Klarm Mould Blog

Injection Molding Runner Design in China

The Advantages Of Good Runner Designs To Help Injection Molding

10/21/2019Klarm Mould

The plastic injection molding process in China is possible because any thermoplastic material can be melted to a predetermined size and the Injection molding machinery is designed such that it can then be injected into a mold or cavity where it can be formed. The parts of the mold which are in the shape of the parts to be manufactured are the cavities. The formed part is then ejected from the injection mold.

The sprue is a part of the runner which injects molten liquid plastic material into the die or Chinese mold through the injection machine’s nozzle. The runner system, as well as the sprue, is the passage that connects the nozzle of the machine to the mold cavities. Runner connects the sprue with the cavity through the gate. The nozzle of the machine is connected to the runner by the sprue and come in designs of hot sprue or cold sprue.

The Injection molding runner design comes in three basic types – hot runner, insulated runner, and cold runner. The runner has to ensure that the liquid material is distributed so that it fills all the China molds under the same conditions and the same pressure at the same time. This will help to prevent flashing of the china injection mold and also helps in producing parts of a uniform and improved quality. Hot runner technology, which is externally heated is more practical and feasible since the plastic is maintained in a liquid state and most China mold makers use this technology.

The usage of hot runners in injection molding machinery is useful since it ensures better quality parts. They are particularly beneficial with uneven-shaped parts which might result in improper cooling or uneven flow. Hot runners also help in reducing plastic wastage. They are designed to reduce cycle time, thus helping to maximize manufacturing productivity. The challenge in design is to maintain the liquid plastic which is molten at an optimum temperature while the china injection mold cavity is being cooled at the same time. Internal as well as external heating methods are used generally in injection molding machinery. Thus the hot runner technology, which was introduced almost 50 years before in the plastic industry, has revolutionized the china plastic injection molding technology and its processing capabilities by enhancing the efficiency of operation, improving the quality of the parts, reducing wastage and scrap and thus in effect saving money.

A very critical consideration for injection molding runner design as well as the china injection molding process is to maintain a uniform temperature in the hot-runner manifold and the sprue bar so as to ensure consistency in quality. Another consideration to be taken by China mold manufacturers is regarding the runner system. The injection mold china cavities will not be filled properly if the runner is too small. If the runner is too large, then cooling time will be increased and the cycle time will be decreased. Proper design for runners for injection molding china is most essential to reduce the effect of sink, stress, and weld marks.

A good and efficient runner design is most essential for plastic injection molding machinery as it helps in producing better quality parts at a very reasonable and affordable rate due to higher efficiency and lower wastage. Currently there are many suppliers who provide injection molding systems from China at very good quality.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

How to calculate the exact gate and runner during mold design?

10/12/2019Klarm Mould

Gates and runners

An injection feeding model of injection molding china consists of various parts including the sprue which connects to the runner. The runner connects to the gate which is the smallest part in the radius, and then the gate finally joins the cavity of the mold. The proper gate and runner calculation of these parts are very important to keep the friction where the shear rate low. Balancing the pressure and temperature for proper flow of the plastic or resin is also essential.

Calculating the runner size

The runner is part of the injection molding unit of a plastic mold manufacturers factory which connects the sprue and the gate. It is a cavity-like portion which holds the liquid plastic before it passes through the gate and fills the mold in the right way. Therefore, the size of the runner must be calibrated and optimized by all means. This is because a proper sized runner will keep the balance of the flow properly and the pressure will be optimized. The pressure plays a very important role to fill the mold and the runner. To keep a balance of the pressure among the two cavities, the runner pressure should be 25 percent or less of the total pressure to fill the mold. A good runner from injection mold maker china will also make sure that the fluid is heated to reduce the excessive pressure push.

Calculating and determining the right size of a runner is very crucial for plastic tooling china industry. Because it will determine whether the mold is filled properly or not. There are two major points to keep in mind. These are the thickness of the runner and morphology of the material to be passed. For Semi-crystalline materials, smaller runners are workable in injection molding tooling china. But there is a need for larger runners to facilitate temperature rise and reduction of pressure for the amorphous materials.

