Find a turnkey injection molding manufacturer in China

To produce superior quality tailor made parts, an entire team of skilled professionals is needed; we have to verify and sourceturnkey injection molding manufacturer in china multiple service providers, such as design & engineering, tooling, troubleshooting, quality control, packaging and shipping providers, while facilitating and organizing the communication among different sides. However, if you choose to work with a turnkey manufacturer, all these sources of stress will be eliminated, which would lead to an all-around one-stop manufacturing solution from an experienced supplier.

The Benefits of working with a turnkey Manufacturer is one of our guides on how an experienced team of professionals is able to streamline all the aspect of a production project, as well as the many benefits that a turnkey injection molding manufacturer brings, such as cost savings and streamlined communication, etc. Now, let’s take a closer look at some of them.

High Efficiency of a turnkey injection molding manufacturer

In a turnkey team, all the members will be working collaboratively to achieve a single target – successfully create the design and build the ideal finished product for you. Without a turnkey supplier, you will have to go through the whole laborious process that includes management of multiple suppliers, sync of supplier schedules, as well as sending (and sometimes resending) plans / prototypes; however, a turnkey team is able to take full responsibility for the production project – from conception to completion –  and offer immediate updates upon a simple phone call.

Advantageous Design, Tool-making and Manufacturing Services

It is made much simpler to change the current designs, thanks to the fact that designers, toolmakers and manufacturers work in close collaboration under the same turnkey company. If you don’t choose to work with a turnkey company, you will have to contact your designer and manufacturer separately whenever something needs to be adjusted. On the contrary, handling a single turnkey company makes it easier and smoother to communicate and more quickly to make changes.

Also, a more unified and consistent process is likely to be guaranteed, because the manufacturing, design and tool-making teams might have prior experience working with each other.

Vested Interest in Your Business

In a turnkey team, all the members will be working collaboratively to achieve a single target – help you complete your project successfully. If you can find a trustworthy turnkey supplier, the overall quality across every aspect of the project can be ensured, since the inevitable quality variance associated with working with multiple different vendors can be eliminated. Usually, you’ll probably get a higher level of custom service, as well as a devoted contact for your project.

In addition, working with several supplier may lead to blames on each other if any setbacks take place, while a turnkey provider is definitely held to a higher level of accountability, so a smoother and less stressful process can be guaranteed for everyone involved.

More Savings

If you entrust your project to a dedicated turnkey injection molding manufacturer, you will save not only time, but also money. A full-service provider is able to offer more discounted rates for the services they offer, when compared with other firms who is only able to handle one step in the whole manufacturing process.

Furthermore, a single turnkey injection molding manufacturer can handle your invoicing in a consistent manner, so as to ensure less confusion and an easier job for your accountants.

Learn More about Us

The skilled engineering and designer teams at a turnkey  injection molding manufacturer are able to ensure faster production cycles, greater service & savings, and higher-quality work.

Enjoying a history of more than 18 years, the ECO molding is able to offer the best quality turnkey services. We work in close collaboration with each of our clients by leveraging our specialized expertise on high-precision and high-volume tailor-made plastic injection molding, so as to ensure a streamlined and effective process, while adding value to your business on basis our profound experience in the industry. Several of the designers at Eco Molding began as toolmakers, so they are able to accurately create a plastic injection mold for manufacturability.

What to consider before getting plastic injection molding quotes?

A plastic part can be manufactured in many different ways. If you anticipate a high enough production volume, one of the most cost efficient ways to get the job done should be the plastic injection molding process.

However, there are multiple considerations when you decide on the plastic injection molding quotes process:

  1. Sales Volume
  2. Appropriate Budget
  3. Specific Application
  4. Time Cost

Sales volume

As stated above, the production method is mainly determined by the sales volume. According to experience, if you are going to sell 1,000 or more parts each year according to forecast (on basis of reliable market analysis, not just because someone said he was going to buy one), it will be worthwhile to consider the plastic injection molding process. Though the startup cost can be a bit too high, after the plastic injection mold is created, it will be quite cost effective to produce the parts. We suggest you get a quote and calculate with your own numbers to maximize return on investment.

mold making company in china

Appropriate Budget for plastic injection molding quotes

Undoubtedly, even though the return on investment from your forecast sales volume pencils out, you will have to make effective budget for other aspects, such as the plastic injection mold, the early stage production run and marketing expenses, etc. In the circumstances that you are not funded by yourself, you probably need to develop a sound business plan, so as to attract investors. In exactly the same way, the plastic injection molded part producer will not invest sufficient resources in your production project, unless you are able to convince them that your project is promising and will be profitable.

