The Evolution of Mold Making Technology

Mold making is a process of making injection molds that are used to produce hundreds of or thousands precision plastic parts. As one of the most significant production investments, it is critical that the molds are made with a great deal of accuracy. Modern mold making requires extreme precision to ensure that parts can be mass-produced with repeatable accuracy.
This perfection is also required in the creation of the tools used to manufacture, hold, or test products during production. Quality precision molds are built to last and represent an essential investment for any company. Variables that can impact the cost of the plastic injection mold include:
. Core Metal
.Number of Cavities
.Mold Base
.Core/Cavity Machining
.Part Complexity
What Has Changed?
Plastic injection molding first gained prominence during the 18th and 19th centuries. With the Industrial Revolution at its peak, toolmakers had to do most everything by hand. Forming tools, heat treating, sharpening, machining metal, and drilling out the design by hand required a significant time commitment.
Due to the uniqueness of anything made by human hands, conformity problems often arose, and no two molds were precisely the same.Now, Computer Numerical Controlled (CNC) milling machines offer so many kinds of tools for cutting that the simple term and concept of “mold making” no longer covers the full gamut of the current capabilities. Today’s technology enables the fabrication of items with much more accuracy and range than ever before. The process is more precise than manual machining, and can be repeated in exactly the same manner over and over again. Because of the precision possible with CNC Machining, this process can produce complex shapes that would be almost impossible to achieve with manual machining.
The use of CNC machines not only speeds up the process but also offers a wide degree of flexibility. Computers can often be programmed to work overnight, providing around-the-clock production. Using computer-generated inputs, CNC machining are able to deliver precision, accuracy, and levels of consistency that manual machining could never before offer.
Working with Jingwei molding
Jingwei molding provides innovative manufacturing solutions that include mold design, mold building, and high-volume parts manufacturing. We are world renowned for the production of injection molded components of the highest quality and precision at highly competitive prices. From concept to completion, we provide all of the necessary resources to promptly and accurately complete your project. We serve industries ranging from consumer products and construction to auto , medical and pharmaceutical, and electronic and other custom plastic parts.



Jingwei molding has more than 15 years experience in plastic injection molding and mold making. Your High Volume, Custom Plastic Parts Injection Molding Specialist. To learn more about our manufacturing capabilities and discover what makes us different, please visit our website: :jweimolding.com . If you're ready to jump into your next project with us, request a quote . No matter your need, contact us today so we can help your business face all of the changes and challenges of today's competitive marketplace.

8 Steps to Injection Molding Process Optimization

When making decisions about process optimization, tool engineers and process engineers work together to proactively identify and correct any tooling weaknesses, following these 8 steps:

1. TOOL FUNCTIONALITY EXAMINATION 
Every aspect of the tool's mechanical functionality is assessed to make sure everything works as designed, using the material settings provided by the supplier of the material to be molded.

2. SHORT SHOT TESTING
Dynamic pressure loss and, in a multiple-cavity tool, cavity imbalance are determined and documented using sample parts. Also, the rheology curve (or viscosity curve) is established to indicate the best fill rate and pattern.

3. GATE SEAL STUDIES
Both the pressure curve and weight of the sample parts are observed to see if the gates fully seal and at what point sealing occurs.

4. SAMPLE PARTS EVALUATION/DATA RECORDING
All defects are examined and recorded, along with recommendations for any adjustments in the process or the tool in order to correct the defects. Likewise, data is recorded with regard to melt temperature, fill time, tool temperature, coolant flow, cycle time and pressure curves.

5. QUALITY CONTROL
The sample parts go to quality control for examination and documentation of their measurements, shot-to-shot consistencies and overall quality.

6. TOOL ADJUSTMENTS
Based on information gathered during quality control, necessary tool adjustments are made, and new sample parts are made.

7. NEW SAMPLE CREATION/QUALITY CONTROL TESTING
The new sample parts are subjected to the same quality testing and more adjustments are made, if necessary.