Calculating the gate size

Gate size is important for filling the part cavity properly since it is the section between the cavity and the runner. Proper pressure is important, which will determine whether the cavity will be filled uniformly or not. The two important things in injection mold tooling china about choosing the right gate size are to minimize the pressure drop and to have balanced control over the packing stage of the gate. There is a different type of gates that can be found in the double color mold parts like a ring, edge, pinpoint, disk and submarine. You have to keep in mind their sizes as well.

Larger gates corresponds to lower pressure increase. Packing stage is longer in this case and vice versa for the smaller gates. The gate is the place where the molten plastic goes through the shearing and has the most shear rate due to smaller cross-section area. Shear rate is influenced by the cross-sectional radius and flow of the material. It is crucial in china mold-building services to keep the shear lower while filling the gate to cause smaller injection damage. This is the reason why shear sensitive materials like heavily filled resins, fiber-reinforced resins, amorphous resins and gates should be larger according to the injection mold makers in china. This will keep the lower the rise in pressure and temperature.

When you choose the china fundamental of plastic mold design or the oem/odm medical injection mold factory, you should keep in mind the size factor. This will make sure that you end up with a high precision plastic making mould china that can be effective in the prototype production.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

Key points to Banana Gate Injection Molding

09/27/2019Klarm Mould

Manufacturing is a simple business of making goods by hand or by a machine. Once the goods are made, they are sold to a customer. There are several different types of manufacturing processes in this world. China Injection Molding is one of them.

What is Injection Molding & an Injection Molding Machine?

Injection Molding is one of the most commonly used manufacturing procedures for the production of plastic parts. As it is used for the molding of plastic, it is also known as plastic injection molding. Different types of products are produced using an injection molding technique – plastic trinkets, automotive parts, toys, mobile cases, bottles & containers. Injection molding is done with the help of an injection molding machine, raw materials & mold. This process consists of 3 valuable steps – designing of product, designing of mold & the manufacturing process. The injection molding machinery uses a melt, inject, cool & pack procedure by converting granules of raw plastic into final molds.

Injection mold design is an important factor in the China plastic injection molding machine & each injection design consists of a gate to allow the melted plastic flow to be injected into the cavity of the Chinese mold. Different issues may arise if the wrong scale of the gate is chosen like uncompleted filling, molding shrinkage & excessive residual stress. There are two types of gates for injection molding machines-one is manually trimmed & the other one is an automatically trimmed gate. Under these two categories, there are 9 different gates called Direct Spruce Gate, Side Gate, Fan Gate, Pinpoint Gate, Disk Gate, Rin Gate, Film Gate, Tab Gate & Submarine Gate. Depending on the part of the design, the gate can be small or large. The location of the gate is also important in the manufacturing process as it decides how the plastic will enter & form into a mold.

China is one of the major producers of plastic injection molding. China mold makers have made notable progress in the last few years in the business of China injection molding. Companies from around the world come to this country with the wrong expectations of purchasing cheap China mold. To avoid delivery fraud, it is better to look for manufacturers around your location. This will also save delivery time.

Banana Gate Injection Molding

This type of molding machine uses the banana gate for its production. The banana gate is similar to the tunnel or submarine gate & it is curved like a banana. This is a new type of gate which is quite trendy in the China plastic injection molding machines. These gates are very useful as they do not leave any marks on the plastic surface. Because of its magnificent curvy shape, it can reach below the part & allows the plastic to be injected into the secluded area of the part. Banana gate injection molding is normally used for ABS & HIPS materials. If these types of gates are not properly designed, then the machine can break easily.

China injection molding is a standard process for manufacturing plastic involving raw materials & molds. It is one of the most cost-efficient manufacturing processes. Injection mold machinery is capable of producing high volumes of high-quality plastic.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

How to make gas assisted injection mold?

09/16/2019Klarm Mould

The gas-assisted injection molding is a process that involves the traditional, low-pressure process of injection molding. This process uses pressurized nitrogen gas to force material into a mold. Let’s find out more about gas-assisted injection molding.

