quality.
Draft angles: The design of the mold must include appropriate draft angles to allow the molded parts to be removed from the mold.
Venting: The mold must be vented to allow air to escape from the mold cavity, reducing the risk of air traps and burn marks.
Maintenance and repair: The mold must be designed for easy maintenance and repair, to minimize downtime and increase production efficiency.

Injection mold design is a complex process that requires expertise in areas such as mechanical engineering, materials science, and manufacturing. It is important to work with a reputable mold designer to ensure that the mold is designed correctly and meets your needs.

CNC programming:

CNC (Computer Numerical Control) programming is an essential step in the manufacturing of an injection mold. Once the mold design is finished, then next step is CNC programming. The following are the main steps involved in CNC programming for injection mold manufacture:

CAD model translation: The CAD model is translated into a computer-aided manufacturing (CAM) program, which is used to create the CNC code for the mold.
CNC code creation: The CNC code is created in the CAM program, which provides instructions to the CNC machine on how to move and cut the mold components. The code takes into account the material and thickness of the mold components, as well as the desired shapes and features.
Tool path creation: The tool path is created in the CAM program, which defines the path that the cutting tool will follow to machine the mold components. The tool path takes into account the shapes and features of the mold components and the capabilities of the CNC machine.
Simulation: The CNC code and tool path are simulated in the CAM program to ensure that the mold components will be machined correctly and to the correct specifications.
CNC machining: The CNC code is loaded into the CNC machine, which then uses the code and tool path to machine the mold components.

CNC programming is a critical step in the injection mold manufacturing process, as it determines the accuracy and quality of the mold components. It is important to work with a CNC programmer who has experience in programming for injection molds to ensure that the CNC code is created correctly and to the correct specifications. This step is also where the mold’s cooling channels, ejector system, and other features are added to the mold components to ensure their proper functioning.

Mold BOM list purchasing

A Mold BOM (Bill of Materials) list is a comprehensive list of all the components and materials needed to manufacture an injection mold. It includes the following items:

Steel for the mold base and core/cavity inserts
Hot runner components
Cooling system components, such as water lines and cooling blocks
Ejection system components, such as ejector pins and sleeves
Sprue puller components
Heater bands and temperature controllers
Mold components, such as bushings, guide pins, and locking devices
Mold inserts, such as slides and lifters
Specialty items, such as date stamps and custom logos

The Mold BOM list is an important tool for procurement and manufacturing, as it provides a clear and detailed list of the components and materials needed to produce the mold. It is used to ensure that all of the necessary components are ordered and on hand when the mold is ready to be manufactured.

It is important to work with a reputable supplier when purchasing the components for an injection mold, as the quality and reliability of these components can have a significant impact on the efficiency and quality of the injection molding process.

Mold rough machining:

Injection mold rough machining refers to the initial machining of the steel components of an injection mold to achieve the basic shape and size of the mold. This step is typically done using computer numerical control (CNC) machines. The following are the main steps involved in injection mold rough machining:

Steel selection: The first step is to select the appropriate type of steel for the mold, such as P20 or H13, based on the desired properties of the molded part.
Steel cutting: The steel is cut to the appropriate size and shape using a CNC machine. This step may also include drilling and tapping of holes for the cooling and ejection systems.
Steel profiling: The steel components are then machined to achieve the basic shape of the mold, including the core and cavity inserts.
Steel inspection: The machined components are then inspected to ensure that they meet the required tolerances and specifications.
Steel cleaning: The machined components are cleaned and deburred to remove any rough edges or debris.

The rough machining process is an important step in the injection molding process, as it lays the foundation for the final, high-precision machining and polishing steps that will follow. It is important to ensure that the rough machining is done accurately and to the correct specifications to ensure that the mold functions properly and produces parts with the desired quality.

Mold steel heat treatment:

Mold steel heat treatment is the process of heating and cooling the steel components of an injection mold to improve their mechanical properties and dimensional stability. The purpose of heat treatment is to harden the steel, relieve residual stresses, and improve its wear resistance and toughness. This is specially for the harden steel of injection mold, if using pre-harden steel to make the injection mold then no need to do this heat treatment jobs. The following are the main steps involved in mold steel heat treatment:

Annealing: The steel components are heated to a specific temperature, usually between 800-900°C, and then slowly cooled to relieve internal stresses and improve the steel’s machinability.
Hardening: The steel components are heated to a high temperature, typically above the critical temperature, and then rapidly cooled, usually by quenching in oil or water. This process hardens the steel and improves its wear resistance.
Tempering: After hardening, the steel components are tempered by heating them to a lower temperature for a specific time to improve the steel’s toughness and dimensional stability.