Specific Application

Another critical factor is the specific application of your final product. Although the plastic is a very excellent material that is able to help you save time, money and lives with an improved sterilization performance, it is not always a perfect choice for all projects. For instance, when you require high strength for your part, which is not available with the plastic, or you specifically require an outstanding durability that enables the product to withstand severe conditions for 5 or 6 years, it will not be a wise choice to adopt the plastic injection molding process.

Time Cost

Typically, it will take 4 – 12 weeks of time to build the mold you need for manufacturing of plastic injection molded parts. Factors that influence the time cost usually range from design revisions, communication lag, part complexity, current load of the tool maker, as well as a diversity of unexpected events that may include shipping delay and production part failure, etc. Due to these factors, you need to allow a longer time to get the final parts produced.

Consider Eco Molding

When you are about to kick off a new project, please consider Eco Molding for plastic injection molding quotes. We believe, we are the perfect plastic injection molded part manufacturer who is able to meet your needs for product development, because we offer a lifetime mold guarantee and enjoy 98% customer satisfaction.

What is the advantages of plastic compare to metal?

With the appearance of engineering grade resin materials, the conversion from metal to plastic was introduced in the 1950s. However, until today a lot of manufacturers are still not familiar with the benefits of the technique.

Now, in the ever changing landscape, many different sophisticated and cost effective plastic materials are being researched and developed, while many industries have come to realize the benefits of replacing metal with plastic when producing parts. As a matter of fact, for most companies which have replaced metal with plastic, they can expect cost savings of up to 25 – 50%.

The plastic molded parts are able to offer a great number of benefits to businesses in any industry, thanks to the plastic material that is as strong and reliable as the metal, while able to be engineered to the same level of tight tolerances.

The Advantages of  Plastic over the Metal

Now, as more and more industries have come to realize the benefits to replace metal with plastic, part manufacturers quickly opt for high volume plastic injection molding as their process of choice.

Plastic parts have multiple common advantages over the metal, such as:

The advantage of plastic molding parts

  • Able to offer a higher tensile strength than a diversity of metal materials
  • Lighter part weight
  • Lower manufacturing cost
  • Extremely flexible design
  • Less material waste
  • More efficient production
  • Easier to meet various regulatory requirements
  • Reduced packaging and shipping costs
  • A service life as longer as six times
  • Higher resistance to corrosion
  • Repeatable and predictable manufacturing

In addition to reduced part weight, as well as improved overall part strength and resistance to corrosion, replacing metal with plastic also allows us to consolidate several different metal parts into a single plastic one. Moreover, apart from providing the equal strength and offering the same level of tight tolerances as the metal, fewer secondary operations are required of a plastic part, thus able to save both time and costs.

Actually, it is possible to build a plastic part that possesses higher quality physical and chemical properties than the metal, with the help of specialized design methods.

Applying Plastic Parts for Cost Reduction

As mentioned above, replacing metal with plastic is able to cut costs by up to 25 – 50%, thanks to the following several factors: one single plastic part is able to replace several different metal parts, so subsequent fastener and assembly can therefore be eliminated; it is able to add colors to the plastic melts during production, so the painting or laser marking processes can thus be eliminated.

In addition to cost reduction, the application of the plastic material can also dramatically enhance parts quality. The advantages of plastic part can be optimized in several ways that include:

  • The plastic materials are able to be reused
  • Product service life is extended
  • Design options are more diversified
  • Secondary processes which are time consuming and costly can be eliminated
  • Product structural strength is improved
  • The product is lighter and easier to use

3D Printing VS Injection Molding

We held a discussion on 3D printing vs injection molding. Although the new printing technology has come into existence for quite some time, it has only been about 5 years since the technique becomes known to the public.

During that period of time, the actual capabilities of 3D printing technology has been overshadowed by how the public perceives it. Now, people would like to inquire more about it along with more recognition of it – every industry player seeks to explore the 3D printing technique, with the aim to find an alternative for their future projects, so that they will be able to move on from more conventional methods, such as the injection molding process.
injection molding company in china

3D Printing VS Injection Molding

Although these 2 processes are similar to each other – both of them are used to produce parts & components from the plastic material, and are able to handle a high level of complexity in geometry – there are significant differences between them too.