8. PROCESS PARAMETER/PERFORMANCE RANGES VERIFICATION
The quality testing and adjustments continue until all process parameters meet their performance ranges. Once verified, the tool is ready for use and the process is deemed optimized.

By leveraging scientific molding, experienced custom injection molding engineers understand each phase of development — from tool design and mold fill analysis to process monitoring and quality control. The result? The most efficient and robust process possible for manufacturing the complex injection molded plastic parts and products you need for complex applications from medical devices,  electronic parts to automotive parts and other custom plastic parts.

Jingwei molding has more than 15 years experience in plastic injection molding and mold making. Your High Volume, Custom Plastic Parts Injection Molding Specialist.Any questions,please feel free to contact us via info@jweimolding.com or visit us at :jweimolding.com

INJECTION MOLDING PROCESS STEPS

In broadest terms, the injection molding process can be broken into three steps:

1. PRODUCT DESIGN
Determining product objectives such as function, aesthetics, assembly, etc., and the requirements for accomplishing the objectives. A team of engineers specially trained in advanced methodologies such as Design for Manufacturability (DfM) is assembled to identify and possibly improve upon solutions to meet the particular project requirements — including the selection of materials for the final complex injection molded part and the tool.

2. TOOL DESIGN
Like product design, a thoughtful approach to tooling proves valuable. In addition to choosing the appropriate material for tool construction — hardened steel, pre-hardened steel, or aluminum — designing for proper gate location, draft, etc., is necessary to prevent costly project missteps.

3. MANUFACTURING
Production is the obvious goal of the step-by-step injection molding process. Achieving successful outcomes brings together the product and tool designs with resins that deliver to project needs (such as strength, heat tolerances, sterility, etc.) and moldability requirements including tight tolerances, uniform wall thickness, heating, cooling, and consistent repeatable cycling.


Jingwei molding has more than 15 years experience in plastic injection molding and mold making. Your High Volume, Custom Plastic Parts Injection Molding Specialist.Any questions,please feel free to contact us via info@jweimolding.com or visit us at :jweimolding.com