Basically, this process is used to produce big parts of plastic using complex designs and beautiful surface finishes. Normally, this process is a great choice for making skins, cabinets, bezels, doors, equipment covers, and handles.

Internal Injection Molding

As said earlier, this process injects pressurized nitrogen gas into a mold. Actually the nitrogen gas is passed through the gas channels for displacing the material through the creation of hollow sections.

The molten resin is pushed against the wall of the cavity until the solidification of the path. The constant pressure of the gas prevents the shrinkage of the part. In addition, it reduces internal factors, sink marks, and surface blemishes. So, this process can work well to hold curvatures and tight dimensions.

External Injection Molding

In this type of injection molding, the material is pushed into the mold. However, the gas is pushed in a very thin layer between the mold core and the back surface of the component. So the front surface of the component is forced against the other side of the cavity of the mold. as the gas cools down, different sides of the component replicate the mold surface.

Basically, this process is suitable for plastic parts that feature large surface areas, especially those parts that require beautiful surface and detailed textures. In this process, the sink and warp marks are removed because in nitrogen gas maintains the material condition.

Just like internal gas assist, the bosses and support ribs are molded into the component and produce the same level of tolerance and dimensional stability. In the same way, molding pressure produces less stress wear and tear.

Cost Considerations

This process also helps save a lot of money. Typically, these processes require a lot less force than traditional injection molding. Therefor it helps reduce the component chords costs and produces less stress as well.

Actually, the mold pressure results in reduced wear and tear. Therefore, there would be less demand for pricey aluminum tooling. Moreover, the parts made are lightweight which will help reduce the freight expenses and boost material handling.

Design Benefits

Moreover, this technology results in a lot of performance and design benefits. For example, multiple parts with different thickness off walls can be molded.

Converting different components to Gas Assist

This type of injection molding is a better alternative to the large metal parts. Therefore, it is possible to eliminate expensive, heavyweight, corrosive components like panels, access doors, enclosures hand covers.

In short, this was a brief introduction to gas-assisted injection molding. Hopefully, this article will help you understand the concept much better.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

How to eliminate injection molding defects?

05/28/2019Klarm Mould

Injection molding is an art, which involves science as well. Actually, injection molding requires great attention to detail as minor mistakes can cause a lot of financial loss to a company. In this article, we are going to discuss how you can eliminate common injection molding defects.

Flow Lines

Flow lines may include lines, patterns, and streaks that appear on the prototype part because of the cooling profile or physical path of the molten plastic while it moves into the cavity.

Fix:

One way to fix the issue is to increase the pressure and injection speed, which will make sure that the mold will fill the cavities.
Another way is to round the locations and corners where the thickness of the wall changes.

Sink Marks

These are minor depressions or craters that form in the thicker areas when shrinkage happens in the internal areas of the end product.

Fix:

Reduce the mold temperature, increase the holding pressure and time for better curing and cooling.
Reduce the thickness of the wall sections that are the thickest. This will allow faster cooling and prevent the sink marks.

Vacuum Voids

Vacuum voids refer to the air pockets inside or near the prototype surface. They occur because of the uneven solidification amidst the inner sections and the surface.

Fix:

Find the gate at the mold’s thickest part
Opt for the plastic that is less viscous, which will reduce the amount of gas trapped.
Increase the holding time and pressure
Try to keep the mold parts aligned

Surface Delamination

Surface delamination happens when thin layers of the surface show up on the part because of a contaminant. Actually, these layers look like coats that can be peeled off.

Fix:

Before molding, make sure you dry the plastic properly
Raise the degree of mold temperature
There should no sharp turns and corners in the mold design

Weld Lines

Weld lines show up on an area where the liquid plastics mixes while they flow from different injection mold parts.

Fix

Increase the temperature of molten plastic or mold
Raise the injection speed
Make adjustments to the design to ensure that the flow pattern is only one source flow

Short Shot

Short shot refers to a situation that happens when a molding shot tends to fall short. In other words, the molten plastic won’t fill the cavity of the mold for some reason. As a result, it leaves a portion where you can see plastic.