Among all the features of 3D printing technology, one of the most attractive one should be the relatively lower costs in the initial stage. On the contrary, the plastic injection molding process requires a much higher initial cost, because it is expensive to create the necessary special dies. Although it might be overwhelming in the beginning, the initial cost can be amortized over the service life of the mold, as well as the duration of the production run. And, in a large volume injection molding project, the initial cost can be amortized over more individual parts, resulting in a relatively lower cost per part.

Apart from the benefits with regard to startup costs,there are a number of limitations that the 3D printing technique has to overcome, especially when in comparison with the plastic injection molding process. The costly and time consuming misprints still tend to be caused by technical and / or software issues. Nowadays, 3D printers are still not commonly seen, the printing process is considerably slower than the injection molding process, and there are also restrictions in the size of 3D printed parts.

Which Method Works the Best for Your Project?

Both of the 2 processes – 3D printing vs injection molding – are able to produce plastic parts with guaranteed high quality and high complexity. To decide which one works better for your future projects, you have consider one of the key factors: the breakeven point.

When we seek to partner with a plastic injection mold maker, there may be a huge startup cost, even for a high volume plastic injection molding order. This is inevitable for the die tooling process, in which the stainless steel is often used for the mold. So, you have to consider the breakeven point — during the production process, whether the initial cost can be amortized far enough to make the plastic injection molding process a more cost effective method than the 3D printing technique. Other considerations include the size and complexity of the part.

When your production volume is lower than 1,500, 3D printing might probably be more cost effective for you project. However, when your volume is higher than that, the plastic injection molding process would be a wiser choice.

Although 3D printing is a very amazing technology, it is only applied to part or product prototyping at the moment, and only able to handle a very limited production volume. Therefore, we would like to encourage the readers of this article to learn more about the injection molding process, which possesses the full capabilities and benefits to handle large-scale production runs.

How to make high quality plastic products in China?

The production of  high quality plastic products can be attributed to several essential elements.  We have a dedicated team of plastic injection molding experts at ECO Molding who have a clear idea about how to create high-performing and reliable plastic parts. Like no others, we are a precision plastic component manufacturer who is able to provide high quality plastic products that are complete and ready to be used immediately. In addition, we keep designing and tooling all our parts in  house, and meticulously monitor each and every step in the manufacturing process.

high quality injection molding company in China

In the following text, we are going to share with you our main areas of focus in the injection molding process, which allow us to create the perfect high quality plastic parts for our clients, regardless of how complicated or uncommon the specific requirements are.

Design of Mold

To begin with, the design of a mold is of critical importance to make sure that the plastic injection molding process is able to produce plastic parts in a high volume, and with ideal productivity and uniformity. With the dedicated team of engineers at ECO Molding, who are good at the design of molds that ensure good quality plastic parts in an extremely efficient way, the risk of costly delays and material waste can be effectively eliminated.

We now enjoy more than 15-year experience in the plastic injection molding field, and our expertise allows us the ability and ingenuity required to build customized molds of any types even in the most challenging circumstances. With the application of cutting edge technologies, such as CAD/CAM systems, our engineers work in close collaboration with the client to thoroughly understand the key requirements for each part, including functions, applications, dimensions, its relation with other components and the ability to withstand certain conditions, etc.

Equipped with such expertise, our engineers are then allowed to identify the main design elements that are required to guarantee that the plastic injection molding process will go correctly as expected. To create the perfect bespoke mold for the client, we will take all the elements into consideration, including wall thickness, rib design, boss design, corner transition, weld line, as well as gate/vent arrangement.

After the draft design is finished, we will initiate the design for manufacturability (DFM) analysis, so as to make sure that our design meets the highest possible standard of quality. Upon design finalization, our engineers will start the new mold building and testing process.

Manufacturing of  Molds

If there is not an ideal mold, it will not be possible to produce high quality plastic products. Therefore, we pay great attention to our mold making process at ECO Molding. Since mold making is a time consuming process and it has to allow for highest accuracy, this procedure always represents the most substantial investment that a company has to make in its manufacturing process. However, precise tooling always plays a critical role in guaranteeing a successful plastic injection molding project.