The heat treatment process is critical for ensuring that the steel components of an injection mold have the desired mechanical properties and dimensional stability, which are essential for producing high-quality molded parts. It is important to work with a heat treatment provider that has experience in treating mold steel to ensure that the heat treatment process is done correctly and to the correct specifications.

Mold cavity and core fine machining:

Mold cavity and core fine machining is the process of precisely machining the internal surfaces of the mold cavity and core inserts to achieve the final shape and size of the mold. This step is typically done using computer numerical control (CNC) machines with high precision and accuracy. The following are the main steps involved in mold cavity and core fine machining:

Surface preparation: The surface of the mold cavity and core inserts are cleaned and polished to remove any residual debris or roughness.
Surface machining: The internal surfaces of the mold cavity and core inserts are machined using CNC machines to achieve the final shape and size of the mold. This includes creating the intricate details and features of the molded part, such as text, logos, and undercuts.
Surface inspection: The machined surfaces are inspected to ensure that they meet the required tolerances and specifications.
Surface polishing: The internal surfaces of the mold cavity and core inserts are polished to a high finish to improve the surface quality of the molded parts and reduce the risk of defects.

Fine machining is a critical step in the injection molding process, as it determines the quality and accuracy of the molded parts. It is important to work with a machining provider that has experience in mold cavity and core fine machining to ensure that the machining is done correctly and to the correct specifications. This step is also where the mold’s ejection system, cooling channels, and other features are added to ensure the proper functioning of the mold.

EDM machining:

EDM (Electrical Discharge Machining) is a process used to make intricate and highly precise shapes in metal parts, including those in an injection mold. The process uses electrical sparks to remove material from the mold surface, creating the desired shape. The following are the main steps involved in EDM machining:

Surface preparation: The surface of the mold component to be machined is cleaned and polished to remove any residual debris or roughness.
EDM setup: The EDM machine is set up with the correct parameters, including the spark gap, pulse duration, and electrode material, based on the material and shape of the mold component.
Spark erosion: The EDM machine produces electrical sparks that remove material from the mold component, creating the desired shape. This process is done incrementally, with the EDM machine gradually eroding the material until the final shape is achieved.
Surface inspection: The machined surface is inspected to ensure that it meets the required tolerances and specifications.

EDM machining is often used for mold components that have complex shapes or small, intricate details that are difficult to achieve with other machining processes. It is also used to produce the sharp edges and corners that are essential for the proper functioning of an injection mold.

The process is highly precise and accurate, making it ideal for producing high-quality molded parts. It is important to work with an EDM provider that has experience in EDM machining for injection molds to ensure that the process is done correctly and to the correct specifications.

Mold surface polishing:

Injection mold polishing is the final step in the injection mold manufacturing process. It involves smoothing out the surfaces of the mold components to ensure that the finished product has a smooth and even surface. The following are the main steps involved in injection mold polishing:

plastic mold polishing

Surface preparation: The surfaces of the mold components are cleaned and prepared for polishing. Any remaining rough spots or machining marks are removed to ensure a smooth surface for polishing.
Rough polishing: The first step in polishing is rough polishing, which involves removing any large imperfections in the surface of the mold components. This step is usually done with a coarse grit abrasive, such as a sandpaper or abrasive brush.
Fine polishing: Fine polishing is the next step, which involves smoothing out the surface of the mold components to a finer finish. This step is done with a finer grit abrasive, such as a finer sandpaper or abrasive brush.
Buffing: Buffing is the final step in polishing, which involves using a buffing wheel and polishing compound to achieve a high-gloss finish on the mold components.
Inspection: After polishing, the mold components are thoroughly inspected to ensure that they have a smooth and even surface, with no scratches, cracks, or other imperfections.

Injection mold polishing is important because it affects the quality of the final product. A well-polished mold results in a product with a smooth and even surface, which is important for product functionality and aesthetics. It is important to work with an experienced mold polisher to ensure that the mold components are polished to the correct specifications and to the desired level of quality.