Top 15 Benefits of Plastic Injection Molding

Are you considering injection molding for the production of a current or upcoming plastic parts project? If so, you came to the right place. Injection molding is the ideal process for the production of a wide range of complex plastic components, and can benefit OEMs across many different industries. It’s consistent, affordable, and creates durable, high-quality plastic parts that can withstand just about any environment.
To understand how injection molding can really help today’s manufacturers, here are the top 15 benefits to utilizing the process :
1. ABILITY TO PRODUCE DETAIL/COMPLEX GEOMETRY
With the right tool design and a scientific molding approach to process optimization, injection molding can help manufacturers produce highly complex, detailed plastic parts.
2. HIGH-OUTPUT PRODUCTION
If you need to produce a large run of a single part/component, the injection molding process is ideal, as it ensures a consistent, repeatable design due to all parts being created from the same mold.
3. COLOR CONTROL
From clear to magenta, whatever color you need your plastic to be, injection molders can make it happen—even including multiple colors in one product when two-shot or overmolding processes are used.
4. FINAL FINISHES
Does your plastic part require a smooth finished appearance? Most parts come out of the mold with a smooth surface finish very close to their final look. Even if you aren’t going for a smooth appearance, you’re still in luck, as injection molding allows for many surface finishes that don’t require secondary operations. From matte finishes and unique textures to engraving, injection molding can provide the desired plastic parts you’re looking for.
5. COST SAVINGS
There are several ways that injection molding can help OEMs experience lower costs, from plastic part consolidation to overmolding. However, the number one way the process leads to low-cost outcomes is by significantly reducing the number of problems in, or increasing the moldability of, the part design before production starts—minimizing the need for expensive tooling changes down the road.
6. PRECISION
For OEMs with complex part designs requiring tight tolerances, injection molders can achieve designs accurate to within +/- .001 inches.
7. EFFICIENCY
If you partner with a sophisticated injection molder, you’ll be working with a team that likely has decades of experience under their belts. This means they know exactly how to optimize design and manufacture your components in the most efficient way possible, and focus on the design upfront to minimize problems down the road.
8. STRENGTH
The strength and durability of plastics has greatly increased over the years, and today’s lightweight thermoplastics can withstand even the most rugged environments. There are many types of engineering grade plastic to choose from, allowing OEMs to find exactly the right options for their applications.
9. PRODUCT DEVELOPMENT TIMELINE
From upfront design support to mold flow analysis software, injection molding can help OEMs achieve a shorter product development timeline, in turn speeding time to market.
10. ABILITY TO SIMULTANEOUSLY USE MULTIPLE TYPES OF PLASTIC
It’s not uncommon for complex part designs to require components made of different materials. Plastics expertise from the molder’s project engineers can help ensure that different polymers are compatible under all conditions to help reduce defects.
11. PRODUCT/PART CONSISTENCY
The production of plastic components for critical-use applications requires a consistent, repeatable process to achieve complex designs with tight tolerances. Injection molding helps ensure a consistent quality by repeatedly using the same mold for each part, and using scientific molding sensors to monitor the activity inside the mold.
12. FLEXIBILITY
Injection molding is all about flexibility. Whether we’re talking about the plastic properties themselves or your ability to be flexible in your color choices and material selection, injection molding gives OEMs lots of freedom with their design choices — especially when compared to metal.
13. LOW LABOR COSTS
Much of the injection molding process is automated by machines and robots, and controlled by a sole operator or mold technician. This keeps labor costs to a minimum and passes on savings to the customer.
14. LIGHT WEIGHTING
From the automotive industry to military applications, many OEMs are turning to plastic to help reduce the weight of their products. Today, high-strength, lightweight thermoplastics can be used to replace metal components with virtually no difference in strength or dependability.
15. REDUCED WASTE
Using plastic regrind can even help OEMs save on money and materials.
Jingwei molding has more than 15 years experience in plastic injection molding and mold making. Your High Volume, Custom Plastic Parts Injection Molding Specialist.Any questions,please feel free to contact us via info@jweimolding.com or visit us at :jweimolding.com

How To Estimate Weight Of An Injection Mold Tool

For those of you who do not have scales here is an easy way to find mold weight.
Calculation For Metric Units (cm)
Measure overall dimensions of the mold.
Refer to above image of mold for length, width & height.
For example:
If Length=80cm Width=90cm Height=45cm
and Weight(kgs)= Length*Width*Height*DensityOfSteel where density is 7.9 grams/cm^3 for tool steel (P20,H13)
then Weight(kgs)= (80*90*45*7.9)/1000= 2,560 kgs
Calculation For Imperial Units (Inches)
Measure overall dimensions of the mold.
Refer to above image of mold for length, width & height.
For example:
If Length=25 inch Width=35 inch Height=20 inch
and Weight(lbs)= Length*Width*Height*DensityOfSteel where density is 0.28 lbs/inch^3 for tool steel (P20,H13)
then Weight(kgs)= (25*35*20*0.28)= 4,900 lbs
All calculations & technical data are for comparison purposes only and are NOT for design or safe working practices. It is derived from sources that we believe to be accurate, but can NOT guarantee its validity. Your specific application should NOT be undertaken without independent evaluation for accuracy.
Bring Your Custom plastic injection mold/molding Project to The JW industry ,we have access to resources that help reduce production costs even further. We proudly offer a total concept solution from design and tooling to material selection, production, and fulfillment .Contact us today to request a free quote and find out how our industry experience and expertise will benefit you with your next project.