ECO Molding is specialized in the creation of high-quality, precise and enduring mold products. We focus our mold making process on several key aspects to make sure that we create the ideal molds that the client needs:

  • Reliable design and engineering
  • Mold bases and cavities made from high-quality stainless steel to ensure the desirable performance and service life
  • Application of the most sophisticated equipment to ensure precise machining
  • Focus on stringent quality standards and strict tolerances

We are clear that creating a high-quality precision mold is a substantial investment for you, so we will make every effort to ensure maximum return on investment for you, mainly from the following perspectives:

  • Core Metal– All the molds we have made employ stainless steel as the core metal. Over the past decades, our molds have been proved to be able to withstand long production runs, while still meeting stringent tolerance requirements.
  • Cavity Quantity– We seek to maximize the no. of cavities in a mold to ensure the optimal level of efficiency.
  • Mold Base– We carry out cost estimation of the mold base, the part that holds all mold components together, including cavities, inserts and more on basis of its size, as well as the type of steel used, to allow for the desired level of customization.
  • Core/Cavity Machining– Our molds are tailored for the client through specific arrangement of cores, cavities, ejectors and cooling channels, etc.
  • Part Complexity– On basis of part complexity, we determine the mold cost by taking the surface finish of the final product, as well as the number of undercuts needed into account.

In order to build a mold, we can reverse the design of an existing part, or construct a mold on basis of the drawing or CAD file that the client provides. With regard to tool making, our team makes use of several different types of equipment that includes EDM, CNC mills, lathes and grinding machine, to build the desired part. Upon mold creation, we are then allow to choose the appropriate resin for production.

Selection of plastic resin

It is also of critical importance to choose the right material for the production of high quality plastic parts, so as to ensure a successful plastic injection molding process. Over the previous decades, the development of polymer technologies has allowed us a wider range of available resins, which leads to an increase in the applications of plastics in various sectors, as well as an improvement in available plastic materials with higher strength and durability. Our manufacturing experts possess the experience of working with a diversity of resin materials for different types of applications.

We work in close collaboration with every client to identify key requirements for the resin, including the desired appearance of the product, e.g. texture, color and transparency, as well as the strength, flexibility, rigidity, chemical & environmental resistance, the regulatory requirements and the service life of the product.

Production & Quality

After the mold is created and the appropriate resin is selected, the production process can finally start. We now have several  state-of-the-art presses in our factory, with different capabilities and performance for the client to choose from. On basis of mold dimensions, the number of cavities and the resin selected, our team of experts will select the right machine to use.

Following that, we will perform a trial run to ensure that no defects will occur. Once any defects are found, we will make corresponding corrections; if everything goes correctly as expected, we will go ahead with the production process, throughout which our team will continue to carry out quality monitoring, in an effort to ensure that all products manufactured meet the highest quality standards.

At ECO Molding, our team takes high quality as the first priority and it is our aim to offer the best high quality plastic products at the most competitive price.

How to choose resin materials for plastic injection molding product?

In today’s market, there are tons of resin materials available for the client to choose for plastic injection molding project. So, the selection process for plastic materials often seems very challenging in the very beginning.

At ECO Molding, we are clear that each type of plastic material boasts unique features and benefits, so we work in close collaboration with the client, in a bid to explore the most appropriate plastic material for their production projects.

plastic resin material

The following are some most commonly used resin materials for the plastic injection molding process:


As it boasts a remarkable impact and mechanical strength, the ABS (Acrylonitrile Butadiene Styrene) is applied in a broad range of industries, from automobile to pipe manufacturing. Metal coatings adheres to ABS easily, so the material is a perfect fit for production of such products as telephones, shower heads and handles, etc. However, the material is not very resistant to chemicals, so it is better not to use it in the applications that require electrical insulation or resistance to UV.

Celcon (Acetal)

Celcon, also known as Acetal, boasts outstanding surface lubricity, resistance to creep (memory) and chemical solvents. It is an ideal material for applications in the food, beverage, mechanical, automotive and household industries. We usually choose this resin to manufacture toy components, as well as gears and bearings. Besides, it is often applied in production of automotive and household products. However, it is not a good choice for applications under high temperature conditions.


