What is Two-Shot Molding?

 

Definition

Two-shot molding, also known as dual-shot, multi-shot, or double-shot molding is a subcategory of injection molding that allows engineers to create multi-material or multi-colored parts without adding extra assembly steps.

The two-shot injection molding process is best understood in terms of the different layers of materials or colors that are created by the injection molding machine. The first material is injected into a mold to create the substrate, around which the other material or materials will be molded. The substrate solidifies and cools before being transferred — by hand, robot arm, or rotary plane — to the other chamber of the mold.

From there, the mold opens and the side with the substrate rotates 180° to meet the other mold chamber and injection molding nozzle. Once the substrate is in place, the second material is injected and bonds with the substrate to form a firm hold.  Once the second layer cools, the final part is ejected.

Engineers should know that two-shot injection molding can be sped up or slowed down based on how the substrate is transferred to the other chamber of the mold. Hand and robot arm transfers take longer than a rotary plane, but rotary platen molding is more expensive and generally only an efficient option for high-volume production runs.

Additionally, it’s critical that molds are made out of materials that will easily bond together and that the molds align correctly to prevent deformities in the part.

Pros and cons of two-shot molding

Two-shot plastic injection molding is an excellent technique for efficient and cost-effective manufacturing. This process also produces highly durable end parts and components.

From a design standpoint, two-shot molding offers designers a lot of flexibility because this process can create complex geometries and accommodate multiple colors, making for more aesthetically pleasing parts.

Further, since one machine makes the whole part and no post-processing is required, engineers can dramatically reduce manufacturing time, which in turn keeps costs low. However, it’s worth noting that the initial two-shot mold costs can be high and the two-shot molding machine is more expensive than a standard injection molding machine. Luckily, these costs are often offset by labor savings and assembly costs on large production runs.

 

We are a TWO SHOT INJECTION MOLDS manufacturer, please contact us if you need them!

Just How Tolerances Influence Injection Molded Plastics?

 

What Is Tolerance?

The tolerance stated in the plastic injection mold is an engineering requirement. In basic terms, they are allowable variants to the initial dimensions of the parts or the base dimension. As it is impossible to generate a product that purely abides by the base measurements, some leeway obtains factored into the design of items.

This margin ensures that all measurements for molded products fit the setting up demands. For example, you may wish to produce products with a size of 2.8 mm. Nevertheless, attempting to produce them might end up with some of them gauging 2.6 mm.

What tolerances do is to establish minimum as well as optimum values for the production process in a way that ensures the product fits. In this case, the reduced limit can be evaluated 0mm while the ceiling is readied to 0.3 mm. By doing this, you are assured products whose diameters range between 2.8 mm and also 3.1 mm.

The important of tolerances

Generating plastic parts for your products calls for that their measurements fit perfectly. It’s very easy to offer dimensions for the type of components you want; obtaining them to have similar measurements to your requirements is a virtually impossible venture to achieve.

The type of making procedure you go for also has a terrific bearing on the high quality of completion product. Injection molding is among the most effective processes you can experience with standards like hubbub 16901 to name a few, but it’s still unable to produce parts with the right fit.

The only escape of such a scenario where it’s impossible to get an exact suit is to leave area for some distinctions in dimension. They don’t need to be major; they simply require not interfere with the item style. This is where tolerances are available in.

What Influences Tolerance?

The kind of polymer utilized throughout the creation of your items substantially identifies whether the tolerances are within acceptable limitations. As distinct polymers obtain injected into the plastic mold, they cool as well as shrink at different prices.

Despite the fact that these shrinkage rates can be quickly represented, completion product will certainly have different tolerance ranges and also discrepancies from the acceptable varieties. The array is a dimension of the difference between the biggest as well as tiniest measurements of measurements in the created batch.

Various other aspects that figure out tolerance consist of the style of the product, the intricacy of the style along with the atmosphere the injection molded parts will certainly be running in.

Minimum/Good Tolerances for Plastic molds

The great, or rather, minimal tolerances are established by the plastic polymer you choose to use for your products. These tolerances also can be found in various forms. For one, there are dimensional, straightness/flatness, and also hole diameter tolerances. They are also divided right into business tolerances and precision tolerances, which are greater in price.

Considered that an injection-molded physical tightening is a result of the cooling, the facet of temperature level decrease is influenced by various other aspects as well. They include the thaw thermal reading, the cooling price, the thickness of the part, the dimensions of eviction, as well as much more.

Furthermore, a section of the molded product that is thicker than an additional will certainly experience even more shrinking. All these variables are since even though it is possible to forecast the behavior of the plastic polymer you wish to be molded; the material will never ever act as anticipated 100% of the time.

