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.