2k injection mold

2k injection molding wiki

In the search for information about 2K injection mold? You have landed on the appropriate webpage.

This FAQ guide will answer every question you have about the 2-shot injection mold.

Define the concept of 2k injection mold?

It is the manufacturing process of molding two colors or materials into one plastic part.

Through the 2k injection molding process, two different colors or two materials are blended into the single end of the plastic part.

2K Injection Molding

In simple words, it is the process of making a part out of two materials. These two materials can be different colors, some soft, and others hard.

In the injection mold, a chemical process mixes two or more materials to make one part.

The selection of material is very important in the 2k injection mold technology for the project’s success.

Nowadays, it is the most innovative,  popular process used in plastic manufacturing.

2k injection molding is a double shot or double injection mold process.

This activity is done in industries that direct two different polymers into a pre-made product.

2k injection mold is a specialized, automated, and meticulous manufacturing process that manages the injection of multiple materials into one ready product.

In this advanced process, we can combine the hard and soft thermoplastic or thermoplastic and thermoplastic elastomer.

What is the difference between a 2k injection mold and over-molding?

When we talk about the over-molding and 2k injection mold process, there is a two-point difference between them.

The first one is to use the 2k injection machine for molding that produces 2-3 material or color products.

While over-molding is just a normal 2k injection molding process where a simple molding machine is used to produce the parts, it means that in over-molding, the device moves the substrate part to the subsequent mould to get the final product.

 Overview of Overmolding

The second one is compared to over-molding; the 2-shot injection mold process is complex but fast, high-quality, and efficient. It is most commonly used for large production scales because of its high production efficiency.

The other difference is that the material should be cold to be removed in the over-molding process.

However, in 2k injection molding, the plastic material (the polymer) is still hot and flexible, which allows for more operations to be carried out. The procedure can be carried out using a wide range of materials as the substance for molding or being molded on. Still, you have to face some limitations in over-molding because over-molding is only metal with plastic or plastic in a few cases.

The chemical procedure is involved in the 2k injection molding as it creates a chemical bond that necessitates the bonding of molecules.

Meanwhile, in over-molding, they are locked mechanically with other substances after making parts.

The over-molding procedure can have some compatibility issues, such as material limitations.

As opposed to overmolding, the 2k injection mold procedure can be carried out in diverse areas, as different types of materials can be used to produce high-quality end products.

Overmolding Vs Insert Molding-Differences In Manufacturing Processes

Give some pros of 2k injection molding.

Design flexibility:

The 2k injection molds are subjected to a high level of pressure that allows a larger portion of detail to be engraved onto the part.

It gives the design flexibility for complex and intricate shapes to be manufactured.

Fast product:

The 2k injection molding process can produce many numbers of parts per hour. Complexity and mold size are the factors that affect the speed of the molding process.

If the size of the mold is large and complex, the machine can take 15-20 seconds per cycle.

Highly efficient:

Double molding is the process that produces highly efficient products that hold top quality.

Low labor costs:

2k injection molding machine is an automatic process in which most of the procedure is performed by machines and robotics.

2K injection molding machine

You can cut the labor cost because a single person can operate, manage, and control the whole process. It also helps to reduce the overall manufacturing costs.

Ability to include inserts:

2k injection mold process can insert metal and plastic in the mold.

High-output production:

This injection molding process produces thousands of parts before the tooling of the machine needs maintenance.

Wide range of material selection:

The 2K mold process offers a variety of polymer resins, from which you can select whatever you like. 2K injection molding technology can also be applied to container molds, bucket molds, spoon molds, and so on.

You can use two different polymers simultaneously, like TPE over mold on the parts of PP.

Color control:

This type of injection molding uses different colors for manufacturing using compounding or master batching.

Improvement in strength:

You can use fillers in the molding material during the 2k injection mold process.

These fillers help decrease the density of the plastic while it is molded and give great strength to the completed part.

Give a good finish:

One of the best things about the 2k injection mold process is that very little post-production work is needed, as parts usually have a good finish.

What benefits can I avail by using the 2k injection mold process?

You can avail a number of benefits from the 2k injection mold process. Here are some of the benefits you can get.

Versatility:

Different industries use this process due to the impressive qualities of 2k mold.