The polymer concerned might likewise experience warpage. This is particularly real with parts that are non-uniform as they shrink at various rates in comparison to components that have uniform wall surface thickness. These non-uniform components can happen whenever the part’s design has a concern.

The final words

WIT MOLD has become one of the best molds in the industry because we combine the essence of the latest technology with proven traditional methods.

With an expert team composed of experienced and knowledgeable experts, we are able to complete custom orders for Custom Plastic Molds and parts that may exceed the capabilities of our competitors. We are also unremittingly committed to improving customer satisfaction, which includes providing comprehensive end-to-end quality assurance for every product we produce.

Structural Foam Forming: Frequently Asked Questions

What is structural foam forming?

Structural foam molding is a process most commonly used to produce large structural parts. Structural foam molding tends to produce thicker walls than other injection molded parts; as a result, structural foam molded parts have a strong and durable surface. During structural foam molding, an inert gas (usually nitrogen) is mixed with the plastic material before it is injected into the mold. As the material is injected into the mold, the gas expands and the plastic hardens as it comes into contact with the cold mold cavity. This process allows for the manufacture of durable products at lower pressures than are typically required using other injection molding processes.

 

What are the advantages of structural foam molding?

Increased strength and stiffness. The honeycomb structure within the parts gives them a very high strength-to-weight ratio and stiffness-to-weight ratio.

No shrinkage on thick parts. You can break a lot of old rules of thumb about part thickness. This gives you the opportunity to make thick, complex parts without dents.

Low stress and warpage. The low-pressure process eliminates these problems.

Superior impact resistance. This is again due to the honeycomb structure.

Sound insulation and electrical/thermal insulation properties. Due to the tiny air pockets within the part.

Lower cost aluminum tooling. Excellent aluminum results due to the use of lower pressures.

Faster cycle times. This is due to the better heat transfer of the aluminum mold.

Lower material costs. Recycled post-consumer materials can be used in the process and the parts produced can be recycled.

Attractive surface characteristics. Parts have a consistent surface finish to get the texture you want.

Excellent substitute for other materials. Parts can replace a wide range of materials, from concrete to sheet metal to fiberglass to wood.

Long tool life expectancy. Despite the use of aluminum tools, it typically lasts as long as steel due to the lower stresses used.

 

Are there disadvantages to structural foam molding?

No injection molding process is perfect, and structural foam molding does have some drawbacks. The process itself takes longer, which means you will have to invest more time in producing structural foam molded parts. Before choosing structural foam molding, it is important to consider how these additional production times will affect your overall performance and productivity.

 

Have more questions about structural foam molding?

If you have more questions about structural foam molding, be sure to get the answers you're looking for from WIT MOLD. We are injection molding and engineering experts with extensive experience in handling a variety of injection molding processes. To get answers to all your injection molding questions and start using our services, contact WIT MOLD today.

 

What Are The Advantages Of Gas Assist Molds?

 

 

Gas assisted injection molding is a process for producing big plastic to get rid of complicated designs as well as excellent ornamental surface area coatings. Continue reading to get more information about the advantages of gas assist molds.

Smooth surfaces

 

Gas assist injection molding likewise produces much smoother surface areas to attain the preferred style. After the plastic product has currently been expelled from the machine, it can already be fit for market distribution with really couple of alterations or secondary procedures needed.

With a smoother surface, producers do not need to make changes to the device– i.e. lowering stress, temperature level, and even the place of the gates. This is since gas assisting can already fix many of the problems that may result on the surface of the plastic. Smoother surface areas use a more aesthetically appealing as well as smooth design.

High functionality

 

In the regular injection molding process, there is no gas channel to transmit a low-pressure nitrogen liquid. This suggests that the process may take a lot longer time because there is no element that is quickening the flow of the material into the mold. As a result of the absence of this part, the material can be prone to bending as well as higher inner stress.

With gas-assist, nevertheless, internal stresses are substantially minimized in the resin, leading to a much faster and freer-flowing product. Integrated with properly maintained mold and mildew dental caries, any kind of product resulting from gas-assisted injection molding will conveniently be better compared to the alternative.

Fewer products needed

 

Depending upon the kind of material utilized, injection molding pellets can cost as much as $5 USD per kg. This, along with the expense of purchase and maintaining the elements of the injection molding device are currently costly alone.

Knowing this, makers take advantage of gas assist when they desire a reduced volume of material to be used. This produces cost-beneficial end results for both the maker as well as the end-user.

