Plastic injection molding company workshop China

The importance of injection mold maintenance

Mold maintenance, or tool maintenance, refers to the cleaning and repairs that are needed to keep an injection mold in the best working order. Maintenance is performed routinely over the life of the mold, and also when any problems arise.Mold maintenance is crucial because it affects the quality of the plastic component as well as a company’s bottom line.

The condition of the injection mold affects the quality of the plastic components produced. Your molds and tools are critical assets to your company, yet many buyers overlook mold maintenance when making sourcing decisions. In fact, how your supplier maintains your molds is a critical aspect of a successful long-term business relationship.

What problems does mold neglect cause?

Injection molds undergo a lot of stress in the course of carrying out the molding process. Depending on the design of your mold, factors like temperature fluctuations, opening and closing of the mold, ejector pin action, and other movements can all cause natural wear and tear on a mold. A good injection mold will be designed to handle this wear and tear, but unpredictable situations can still arise as a result of these numerous stresses and the nearly innumerable permutations in which they can interact.

Temperature fluctuations, for instance, can cause both internal and external stress on the mold. Especially if the mold is not designed in such a way as to allow for more uniform cooling, molds can expand and contract in response to heating and cooling, and can weaken from the stress — and potentially even crack.

The moving parts of the mold are susceptible to friction, rough points of contact, and mechanical breakdown. A mold that doesn’t open and close smoothly, for instance, may be subject to impact stress as the two halves meet each other. Ejector pins may not function properly after a certain number of molding cycles. What’s more, the friction of the moving parts, in addition to creating extra heat, may eventually wear away at critical parts of the mold, creating unintended cavity shapes or compromised contact points.

Aside from the aspects inherent to the mold itself, there are also maintenance issues related to the material injected into the mold. As the mold completes more and more cycles, minute amounts of material residue can begin to collect inside the mold cavities. Over time, these deposits can accumulate and affect the interior shape of the cavity — and thus, the shape of the finished part. Deposits in mold runners or the mold cavity can also affect cycle time and, left unchecked, can even begin to prevent the substrate from reaching areas of the mold.

If a mold is used with different materials, these deposits might also create unintended interactions, depending on the chemical makeup of those materials. This, in turn, can affect the structural integrity of the finished product.

What does injection mold maintenance involve? 

The most important part of mold maintenance is creating a maintenance schedule and sticking to it tightly. Molds must be maintained regularly if their lifespan is to be prolonged. Ideally, manufacturers should perform cleanings, inspections and maintenance on molds after they have undergone a set number of cycles. However,Setting the schedule can be tricky, because different molds age at different rates, conditions wearing them out differ from manufacturer to manufacturer.  

One way to begin figuring out how often a facility should perform maintenance on each type of mold is to keep a log of all mold maintenance and repairs that become necessary. Be sure to keep track of the data and information you collect in a centralized log for easy reference.Knowing how often a given type of mold will break down without maintenance can help factories determine how often it needs to be inspected. The manufacturers of the injection mold will also be able to provide information on how often the mold will likely need maintenance. Advice from manufacturers will of course be more helpful if they have adequate information about the environment in which the mold will be used.

Regular mold maintenance and cleaning can improve shot quality, as molds will be in a more uniform state of cleanliness and wear and thus produce more uniform results. The most important factor in making sure molds are always in good condition is the regularity of maintenance, it is also essential that the right kind of maintenance is performed. It is especially important to pay attention to hot runners and water lines, as they often cause mold performance problems. Mold maintenance should also of course include lubrication, cleaning and tightening of all parts. Finally, rust prevention sprays must be applied to a cool, dry mold if they are to work.

Working with a reliable injection mold supplier as a strategic partner can help reduce many of the risks and costs. Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing injection mold.Please visit us at :jweimolding.com or contact us via info@jweimolding.com.

Choosing the Right Material for Injection Mold Tooling

With many different types of mold material options available(Hardened steel,Pre-hard Steel,Aluminum) ,all formulated to meet specific requirements, ensuring the material used to produce your injection mold has a positive impact on the success of your next project. Similar to plastic resins being formulated to meet performance criteria in various applications, steel is also alloyed to meet specific requirements.Choosing the proper material for your next plastic injection mold can often be as critical as choosing the right plastic resin for your part.

Circumstances that effect choosing the proper injection mold material include:

• ensuring parting line integrity;
• wear resistance because of mechanical fatigue;
• wear resistance because of abrasive or corrosive plastic resins;
• inclusion of thermal properties needed to successfully mold your plastic part.
  

The most common materials used to construct plastic injection molds are pre-hard steel, hardened steel, and aluminum. This 3-part series will explore each and answer the important questions you should consider before choosing your material:

1,How many parts are expected to be molded?

Pre-hard Steel: Typically found with a Rockwell rating of RC 30-42 (in its pre-hardened state), this material is quite tough, easy to machine and relatively inexpensive. 250,000-500,000 cycles can easily be achieved when molding unfilled materials, and 50,000-100,000 cycles can be obtained with filled materials. The range is dependent on the amount of filler present in the plastic material. When total expected volume is less than 250,000 cycle’s, pre-hard steel is the way to go.
Hardened steel:Typically found with a Rockwell rating of RC 46-62 , it can be a great material for creating core and cavity detail. With hardened steel molds, one can easily achieve 1,000,000 cycles for unfilled materials and 250,000-500,000 cycles with filled materials. Once again, this range is dependent on the amount of filler present in the plastic material.
Aluminum: Generally speaking, aluminum molds are used in lower volume productions, not exceeding a few thousand parts.

