Two-Shot Plastic Injection Molding – What you need to know?

Two-Shot Plastic Injection Molding – What you need to know? makenica.com/two-shot-plastic-injection-molding-what-you-need-to-know April 9, 2021

Two-Shot Plastic Injection Molding Service- Producing two-color or two-component injection-molded pieces from two different thermoplastic materials in a single process, quickly and efficiently:

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Variations of advanced molding technologies include two-shot plastic injection molding, co-injection, two-color, and multi-component Molding.

Using hard plastics in conjunction with soft materials During a single press machine run, a two-step procedure is carried out.

Consolidates two or three parts, resulting in lower manufacturing costs.

The technology of plastic Injection molding service is becoming more advanced.

Processors will now make injection molded components out of two different thermoplastic materials thanks to cutting-edge fabrication technologies.

Complex functional parts can now be manufactured economically and reliably by injection molding companies in large quantities by mixing these various materials with everimproving molding technology.

The polymer form and hardness of the materials can vary. They can be manufactured using molding techniques employed by plastic injection molding companies such as dual injection molding service, two-shot Molding, two-color, two-component Molding, and multi-shot Molding.

Whatever its designation, a sandwich configuration has been created in which two or more polymers are laminated to benefit from the properties that each adds to the structure. The thermoplastic parts provided by these moldings have outstanding performance characteristics while being inexpensive.

How Does It Operate?

Two-shot machine with two separately operated injection system Molding a single component out of two different materials or shades Two cavity mold (one + one) The first material is inserted into the first cavity, the mold is opened and rotated to the second cavity position, the mold is closed, and the second material is injected.

Once the part has cooled enough, the mold is opened, and the part is expelled.

Critical factors: material(s) melt temperature mold wall temperature injection speed delay time between injections part temperature A system with two independent injection units, each of which shoots a different material, is needed for the two-shot plastic injection molding operation. As in a standard injection molding cycle, the first material is pumped into a primary runner system.

During the injection, the primary runner system is disconnected from the mold volume occupied by the second material. After that, the mold is opened, and the center layer is turned 180 degrees. The mold is closed once more, and the secondary runner system is

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connected to the volume to be filled. Once the part has cooled enough, the mold is opened, and the part is expelled.

An indexing device (a round table revolving around a horizontal axis) with a primary and secondary station may also be used to execute the two-shot operation. The first injection is performed at station #1, while the second injection is performed at station #2.

A separate injection unit controls each injection station. This allows for the regulation of injection speeds and pressures for each material used.

Design principles of two-shot injection molding service Classification Two-shot injection molding service: Two types of plastic materials are molded in two parts on the same injection process, but the result only molds once. This double injection molding technique, also known as double-material injection molding service, usually consists of two molds.

One half mounted on the machine's fixed plate and the other half mounted on the rotary plate. The male molds of these two molds are similar, but the female molds are not. When the first color of plastic is injection molded, the male and female molds are opened only once.

The male mold is then rotated 180 degrees with the product once to meet the second color injection molding location, and the two-color workpiece is made. Each molding cycle can produce semi-finished and finished products.

Insert Molding: "fake two shot injection moulding," insert Molding involves molding two different types of plastic components on different injection molding machines and in two sections. Products are removed from one set of molds and placed in another set of molds.

The second is the injection molding process (so we call the first shot is inserted). This double injection molding service is usually accomplished with two sets of molds and does not necessitate using a special two-color injection molding system.

In most cases, a two-shot injection molding service can be used in no more than the following conditions.

1. Product feature specifications. For instance, a power switch, a cell phone button, a keyboard indicator, a car switch, and so on. Part of LED must be transparent—for instance, a power switch button or an LED light.

2. Enhance the feeling. Some hand-held items necessitate the use of rubber in the hand-held component, which increases hand comfort. For starters, a walkie-talkie case, a power tool handle, a wrench, a screwdriver handle, a toothbrush handle, a vacuum flask, and so on.

3. Incorporate beauty. For example, if you use two-color injection molding as a decoration, it is stunning and will not be rubbed off.