We can use different types of product design in this process and make products such as automotive parts, cameras, medical services, and power switches.

Enhance Features:

2k mold is the process that enhances the cosmetic and tactile features of the product.

 Advantages of  Injection Mold

Time:

The molding process reduces the secondary processing, making it a constant process again in cycle time.

The result of this is greater efficiency and less assembly time.

Reduce handling:

The 2k injection mold process is an automatic process, so there are fewer chances to work on the finishing look of the product after it’s done.

Increase marketability:

This high-efficiency 2k injection mold process advances the practical use of the product and even increases its market value.

Advance quality:

2k injection mold process uses transparent plastic, neat finishes, and colored graphics that give the multi-material efficient product.

This process also offers extended durability and is aesthetically pleasing because many colors blend in the manufacturing process.

Expense:

The 2k injection mold procedure is a streamlined process that lowers the price by combining all assembly steps into one molding process.

Custom-made product:

The plastic used in the injection mold process is easy to handle and increases user comfort. Thus, you can make tailor-made products according to customer demand.

What is the draft guide for 2k injection mold?

When you make a mold draft for 2k injection molding, precise manufacturing, and precise manufacturing are the key to success.

Durability, efficiency, and maintenance are the basic principles for designing the perfect mold.

The following are the important factors that influence the functional design of the 2-shot injection mold process.

• Component ejection system
• Number of cavities
• Air vent
• The core and cavity of the mold and its cooling system
• Shrinkage for both materials
• The width of the walls of the mold
• Runner and gate

Now we discuss the design guide of the 2k injection mold:

• Futuba mold base is the most common to get an accurate mold base.
• The guide bush and pin of the ground you use to shape the mold must be symmetrical about the left, right, top, and bottom.
• The core and cavity of the mold are also balanced.

Make sure your mold core is placed and rotated 180 degrees, and the cavity sides are closed tightly together.

 Design for Injection Mold

• The area between the nozzles of the 2k injection molding machine determines the arrangement of the products.
• Some of the spacing nozzles of the 2k injection molding machine are adjustable, while some are not, like domestic ones are not flexible.
• The ejected bar and independent ejector system are two.
• The ejector pin is the same as the ejector bar and system, and the two parts of the cavity are also identical.
• Use the spring to reset the eject plate because it is not possible to reset it with the screw.
• All four sides must have a side lock to hold the center of the mould more firmly.
• If the core and cavity of the molds are not symmetrical, they will not be associated with the hollow side of the mold when the central site is rotated 180.
• Make sure the track of the corresponding nozzle of the 2k injection molding machine is the y-axis or the x-axis. This directive controls the design of the product place.
• The initial and out way of each direction of the cooling water must be on a similar side.
• Make sure the direction of the inlet is not on the top side and the direction of the outlet on the cooling water is on the bottom side.
• The freezing water cannot be elated if it surpasses the height of the water tank of the 2k injection molding machine.
• Remember to inject the first material on the non-operating side, making it simple to take the product out.
• The operating and non-operating sides are the slots for clamping for the export mold, not on the bottom and top sides because their product should be fully running automatically.

State some cons of using a 2k injection mold

Everything has advantages and disadvantages. The 2k injection mold process has drawbacks, which are given below.

Not perfect for small runs:

It can be too expensive if you plan to use a 2k injection process for small production.

Tooling cost:

Due to the testing, design, and required tooling, the up-front cost of 2k injection molding is slightly high.

First, you have to make an initial design using CNC prototyping or 3D printing. Then, this prototype design mold makes copies of the product in bulk.

Injection Mold Maker

In the end, you have to undergo an expensive testing process, and then you can inject the material into the mold.

Design restrictions:

Consider and follow the rules and procedure of 2k mold when designing the plastic parts.

Avoid cuts and sharp edges. Draft angles are recommended for better de-moulding. Control the thickness of the mold walls to prevent inconsistencies in the cooling process, such as sink marks.

Ensure that all these are controlled because it can be challenging to make changes in the designs, as tools are typically made from aluminum or steel.

By cutting away the aluminum or steel, you can design the tool cavity bigger, but in the case of plastic, you have to decrease the size of the tool cavity.

