Injection Mold

In modern industrial production, mold is an important technology used in shaping products (including metal products and nonmetal products) for all of the industries. Meanwhile, it is the ‘magnifying glass of efficiency and profit’ to the raw material and equipment, because the value of the final product made in the mold is often tens of, even hundreds of times as valuable as that of the mold itself.

The mold industry is the basic industry of the national economy, and it is called ‘the mother of industry’. Every aspect of human life such as clothes, food, housing, and transportation is closely connected with the mold industry. Therefore, the level of injection mold technology has been a significant symbol to measure a country’s developing level of mechanical industry.

And mold can be divided into two kinds of them: mold for metal products and nonmetal products.
The metal products mold include cold-press mold, pressing mold, forging mold, press casting mold, precise casting mold, stamping tool, punch tool, and dust metallurgy mold, etc. These kinds of mold have extensive apply-cation in electrode-cranial products, automobiles, aviation instruments, and other metal products.
The nonmetal products include plastic injection mold, ceramic mold, rubber mold, glass mold, food mold, and ornament mold. These kinds of molds have extensive apply cation in our lives, at this page we are talking about injection mold. this is the most papular modern technology which used in our life everywhere.

An injection mold used to form a plastic product using the injection molding process. A standard injection mould is made of a stationary or injection side containing one or more cavities and a moving or ejection side.

The resin, or raw material for injection moulding, is usually in pellet form and is melted by heat and shearing forces shortly before being injected into the mould. The channels through which the plastic flows toward the chamber will also solidify, forming an attached frame. This frame is composed of the sprue, which is the main channel from the reservoir of molten resin, parallel with the direction of the nozzle, and runners, which are perpendicular to the direction of the nozzle and are used to convey molten resin to the gate(s), or point(s) of the gate and feeding the molten material into the mold cavity. The sprue and runner system can be cut off and recycled after molding. Some moulds are designed such that it is automatically stripped from the part through the action of the mould. For example, the submarine gate or banana gate, if using hot runner systems then there will be no runners.

The quality of the injection molded part depends on the quality of the mould, the care taken during the moulding process, and upon details of the design of the part itself. It is essential that the molten resin is at just the right pressure and temperature so that it flows easily to all parts of the mold. The parts of the injection mold must also come together extremely precisely, otherwise small leakages of molten plastic can form, a phenomenon known as flash. When filling a new or unfamiliar mould for the first time, where shot size for that particular mould is unknown, a technician should reduce the nozzle pressure so that the mold fills, but does not flash. Then, using that now-known shot volume, pressure can be raised without fear of damaging the mould. Sometimes factors such as venting, temperature, and resin moisture content, can affect the formation of flash as well.

Injection Mold Material

Traditionally, molds have been very expensive to manufacture therefore they were usually only used in mass production where thousands of parts are being produced. Injection Molds are typically constructed from hardened steel or aluminum. The choice of material to build a mold is primarily one of economics. Steel molds generally cost more to construct, but their longer lifespan will offset the higher initial cost over a higher number of parts made in the mold before wearing out. Aluminum molds can cost substantially less, and when designed and machined with modern computerized equipment, can be economical for moulding hundreds or even tens of parts.

Requirements for the injection mold

ejection system

An ejection system is needed to eject the molded part from the cavity at the end of the molding cycle. Ejector pins built into the moving half of the mold usually accomplish this function. The cavity is divided between the two mold halves in such a way that the natural shrinkage of the molding causes the part to stick to the moving half. When the mold opens, the ejector pins push the part out of the mold cavity.

cooling system

A cooling system is required for the mold. This consists of an external pump connected to passageways in the mold, through which water is circulated to remove heat from the hot plastic. Air must be evacuated from the mold cavity as the polymer rushes in. Much of the air passes through the small ejector pin clearances in the mold. In addition, narrow air vents are often machined into the parting surface; only about 0.03 mm (0.001 in.) deep and 12 to 25 mm (0.5 to 1.0 in.) wide, these channels permit air to escape to the outside but are too small for the viscous polymer melt to flow through.