Fix

Opt for a plastic that features higher flow and less viscosity
Raise the mold temperature for better flow
Get a machine that features more material feed

To cut a long story short, you may have to face a lot of defects during the process of injection molding in China. What you need to do is follow the tips given in this article to fix or eliminate these issues to make the process error free. Hopefully, you will find these tips helpful.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

Difficulties of molding different plastics on injection molding

05/18/2019Klarm Mould

When it comes to plastic injection molding, manufacturers have a lot of problems and difficulties to deal with. Manufacturers use plastic for many reasons, such as design flexibility, affordability, and lightweight, just to name a few. Making parts and designs with injection molding has some difficulties. Let’s take a look at them.

During the injection molding process, you may have problems, such as parts deformation, structural weakness, surface blemishes, warpage, shrinkage, parting lines, voids, and air traps, to name a few.

All these problems may add to the cost of manufacturing. For streamlining the process, you have to use the trial-and-error prototyping process in a virtual environment.

Making tools that can help make high-quality injection-molded parts requires you to consider a lot of variables. For instance, it includes the optimal temperatures of the plastic, cooling channels, and the configuration of these systems, to name a few. Aside from this, you also need to consider pressure, flow rate, thermoplastic material type, solidification time, and so on.

If you have the required mold-filling simulation, you can easily balance the design against manufacturability. Moreover, mold makers can choose to optimize tools without the need for prototype molds. This way the manufacturers can also reduce run cycles, which results in better quality, reduced costs, and less time consumption.

Actually, the primary factor that you need to keep in mind in order to avoid the traditional problems associated with plastic injection molding is the accuracy of simulations.

Evaluating Manufacturability

With plastic injection molding simulation, designers can get answers to common questions related to part filling, air traps, voids, and gate locations, to name a few. With the help of these analyses, designers can perform the simulation of the mold-filling stage in order to understand whether it can speed up the tooling design and production process.

Optimization of the Mold Design

The primary goal of a Chinese mold maker is to develop injection molding tooling that can produce quality parts without costing a lot of money. Moreover, this simulation offers extra tools to optimize tooling designers of different complexity levels. And this helps mold makers simulate different phases like filling and packing.

Improving Cycle Times

It’s really important to reduce cycle times by ejecting quality parts in the shortest time span possible. If advanced capabilities are used, plastic injection molding can help specialists hit the best balance between quality production and short cycle times.

All of this helps the designing and simulating of the cooling line layouts, processing parameter optimization and the making of conformal cooling systems.

Improving Mold-Filling Simulations

Nowadays, manufacturers can enjoy a lot of benefits by molding plastic parts instead of using the traditionally machined parts. For instance, they can reduce costs, scrap, weight and increase the design flexibility via the production of design and shape geometries that are more complex.

However, they can only enjoy these benefits if they boost the design and the productivity of the tooling. Nowadays, manufacturers can improve the performance and efficiency of their operations if they choose to replace or improve the conventional mold using the mold-filling simulations.

So, this was a description of some of the difficulties that manufacturers face during the plastic injection molding process and how these problems can be fixed.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

What are injection mold cooling systems?

02/26/2019Klarm Mould

As far as the plastic molding process is concerned, the injection mold cooling system plays a great role. Actually, this system directly affects the production efficiency, machine speed and the quality of end product. In the case of semi-crystalline polymers and amorphous, the highest level of heat efficiency is required. Let’s know more about this system.

The Design of Injection Mold Cooling Systems

First off, it’s important to keep in mind that the design of this system is of paramount importance. In fact, the cooling time accounts for up to 80% of the cycle. If the cooling system is properly designed, it can reduce the molding time for better efficiency. On the other hand, if this system is poorly designed, the reverse may happen.

So, the question is, what factors should be kept in mind for effective cooling? Given below are some of the major factors.

Plastic wall-thickness

If the plastic thickness is higher, it will take much longer to cool down. As a general rule, the cooling time depends upon the thickness of the parts of plastic. Ideally, it’s better to keep the thickness as low as possible.

It’s possible to choose low thickness, but it may not be possible for all types of projects. So, if the project allows some flexibility, the designers should not go for a higher wall-thickness. This is the number factor on the list.