Tips for achieving tight tolerances in injection molding

When it comes to designing and launching a new product or component, there are three things design engineers can always count on:

• The design is the driving factor behind the success of the product or part and its performance
• If something goes wrong, the design should be the first place you look
• The importance of design is magnified considerably with tight tolerances

As you can see, there’s a lot riding on designers to develop complex plastic parts and products with tight tolerances, especially when they’re used in medical, automotive, or defense applications. There’s no room for error when designing these critical-use parts, especially when the margins are as slim as +/- .001 inches.
In order to ensure those tolerances are met, it’s crucial that you get control of them early on in the design phase, and to help you do that – as well as take some pressure off designers – here are some tips for achieving tight tolerances in injection molding.
It Starts with Design
Identifying tight tolerances early in the design phase is key, because design engineers must factor in requirements for part geometry, overall size, and wall thickness – all of which have an influence on tolerance control.
If your design has thick walls, for example, they may have differential shrink rates within the thick sections, making it difficult to hold tight tolerances since the variable shrink can “move“ within the section. Likewise, when it comes to part size, the larger the dimension; the harder it is to hold tight tolerances. A larger dimension also equates to larger shrinkage, which makes it more challenging to maintain and control it.
Pay Attention to Complexity
Another major factor in the design phase is the complexity of the part or product. When done right, that complex design can help aid in the control of tight tolerances. However, common issues with complex designs include shrinking and warping. If the part has too much shrinkage or warpage, the molding process may not be repeatable. That's why it’s absolutely essential for the product design and manufacturing teams to be on the same page.
Also driving the success of managing tight tolerances is the ability to fill cavities quickly, maintain proper cooling temperature, and manage the overall cooling process – which all revolve around tooling design and material flow. Moldflow analysis is critical here, as it can accurately predict mold heating and cooling, as well as shrinkage and warpage. By taking this Design for Manufacturability (DfM) approach, designers can do what’s needed for optimal
control.
Environment Impacts Tolerance
When designing your part or product, it’s critical that your designers have a clear understanding of the environment where the part or product will be used.
Why is this so important? Because the environment influences the behavior of plastic, which in turn, affects tolerance. To better illustrate, consider that plastics typically have large thermal expansion coefficients. That means parts may have to be measured at a consistent temperature to ensure accuracy in determining the part’s ability to maintain a tight tolerance.
For example, if the part or product will be exposed to temperature extremes during normal operation, it will expand and contract. Knowing this beforehand might mean exploring alternative options to a tight-tolerance part or product, and save designers a lot of headaches. This is why it’s so important to consider temperature in the design phase.
While the tips above provide a good start, there’s much more to the success of tight tolerance parts or products than the design alone. While it’s the obvious place to start since design plays a major role in the overall success of a project, it’s always a good idea to get up to speed on other factors involved in working with tight tolerances, ranging from material selection to tooling, and even process design and control.
Jingwei industry has served the electronic industry for years develop and manufacture parts and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing injection molded plastic medical parts . visit us at :jweimolding.com Or contact us via info@jweimolding.com for your project.

Introduction to Injection Molding

Injection molding is going be a big part of your journey to market. Regardless of your technical background you at least need to understand injection molding at a basic level.3D printing is the technology used for prototyping plastic parts, injection molding is the technology used for manufacturing.

Basics of Injection Molding

Injection molding is an ancient technology that has been used since the late 1800’s. Injection molding machines incorporate a huge screw to force molten plastic into the mold at high pressure. This screw drive method was invented in 1946 and is still the method used today.
An injection mold consists of two halves that are forced together to form a cavity in the shape of the part to be produced. Hot, liquid plastic is then injected at high pressure into this cavity.
The high pressure is needed to ensure that the plastic resin fills in every crook and cranny of the mold cavity.
Once the plastic has had time to cool, the two halves of the mold are pulled apart, and the part is ejected.
Although designing for injection molding can be quite complicated, and the cost of the molds themselves are incredibly expensive, there is one huge reason why injection molding is still used today.
No technology can beat injection molding when it comes to producing millions of identical copies of a part at an incredibly low price.