All of the information we referred from Wikipedia, but we sort out together for easy to read, if you want to know more, please go to injection mold Wikipedia.

 

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Flexible Gating Advantages, Dependable Reproduction, Economical Process, Easy to Maintain, Fast Molding Cycle, Decreased Tool Wear

SINCERE TECH is mold manufacturer china company that provides plastic mold making and plastic injection molding solutions to industries of the world, started since 2005 we specially make plastic molds for the customer, after 2016 we have bought a plastic injection molding company to mold the molded part for our world customers.

Our advanced manufacturing facilities include a wide range of thermoplastic injection molding solutions for many types of plastic parts, including processes for Hot Runner mold Systems and Cold Runner mold Systems.

Insulated Runner Molds: Hot Runner System With A Twist

Insulated runner systems are inexpensive alternatives to traditional hot runners, where the mold is not heated, but the runner channels are extremely thick and stay molten during continuous cycling.

This feature provides the flexible gating advantages of hot runner switch out the added cost of the manifold and drops of a heated hot runner system.

Properly designed insulated runners, with thermally controlled gate, offer several advantages over hot runner mold systems, including:

  • Dependable reproduction – no “dead spots” in mold
  • Uniform temperature distribution – thermal insulation forms through melt deposited at the wall
  • Economical process for continuous operation of uniform cycles without extended interruptions
  • Easy to maintain – quick to clean
  • Fast production color changes
  • Molds are less expensive to build and to maintain than hot runners
  • Minimal heat loss – thermal equilibrium reached quickly
  • Low energy input on startup – reduces energy cost
  • More consistent volume of polymer per part
  • Faster molding cycles
  • Elimination of runner scrap — less regrind

    Mold manufacturer China

    Mold manufacturer China

  • Improved part finish
  • Decreased tool wear

However, as with hot runners, the insulated runner system also has disadvantages when compared to cold runner systems. The increased level of technology required to manufacture and operate the mold results in:

  • More complicated mold design
  • Higher mold costs
  • More difficult start-up procedures
  • Possible thermal degradation of the polymer melt
  • More difficult color changes than with cold runners

For a quote or more information about how we can help your project, please call us or send us an email, we will quote you in 24 hours.

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Molding Flash or burrs

Cold Runner Mold: Plastic Injection Molding, Simple Part Design, Limited Production Runs, Low Maintenance, Change Production Color, Low-Cost Mold

What is cold runner mold

A cold runner mold is a type of injection molding tool where the plastic material is cooled in a separate channel or “runner” before it reaches the individual cavities of the mold. The plastic resin is injected into the cold runner system, where it solidifies before being directed into the cavities to form the final parts. The term “cold” refers to the fact that the runner system is not heated, unlike a “hot runner” mold. Cold runner molds are often used for producing large numbers of small, simple parts and are relatively low-cost to produce.

SINCERE TECH (plasticmold.net) provides plastic injection mold solutions to industries of all types and sizes.

Our state-of-the-art mold building facilities include high-speed CNC Milling and mirror EDM Machining for many types of complex specialty injection molds, including insert molds, gas-assist injection molding, 2K mold, multiple cavities mold and unscrewing molds. We can build molds from small to big (25 ton) for both hot runner mold systems and cold runner mold systems.

Cold Runner Molds: Efficient and Economical

Each system has it’s advantages and disadvantages. Choosing the correct system depends on the requirements of the part to be produced. A few of the considerations include:Cold runner mold

  • Part complexity
  • Color requirements
  • Physical characteristics of the material
  • Type of material – virgin or “regrind”
  • Color changes during the production run

Cold runner systems are best used:

  • When the parts produced are of simple design,
  • For limited production runs, or
  • When a rapid change in production colour is needed

In a cold runner mold, the runner (excess material retained in the feed channels) is cooled and ejected with the part. Every cycle, apart, and a runner is produced.