Mold steel

If the steel has a higher thermal conductivity, more heat can be transferred. As a result, the cooling time will shrink. Typically, China injection mold maker uses copper in place of steel in order to get better results.

The layout of the Cooling line

It’s better to keep the mold cavity near the cooling pipes. Also, it’s better to have cooling pipes with higher diameters for better cooling. Therefore, the designer should consider these parameters in order to enjoy the best cooling effect.

Coolant

As the name suggests, coolants are the things used to cool down the plastic parts. Designers use different types of coolants. The two most common ones are oil and water. In addition, the thermal conductivity and viscosity of the coolant may also have an impact on the heat conduction. If the fluid viscosity is low, the thermal conductivity will be high.

The rules of designing a Cooling system

Ensuring highest cooling efficiency
Ensuring consistent cooling in order to avoid deformation of the objects
Facilitating the process of manufacturing

The goal of the cooling system is to ensure faster dissipation of heat from the objects. This ensures the best physical and dimensional properties. This requires a solid engineering approach in order to measure the injection mold performance with the help of water circuits.

Long story short, this is not a thorough list of factors that should be kept in mind when designing the perfect cooling system for injection molding company in China. However, with the help of this approach and good engineering knowledge, designers can get the best results. This will help them employ the right engineering practices and tools.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

How to design injection mold gate?

01/17/2019Klarm Mould

An injection mold gate is a small hole that allows the molted stuff into another mold chamber. For a successful design, designers have to consider a lot of factors, such as mold pate types, materials, location, dimensions, gate type, and many economic factors, just to name a few. Let’s find out how an injection mold gate is designed by a Chinese injection mold making factory.

Gate design carries a lot of importance if you want to get high-quality mold parts. Given below are a few factors that should be considered when designing the injection mold gate with injection mold design services in China. Read on.

Material

First off, choosing the right material is really important for the design process. Use the wrong material and be ready to suffer a loss. Based on the type of machine, the right material should be used.

Keep in mind that castings are strong enough to withstand the stress. For stronger parts, the cast material should be machined first. If you need to work on sharp corners, know that it can create difficulties during the molding process.

Size

The size of the gate also depends upon the resin and the part that you are going to mold. It’s important to note that small gates offer a better look but they take higher pressure or longer mold time for proper fill.

Also, high pressures in the cavity cause more stress, which can result in a structural failure.

On the other hand, bigger gates allow smoother resin flow and reduced mold time. Now, if the size of the gate is not right, it may restrict the molten resin. As a result, the material won’t be able to reach the next cavity. In another scenario, this restriction may slow down the filling rate, which may reduce the process efficiency significantly.

In the worst case scenario, if the size is not right, you may end up with gate defects, such as black streaks and mold warpage, just to name a few. So, the size of the gate is of great importance.

Location

Just like size, the location of the gate can have an impact on different factors. And these factors are extremely important for the whole process. Given below are some of those factors.

Aesthetics (flow lines, voids, sink marks, gate marks)
Operational considerations
Wrong flatness or roundness
Mold warpage
Part shrinkage
Wrong structure or strength of the part
Molecule orientation

At times, multiple gates are required in order to enjoy the best results. However, for using multiple gates, designers may want to take into account the meeting area of the flows, as this can cause many issues related to aesthetic and component weakness.

Defects

Now, let’s talk about the defects. Know that whether it’s the wrong position or size, any defect may cost a great deal of time and money. To correct the issues, the location of the gate may need to be changed. In some cases, the entire mold has to be re-configured.

So, these are a few things that can help you find out how you can design an injection mold gate by an injection mold maker in China.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

What Are The Purposes Of Hot Runner In Making Plastic Injection Molds?

12/14/201812/14/2018Klarm Mould

Basically, the injection molding process has been used the traditional way, which is known as the cold runner system. Nowadays, another method is getting popular. It’s known as the hot runner system. In this process, liquid substrate is put into the mold via a nozzle. So, the runner is kind of a passage through which the material travels. During the process, the substrate doesn’t cool down or get hard. Let’s find out why most people go for the hot runner for their plastic injection molds.