2,What surface finish requirements are expected of the molded part?

Pre-hard Steel: This may include light to aggressive textures, EDM finishes or polish. An A-1 or better polish can be achieved but this is grade specific.
Hardened steel:As long as your requirements do not exceed that of an A-3 requirement, pre-hard steel is a great choice.
Aluminum: Most grades of aluminum machine, finish and accept texture proficiently. Most high-end aluminums have the ability to accept a polished surface, often ranging between a B-1 and A-3 polish.

3,What steel conditions exist as a result of the part design and are they conducive of excess wear?

Hardened steel: With hardened steels you can decrease the amount of draft of wiping shut-offs to about 3 degrees.
Pre-hard Steel:pre-hard steel has fair compression strength. Because of this, pre-hard steel is a great candidate for lower volume production tooling, including insert molding and overmolding.
Aluminum:Aluminum has very poor compression strength. If you happen to close the mold on a single part or insert, the aluminum will “hob” and become damaged, requiring expensive repair. For these reasons, aluminum is not well suited for any type of insert or over molding.

4,What type of plastic resin will be used on the molded part?

Pre-hard Steel:If molding highly corrosive molded resins, like PVC, common metals can quickly corrode, so 420SS is highly recommended. There are many options that offer different levels of hardness, as well as corrosion resistance.
Hardened steel:High heat resins such as PEI, PPS, PPSU, PPA, and PEEK, as well as filled materials (long and short glass fiber, carbon, stainless steel, etc.), can often be tough on pre-hard steels from a wear perspective. While certain steps can be taken, like inserting the gate area for easy maintenance and replacement, it should be expected that the life of the mold will decrease in these circumstances. If you find that your project requires between 50,000-100,000 parts over the life of your program, pre-hard steel is certainly adequate.
Aluminum:Aluminum is very vulnerable to fast wear and fatigue when high heat or highly abrasive materials are being molded, and should not be considered for any type of production molding. However, it can still be a great choice for extreme low volume (truly prototype) and non-cosmetic parts, even when running such materials.

By considering these 4 basic questions, you can make a more educated choice as to what the correct material is for you. While choosing the best option for your mold is not complicated once you understand the pros and cons of each material, it is a critical part of the process that can affect the success of your project. Research done prior to mold construction, and more importantly vendor selection, can help ensure you receive the performance you expect from your next mold.Jingwei industry has served the injection molding industry for over 20 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing injection mold.Please visit us at :jweimolding.com or contact us viainfo@jweimolding.com.

Basics of Plastic Injecion Molded Parts Production

Creating a plastic part using injection molds requires three important components:The mold;An injection molding machine;Raw plastic.Making a basic plastic part is relatively simple if you have the right tools. Knowing what is needed can help you understand how your requirements will be met, and you can more easily communicate your needs to a plastic injection mold manufacturer.
Consider the size of the final part when you determine which machine to use. The more complex your design, the more features you are likely to need to consider. This ensures that you are able to select the right raw material and machine to complete your injection molded parts.
The strength and durability of the final product depends on which raw material you select for your injection molds. Molds for plastics come in many different shapes and sizes, and the success of your final product starts with the raw material.
The plastic mold itself is typically something you will have to develop. Experts can help you interpret your needs and design the right type of plastic mold for each unique project.
Before launching your next plastic mold project, remember these simple steps. Although the manufacturing process is straightforward, you need the right expertise for a high quality, on-time, cost effective finished product.Jingwei industry has served the injection molding industry for over 20 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing.Please visit us at :jweimolding.com or contact us via info@jweimolding.com.

How to Optimize Your Plastic Injection Mold Designs

Designing better parts initially will help ensure a smoother transition to production and faster delivery of your new products.A lot of time and attention goes into making a successful plastic injection mold design. If you don’t get the design right, nothing you do is going to compensate for that later. Here are a few simple guidelines to help you get the right design from the beginning:

• Size of the mold:The maximum part outline that can be molded is approximately 18.9 in. (480mm) by 29.6 in. (751mm) or roughly equivalent to 175 sq. in. (1,129 sq. cm.). A maximum part volume of approximately 59 cu. in. Depth up to 4 in. (101mm) from the parting line with 3 degrees of draft, or up to 8 in. (202mm) total if the parting line can pass through the middle of the part, inside and outside. Deeper parts are limited to a smaller outline
• Tolerances:Typically,Jingwei industry can maintain a machining tolerance of ±.003 in. (0.08mm) with an included resin tolerance that can be greater than but no less than ±.002 in./in. (0.002mm/mm).
• Wall Thickness :With injection-molded parts, observing proper wall thickness helps parts avoid potential issues such as sink marks and warpage.
• Drafts :Drafts  are actually vital to ensuring that you have taken all of the other aspects into account and have worked to improve the mold based on any new information. Drafts give you a way of seeing where you have been and what did not work before or highlight areas where you think previous design versions were better.

Every mold design needs to take above four primary factors into account before being made.Size,Tolerances,Wall thickness should be located on the specifications or requirements for the mold. If you do not have these, that should be the first step in the process because these three factors tend to be the reason that a mold either succeeds or fails.