There are two major types of cold runner molds:

  • A two-plate cold runner mold is the easiest and least expensive type of mold to produce. Two plate molds have a single parting plane, and the mold splits into two halves at the plane. Because the runner system must be in line with the parting plane, the part can only be gated on its perimeter.
  • A three-plate cold runner mold differs from a two plate in that it has two parting planes, and the mold splits into three sections every time the part is ejected. This feature provides greater flexibility of design, allowing gating to be placed in the most efficient locations. Since the mold has two parting planes, the runner system can be located on one, and the part on the other, for easier separation.

Cold Runner Mold Systems: The advantages & disadvantages

There are many significant advantages to using a cold runner mold system:

  • Simple, lower-cost mold design and construction
  • Considerably less expensive than a hot runner system
  • Moulds require less maintenance
  • Easier to set up and operate
  • Colour changes are easy – all plastic in the mould is ejected with each cycle

While it is a less expensive process that hot runner systems, there are a few disadvantages to cold runner systems that need to be considered, including:

  • Waste plastic generated
  • Runner material must be either disposed of or
    reground and reprocessed
  • Additional steps in the manufacturing process
  • Regrind will increase variations in the injection 
    molding process
  • Regrinding could decrease the plastic’s strength characteristics and mechanical properties

Is your project ready for molding parts yet? Welcome to send us your requirement for quotation, we will provide you with the best solution base on your part design?

Injection moulding service
plastic cup mold

When you have a project then you may need plastic injection molded parts, the first thing you need to do is finding a plastic mold company to make mold & molded parts, but before start this I think you need to check injection molding cost and mold cost in advance for investment budget, multi cavity injection molding will be one of the best way to save unit production cost, but not suitable for all of project, below are some suggestions on how to save injection molding cost, there have both advantages and disadvantages, by reading this you could choose the one base on your project requirement.

What is multi cavity injection molding

Multi-cavity injection molding is typically used when high volume production of identical parts is needed. It allows for the efficient production of multiple parts in a single cycle, which can significantly increase production rates and reduce the cost per part. Additionally, using a multi-cavity mold can also help to reduce the overall cost of the mold itself.

Multiple cavity mold means the number of cavities greater than one, which means that has more than one part in an injection mold, It is usually professional to say cavity, One cavity or two cavities, for examples 8 cavities mold means one molding cycle to mold 8 parts with the 99% same part feature, dimension, shape, size, etc.

Some examples of products that may be produced using multi-cavity injection molding include automotive parts, electronic components, toys, and household items. It is also commonly used in the production of medical devices, personal care products and packaging.

24 multiple cavity mold

24 multiple cavity mold

When do we need multi cavity mold?

There are some factors to make decisions before starting to make your plastic mould.
1, the size of the product,
2, the number of the product requirement
3, the size of the machine, if you only buy plastic molded parts then you do not need to care about this point, you plastic molding supplier we check this.

If the size of the product is small, such as the computer keyboard button, usually make 24 or 48 cavities, you must say why not make 30 or 40, this is because for the balance mold layout and material filling balance, especially when you use cold runner mold. so normally multi-cavity mold is 4, 8, 16, 24, 48, 96 cavities are better options.
When we make multiple cavity mold and the cavities are more than 24, we normally suggest making hot runner mold, one part per hot-drop, at least to use 6 hot runners to the cold runner, which means four cavities per hot drop. this could save the cycle time and keeping the best quality of injection molding parts.