Polypropylene, commonly known as PP, is best known for flexibility in the industries including packaging, fluid management & processing, household products and production of some automotive parts. Although polypropylene is a flammable material and susceptible to UV radiation, it still provides good chemical and electricity resistance. The majority grades of polypropylene are flammable and subject to degradation by UV radiation.


HIPS, short for High Impact Polystyrene, is a tough material with a low-cost performance and customizable surfaces. This material is able to be easily printed, glued, bonded and decorated, and is commonly seen in such industries as merchandising, displays, printed graphics, as well as prototypes. Though it is flammable, there are flame-retardant varieties available on the market.


LPDE, i.e. Low-Density Polyethylene, is the version of polyethylene with the highest flexibility. It boasts a strong resistance to moisture and a high impact strength. The LPDE material is usually used in production of many consumer products, housewares, as well as medical supplies and electronic wires. However, this material is difficult to bond, so it is better not to use it in extreme weather or high-temperature conditions.

Key Considerations for Selection of Plastic Injection Molding Materials

Keep the following variables in mind when selecting a resin materials for your production project:injection molding manufacturer in China

  • Impact Strength – The production of some parts requires a higher base strength than the rest of them, so the IZOD impact strength of a resin material should be identified from the very beginning.
  • Tensile Strength – We use ultimate tensile strength or ultimate strength to measure a resin’s tension resistance and its capability to withstand a certain amount of load without falling apart.
  • Flexural Modulus of Elasticity – This term measures how much a material can be bent without being damaged and is still able to return to the original shape.
  • Heat Deflection – For production of products that requires insulation or tolerance for a relatively wider range of temperature conditions, the heat deflection performance is of great importance.
  • Water Absorption – It measures how much liquid is taken by a material after 24 hours of immersion, usually measured in percentage.

Selection of  Resin Materials for Custom Applications

If you choose the most appropriate material from the very beginning, you will not only save time and money, but also you will ensure the highest possible level of performance and manufacturability. To identify the ideal material choice, we suggest you research your options in a careful manner while consulting with a qualified plastic injection molding maker.

How to find a good injection mold maker in China?

Let me ask you a question: how frequently do you look for an good injection mold maker? Most firms and project managers would reply “seldom”. The benefit is that once you have decided on an injection mold maker to work with, you will probably stay with it for quite a long period, provided that they are able to produce plastic parts with the desired quality.

good mold maker in China

In the following scenarios, you may need to look for an injection mold maker:

– A newly designed product of your firm requires injection molding

– An existing injection molded part of your firm has been redesigned by your engineers

– The current injection mold maker can no longer meet your requirements for high quality

– Your manufacturing location has changed

As a result, when you are looking for a new mold maker, how can you make sure that you select the right plastic injection mold maker for the job?

We have collected the FAQs and then offered replies to each of them.  If you can review these questions before you visit an injection mold maker, you will probably get the information you need, so as to do a proper assessment.

The following are some samples :

Q:  Does the plastic injection mold manufacturer possess a qualified in-house mold/tool design and making team?

A:  There are several advantages if you partner with an injection mold maker who possesses the in-house capabilities to help carry out your project through from conception to completion.

– During the development process, design refinements are often made in the early stages.  If you are able to work with a turnkey mold maker, the refinements can be made and reviewed within a shorter period of time.

– Through dedicated training, designers are able to create the best design for a project. They possess the required expertise to create the molds that will help produce the desired parts in the highest quantity and with the highest quality.

– Look for a plastic injection mold maker that employs the latest technologies in precision CNC and EDM.

Q: What is their product lineup and what are the specs (capabilities)?

A:  The mold maker with a larger number of presses is able to cope with more projects within a given period of time, but they also have to have a wider range of machine sizes. The measurement of an injection molding machine is pressure or tonnage.  A plastic injection molding machine is able to run from 40 to 4,000 tons.  The larger the machine is, the larger mold it is able to accommodate. Yet, not all parts are able to run well on larger size machines. Your mold maker will help you identify the most appropriate machine on basis of the quantity and dimensions of the part, as well as the material selected.

Q: Will they guarantee the mold throughout the life of my project?

A:  This question is of critical importance.  When you are working in collaboration with the manufacturer who has engineered the mold for you, they should definitely offer guarantees.  If you need to make a slight adjustment or repair to the mold, the mold maker should fulfill their due obligation.