• Surface finish:Surface finishes play a critical role in both functionality as well as the cosmetic look and feel. Parts that are hidden may not require a surface finish at all;
• Undercuts:An injection mold undercut is any indentation or protrusion that prohibits an ejection of a part from a one-piece mold.Reducing the number of undercuts often helps to reduce the initial cost of tooling.Undercuts are critical on things like bottle caps, but not all molds will require undercuts as part of the plastic injection mold design.

Jingwei industry has served the injection molding for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing your new products.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

Things About Injection Molds Your Boss Wants To Know

Injection molds are one of the reasons why mass production has become so popular, and why so many manufacturers rely on custom mold makers to produce the perfect mold. Here are things that you may not know about injection molds.

1. Injection molding can be fully automated and thus permits very high rates of production (you can mass-produce parts very effectively through injection molding processes).
2. Injection molding allows for the production of highly detailed and intricately designed parts. You will need an engineering design firm or an in-house department to make credible designs, however, once the part is ready for and produced via injection molding,Custom mold makers have perfected the process well enough that final products can have fine details and incredibly intricate designs to meet very strict requirements.
3. Custom injection molds are often cheaper and more durable than 3D printed molds because the amount of time required to make a complete part is usually in the cooling process.
4. You can use a variety of materials in injection molding as well as combine different materials to synthesize desirable material properties in your final product. The combination of more than one injection molded material  is known as co-injection molding.
5. Injection mold makers can actually use aluminum in the products. It is not a common material, but can be used alongside the more common plastic injection molds. This addition will help when a higher heat tolerance is required.
6. It is rare that a mold is perfect the first time, even with a production mold. so if you work with a tool maker who gives you an 8 week delivery on the tool, be aware that that does not necessarily mean that your part will be useable in 8 weeks.Experts are required to ensure that the final product meets your needs. They can test and measure the mold and first round of injections to see if there is a problem and determine the best way to fix it.
7. Mold inserts can be used to make new parts so that you do not have to recreate a similar insert for different projects. It is a matter of changing the internal cavity instead of redesigning and machining the mold.

Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing your new products.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

4 Steps to Achieve Proper Tolerance for Superior Product Performance in plastic injection molding

Tolerance is an acceptable limit of variation in a physical property or dimension.Defining a tolerance will identify boundaries for acceptable variations that will not affect the function of a part or system.
With the injection molded process, major factors that impact tight tolerance include part design and complexity, material selection, tooling, and process design and control. They can make it difficult to hold dimensions to the exact value. That is why an acceptable tolerance is necessary.
If tolerance is not done correctly, parts and products will underperform or possibly fail, resulting in customer dissatisfaction and a tooling and/or process overhaul，delays in production and unexpected additional costs. Below are 4 aspects that play key roles in aligning proper tolerance for superior performance.

1. Part Design and Complexity

The first step to controlling tolerance is to establish the tolerance zone during the design phase. Designing the part is the biggest factor in controlling tolerances. Making improvements during the design phase will not only achieve repeatable tight tolerances, but also improve manufacturability, quality, and customer satisfaction, all while reducing costs.

• Shrink rates can vary depending on the material selection and product wall thickness. Thicker sections may shrink at a different rate than thinner sections. Varying shrink rates can affect the ability to hold tight tolerances.
• Part size can affect shrink rates as well. Small components have smaller shrinkage and are easier to maintain tighter dimensional control. However, large parts can be challenging to hold tighter tolerance as they shrink over a greater distance.
• Analyzing mold flow before production can be beneficial. Accurately predicting gate location, fill speed, shear stress, packing, cooling and shrinkage will help define the tolerance zone.
• Avoid tight tolerance in areas that are prone to warp, shrinkage or distortion.

2. Material Selection

Material selection is another decision that must be made early in the design process. Different resins can produce different tolerances for the same part, so sometimes a tradeoff must be made between tolerance expectations and the physical properties of the resin.

• A components environment can affect plastic properties and can result in a deviation from the tolerance. Plastics have larger thermal expansion than many other materials. Testing and measuring tolerance along with thermal expansion and part shrinkage in the components normal operating environment is crucial to controlling tolerance, but most importantly tight tolerance. Climate-controlled environments hold tighter tolerances well. On the other hand, tight tolerances are not always necessary in environments where temperatures are uncontrollable or where plastic expansion or contraction occurs.
• As mentioned in the design phase, shrinkage can affect tolerances. Part geometry can cause different shrink rates. Different resins also have different shrink rates. It is important to know resin properties in combination with part complexity to understand shrink rates to align proper tolerance zones.

3. Tooling

Tool design, tool material, and cavitation all impact tolerance. The need to heat and cool tools, and the number of cavities in the mold, can make holding tolerances more of a challenge. If tooling is not designed to provide consistent, repeatable cooling, shrink rates will vary and tolerances will be harder to achieve.

• Complex parts require complex tools. As a tool becomes more complex and additional components and features are added, it is important to make sure all components are transferring heat properly, allowing for acceptable resin and part cooling.
• Monitoring pressure will identify resin viscosity, fill time and many other production processes that can affect resin properties and result in deviations and application failures. Utilizing in-mold pressure sensors will help track the proper pressure at each stage of the molding process.
• Identifying an adequate gate location is important to achieve optimal material flow. This will contribute to avoiding unexpected shrinkage and warping.

4. Process Design and Control

Setting up the ideal process for the part, and being able to repeat it, is the key to molding tight tolerance parts. Proper process and document control from the beginning of production will ensure the component does not experience unnecessary pressure, stress, heat, or additional factors that can disrupt resin properties or application function.