The advantages of multi-cavity mold

The reason we make multi-cavity mold, the question is simple, we need to save production unit cost for each plastic molded parts, multi-cavity molds have several advantages over single-cavity molds in injection molding:

  1. Increased production efficiency: By producing multiple identical parts in a single cycle, multi-cavity molds can significantly increase production rates and reduce the overall production time.
  2. Reduced cost per part: Multi-cavity molds can produce multiple identical parts at a lower cost per part than single-cavity molds.
  3. Reduced tooling costs: Since multi-cavity molds require only one tool, the overall cost of the mold is typically lower than that of multiple single-cavity molds.
  4. Better consistency: By producing multiple identical parts in a single cycle, multi-cavity molds can improve the consistency of the final product, reducing the need for rework or scrap.
  5. Reduced labor costs: Multi-cavity molds require less labor to operate than multiple single-cavity molds, as the operator only needs to monitor one machine.
  6. Reduced material consumption: By producing multiple parts in a single cycle, multi-cavity molds can also reduce the amount of raw material required to produce the final product.
  7. Improve part quality: Due to the consistency in the process and the precision of the machinery, multi-cavity molds can produce parts with tighter tolerances and better surface finish.

The disadvantages of multi-cavity mold

We all know that all of the customers prefer the multiple cavity mould since this can save lots of production cost, but there are other factors you need to think about before making decision, because make plastic mold is not cheaper, make multi-cavity mould is more expensive than single cavity mold, some times double or even 3 times expensive than single cavity or two-cavity mold, for example if you make 24 cavity mold, then you at least us 6 hot runner drops for the mold, the pure hot runner cost is around USD 5400 ( YUDO brand), if use China local brand of hot runner still need USD 3000, and this cost some times is enough to make 2 cavities cold runner mold, since there are many cavities in one mold, the mold manufacturing cost is high than the less cavity mold as well, this is another cost, so total cost is two or three times more is not surprised, below listed some disadvantages while use multi cavity mold:

  1. Higher initial cost: The initial cost of a multi-cavity mold can be higher than that of a single-cavity mold, especially for complex designs.
  2. Greater complexity: Multi-cavity molds are more complex than single-cavity molds and require more precise machining and design. This can lead to longer lead times for tooling and increased risk of defects.
  3. Higher maintenance costs: Due to the complexity of the mold and the increased number of moving parts, multi-cavity molds may require more maintenance and repairs than single-cavity molds.
  4. Greater risk of defects: With multiple cavities, the risk of defects is greater, as a problem in one cavity can affect multiple parts.
  5. Increased cycle time: Multi-cavity molds have longer cycle times than single-cavity molds as the machine has to fill multiple cavities at once.
  6. Greater potential for warpage: Multi-cavity molds have to be designed to account for the potential warpage that can occur during the cooling phase of the injection molding process.
  7. Increased risk of sink marks: As the material cools it will shrink, if the mold design is not optimized for multi-cavity, sink marks may appear on the surface of the parts.
  8. Increased risk of flash: Flash is the excess material that is extruded from the mold. Multi-cavity molds can be more prone to flash than single-cavity molds as the pressure and flow rate of the material is increased to fill multiple cavities.

When do you need multiple cavity mold

There is some simple suggestion when do you need to single cavity mold (may 2cavities at fist), when you should make the multi-cavity mold, like 8 cavity mold, 16 cavity mold or more. When you are sure that you will need the plastic parts more than one million or at least 0.5 million, then go to 8 or more mold cavities will surely save cost for you, you may need to pay more cost on plastic mold manufacturing, but compare the production cost you are going to save, this injection mold cost is insignificant, because you will save 10 times more than this injection mold cost.
If you are not sure how many plastic moulding parts needed at the first, or this is depending on your business market sell, then we suggest use the 2 cavity mold at first, because this can save the plastic mold cost for you in advance, after you open your market, and the requirement of injection molded parts increased, you still can save injection molding cost by making new multiple cavity mold, you use the existing mold to produce the parts at the same time and  make new multi-cavity mold, this will not have a delay as well, after the multiple cavity mold finished then you only need to run this multi-cavity mould, but if the quantity requirements are not so high, then you use the currently molds to produce, so you still have good profits with less investment (compare to make multi-cavity mold at first beginning).