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4. A part of the product that involves electroplating. Just ABS and polysulfone (PSU) surfaces in the plastic family can be plated. If only a single side of the product has to be plated, the plating region should be injected into ABS. In contrast, the remainder of the product should be injected into other materials such as PC. Design requirements for two-shot injection molding Two-shot injection moldings are very popular in plastic injection molding companies today because they enhance the appearance of the product and allow for quick color adjustments without spraying. The following are the key points of two-shot injection molding design to be considered by injection molding companies: 1) Two different shapes of the cavity are used to create one component, while two different cavity shapes are used to create the same product.

2) After turning 180 degrees from the core, the front and back molds must be aligned.

This must be tested during the design process.

3) Pay close attention to the top stick hole's location; the required distance is 210mm. The number of jackholes in wide molds must be sufficiently increased.

Furthermore, since the top stick attached to the injection molding machine is insufficiently long, we must design along with the top stick in our mold, and the top stick grows approximately 150 mm from the bottom of the mold frame. On the bottom plate of the back mold, two positioning rings must be installed.

4) The overall thickness of the front mold panel plus the A board cannot be less than 170mm. Other comparison data for this type of injection molding system, such as maximum die thickness, minimum die thickness, and top hole diameter, should be reviewed.

5) The three-plate mold's nozzle can be equipped for automated de-molding. Pay careful attention to the consistent de-molding of soft glue nozzles.

6) The depth of the front side SPRUE shall not be greater than 65mm. The distance between the top of the upper side (large nozzle) SPRUE and the middle of the mold base must be at least 150 mm.

7) Certain pieces should be designed to prevent CAVITY insert (or rubbing) damage to the first molded metal glue area while constructing the second injection molding cavity.

However, each seal position's reliability must be closely considered if the plastic mold pieces will be deformed in the injection under a heavy injection load, possibly resulting in a burr in the second injection.

8) Before injecting, the first injection product's dimension should be marginally wider so that it can be squeezed closer with another CAVITY in the second Molding to produce the sealing effect.

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9) Take care of whether the plastic movement in the second injection can impinge on the first molded product, allowing the plastic position to be deformed. If this is practicable, we must formulate a plan to boost it.

10) Before clamping A and B plates, check whether the front die's slider and lifter can reset first to crush the product. In this case, find a way to clamp A and B boards first and then reset the slider or lifter in the front mode.

11) The water transport configuration of these two cavities and CORE must be as full and balanced as possible.

12) Generally, inject the hard plastic mold part of the component first, followed by the soft rubber part since soft rubber deforms easily.

13) To make two plastics "stick" tighter, consider the "stickiness" of the materials and the roughness of the mold surface. A special TPU is used in two-color injection molding. The finer the color of the mold, the more "sticky" it is.

14) In plastic molding processing performed in injection molding companies, pay close attention to the front and rear molds; both injection and slope of the broken surface should be as high as possible and greater than 0.1mm.

Assembling Injection Molded Components There are many methods for combining custom injection molded plastic parts with building a larger and more complicated product. Still, each has its own collection of tools, prices, and labor specifications.

The final product's strength determines the joining method chosen by injection molding companies and whether the part would need to be disassembled at some point. The easiest way to connect plastic parts is to insert a fastening feature into the part, such as a hinge or lock.

Since the joint must withstand repetitive use, load, and strain during installation, stronger plastics are needed.

What are the Advantages?

Reduced component expense: cost savings in manufacturing, handling, assembly, and inventory.

With higher quality fabrication, it simplifies the manufacturing process.

Secondary activities will be removed.

Enhances the product's credibility Product characteristics and attractiveness are improved: tactile, ergonomic, and cosmetic.

Design possibilities are expanding.

Packaging applications requiring a secondary color to give products a distinct look Added features to enhance the functionality of the part:

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several colors surface with gentle grip seals and gaskets The real payoff of two-shot thermoplastic injection molding is economical. With the speed, performance, and economy of thermoplastic manufacturing, sections of two different materials can be manufactured by injection molding companies.

This replaces the labor-intensive secondary operations in plastic injection molding companies that have been used for several years with high-speed automated operations, resulting in a more reliable, higher-quality manufactured component at a substantially lower cost.

Two Shot Molding is ideal for: Soft-touch handles, grips, and other components Multi-color buttons, switches, and knobs Movable segments or components Water shield and protection Caps and enclosures Back-lit buttons, dials, and other instrumentation products Drop protection Vibration and noise dampening and isolation

Read More : Injection Molding Vs. Transfer Molding: What’s the Difference?

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