Mold fitting

Mold fitting is a specialized job within the field of injection molding and involves the assembly, installation, and testing of injection molds. Mold masters are responsible for ensuring that the mold components are properly assembled and functioning correctly, and that the mold is producing parts with the desired quality and performance standards. Some of the main responsibilities of mold fitters include:

Assembling the mold components: Mold masters are responsible for assembling the various components of an injection mold, including the cavity and core components, runner system, and any auxiliary components.
Installing the mold onto the mold fitting machine: Moldmaster must be able to mount the mold onto the mold fitting machine in a way that ensures proper alignment and functioning of the mold, if has no any mold fitting machine then use manual way to fitting the mold, this is most of companies do.
Testing the mold: Mold master is responsible for testing the mold to ensure that it is producing parts with the desired quality and performance standards. This includes inspecting the parts for any defects, such as warping, shrinkage, or other quality problems.
Adjusting the mold: If any issues are found during the testing phase, moldmaster is responsible for making any necessary adjustments to the mold to ensure that it is producing parts that meet the desired specifications.
Troubleshooting: Moldmaster must be able to identify and troubleshoot any problems that may arise during the mold fitting process.

Mold fitting jobs require a combination of technical knowledge, manual dexterity, and attention to detail. Mold masters must be able to work with a wide range of tools and machinery, as well as understand the complex processes involved in injection molding. It is important for mold fitters to have a good understanding of the injection molding process, as well as experience working with different types of molds and materials.

First Injection molding trial or shooting:

Injection molding trial shooting refers to the process of testing the injection mold to produce a sample part using the injection molding process. This process is a critical step in the injection molding process, as it allows the manufacturer to evaluate the performance of the mold and make any necessary adjustments before producing a large quantity of parts.

The injection molding trial shooting process typically involves the following steps:

Preparation: The mold is installed on the injection molding machine and the machine is set up for the shot. The hopper is filled with the plastic resin.
Melt temperature control: The melt temperature is controlled to ensure that the plastic resin is heated to the correct temperature to produce high-quality parts.
Injection: The molten plastic is injected into the mold under high pressure. The pressure is maintained until the mold is filled with the plastic resin.
Cooling: The mold is cooled to solidify the plastic resin and form the part. The cooling time is determined by the type of plastic resin being used and the size and shape of the part being produced.
Ejection: Once the part is solidified, it is removed from the mold. The ejector pins are used to push the part out of the mold.
Inspection: The part produced from the mold is thoroughly inspected to ensure that it meets the desired specifications and quality standards.
Adjustments: If necessary, adjustments can be made to the molding process to improve the performance of the mold and the quality of the parts being produced.

The injection molding trial shooting process is an important step in the injection molding process, as it allows the manufacturer to evaluate the performance of the mold and make any necessary adjustments before producing a large quantity of parts. This process helps to ensure that the mold is producing high-quality parts with the desired specifications.

Mold packing and ready for production:

Once the mold is completely finished by the mold maker, then next step is for the massive production. Mold packing and preparation for production is the final step in the injection molding process before mass production can begin. This step involves the following tasks:

Cleaning and maintenance: The mold is thoroughly cleaned and inspected to ensure that there are no debris, dirt, or damage to the mold.
Packing and storage: The mold is carefully packaged and stored in a secure location to prevent damage and ensure that it is ready for use when needed.
Testing and adjustment: The mold is tested for any issues, such as leaks, poor filling, or improper part ejection, and any necessary adjustments are made to ensure that the mold is functioning properly.
Production setup: The mold is installed into the injection molding machine and all necessary settings, such as temperature, pressure, and injection speed, are adjusted to meet the specific production requirements.
Start of production: The first batch of parts is produced, and the process is monitored to ensure that the parts meet the required specifications and quality standards. Any necessary adjustments are made to optimize the production process and ensure consistent quality.

Overall, the preparation of the mold for production is an important step in the injection molding process that helps to ensure the success and efficiency of the production run.

Above information is procedures for making an injection mold, maybe there are some small things missed but the most of things are above, as you can see making an injection mold is not easy case, if you have an injection mold project in handle, you need to find a professional injection mold maker to service you, this will make sure your project is running successfully.

Sincere Tech is a professional China mold factory specializing in the manufacture of custom injection molds. They have experience and expertise in the design, development, and production of high-quality injection molds for various industries and applications.

They provide a range of services, including mold design, prototyping, mold production, and post-mold processing, to ensure that their clients receive the best possible results. With their focus on quality, precision, and customer satisfaction, Sincere Tech is a reliable and trustworthy partner for all your injection molding needs. Contact us to get e price for your project now.