What do you think? by reading above I assume you have the idea on how to save injection molding cost for your project.

If you have any project in hands that need to make injection mold for your business, you are welcome to contact us, we will give you some good suggestions and ideas, to help you spend min investment on plastic mold cost and open your market rapidly.

Sincere tech is plastic mold manufacturer in China, we make custom single cavity molds, multiple cavity molds, hot runner mold, cold runner mold, overmolding, 2k injection molding and more, you can call us or send us an email for a quote

Plastic molding technology

Plastic molding technologyPlastic molding technology continues evolving with the market and with the advances in science. Plastic molding is the process used in producing plastic components for a variety of industries.

When plastic resin materials are heated the resin will flow, and can then be injected into a mold. A plastic mold consists of two halves referred to as the “A” side (cavity side) and the “B” side (core side). The “A” side is where the molten plastic enters the mold, and the “B” side contains the ejector system which removes the parts from the mold.

Plastic Molding Includes Many Terms and Components

Plastic molds are required to have many components in order to make high-quality plastic parts. Below is some of the terminology used to describe the components and processes that are required when producing injection molded parts:

  • Sprue – this connects the nozzle of the injection molding machine to the main runner, or cavity
  • Runner – this component conveys the melted plastic from the sprue to the gate and into the part
  • Gates – these are the openings that allow the molten plastic to be injected into the cavities of the mold
  • Cold Runner mold – this design involves the plastic entering into the “sprue” and then traveling through the “runner” where it then enters the part cavities through the various “gates.”
  • Hot Runner mold – this design is an assembly of heated components used to inject molten pPlastic moldslastic into the cavities of the mold. Hot Runner mold usually makes mold more expensive to manufacture but allow savings by reducing plastic waste and reducing the cycle time.

When observing plastic molding products, you will often see a line running between different sides of the finished plastic part. Here are some descriptions of why parts have a specific appearance:

  • The Parting Line – this occurs anywhere there are any two pieces of mold that meet.

There are also several configurations of plastic molds. These configurations are described as

follows:

  • The Two Plate Mold – consists of one parting line where the mold splits into two halves.  The sprue, runners, gates, and cavities are all on the same side of the mold.
  • The Three Plate Mold – has a runner plate in between a moving half and a fixed half.  These molds will have two parting lines and are used because of their flexibility in gating locations.
  • An Unscrewing Mold – is what is used when there is a requirement for male or female threads on a plastic component
  • The Action Mold – these consist of a mechanical cam action incorporated in their design, when a hole, slot, undercut or thread is needed that is not perpendicular to the parting line.
  • The MUD Unit Mold– these are standard frameworks for toolsets (u-frame), which allow for custom-machined tooling inserts to be made for specific components.

Large Plastic Molding Runs Cost Less 

Plastic injection molding offers many industries a huge number of benefits.  In large runs, molding is much cheaper than when machining the parts individually. The over-all manufacturing speed is much faster with this approach as well. This is one of the many reasons there are so many different types of injection molding processes. Some of these include:

Cold runner mold

Insert Molding – This is the process of putting a metal insert into a mold and then molding plastic around the insert.  Since multiple parts are manufactured together – this eliminates the need for a secondary assembly operation.

OverMolding – This is the process of over-molding, and the production of injection molded parts that seamlessly combines a rigid plastic with a rubber-like elastomer.

Family Molding – This is a process that utilizes a mold that contains various shapes of cavities to mold all the plastic components for one completed part.  Family molds are used when the different plastic components are made from the same material.

Injection Molding CleanRoom – This is the process used primarily for medical components. It is the injection molding process that is performed in a cleanroom environment in order to protect the parts from any contaminants.

When considering having plastic parts custom designed and molded – SINCERE TECH is the ideal partner for your plastic component or device.

SINCERE TECH is your single-source solution for your device by providing mold building, design, and engineering, injection molding as well as injection molding cleanroom and any secondary operations that may be required to complete your project. contact us now to know more information