During a hot runner process, the mold is heated up and then cooled down once all of the cavity is full. Remember: the hot runner process may use many ways to heat up the injection mold, such as hot oil, hot water, induction/steam heating for quick heating. Unlike the cold runner system, this system cause fewer issues.

Now, let’s discuss why people go for the hot runner system in the injection molding process.

Less waste: This is an important point. In the hot runner system, the substance that passes through the chambers remains hot even when it reaches the last stage. In the cold molding, on the other hand, the runner is either discarded (waste) or recycled/reground. This is a disadvantage.

Quick cycle: As said earlier, the runner process requires time and may cause a loss of resource if enough time is not given. By fixing these problems, the hot runner system can boost the cycle times.

Keep in mind that the cooling and heating mold takes more time. Often, the time is offset through the savings from the elimination of the runner. However, it’s better to discuss the topic with your service provider.

Quality output: the removal of runners from the cold molded components requires a mechanical process. The product may get rejected if it is not up to the mark. In other words, the look and function of the product should be acceptable.

On the other hand, the hot molding can help resolve many issues, such as surface irregularities and burn marks, just to name a few.

Lower costs: cost is an importance consideration when opting for a cold or hot molding for a long-term. The initial cost of cold molding is less but the hot the hot runner system is a cost effective option as far as the long-term use is concerned.

Range of material: Actually, the inherent chemical composition of most of injection molding substance makes them a bit too “allergic” to temperature changes. The impact is stronger in extreme temperatures. So, for lower temperatures, the hot runner system is the way to go.

Colorant options: The hot runner system allows you to benefit from colorant mixtures in the process. So, this is another reason people opt for the hot runner process.

Long story short, these are the reasons the hot runner is an ideal choice for the majority of plastic injection mold projects. If you are looking to increase production in an efficient manner, we suggest that you give a go to this process. Hope this helps.

When it comes to hot runner injection mold, china plastic injection molding is the best choice.

Resource box: This article is originally posted in https://www.injectionmouldchina.com.

How to calculate production costs of making an injection mold

10/10/2018Klarm Mould

With the coming of the modern age, there have been a lot of new techniques that have been developed, but one can safely say that not all of them have been adopted by the industry. There are many reasons for it like they are not eco-friendly, or they can’t be easily automated, but the major reason that leads the way is they are not economically viable. There is no point in appointing a technique to produce something which is not worth the cost that one spent on creating it.

Injection molding is one such technique that has gained the attention of various industries and everyone is talking about it, but the same question still worries everyone, that what is the cost associated with it. In this article, we will try to describe how one can get a rough estimate of how much cost it will be on them once they start implementing the method.

Production rate: – One must have an idea about the product that they are going to make and how many cavities will be in there as it plays an important role in deciding the amount of material required which directly controls the total cost. Another thing that they need to aim for is the number of parts that will be produced in each cycle and the number of cycles in an hour. The larger the number of products produced in each cycle and the number of cycles in an hour, lower the cost of production.
The injection molding material used in each cycle: – It is not a good idea to simply measure the weight of the end product and then decide on how much material do you want. A substantial quantity of material is also scraped and wasted here and there and must be considered as well while calculating the material cost. An idea about the number of cavities that you will be having will also help with this
Other costs: – Other costs include the number of workers that you will be needing to carry out the different manual or automated operations. Workers doing manual work have low wages, but they will be needed in a large number while the workers working on the automated machine are skilled and will have a higher wage as compared to the workers doing manual work. Factors like the idle time of the different machines, post-processing time and the cost associated with giving final touches to the product must also be taken into consideration.

These are just some of the factors that go on deciding what the total cost will look like as they cover the core operations associated. Even the smallest of changes can go on to affect the total amount by a good amount and that’s why one should always aim to find the optimum method so as to balance all the cost involved resulting in the maximum profit that is the main goal.

Since China is the best place for any company to set up their factory, it is important to know about the China injection mold cost and on what factors does this amount depend on.

Resource box: This article is originally posted from https://www.injectionmouldchina.com.