It can be a tough task to find an appropriate mold maker for you company from the enormous plastic injection mold makers across the whole world. We have compiled this questions and answers in the hope to help you make a comparison between injection mold makers, so that you can choose the most appropriate one for your future projects.

How much does a plastic injection mold cost in China?

To some extent, it is a lot to ask how much a plastic injection mold costs. It is a like asking “How much does your car cost?” Will your mold be a Toyota or a Bentley?

injection mold cost in china

The factors that determine the cost you pay for a mold are a combination of several elements, including part dimensions, complexity, selected materials and required quantities. For example, if you need 1,000 simple parts every year, we will recommend a single-cavity mold to you, i.e. it produces one part in each cycle. In this case, the mold will probably cost you 1,000 – 2,000 USD.

Another example: if you need 1,000,000 remote controllers per month, we will create a 16-cavity mold for you, which makes 8 covers and 8 bottoms in every cycle. In this case, however, you will need to pay 4,000 – 10,000 USD  or more.

Surely, the 2 examples mentioned above are every extreme, but it gives us a general idea about how much a mold would cost you, and your specific part will probably fall somewhere in between.

In addition, the selection of material is another factor that determines how much a plastic injection mold may cost. For example, if you require a fiberglass filled product, you will probably need a mold that is made from hardened tool steel, so as to cope with the wear such materials might cause during the injection molding process under high pressure conditions.

It will be useful to tell your mold manufacturer if you already have a target price in mind for your parts. When they design the mold, they can keep your target price in mind, and then make appropriate planning to achieve your desired price with expertise. Although you do not need to know all the details about the available molds, it is better that you come prepared. If you are able to offer the basic information to the mold maker, it will be helpful for them to create the most appropriate mold for your production project. We also recommend that you look for a mold manufacturer who also possesses production capability. A company that is responsible for the production will not create a substandard mold, since they have to reply on it for production activities.

No matter what your project needs, One thing ECO Molding would not do is to suggest you invest in a Porsche when all you need is a VW.

Commonly Seen Mainstream Injection Molding Machines Brands

injection molding company in China

The injection molding machine industry has experienced rapid development across the whole globe. Especially, in the era when Chinese manufacturing industry develops at a very fast pace, many Chinese and foreign injection machine brands are widely used in enterprises which produce plastic products. Among them, the more famous ones include Chen Hsong from Hong Kong, Victor Taichung from Taiwan, Haitian/Haitai/Bochuang from mainland China, Mitsubishi/Toshiba/Sumitomo from Japan, and Demag/KRAUSS MAFFEI from Germany. Comparatively speaking, Japanese injection molding machines enjoy the longest service life while German ones follow the highest safety standards.

(1) German Demag Injection Molding Machine
Demag is a world famous injection molding machine brand of the German Demag Ergotech. Its main characteristics include: the hydraulic mold clamping structure and the computer-aided optimized location control of the injection machine match quite well with preset acceleration curves, to ensure the fast and balanced mold clamping action, thus keeping mold intactness and shortening cycle time. Its hydraulic ejection mechanism is very easy to assemble and disassemble, since there is no abrupt hose while the clearance between tie bars is big enough to accommodate large sized molds. The injection molding machine employs DFE, which has achieved a closed-loop oil pressure control, thus able to meet the requirements for any high precision and high response; at the same time, it is able to minimize energy consumption, thus meeting energy-saving requirements (saves up to 30% energy when compared with conventional injection molding machines); adopts the Ergotech Control unit, which allows to switch over from injection to holding based on the required time, pressure and flow; the value can be set as per percentage or input physical values; NC4 can be used to control exterior devices, with a special page provided to set various process parameters for quality control. All process control is completed automatically by the NC4 control system.

(2) German KRAUSS MAFFEI Injection Molding Machine

KRAUSS MAFFEI is a main high-precision injection machine brand of Germany. EX, the all-electric injection molding machine KRAUSS MAFFEI has launched possesses the characteristics of fast speed, high precision, cleanness, as well as energy saving. Though designed with a very short drying cycle time, it features very high precision, thus able to guarantee the quality of molded products.