This process is complex; most of the time, tools start scrapping, and you have to start over. Make sure the size and weight of the part are perfect because this determines the size of the tool and press.

If the part is too large, it will be more expensive and complex.

Cost:

One of the significant disadvantages of the double injection mold process is the cost of it. This 2k injection molding process has a high start-up cost.

Explain the working process of 2k injection molding

Here is the detailed working process of 2k injection Molding given below:

Dried polymer granules were placed in the hopper. These polymers are mixed with coloring pigments or other additives in this hooper.

Then these granules were heated in the barrel and moved while mixing toward the mold by an adjustable pitch screw.

The perfect barrel and bolt can optimize the pressure, take it to the correct level, and melt the plastic.

Figure 8 Working of 2k Injection Mold Machine

After this, the melted plastic moves forward and is injected into the mold, passing through the runner system by filling the whole cavity.

When the plastic cools, it solidifies again and holds the shape according to the mold.

Now, open the mold and push out the solid part using ejector pins. After taking it out, close the mold and repeat the procedure.

What is the 2k injection mold machine?

The 2k injection mold process is performed through a specially designed machine programmed to perform two shots in one cycle.

A nozzle injects the material into the mold in one cycle, and then the mold starts rotating automatically

While rotating, various types of colored plastic are inserted into the mold from the second mold.

The 2k injection mold machine uses different polymers to create highly effective results.

Is the 2k injection mold process expensive?

Yes, for small runs.

The 2k mold process is not perfect for small runs. The start-up cost of the 2k injection mold procedure is high as it needs tooling, testing, and mold design.

 2K Injection Mold Cost

2k injection mold is perfect for large industries compared to the single-stage injection molding.

Because of this, its cost can be controlled quickly by reducing the assembly steps and eliminating hand labor.

Give some applications of 2k injection mold?

If you want to combine hard and soft plastic material to make a product, the 2k injection mold process is perfect as it is the process to inject two colors of plastic into one product.

Here we listed some of the practical applications of the 2k mold process:

• You can build molds with two productive cavities through the double injection mold procedure.
• It gives the product soft-touch enhancement.

Different Applications of 2K injection Molding

• By using additional colored resins in the 2k injection mold process, you can enhance cosmetic features and make the graphics permanent.
• The advanced molding procedure improves performance by combining many material properties to produce the ideal product.

Where can we find the best quality 2k injection mold parts in China?

Go4mould is the number one choice in China for 2k injection mold parts. They have over ten years of experience.

This manufacturer is the one-stop injection mould parts that provides more than 200 sets of injection mold capacity.

Figure 12 2K Injection Mold Factories in China

They are the best 2k injection mold manufacturer in China, and they follow the ISO9001 quality management system.

Why choose a 2k injection mold?

2k injection mold is the top pick for large industries because this process is best for combining soft and hard plastics.

Also, it saves them time and cost by combining all steps into one.

The 2k injection molding process reduces the secondary processing, making it a constant process again in cycle time.

 Double injection Mold Product

The result of this is greater efficiency and less assembly time.

The 2k injection mold process is an automatic process, so there are fewer chances to work on the finishing look of the product after it’s done.

This high-efficiency 2k injection mold process increases the product’s practical use and even its marketplace value.

Is the 2k injection mold process safe?

Yes, partially.

You can say that the 2-shot injection mold process is safe.

However, during the 2k injection molding process, plastic material is melted and injected into the molds.

 2K Injection Mold Processing Machine

All of this is done within minutes. Some hazardous vapors and fumes are released that can cause respiratory issues at the workplace if they are inhaled.

You can control this situation by taking precautionary measures at the workplace.

What are the variations of 2k injection molding?

There are a few variations of the 2k injection procedure that including:

1. Moveable core
2. Rotary platen
3. Overmold

Moveable core and rotary platen are the variables that need an additional injection component, 2 processes, and the runner system.

While oversold involves two separate molds, in most cases, each mold is for a particular material.

Overmold can also run on a single mold, pick-and-place part transfer, and two two-runner systems.

What are the common mistakes in 2k injection mold machines?

We have mentioned some of the most common mistakes people make when selecting 2k injection mold machines.