• Many parameters and variables must be carefully controlled during injection molding to achieve tight tolerances. Proper process control and process development ensure the part does not experience unnecessary pressure or stress during the molding process. Matching pressure curves versus simply using machine parameters such as time, temperature, and pressure help eliminate the lot-to-lot variation that is common in the industry. Conducting injection-molding operations in a climate-controlled facility also reduces process variation.
• Understanding end user intent, life cycle expectations and environmental encounters are important to share and discuss with your plastic manufacturing partners. Keeping lines of communication open with your plastic manufacturer will aid the success of your application.
• Repeatable processes can be achieved by conducting a Rheology test and a gate test. These tests will show you how repeatable your process and machines are, as well as, aid the optimization of your process and cycle time.

Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing your new products.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

Finding the Perfect Color for Your Plastic Parts

The colored plastic is more valuable and desirable than untreated plastics.The color of your plastic part can be an important aspect of its perceived quality. In this industry, many of the materials (or resins) that are used are off-white, translucent, or blue and those bland colors can have a negative impact on the appearance of your end product and your customers' opinion of the piece. Consequently, you should give serious consideration to the color of your parts.

The process of adding custom color to your part can range from a rather simple process to something that can be incredibly complicated. It all depends on how particular you are about the specificity and consistency of the color. Here’s a quick explanation of the two most popular coloring methods that will help you determine which one would make the most sense for your future projects.

Mixing Colorant With the Natural Material.Dye pellets are added simultaneously with the natural pellets into the injection molding machine. The pellets are then heated in preparation for the molding and mixed together creating the colored resin. The higher the ratio of dye pellets, the deeper and richer the color. This is usually the simplest and most cost-effective method when conducting low-volume production. Another benefit of this method is its ability to have a quick turn around time.Disadvantages of this method include swirling (an incomplete mixture of color), loss of resin characteristics (flame retardancy or food compatibility for example), and possible appearance of the base resin shade.

Purchasing Custom Compounded Plastic. These custom-colored plastic pellets can be purchased from a number of specialized vendors. However, there is a minimum of one ton that must be purchased on the open market, making this a suitable option for only large scale productions. This process consists of the vendor mixing the colorant with the base material, melting and extruding the resin and then re-pelletizing this mixture. Although this option requires large-scale production and is a bit pricer, it provides the most color consistency and keeps resin characteristics intact.

While these are not the only two methods that can be used to add color to your parts, they are the most reliable and environmentally friendly. Unlike painting or plating, the processes above use the color as a component that is woven into your part, not just applied to the surface. There is no risk of scratching or peeling revealing an underlying color and the overall quality is much higher.

Jingwei industry has served the injection molding industry for over 15 years ,and we hope this information is helpful as you consider your next color-specific small parts plastic injection molding project. To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.We will be able to provide you with samples, so that each client has a direct hand in making sure the final product is perfect.

Plastic injection molding gate types & gate designs

In plastic injection molding, one of the most important aspects of the mold design is how and where it is gated. By definition, an injection molding gate is an orifice through which the molten plastic is injected into the mold.The location, size, and shape of the gate plays a very significant role in the process of injection molding.

Gate Types:

There are two types of gates that are used in plastic injection molding: manually trimmed and automatically trimmed gates.

Manually trimmed gates are chosen for several reasons:

• The gate is too thick to be separated automatically

• Shear-sensitive materials such as PVC cannot be exposed to high shear rates

Automatically trimmed gates are used for several reasons:

• Avoiding gate removal as a secondary operation, reducing cost

• Maintaining consistent cycle times for all parts

• Minimizing gate scars on parts

Common Gate Designs:

The largest factor to consider when choosing the proper gate type for your application is the gate design. There are many different gate designs available based on the size and shape of your part,four of the most commonly used are:

• The Edge Gate is the most common gate design. As the name indicates, this gate is located on the edge of the part and is best suited for flat parts. Edge gates are ideal for medium and thick sections and can be used on multicavity two plate tools. They leave a scar at the parting line.
• The Sub Gate is the only automatically trimmed gate on the list, and it requires ejector pins. A very common gate, it has a number of variations, such as a banana gate or tunnel gate. The sub gate allows you to gate away from the parting line, giving you more flexibility to place the gate at an optimum location on the part. This gate leaves a small scar on the part.
• The Hot Tip Gate is the most common of all hot runner gates. Hot tip gates are typically located at the top of a part as opposed to the parting line, this type of gate is great for conical or round shapes that require uniform flow. This type of gate requires a heated element to deliver hot material directly to the part, but it can improve flow and reduce cycle times. It leaves a small raised spot on the surface of the part.
• The Direct or Sprue Gate is a manually trimmed gate that is used for single cavity molds of large cylindrical parts that require symmetrical filling.Easy to design and with low maintenance costs, it produces parts that are typically lower stressed and high strength. This gate leaves a large scar on the part at the point of contact.

In our more than 15 years in plastic injection molding,we have significant expertise in this area and can provide tremendous insight on your mold design. Please visit us at :jweimolding.com or via info@jweimolding.com and let’s talk about your next project.

Injection Molding vs CNC Machining

When moving from design to creating your parts, you must decide how to make the parts. Two common methods are CNC machining and injection molding. Both of these have advantages and disadvantages when choosing between them. Which is the Right Choice?