Cost of Molds

Injection molds are expensive, and you’ll most likely need a few of them, so their total cost can be quite significant. The more parts you need to produce with the mold the more expensive the mold.This is because the mold must be designed to withstand incredibly harsh conditions. Over and over again a mold is subjected to high temperature and high pressure.These two destructive forces act to quickly degrade the molds to the point of not producing parts of sufficient quality.
In order to tolerate this harsh environment injection molds are made from hard metals. The hardness of the metal required is typically determined by how many parts you plan to produce with the mold.
For example, a mold designed to produce 10,000 parts can be made of a much softer metal than a mold designed to produce 1 million parts.
Aluminum is a popular choice if you are producing less than 10,000 parts and works well for low volume production. Once you reach higher production volumes you will need to switch to a harder metal such as steel.
The harder the metal, the more difficult it is to make the mold, so the higher the cost. It also takes much longer to produce a mold from a hard steel. This is because molds are created by milling so a hard mold requires even harder milling tools.

Design for Manufacturing

The high cost of the molds is only one of the issues with injection molding. The other downside to injection molding is that it greatly complicates, and restricts the actual design of your plastic pieces.
Once you have a perfectly working prototype from a 3D printer, you then have to spend significantly more time and cost making it work for injection molding.
Keep in mind that you should design your plastic parts for injection molding from the beginning. Some requirements of injection molding, such as draft, can be delayed at least until your second prototype.
But other requirements, such as uniform wall thickness and undercuts, need to be implemented from the very start.
Draft
A main issue with injection molding is that your plastic parts have to be removed from the mold. Once the plastic has cooled, the two halves of the mold are opened and the newly formed plastic piece is removed.
For example, any 3D design for injection molding must incorporate draft. Draft simply means adding a slight angle to any surfaces that are parallel to the direction the part is pulled from the mold. In most cases 1 to 2 degrees is sufficient.
Some experts will tell you that you should include draft in your 3D model from the very start.
While I agree that incorporating draft is important to do early in the development process, I’ve found that it creates unnecessary complications with your first few prototypes.
I generally recommend adding draft once you have a high degree of confidence in your prototype. For most products this means adding draft after the first or second prototype version.
Ejector pins
Ejector pins are used to remove the plastic parts from the mold. As the name implies, these are small cylindrical pins which push outwards to eject the part from the mold.
The location of the ejector pins is not trivial so you need to give some thought to their placement. Ideally, you want them to be located where your part is structurally strong to prevent the part from warping on ejection.
Secondly, the ejector pins tend to leave small marks on the product where they make contact. If you look closely at most plastic parts you will be able to see these tiny, circular indentations from the ejection process.
You want to design your product with this in mind. Strive to have these pins make contact with the part in places that are not critical for the appearance of your product. You may even try to hide the ejector pin marks under a label or logo.
Side actions
If you are unable to easily remove your plastic part from a simple two-piece mold you can use something called side actions.
Side actions are parts of the mold that are inserted during molding, then pulled out before the main mold sections are pulled apart. Their direction of movement is perpendicular to the pull director of the two main mold halves.
Try your hardest to avoid needing side actions, since they add considerable cost and complexity to the molds.
One of the main ways to eliminate side actions is by avoiding the design of undercuts. An undercut is a feature that prevents the part from being removed from the mold with a single pull.
Many times placing a slot underneath the feature will allow the use of a single pull mold instead of requiring side actions.
Uniform wall thickness
One aspect of injection molding that has a huge impact on your product design is the requirement for uniform wall thickness.
After injecting plastic into the mold it is essential that the plastic cools at a uniform rate. If cooling isn’t uniform the part may warp.
Therefore, when designing products for injection molding it’s key to use ribs instead of thicker sections. Designing a part that keeps a uniform wall thickness definitely takes some experience to do correctly.
Two of the most common errors made by 3D designers who don’t understand injection molding are using non-uniform wall thicknesses and requiring the use of side actions.
So make sure whoever does your 3D design knows not to make these rookie mistakes.
Radius/chamfer corners
Perfect corners and edges are not practical to achieve with injection molding. The hot resin simply can’t be forced with enough pressure into the mold to perfectly fill sharp edges. At least, not reliably over large production volumes.
Therefore, all edges and corners should be either rounded or chamfered to allow the resin to fill them more uniformly and consistently.
Cold runners versus Hot runners
Runners is the term used for the channels incorporated into a mold for the hot resin to travel through to reach each cavity.
Larger runners allow the resin to flow more easily and at lower pressures. However, large channels require more time to cool and create more scrap, both of which impact the part cost.
Smaller runners, on the other hand, minimize cooling time, scrap, and ultimately part cost. The downside to small runners is the higher pressure required to force the hot resin to flow through them.
A solution that facilitates the use of small runners while also minimizing the required pressure is to use what are known as hot runners.
Small heating elements are incorporated into the mold near the runners so as to keep the resin more molten allowing it to flow more easily at lower pressure.
Nothing is ever free though, and the downside of hot runners is the additional mold complexity which always translates into additional costs.
In most cases, at least initially, you are best off using only runners without heating elements which are referred to as cold runners. Remember, always start with the simplest, lowest cost solution.
Small heating elements are incorporated into the mold near the runners so as to keep the resin more molten allowing it to flow more easily at lower pressure.
Nothing is ever free though, and the downside of hot runners is the additional mold complexity which always translates into additional costs.
In most cases, at least initially, you are best off using only runners without heating elements which are referred to as cold runners. Remember, always start with the simplest, lowest cost solution.

