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

How to Manufacture the Perfect Plastic Parts

A precision plastic part begins with a precision mold. Building the tool takes time and a great deal of accuracy. So, if your business doesn’t have the skill or capability to make quality precision molds in-house, the most important step your business can take toward ensuring product quality is to partner with an experienced and capable turn-key manufacturer that can.

There are a number of factors to consider when discussing precision molding. Let’s take a more in-depth look at each step of the precision mold-making process.

Time, Commitment, Teamwork

Perfect precision molds are not made overnight. A lot of hours go into testing and planning a mold, before it is fully realized. Creating a high-performing, quality mold takes teamwork—and a lot of it. Partnering with an experienced precision mold manufacturer is the easiest way to avoid many of the common problems that inexperienced precision molders face.

A turn-key manufacturer will provide you with the complete package. Unfortunately, a lot of businesses make the mistake of separating the main tasks that need to be accomplished to make a precision mold. They will hire one company to design the mold, another company to manufacture the mold itself, and yet another company to run the actual parts. This practice leads to less overall accountability, control, and general product quality. It is not impossible to get a good mold made in this manner, but it is certainly a lot harder and if something goes wrong, it’s difficult to determine who or what is to blame.Jingwei industry have more than 15 years experience in Plastic injection molding and have innovative solutions based on a varied industry experience.

Design

This is the very beginning of the precision mold process, and this is where most of the problems can occur if you don’t know what you’re looking for. That’s where the professionals come in. Even if you already have detailed blueprints or a prototype in place for your mold, you need to know how to optimize your design so you can avoid the costly delays caused by potential defects. Your mold needs to be able to perform at the highest level of production standards, so you can ensure the quality and consistency of your products.

Selecting Resin

Once you have your design perfected, you will need to choose the right resin for the job. Thanks to advances in polymer sciences there are a lot of different options to choose from when selecting a resin for your mold. One of the most important things to consider is whether or not the resin you choose is compliant with the regulations specific to your industry. Second, you need to know how your mold will be used and what kind of resin will be best for your target application. Consulting with an expert can help you make a more confident and informed decision.

Testing

Before the mold is used in mass production it is important to make sure that everything is in order and to specification. Pre-production testing and mold building ensures that the design is not only perfect, but also that the resin and finish selected is what you have envisioned for the final product. This stage of the process gives you the chance to see the final product and make any necessary adjustments before it goes to production.

Making perfect precision molds is a complicated, but important, process. It is a smart decision to partner with a manufacturer that has industry experience and can help you through each step of the process, from the initial design to mass production.

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 medical instrument parts.To know more on Build a Precision Mold for Perfect Parts,Please visit us at :jweimolding.com or via info@jweimolding.com

Advantages of plastic medical device

Using plastic medical instruments called a major initiative of the medical profession.Medical instrument market demand potential is so great,Why largely because of its advantage following aspects:

1, Light weight,help reduce fatigue caused by surgery doctor for a long time. More suitable for human blood and muscle tissue, so the more effective.
2, Toughness is good, anti-permeable, durable, plastic parts can also be used normally at high temperatures.
3, Transparent , medical procedures can be better observed, especially during surgery.
4, Easy to molding, suitable for the production of a variety of shapes, complex medical equipment and supplies, and simply use the low-cost production process.
5, More secure, especially as packaging material.

Aging population will up medical instrument quantity demanded

With the increase of the proportion of population growth and an aging population, the demand for plastic medical instrument continued to expand. The use of medical instrument to diversify from a single, volume size is shrinking, now one can replace equipment more than the previous equipment. Because many outstanding advantages of plastic medical equipment, pharmaceutical industry in the future course of development, its market share and influence will grow.

Jingwei industry has served the plastic 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 medical instrument parts.To know more on Build a Precision Mold for Perfect Parts,Please visit us at :jweimolding.com