Let’s look at each process:

CNC Machining:
CNC Machining is a process used in the manufacturing sector that involves the use of computers to control machine tools. Tools that can be controlled in this manner include lathes, mills, routers and grinders. The CNC in CNC Machining stands for Computer Numerical Control.
Injection molding:
Injection moLding process produces large numbers of parts of high quality with great accuracy, very quickly. Plastic material in the form of granules is melted until soft enough to be injected under pressure to fill a mould. The result is that the shape is exactly copied.

Which process is right for you?
In general, this can be looked at as a trade off between multiple of different characteristics; speed, volume, material,
tolerances/surface finish, and design. Each on of these can be a gating facture in using one process vs. the other and might even require changes to the part in order to manufacture.

Volume:
The main focus here is price per part. Which is cheaper changes depending on volume. CNC is cheaper when you need a few parts up to a few hundred. While you do get some benefit of volume in the price, it is typically seen between a few parts and a hundred. At larger volumes, you do not get any additional benefit of volume. This is from distributing the setup cost over the number of parts made.

The actual cost per part of injection molded parts is significantly cheaper that machined parts. Unfortunately, for injection molding, the creating of the mold can be a large upfront cost. This is spread out across the number of parts made to determine the cost per part. At a certain volume, even with the large upfront cost of the molds, injected parts become cheaper than machined. As more parts are created, the gap in cost becomes greater. This crossover can occur from as little as 100 parts up to about 5000.
Speed:
This is the simplest. For low volume of parts, CNC machining is the fastest. If you need 10 parts in 2 weeks, CNC machining is probably your only solution. If you need 50,000 parts in 4 months, injection molding is the way to go. Injection molding requires time to make the mold and ensure the parts are in tolerance. This can take anywhere from a few weeks to a few months. Once this is done, creating parts using the mold is a very fast process. The up front time investment of injection molding will pay off at high volumes.

Material:
CNC machining offers a greater selection of materials that can be used to create the parts. This can be very important deciding factor if a high performance plastic or a specific plastic is required.

For injection molding, the material selection can be more limited.

Tolerance / Surface Finish:
The advantage of CNC machining. With most materials, a tighter tolerance can be held and a better surface finish can be obtained. One advantage of injection molding is the repeatability from lot to lot. Molds can last for millions of parts with minimal wear. This allows for the parts from one batch to the next to be almost identical. With CNC machining, each part is put on the machine to be created and more variability will be seen.

Design:
Machining allows for great flexibility in the design. Many features can be easily made with machining that would be very difficult or cost prohibited in molding. Some of these include, overhangs, large walls with no drafts and variable wall thicknesses.

On the other hand, injection molding allows for deep features, square holes and living hinges to be produced easily that could be difficult and expensive with machining.

As you can see, the decision between machining vs. injection molding is not straightforward. You need consider the advantages of both from tolerances, price and design features to perform the final desicion.

Jingwei industry has served the injection molding and CNC machining industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing your new products.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

Plastic Injection Mold Design and Process Tips

Plastic Injection Molding has established a significant place in the manufacturing industry, mostly as plastic has emerged as the fastest growing material in use today. Plastic Injection mold design is a complicated part of Injection molding process and needs to be understood well in order to gain maximum benefits from Plastic, as properly designed plastic parts are fast replacing their metallic and wooden counterparts in almost all industrial and domestic machinery components.Over the years, it is apparent that many industries have taken notice of the advancements made when it comes to the plastic injected molding of products. Auto companies now use plastic for many of their auto parts, and the same goes for Medical Device Parts,Appliance Companies, Electronic Industry too.

Plastic Injection Molding Process: Plastic in the molten form is injected or forced by pressure into a die, known as mold, and held in the mold at a high pressure until the plastic solidifies. For reducing the time required to cool the plastic, cooling channels are provided. Water is circulated through these channels at a decided temperature, which is defined by the plastic resin being used, and the molding machine’s toggle unit provides the pressure needed to carry out the operation without any opening of mold halves.

The mold is split into two halves :Core and Cavity, sometimes more (Sliders and Angular ejectors or lifters), depending on the shape of component to be molded. This splitting provides a means of ejection of parts from mold after complete injection cycle and also facilitates in the easy machining and replication of shape of part. The More complex a part is, the more parting lines are needed to successfully eject it without damaging the part or the mold. If it has opening or bosses perpendicular to the opening direction of cavity and core, then we need to make use of sliders or angular ejectors (also called as lifters).

A mold designer has to be conversant with a number of important aspects about mold tooling and plastic resins. He needs to be able to clearly distinguish the type of resins or plastic material to use for a specific application and function. He needs to know which materials or alloys to use for making the core and cavity of the mold and which ones to use in the manufacturing of the other mold plates and standard parts such as ejector plates, ejector pins, sprue bush, knockout rods, support pins etc. Further, he needs to have basic understanding of injection molding machines, process, injection conditions and parameters, part design related aspects such as sink marks and weld lines. It usually takes years of experience to become a complete mold designer. Due to constant developments in
both, the engineering plastic resins and mold materials, he needs to keep himself updated with the latest trends and make use of them while actually designing the molds.

Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.For more information related to Plastic Injection Molding Design and Process Tips, Please visit us at:jweimolding.com or via info@jweimolding.com.

Plastics Testing Methods

What Is a Plastic Test
A plastic test is any type of test done on a sample of plastic. These tests can be used to determine the strength, flexibility, or durability of a plastic and are often used as a measure of quality control. Laboratories that offer to perform plastic tests use a variety of different machines and techniques to determine the quality of the plastic.