The most common mistake is to buy a used 2k injection molding machine that doesn’t work correctly. So, before buying, make sure to test and inspect it thoroughly.

It selects the large screw diameters that generate shearing forces during screw rotation and degrade the material.

 Perfect Injection Mold Machine

When you select the large diameter screw, it reduces the value of the produce part due to material degradation.

Another common mistake is not controlling the injection pressure, which causes short moldings and decreases the quality of the parts.

You will face difficulty producing quality parts when you keep the inadequate clamp tonnage too low.

Give the basics of 2k injection mold machine selection.

Calculate the clamp tonnage requirements and the injection unit size when selecting the 2k injection machine.

Before buying, check the plastic parts you want to mold and the type of machine you want, such as hybrid, hydraulic, or electric.

How can we maintain the 2k injection mold?

Here are some of the suggestions to keep the 2k injection mold in good shape:

• Always check the damaged and loose fastening parts of the 2k inject mold. If they are, replace them immediately.
• Make sure to clean the edges and ground after using the mold. If you do not pay attention to it, blockage of the material will be caused.
• Check whether elastic parts like springs have been damaged during use. If yes, then make sure to change them.

Maintenance of Injection Mold Machine

• Pay attention to the specifications of the mold spring while replacing it.
• Check the top plate, pressure plate, and other parts of the 2k injection machine regularly.
• What are some exemplary suggestions for 2K Injection Mold?

Why is material selection important in 2k injection mold?

Material selection is important in the 2k injection mold process. Different types of materials with different colors are used in the molding process.

It can be made of two different materials in different colors. One thing to check while selecting the material is the interface of the two materials.

Other considerable things are processing parameters and differences in the shrinkage hole.

The first molding material is important as 2k mold shrinkage depends on it.

 Selection of  Injection Machine

There are many considerations to keep in mind while selecting the material because the main material has already braced the secondary material that does not shrink more.

The important factors are the shape of the plastic products and the fluidity of the raw material.

How does the location of the gate affect the 2k injection mold?

The gate is the entrance point of the plastic in the mold, so it is of great importance. Therefore, it is important to carefully select the gate in the 2k injection mold.

A subgate is best for the first molding, which helps the runner and the product detach automatically.

If the sub gate is not accessible, a three-plate mold or hot tip is perfect for use.

 Gate Design for 2K Injection Mold

When the first shot is a piercing gate, the cavity of the mold should be planned with a wave. During molding, try to evade husks that remain in the gate’s break to penetrate the secondary material.

Why is the position of thimble and shrinkage important in a 2k injection mold?

Automatic gate separation is important in a 2l injection mold so the product doesn’t drop when the machine rotates.

If we talk about the place of the thimble in injection molding, the core of the soft gel is the perfect place for it.

Ensure that the thimble hole’s position has a minimum interval of 210 mm.

Most of the time, 2k injection mold machines come with a thimble that is not large enough, so it is necessary to design a long thimble for the molds.

Figure 21 2k Injection Molding Placements

Make the thimble 150 mm longer than the base mold in the 2k injection mold.

Also, shrinking plays an important role in the injection mold process. So, special attention should be paid to it because it will automatically shrink the hard plastic when entangled with the soft plastic.

To avoid this, we connected a contour to the machine that causes both materials to shrink. We will also use multi-component injections.

How much is the tolerance reference of the 2k injection mold?

The rear and front flange in the 2k injection mold have dimensions tolerance of -0.05 mm.

The spacing tolerance is + or – 0.02 between the two flanges. The distance gap between the top stick hole and to stick is 0.1 mm on a single side.

The center-to-center acceptance power of the rear and front bushing mols and the guide post is + or -0.01.

It is important to remember that tolerance is added to all quatern sides and the depth of the 2k injection mold frame.

If it is not done correctly, burns are generated when the back mold is alternated 180 degrees because of low and high inconsistencies.

The final depth tolerance of the 2k mold is -0.02 mm.

How can we make a conventional design of the 2k injection mold?

First, in a 2k injection mold machine, control the track of the equivalent nozzle. Make sure they are in the way of the x-axis and y-axis.

This will help you determine the product placement. It is important to match the mold guide and post-guide sleeve.