Single-cavity / Multi-cavity

You can eventually decrease your molding time by using multiple cavity molds. This serves to increase your production speed and reduce your manufacturing part cost.
Multiple cavity molds allow you to produce multiple copies of your part with a single injection of plastic. But don’t jump into multiple cavity molds until you have worked through any tweaks or changes to your initial molds. It is wise to run at least several thousand units before upgrading to multiple cavity molds.
Entrepreneurs with a limited budget will want to maximize the use of single cavity molds unless you have a manufacturer financing your mold costs.

Family molds

In most situations, you will need a separate mold for each custom plastic piece required for your product. At a minimum you’ll need at least two pieces: a topside and a bottom side.
But many, if not most, products require more than just two pieces of plastic. Molds are very expensive so the cost to purchase multiple molds is a huge financial obstacle.
You should always strive to design your product to minimize the number of unique custom plastic pieces required.
Another option to reduce the number of molds needed is through the use of a special type of multi-cavity mold called a family mold. A family mold allows you to consolidate multiple molds all into a single mold.
Whereas a typical multi-cavity mold creates multiple copies of the same part, a family mold creates different parts at one time.
Sounds great doesn’t it? Unfortunately, nothing is ever easy and every solution has tradeoffs. The main issue with family molds is they require each part to be pretty much the exact same size.
Otherwise, one part will fill up with resin before the other cavities. A family mold must be designed so all of the cavities fill up with resin at nearly the same rate.
That obviously limits their usefulness since it’s unlikely that all of the pieces needed for your product will be the same size.

Material selection

There is an incredible variety of plastic resins at your disposal each with its own characteristics. Two of the most commonly used resins for hardware products are Polycarbonate (PC) and acrylonitrile butadiene styrene(ABS).
Polycarbonate has a much higher impact strength and has a much higher-quality appearance compared to ABS. However, PC is of course more expensive than ABS.
Polycarbonate is the most popular plastic used in higher end hardware products because of its higher impact strength and its better aesthetics.
If appearance is critical for your product then PC is most likely the way to go. If your product is low-cost then ABS may be the best choice.
Bring Your Custom plastic injection mold/molding Project to The JW industry ,we have access to resources that help reduce production costs even further. We proudly offer a total concept solution from design and tooling to material selection, production, and fulfillment .Contact us today to request a free quote and find out how our industry experience and expertise will benefit you with your next project.