The evaluation of plastic materials may include the determination of material flammability, ignition characteristics from various thermal and electrical sources, electrical tracking and additional electrical characteristics, and analytical tests. Property retention following exposure to long-term elevated temperature, water, ultraviolet light, cold, and other outside influences may also be evaluated.

Plastics Testing Methods:

One common type of plastic test is a test of how the plastic holds up under different temperatures. For this type of test, a sample of the plastic is placed in a chamber where the temperature is either raised or lowered at a slow but constant rate. Engineers watch for changes in the quality of the plastic, such as expansion, breaking, melting, or contraction, depending on the specifications of the test, and note the temperature at which the change took place.

Plastics may also be tested for how durable they are under stress. One plastic test that determines durability uses a machine that bends a piece of plastic until it breaks. In another type of test, a piece of plastic may be pressed firmly between two sides of a machine until it compresses or cracks with the strain. Engineers may also use a machine that hits the sample, testing the capacity of the plastic to resist the impact and slow it down. Examining the forces used in each of these types of stress tests gives engineers information about how strong a sample of plastic is.

Some plastics that are intended for use as lenses may also undergo a plastic test that determines how the plastic interferes with light that passes through it. In one such test, a light with a specific wavelength is viewed through the sample, and the color and quality of the light is compared to the color and quality of the same wavelength of light that has not passed through a lens. Haze, or the amount of visible light that is refracted as it passes through a plastic lens, may also be tested in a similar plastic test.

For plastics that are intended for use in different types of conditions, weathering tests may also be performed. A sample can be tested to see how much water it absorbs or to see at what temperature it will catch on fire. A machine that mimics the effects of weather over a long period of time may be used in a plastic test that determines how a sample will hold up over time and exposure to the elements.

Jingwei industry has served the plastic injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

5 Design Rules of Problem-Free Injection Molding

Injection molding is the most commonly used manufacturing process but due to its intricacies product designers need to make adequate design considerations to ensure that part designs focus on maximizing molding performance and reducing tooling costs.
Plastic part performance and cost can be significantly enhanced by proper part design features. Through the use of simple designs and by following general mold ability guidelines for plastic parts, design engineers can avoid problems occurring during manufacturing and also reduce the cost of parts. These factors require designers to introduce adequate design features that can lessen the stress level within a part and help develop low-shrinkage, warp-free parts.Consider the following injection molding design considerations for designing better plastic parts:

Rule 1:Radius
During injection molding, the molten plastic has to navigate turns or corners. Rounded corners will ease plastic flow, so engineers should generously radius the corners of all parts. In contrast, sharp inside corners result in molded-in stress—particularly during the cooling process when the top of the part tries to shrink and the material pulls against the corners.

The radius should always be with regards to the part thickness thereby eliminating the prospects of high-stress concentration and resulting in the breakage of the plastic part. General guideline suggest that the thickness at the corner should be in the range of 0.9 times the nominal thickness to 1.2 times the nominal thickness of the part.

Rule 2: Determine an apt location for gate
If varying wall thickness cannot be avoided, then designers should provide for proper gate location. If this is not supplied, then attaining uniform pack of the molded part will be nearly impossible. The most effective gate location is when the melt enters at the thickest part of the cavity and then flows to the narrower areas.

Rule 3: Determine Optimal Wall Thickness
Theoretically, there is no maximum wall thickness for injection-molded parts. But designers are more concerned with determining the minimum wall thickness because thinner is almost always less expensive. Two factors contribute to this: first, thinner parts require less raw plastic material, and second, they cool faster. To determine the most suitable wall thickness, engineers should first consider product requirements. Generally, strength dictates the wall thickness. Engineers can also rely on a finite analysis to select the optimal wall thickness.

Rule 4: Keep Wall Thickness Consistent
Plastic part walls must be uniform in thickness. This is the most basic design parameter, and strict adherence to it will eliminate many manufacturing problems. Parts with uniform walls will not warp, will fill properly and will fit together because variable shrinkage is minimized. Wall thickness variations should not exceed 10% in high mold shrinkage plastics. In fact, even this slight disparity can introduce processing and quality problems.

Rule 5: Select Suitable Draft Angles
From a cost and manufacturability viewpoint, the ideal draft angle is the largest angle that will not lessen the customer’s satisfaction with the product. The minimum allowable draft angle is harder to quantify. Plastic material suppliers and molders are the authority on what is the lowest acceptable draft. In most instances, 1° per side will be sufficient, but between 2° and 5° per side would be preferable. If the design is not compatible with 1°, then allow for 0.5° on each side. Even a small draft angle, such as 0.25°, is preferable to none at all.

Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

Advantages of plastic molding parts over metal parts

Generally speaking, when you think of molding a product or part, you have two options of either plastic or metal.Some applications work only in metal and others only in plastic. Many, however, occupy a large middle ground in which either will work. At such times, plastic is often the material of choice given its many benefits.

Over the years, it is apparent that many industries have taken notice of the advancements made when it comes to the plastic injected molding of products. Auto companies now use plastic for many of their auto parts, and the same goes for Medical Device Parts,Appliance Companies, Electronic Industry too.

As plastic injection molding machinery continues to get better and produce high-quality plastic, there are several advantages of plastic injection molding  parts vs. metal parts.There are actually a lot of instances where plastic is a much better choice.

Plastic Molding is Less Expensive
Since plastic is much lighter than metal, plastic parts are better logistically. Metal is heavy, thus, would make it way more expensive to ship from the manufacturer to the client.