(3) Japanese Sumitomo Injection Molding Machine

Sumitomo is the no. 1 injection molding machine brand of Japan, as well as the no. 1 all-electric injection molding machine brand of the whole world. The all-electric injection molding machines of Sumitomo rank top in the world for five years in a row when market share is concerned. Sumitomo has been engaged in injection molding machine R&D and manufacturing for more than 40 years and is always well-known to the world for its high speed and high pressure. After the all-electric injection molding machines have gained widespread application, Sumitomo has become the leader of the injection molding machine industry by virtue of its strong R&D and innovative capabilities. Currently, Sumitomo has developed countless propriety technologies, such as Direct Drive, Double Center Press Platens and DST-Press etc., which enable the company to give an outstanding performance in the industry. In recent years, Sumitomo produces approx. 5,000 all-electric injection molding machines per year, ranking no. 1 among the leading Japanese all-electric injection molding machine brands for 5 consecutive years.

(4)Hong Kong Chen Hsong Injection Molding Machine
Hong Kong Chen Hsong is one of the top-selling injection molding machine manufacturers in the world, with one unit sold in every 10min on average. The company boasts an annual production capacity of nearly 15,000 units, and the whole product lineup covers the clamping force ranging from 5 to 6,500t and injection volume ranging from 1 to 100,000g. With technological innovation as the core purpose, in the early days of its foundation, Chen Hsong independently developed the first two-color blow molding machine of Hong Kong, which attracted the attention of the players in the industry. In 1960s, Chen Hsong became the first one to invent the screw injection molding machine, laying a solid foundation for the company to become the leader of the injection molding industry. Coming to the 21st century, the manufacturing technologies of Chen Hsong injection molding machines have reached the world top level. In recent years, Chen Hsong keeps launching new products and new technologies. In 2000, it launched Asia’s first PET preform injection molding system which included mold, injection machine and manipulator. In 2001, it launched the all-electric injection molding machine, and in Sept. of the same year, it launched the high-precision ultra-high speed injection molding machine.

(5)Victor Taichung Injection Molding Machine
Victor Taichung is a company in Taiwan China which has successfully developed the all-electric injection machine and realized SOP. Based on its more-than-50-year mature technologies for injection molding machine manufacturing, Victor Taichung has so far developed a complete set of injection molding machines that include five variants of 50t, 80t, 100t, 150t and 200t, as well as 11 modular combinations, which are being sold to the US, the UK, South Africa, Japan, Philippines and Malaysia, etc. In the future, it plans to launch medium-/large-size electric injection molding machines, including 250t, 300t and 350t, while extending the range of electric injection molding machines, so as to satisfy customer’s increasing demand.

(6)Ningbo Haitian Injection Molding Machine
Chinese injection molding machine manufacturers are mainly located in the southeast coast and the Pearl River Delta, among which the Ningbo region has been enjoying the strongest momentum of rapid development, so it is now the largest manufacturing base of injection molding machines in China, with an annual production capacity accounting for 1/2 of the total annual production in China and 1/3 of that across the globe. The Haitian injection molding machine series is one of the representatives. Founded more than four decades ago, Haitian Group has now become the largest production base of injection molding machines. As a high tech enterprise that’s specialized in the production of injection molding machines, Haitian is famous in the domestic injection machine industry for its high quality, high efficiency, high grade and economic returns. Its products include the plastic injection molding machines of nearly 100 types, of which the clamping force mainly ranges from 58 to 3,600t (injection volume ranging from 50 to 54,000g), boasting an annual capacity of nearly 10,000t, with both production and sales ranking no. 1 in the China market. The company has comprehensively introduced the world-class fully computer-aided and fully automatic processing centers from Japan, Germany, the US and the UK, so as to turn out the Haitian injection molding machine series with high precision and high quality, including five series of HTB, HTF, HTW, HTK and DH, and boasting more than 100 machine types, so as to meet the different needs of different customers.

How to set the hold pressure?

The setting of hold pressure is aimed to prevent resin backflow, while at the same time compensating for resin shrinkage caused during the cooling process, so as to achieve the optimal molding outcome. If the holding pressure is set too high, the product will be prone to flash, over filling or stress concentrating near the gate, etc.; on the other hand, if the holding pressure is too low, excessive shrinkage and dimensional instability will be likely to occur.

hold pressure setting

Holding pressure only works well along with the settings of pressure switchover point and holding time in the plastic injection molding process.