Using less product can help them save added resin pellets for future usage without giving up the top quality. When a consumer desires a model to be done, on the other hand, they could almost request the much more cost-friendly and also economical gas assist process.

Minimizes fabrication defects

 

There are lots of common sorts of injection molding flaws– from something as minor as circulation lines as well as staining to something as complex as distortion and warping.

To avoid these issues from occurring, injection molding tools operators need to embark on a series of modifications on the device. For instance, they might intend to create another mold and mildew layout, increase/reduce stress and also temperature level, and even utilize various resins entirely.

Gas assist offers a reliable as well as all-around service to these flaws. As claimed before, the low-pressure nitrogen gas is constantly and also uniformly sent to the molten material. It permits the product to be firmly pressed as well as portable itself onto the walls of the mold tooth cavity. The outcome– a high-quality product that’s devoid of stress and takes the intended design and shape of the producer.

 

 

Lighter

 

Plastic has actually been a preferred material for several sectors as a result of its lightweight residential or commercial properties. With the right tools and also maker handy, it’s feasible to come up with acrylic, HDPE, polyethylene, and even polytetrafluoroethylene injection-molded items that are less thick than the typical material yet can still be used in functional applications.

Like the materials over, materials that have undergone gas assist injection molding are far lighter in weight in contrast with the typical injection molding procedure. The main consideration for this is that the procedure uses up much less area and material, leading to a sturdier and also extra long-lasting product that is not also cumbersome.

Critical takeaway

 

Several benefits of gas assist injection molding consist of the following: much better dimensional quality, enhanced efficiency, much less product, lighter product weight, smooth surface areas, and much less warping.

For both manufacturers as well as end-users, the gas assist injection molding strategy uses a number of advantages. Before deciding on whether or not the gas assist procedure is the right one for you, establish your item needs as well as factors to consider such as production as well as procurement expense, parts needed, high quality of the material, and so forth.

Improved sizing quality

 

The procedure of setting up multiple or particular gas channels in a single plastic injection molding equipment is absolutely nothing brand-new. As a matter of fact, gas assist is widely made use of in producing specialty items– specifically those that have special dimension styles and patterns.

Ribbed plastic items, as they’re called, are the result of a finely-tuned gas assist injection molding strategy. This process is one of the most efficient selections for generating these stylized products as a result of the boosted dimensional precision as well as quality that it provides. You’ll frequently locate everyday materials like container caps, water drums, containers, as well as much more.

 

We are a gas assist mold supplier, please feel free to contact us if you need them.

How do you make a plastic mold?

In today’s manufacturing environment, plastics are used to manufacture a variety of items. Each application requires a special manufacturing process, which can shape parts according to their specifications. If you are making plastic parts, the first thing you need to determine is the type of molding that is best suited to your particular application.At WIT MOLD,We focus on custom plastic molding. This paper briefly summarizes five different types, their advantages and applications.

1>Blow molding – suitable for hollow objects, such as bottles

This process follows the basic steps in glass blowing. The parison (heated plastic block, usually pipe) is inflated by air. The air pushes the plastic against the mold to form the desired shape. After cooling, the plastic is ejected.

The blow molding process aims to produce large quantities of integrated hollow objects. If you need to make a lot of bottles, this is the process for you. Blow molding can produce very uniform thin-walled containers. Moreover, it can do this very economically.

 

2>Extrusion molding – suitable for long hollow molding applications, such as pipes, pipes and straws

Although other forms of molding use extrusion to put plastic resin into the mold, this process extrudes the molten plastic directly into the mold. The shape of the mold, not the mold, determines the shape of the final product.

Extrusion molding involves forcing molten plastic through a mold to form a shape with a fixed cross-section. This is an effective way to produce multiple shapes. Since plastics are melted from solid form and then re cured, only thermoplastics can be extruded. The extruded “pipe” can be cut or rolled up for shipment after cooling.

 

3>Injection molding – suitable for high quality and mass parts manufacturing

Injection molding is by far the most widely used of all injection molding technologies. The presses used in this process vary in size and are rated according to pressure or tonnage. Larger machines can inject auto parts. Smaller machines can produce very accurate plastic parts for surgery. In addition, many types of plastic resins and additives can be used in the injection molding process, which adds flexibility to designers and engineers.

The process itself is quite simple; However, there are many enhancement and customization technologies available to produce the required finishes and structures. Injection molds are usually made of steel and contain cavities for forming parts. Molten plastic is injected into the mold to fill the cavity. The mold cools and the parts are ejected through pins. This process is similar to a jelly mold, which is filled and then cooled to make the final product.

This method has high cost of mold making; However, the cost per part is very economical. Low part costs and resin and surface treatment options have contributed to the popularity of injection molding in today’s manufacturing field.