Plastic Molding is More Resilient
Parts made of plastic are very resilient contrary to popular belief. When a plastic molding product is made correctly, they are actually non-corrosive, spark resistant, and even mildew resistant.

Plastic Molding Has Memory
Unlike metal, plastic molds have a lot of memory. As a very forgiving material, plastic can easily return to its previous size if needed. This helps minimize errors and produce a product faster.

Plastic Molding is More Consistent Balancing
When melting materials for the injection molding machines, the way the molds fill with the material can greatly impact the size, strength, and appearance of the mold. This is called balancing, and with plastic injection molding, balancing is much easier and consistent making for a better part or product.

Plastic Molding is Easier to Assemble
Just as plastic is pliable, this also makes any plastic injection mold easier to assemble, which too helps make plastic molding less expensive than metal.

At Jingwei industry, our goal is to provide high-quality, cost-effective plastic injection molding. As a plastic injection molding manufacturer, we work to transform your design into a finished product and have over 15 years of experience successfully doing so.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

Manufacturing Plastic Injection Molded Parts with 100% Quality Assurance.

custom electronic switch

Jingwei industry has served the plastic injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.We can guarantee that only the highest quality plastic products are delivered to our customers.

Quality plastic parts from design, tooling ,manufacturing, assembly, and packaging.Jingwei industry uses injection molding to produce quality plastic parts. Injection molding is a manufacturing process that feeds melted thermoplastic polymer into a precision-machined steel or aluminum mold.

We can mold a wide range of part sizes, as our injection molding machines range from a 33 Ton 3 oz. to an 800 Ton 100 oz.

From our workshop,we process a wide variety of thermoplastic resins. They include filled and unfilled commodity and engineering resins such as polypropylene, polyethylene,polyolefins, polystyrene, nylon, vinyl, polycarbonate,ABS, PVC, PEI, PPO, and so on.

From part design and tool engineering through molding, finishing, and packaging, we create your parts with complete traceability. We have manufactured quality plastic parts for customers in the auto parts,medical equipment, sports industries,electronics industry,Home Appliance Parts,Housewares Parts and so on.

We inspect every plastic molded part multiple times to ensure satisfy your expectations.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com

History of Plastic Injection Moulding

The plastic injection molding has seen steady growth since its beginnings in the late 1800's.Today, plastic injection moulding is responsible for the creation of products for all industries,Such as Electronic industry,Automotive industry,Home Appliance Parts,Housewares Parts,Medical industry and so on,varied from buttons to parts for aerospace products. A versatile and incredibly useful process, plastic injection molding has paved the way for modern invention and design, and is something the world today could not function without. But Who invented it?Where did it originate?How did it catch on? You’re in luck, because all of those burning questions are about to be answered as we delve into its interesting history.
Origins
In 1868, perhaps in response to a request by billiard ball maker Phelan and Collander, John Wesley Hyatt invented a way to make billiard balls by injecting celluloid into a mould. By 1872, John and his brother Isaiah Hyatt patented the injection moulding machine. The machine was primitive yet it was quite suitable for their purposes. It contained a basic plunger to inject the plastic into a mould through a heated cylinder.
Evolution
Revolutionizing the plastics industry in 1946, James Hendry built the first screw injection moulding machine with an auger design to replace Hyatt's plunger. The auger is placed inside the cylinder and mixes the injection material before pushing forward and injecting the material into the mould. Today, almost all injection moulding machines use this same technique.
Modern Incarnations
Today, the product design of injection moulding machines is much sleeker, although the technology itself has not changed very much. With computer technology we are able to achieve more specificity through injection moulding, which is why it accounts for such a large range of products on the market today. In almost any shop or home in the world, you would be hard pressed not to find at least something that was created through the process of plastic injection moulding. It forms an integral part of today’s design and manufacturing industry.
Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

The Main Factors to Consider When Seeking a Plastic Injection Molding Manufacturer

Selecting the best plastic injection molding company from the suppliers out there can be a difficult task.There are several different types of companies, and many tend to specialize in certain industries or areas. To ensure you are able to determine which of the numerous plastic mold manufacturers is right for you, Let's take a look at how to find the best molding company for you budget by following these steps.

Your Needs

In order to begin evaluating plastic injection molding companies, it is important to know what you need them to mold for you. Specifically, you will need to have a fully defined 3D Model and engineering drawing of the plastic component you wish to have molded. Take the time to discuss the different options and specifications with the plastic mold manufacturer you consider. In order to ensure the injection molding company can offer the right services for your needs.It may take a while to discuss the process and requirements to ensure the manufacturer knows what you need.

Injection Mold Manufacturer's Reputation/history/ capabilities
If you prefer to consider a plastic mold manufacturer, looking over the online reviews and checking out their reputation can help you determine if they are likely to be a good fit. Calling the plastic mold manufacturer and asking questions of their customer service can give you a good feel for how well they relate to their customers.when evaluating a potential injection molding company, it is very important to learn about the history of the company and their capabilities. How long have they been in business and what industries do they typically mold parts for?

The Price
Once you are confident that a company is likely to treat you well, you should find out how much each company charges for their products. This is usually the first factor people consider, but if you take the time to learn about a particular plastic injection molding manufacturer, you will have more confidence in the price they quote.Based on the project your company is working on, determine if there are absolute restrictions on price as this will be important to know.
Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection molded parts.To know more,Please visit us at :jweimolding.com or via info@jweimolding.com.