Insufficient holding pressure will lead to: 1. dents; 2. bubbles; 3. increased shrinkage rate; 4. decreased product dimensions; 5. larger dimensional fluctuation; 6. inner-layer orientation caused by melt backflow, etc.

Excessive hold pressure will lead to:

  1. Stress in the sprue area;
  2. Difficult mold release;
  3. Tensile stress on the outer layer;

Gradual decrease of holding pressure during the pressure holding time may be able to (multistage holding pressure):

  1. Reduce warpage, as well as shrinkage difference in the product molding section between the gate and the far end;
  2. Reduce internal stress;
  3. Reduce energy consumption.

The setting of pressure holding time is aimed to control the duration of the holding pressure effect. An insufficient holding time will result in product dimensional and weight instability. However, if the holding time is set to be too long, molding efficiency will be affected. A proper pressure holding time should last till the gate solidifies. In the meantime, appropriate coordination between the value and time of holding pressure is able to bring the effect of the procedural holding pressure into full play. The purpose of holding pressure is to seal the sprue and compensate for material shrinkage after injection is completed. As a result, the holding pressure must be greater than the internal pressure.

If the hold time is set to be shorter than the maximum effective pressure holding time, i.e. insufficient holding time, the following results may occur: 1. dents; 2. bubbles; 3. underweight; 4. smaller dimensions; 5. internal orientation caused by melt backflow; 6. greater warpage, especially for semi-crystalline materials; 7. larger dimensional fluctuations; 8. increased shrinkage, etc. The set holding time must effectively last till the sprue solidifies. Usually, a sufficient holding time is approx. 30% of the cooling time.

In general, injection pressure control is composed of first-stage pressure, second-stage (holding) pressure or more stages of injection pressure control. An appropriate pressure switchover plays an important role in the avoidance of overpressure, overflow or incomplete filling. The specific volume of a molded product is dependent on the melt pressure and temperature during the pressure holding time when the gate is closed. Every time when switching from pressure holding to product cooling, if the pressure and temperature can be kept consistent, the specific volume of the product will remain unchanged. Under consistent mold temperature conditions, the value of holding pressure is the most important parameter that determines product dimensions, while the value of holding pressure and temperature are the most important variables that influence product dimensional tolerance. For example, after injection is completed, the holding pressure decreases immediately, and when the surface layer reaches certain thickness, the holding pressure will rise again. This way, thick-walled large products can be molded with a low clamping force, so as to eliminate dents and flash etc.injection molding tooling company in china

Hold pressure and speed are usually 50% – 65% of the top injection pressure and speed. That is to say, the holding pressure is approx. 0.6 – 0.8MPa lower than the injection pressure that feeds plastic into the mold cavity. Since the holding pressure is lower than the injection pressure, during the relatively long holding time, the hydraulic pump will be working under a low load, so its service life will be accordingly extended. At the same time, power consumption of the pump motor will also be brought down.

While facilitating smooth and complete mold filling, holding pressure can also eliminate product defects like weld lines, dents, flash and warpage, etc. It is thus very helpful for the production of various types of parts, including thin-walled parts, multi-headed small parts, long-cycle large parts, as well as parts with an unbalanced cavity or even those with insufficient clamping force.

During the plastic injection molding process, the molten material shrinks due to cooling. However, the screw needs to keep moving forward slowly, so that the molten plastic in the barrel can continue flowing into the cavity, to compensate for the shrinkage. This process is known as pressure holding. To put it simply, its purpose is to compensate for product shrinkage, as well as ensure a stable production process. In addition, the hold pressure is also able to adjust product dimensions, and effectively eliminate weld lines, dents, flash and warpage at the same time.

As a matter of fact, hold pressure and injection mean the same thing – applying a force to push the screw forward. The only difference is that in the injection process, the screw is pushed to move at a set injection speed and the max injection pressure; during the pressure holding time, the screw is pushed to move at a set injection pressure and the top pressure holding speed.

Multistage injection molding is able to adjust the speed and pressure at which the raw material flows into the mold cavity. This way, the defect rate of some complicated structure products will be decreased, and at the same time, the small inserts in the mold will be well protected. For example, when the raw material flows into the mold, its speed and pressure can be reduced when reaching a small insert, so the insert will not be prone to damage. Multistage holding pressure is also able to reduce the occurrence of dents – another benefit that helps reduce product defects.