The spacing of the 2k injection mold machine’s nozzles determines the products’ spacing.

The 2-color injection mold machine nozzle spacing is adjustable, while some are not.

Parting surface is important in 2k injection molding, which is obtained after combining two products. The obverse parting surface mold must be taken from a single product.

Customized Design for 2K Injection molding

Make sure to review all the other reference data for the 2k injection mold machine, such as the minimum die thickness, the maximum die thickness, and, most importantly, the top hole spacing.

When you design the injection mold cavity, make sure to project the partial evasion to prevent the cavity from scraping the primary molded part.

Consider the strength of every seal position because the plastic material deforms under high injection pressure.

When you clamp both a and b plates, pay special attention to resetting the slider before clamping.

If you do not avoid this situation, the product will be crushed.

Ensure the water positions of the two centers and chambers are occupied and balanced simultaneously.

In most cases, the product from the hard plastic is formed first. Then the lenient plastic part is moulded because it is easy to deform the soft rubber.

The first molded product must be displaced perfectly as it directly impacts the additional injection mold that causes the modification in the plastic wall.

Give some suggestions for rotary die design

• Use two top sticks and two separate ejector systems.
• Ensure the inlet and outlet of the water direction are on the upper and subordinate edges.
• Don’t mistake inflowing the water from the higher side for releasing it from the lower side.
• Ensure that the side locks are the same after rotation as the two forward-facing side locks.
• If the rear and front molds do not match the double injection mold process, meddling with the visible mold can cause problems by failing to close.

Figure 23 Animated Design of  Injection Mold

• Don’t use force to reset the ejector plate with a screw, as it can only be reset with the spring.
• When the mold is designed, rotate it to 180 degrees. Ensure the injection mold machine’s Gelin column cannot interface with the mold.
• Inject the first material project from the no-operating side and rotate it 180 degrees.
• When rotation is done, ensure the rear and front molds are matched.
• If the secondary molding machine cannot use the ejector mechanism, a hydraulic ejector mechanism should be provided on the rotatory table.

How many types of gates are utilized in 2k injection molding?

There are four main types of gates that play different roles in the 2k injection mold process.

• Tunnel Gate
• Edge Gate
• Hot Tips
• Post Gate

Edge gate

This is the most common type of gate, which inserts plastic through the parting lines of the two mold shares.

In the 2k injection mold, a small imperfection remains at the injection point due to the exclusion of the runner system.

Tunnel gate

This tunnel gate is ideal for very large volumes. It injects plastic material below the final lines.

The tunnel gate needs a manual assistant to remove the runner system as the part is evicted from the mold.

Hot tips

These inject material from the top side of the part in a double injection mold and are directly connected to the spur.

Hot tips are very useful, save material from waste, and make the 2k injection mold ideal for large-scale production. In some cases, a dimple can be seen at the injection point.

What is the process of injecting material 2k mold?

It injects plastic into the model, also known as the runner system, that guides the melted material into the mold cavity.

This runner system controls the pressure and flow of the liquid plastic injected into the mold.

There are three main sections through which melted plastic is injected into the 2k injection mold.

• The Sprue
• The Runner
• The Gate

The spur

The spur is the first section of the 2k injection mold in which all the melted material initially flows and then enters the mold.

The runner

The runner is the second section in the 2k injection mold process. It spreads out the melted material along the face where two halves of the mold are connected.

 Runner for Injection Mold

There can be more than one runner for guiding the plastic toward one or multiple parts.

After ejection, the runner part cuts off, and material is wasted in the injection molding. This wasted material can be reused and recycled.

The gate

The gate is the last section of the 2k injection mold process and is where the melted plastic enters the mold’s hole.

The location of the gate is important because it regulates the movement of the material.

What are the two sides of the mold in 2k injection molding?

The 2k injection mold has two sides. The first side faces the cavity or front half of the mold, and the other side faces the core or backside of the mold.

The front side must have a better appearance, commonly known as the cosmetic side.

According to the input design, the part that faces the front side will be smooth and have a pattern.

The backside of the mold in the 2k injection process plays an important role by containing the part’s hidden structural elements. That’s why it is known as the functional side.

It has a rough finish and prominent marks of ejector pin on the product.