How to choose the correct mold steel and gate type

Choose the correct mold steel:

The mold steel  mainly depends upon the annual shot quantity requirement. But it also depends upon part design and part plastic material.
For shot quantity requirements of less than 500,000 prehardened tool steel (called P20) is most commonly used for cores and cavities and the mould base.
Although mild steel could also be used for the mould base as well.This steel is cheap.
Also, aluminium is growing in popularity in the automotive sector.Aluminium is much easier to machine and handle compared with tool steel so the cost of manufacture is less.Cycle times are also better but mold maintenance is critical to ensure part quality – any build up of residue will damage the shut off surface and cause part flashing.
Anything above 500,000 the use of thru hardened tool steels such as H13 or H11 should be considered for the cores and cavities. These materials will produce quality parts for much longer than P20 or aluminium because mould wear is less.
For corrosive environments such as when molding PVC plastic, stainless steel tool steels can also be used in mold construction. Stainless steels will minimize corrosion.
In addition to the above, part design & mould design play a role in material selection. Some part designs will require moving or rotating components in the mold design. One option is to use nitriding steels so that “pick up” or damage does not occur when mould components move relative to each other. Examples of nitriding steels are P20 & H13.

Choose the correct gate type:

The type of gate depends upon a number of factors including the following:

1. Hot runner or cold runner? Both runners have a number of gate types to choose from. For example, commonly used gates for cold runners are tab, submarine and pin gates. For hot runners hot tip and valve gates.

2.Part material. Some plastic materials require a larger gate because they are shear sensitive (such as PET) than other materials so a large tab gate for a cold runner design or a valve gate for a hot runner design are often used. Pin gates or hot tip gates should be avoided with shear sensitive materials. 

3. The shape of the part influences the type of gate. For example, flat parts often use a tab gate. Flat parts can also use valve gates for hot runners and allow gating in the centre of the part (such as a lid) and leave a clean flat gate mark.

4. Part cosmetic requirements. Some gates are designed to leave minimal gate vestige such as a submarine gate.
Finally, the type of gate used is very dependent on the application. Every part has different requirements so each one must be studied on a case by case basis.

Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing plastic injection mold.To know more,Please visit us at :jweimolding.com  or email us :info@jweimolding.com

Common Injection Molding Defects And How To Fix Them

Injection molding is a complex technology with possible production problems. They can either be caused by defects in the molds or more often by part processing (molding).Here are some Common Injection Molding Defects :

Molding Defects	Alternative Name	Descriptions	Causes
Blister	Blistering	Raised or layered zone on surface of the Plastic part	Tool or material is too hot, often caused by a lack of cooling around the tool or a faulty heater
Burn marks	Air Burn/Gas Burn	Black or brown burnt areas on the plastic part located at furthest points from gate	Tool lacks venting, injection speed is too high
Color streaks (US)		Localized change of color	Plastic material and colorant isn't mixing properly, or the material has run out and it's starting to come through as natural only
Delamination		Thin mica like layers formed in part wall	Contamination of the material e.g. PP mixed with ABS, very dangerous if the part is being used for a safety critical application as the material has very little strength when delaminated as the materials cannot bond
Flash	Burrs	Excess material in thin layer exceeding normal part geometry	Tool damage, too much injection speed/material injected, clamping force too low. Can also be caused by dirt and contaminants around tooling surfaces.
Embedded contaminates	Embedded particulates	Foreign particle (burnt material or other) embedded in the part	Particles on the tool surface, contaminated material or foreign debris in the barrel, or too much shear heat burning the material prior to injection
Flow marks	Flow lines	Directionally "off tone" wavy lines or patterns	Injection speeds too slow (the plastic has cooled down too much during injection, injection speeds must be set as fast as you can get away with at all times)
Jetting		Deformed part by turbulent flow of material	Poor tool design, gate position or runner. Injection speed set too high.
Polymer degradation		polymer breakdown from oxidation, etc.	Excess water in the granules, excessive temperatures in barrel
Sink marks		Localized depression (In thicker zones)	Holding time/pressure too low, cooling time too short, with sprueless hot runners this can also be caused by the gate temperature being set too high
Short shot	Non-Fill/Short Mold	Partial part	Lack of material, injection speed or pressure too low
Splay marks	Splash Mark/Silver Streaks	Circular pattern around gate caused by hot gas	Moisture in the material, usually when resins are dried improperly
Stringiness	Stringing	String like remain from previous shot transfer in new shot	Nozzle temperature too high. Gate hasn't frozen off
Voids		Empty space within part (Air pocket)	Lack of holding pressure (holding pressure is used to pack out the part during the holding time). Also mold may be out of registration (when the two halves don't center properly and part walls are not the same thickness).
Weld line	Knit Line/Meld Line	Discolored line where two flow fronts meet	Mold/material temperatures set too low (the material is cold when they meet, so they don't bond)
Warping	Twisting Part	Distorted part	Cooling is too short, material is too hot, lack of cooling around the tool, incorrect water temperatures (the parts bow inwards towards the hot side of the tool)

Keep these factors in mind when designing your plastic injection molded parts, and remember that it is easier to avoid problems in the beginning than change your design down the line.Jingwei industry has served the injection molding industry for over 15 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing .To know more on Build a Precision Mold for Custom Plastic Parts,Please visit us at :jweimolding.com  or via:info@jweimolding.com