 

4>Compression molding – suitable for large objects, such as automobile parts

The name of this forming method says everything. The heated plastic material is put into the heated mold and then compressed into shape. Plastics can be in bulk, but usually in sheets. The heating process, called curing, ensures that the final part remains intact. As with other forming methods, once the part is formed, it is removed from the mold. If sheet plastic material is used, trim the material in the mold before taking out the part.

This molding method is very suitable for high-strength compounds, such as thermosetting resins, as well as glass fibers and reinforced plastics. The excellent strength characteristics of the materials used in compression molding make it a valuable process in the automotive industry.

 

5>Rotomolding – suitable for large, hollow and integrated parts

This process uses high temperature and rotary motion to coat the interior of the die and form parts. The continuous rotation of the die will produce centrifugal force, so as to form a product with uniform wall. Because it is very suitable for large hollow containers, such as cans, it is not a fast-moving process. However, this is a very economical process for specific applications and is cheaper than other types of molding. This process wastes few materials, and the excess materials can usually be reused, making it an economic and environmentally friendly manufacturing process.

Each type of molding has its advantages and disadvantages. Designers and engineers need to understand these differences and available production options, and there are always many ways to make the final solution.WIT MOLD has become one of the best molds in the industry because we combine the essence of the latest technology with proven traditional methods.

 

With an expert team composed of experienced and knowledgeable experts, we are able to complete custom orders for Custom Plastic Molds and parts that may exceed the capabilities of our competitors. We are also unremittingly committed to improving customer satisfaction, which includes providing comprehensive end-to-end quality assurance for every product we produce.

Common Defects Of Injection Molds And Their Solutions

 

 

An injection mold is a tool for producing plastic products and for giving them a complete structure and precise dimensions. Read on for more information about common problems and solutions for injection molds.

 

A mismatch between mold and injection molding machine

Causes:

1. Positioning ring position is not correct, size is too big or too small.

2. Wrong position and size of the ejector hole of the mold; wrong position and size of the forced pull reset hole.

3. Mold width size is too big; mold height size is too small.

Solution:

1. Adjust the ejector hole position and size; adjust the reset hole position and size.

2. Replace the positioning ring; adjust the position and size of the positioning ring.

3. Change the tonnage of a large injection molding machine; increase the thickness of the mold.

 

Bad quality of parts

Causes:

1. The fit-gap is too large.

2. Poor glue walking, trapped air.

3. Ejector pin is too small, uneven ejection.

4. Too small bevel, burr, hardness is not enough.

5. Uneven injection pressure, insufficient strength of product form.

6. Processing error.

7. Far from the gate, low mold temperature.

Solution:

1. Trim the gate, pressure uniformity, strengthen the product strength.

2. Reasonable adjustment of clearance and grinding work part of the parting surface.

3. Improve the gate, increase the mold temperature.

4. Add local glue, add exhaust.

5. Re-processing.

6. Increase the ejector pin, evenly distributed.

7. Repair burr, increase slope, nitriding.

 

 

The parts are difficult to fill and difficult to take

Causes:

1. The pouring system is blocked, the runner cross-section size is too small, the gate arrangement is unreasonable, and the gate size is small.

2. The limit stroke of the mold is not enough, the extraction stroke of the mold is not enough, the ejecting stroke of the mold is not enough.

Solution:

1. Check whether the limit, core extraction, and ejection strokes meet the design requirements and adjust the strokes that do not meet the requirements.

2. Check the runner and gate of each section of the pouring system, and fix the parts concerned.

 

Mold opening and closing ejecting reset action is not smooth

Causes:

1. Slanting ejector, ejector pin sliding is not smooth.

2. Mold frame guide column, guide sleeve sliding is not smooth, with too tight

3. Reset spring elasticity or pre-pressure is not enough.

Solution:

1. Increase or replace the spring.

2. Repair or replace the guide pillar, guide bush.

3. Check and repair the slanting top, ejector pin.

 

Mold water transportation is not working or water leakage

Causes:

1. Water sealing rubber ring and water pipe joint are not sealed enough.

2. The mold water channel is blocked and the inlet and outlet water pipe joints are connected in the wrong way.

Solution:

1. Check the cooling system inlet and outlet water pipe joints connection and each section of the waterway, repair the relevant parts.

2. Check the water sealing rubber ring and water pipe joints, repair or replace the parts.

 

WIT MOLD is a very professional mold design and mold manufacturer located in southern China and has passed the ISO2009:2015 international quality Our injection molding process can be customized according to your unique project. If you are interested, please feel free to contact us.