Plastic Mold Manufacturing

Inox Cast Plastic Mold Manufacturing

Looking for professional partner and custom supplier of plastic mold in China? Inox Cast can help you solve your problem.

Inox Cast is your premier choice to get the best plastic mold and ensure the perfect customizations according to your products. Our plastic molds are made of durable materials that able to mold and create different shapes and products from small sizes to large product sizes and parts.

Inox cast plastic molds can produce the best surface finishing and different textures according to your product types. We support different industries and supply all types of plastic molds from kitchenware, household appliances and materials, tools, computer parts, medical devices, covers, and more.

Our plastic molds are applicable and widely used for industrial and commercial use. Just send your product types and types of productions so we can give you effective suggestions. Our plastic molds can surely provide perfect durability. It hardened molding well and ensures to provide perfect shapes.

Inox Cast plastic mold has different process like extrusion molding, compression molding, blow molding, injections molding, rotational molding, and more. Extrusion molding provides customizable shapes with liquid plastics. It is widely used for PVD pipes which created at high volumes.

Compression plastic molding produce a strong, durable and perfect surface of products because it provides higher volumes which also accessible in different cavity count. The blow molding has also great performance that able to produce different quality plastic bottles, drums, thin-walled, tanks, and more industrial uses.

Whatever your products and purposes, Inox Cast will fully support your expandable business. We can help you develop your sales and production with our outstanding quality plastic molds.

Send your inquiries to know more and get great benefits for your business. Get in touch!

Plastic Mold Manufacturing: The Ultimate Guide

Choosing a suitable plastic mold is an important step in plastic injection molding process.

So, this guide explores everything you should know about plastic mold manufacturing.

Let’s dive right in:

1.  What Is Plastic Mold?

This is the component of the injection molding system that is responsible for transforming the molten plastic into distinct plastic parts.

plastic mold

2.  Factors Determining Injection Mold Tooling Cost

The cost of your injection mold tooling is dependent on the following factors.

Design of plastic part: Complex part designs costs more to manufacture because they require complex molds and sometimes even secondary EDM processes.

Material used to fabricate the plastic part: The type of resin selected for manufacturing the part directly affects the maintenance requirements of the mold.

Resins that require higher temperature molding also increase the mold tooling cost.

Material selected for constructing the mold: Materials like hardened steel are stronger and more durable than alternatives like aluminum.

However, they are also more expensive.

Cavities and volume: Forming complex parts demands molds with more cavities. Similarly, high volume production also requires more cavities.

The higher number of cavities increases the press time which increases production time and tooling cost alike.

Location of mold manufacturer: The cost of your mold tooling will increase with shipping distance.

3.  Manufacturing Plastic Mold

Manufacturing a plastic mold depend on the design of the mold.

Some plastic molds have very complicated designs and require a lot of time to manufacture precisely to the mold design specifications.

The following factors go a long way to ascertain you produce high-quality plastic molds.

Designing The Part

Before you begin any actual manufacturing, you have to first design the part model and submit it for approval.

You have to take into account the technicalities of the plastic part when designing it.

Key among these include the application of the plastic part, dimensional accuracy, and craftsmanship.

Designing The Mold

In designing your plastic molds, you can use CAD for 2D or 3D models. You have to carefully consider the following key components when designing your plastic molds.

The steps involved in designing the plastic mold are:

Categorizing The Plastic Parts

You can use the mold structure and a considerable injection process to rank the parts by the requirements of your customer.

This procedure will directly influence the process of injection molding in the latter stages.

Developing A Design Sketch And Material Acquisition

The next step involves developing a detailed quotation sketch which is a diagram of your plastic. You have to then attach it as a mold order reference.

The sketch must detail information on the actual size, base, and structure of your mold when manufactured.

Fill in the mold order form alongside your quotation sketch.

Factors That Determine The Structure Of Your Mold Design

Two main factors will influence the structure of your mold design, the plastic part characteristics and the type of injection machine.

You should consider the following aspects when designing the structure of the plastic mold.

Gates

These are the mold components that control how molten plastics flow into the mold cavity.

Your model design must optimally locate the gates for the acquisition of optimal functionality.

The location of the gates has a significant influence on the tolerance, time to cooling, fill pressure, and flow of molten plastic.

Draft

Your model design should ensure that the part can be ejected from the mold without any deformities or surface damage.

You can navigate around these challenges by applying a draft angle to the mold’s sidewalls.

The draft angle varies from 1˚C to 5˚C and tends to increase with increasing depth.

You should also ensure that mold features are not aligned as overheads on the side from which the mold opens to release the molded part.

Surface Finishing And Texture Of The Finished Parts

The choice of surface finishes for the final product depends largely on the cooling of the mold and part.

Depending on the requirements of the finished plastic, you could also pre-apply patterns and texture before ejecting the finished product.

You may also need to readjust your design to account for draft angle placement for efficient removal of the finished part from the mold without damage.

Other parts of the mold that must also receive considerable attention include:

• Material for mold construction selection
• Process requirements of the plastic of choice
• Temperature controls of the mold
• Exhaust
• Forming parts

Manufacturing The Mold

Programming And Removal Of Electrodes

The engineers consider a detailed review of each component’s processing condition when designing a CNC program.

The review process will also inform on whether the electrode EDM processing should be removed or not.

Machining

There are diverse types of machining you could use for manufacturing your plastic molds.

Some of the most commonly used machining types are CNC, Wire Cutting, EDM, and Deep Hole Drilling.

Acquire the mold base and the materials the mechanically process them into diverse mold parts.

Assembling Fitters

Fitters are vital components in the mold manufacturing process. They must be kept on throughout the process.

Fitters ensure proficient mold assemblage, turning, grinding, milling and drilling.

Polishing And Saving Molds

You can use oil stones, diamond pastes, and sandpaper to polish your mold after machining and fitter processing procedures.

You can assemble your mold after furnishing it through savings and polishing.

Inspection And Testing

You should inspect your mold assembly after fitting it to ensure that all critical components are correctly placed.

You can check for the smoothness of the thimble and the placement of the red pill.

After ascertaining the proper assemblage of your mold, you can subject it to trials. You can test the operational capabilities of your mold in an injection machine.

Assess the quality of the plastic parts and ascertain that the mold is operating according to set industry standards.

Modifications

There may arise a need to modify the structural design or settings of your mold depending on the test results.

Once you construct your mold, you should only implement changes based on specific situations as this is a very difficult process.

Changes in structural designs have to accommodate the functionality of the mold and ease of implementing such changes.

In the case of mold cooling systems, process the front and the rare mold water transport requirements in the first and second mold modifications respectively.

Maintainance

You should coat your mold with butter and anti-rust oil to protect your plastic mold when you are not using it to process beer.

4.  Parts Of Plastic Injection Mold

There are two main components of the injection mold, the core, and the cavity. Closing the mold creates an open space known as the part cavity.

This space is where the molten plastic pours in the course of mold operation.

These are the components of an injection mold:

• Top plate
• Cavity plate
• Sprue brushes
• Sprue puller pin and bushes
• Registering ring
• Core plate
• Core backplate
• Ejector guide bushing and guide pillar
• Ejector plate and ejector backplate
• Centering bush
• Heel blocks
• Bottom plate
• Rest button

plastic mold parts

5.   Choosing Plastic Mold Material.

The rate of wear and tear differs by material and selecting a strong material that suitably aligns with the above factors is highly desirable.

Steel and aluminum are among the two most highly ranked materials for the construction of injection molds.

Steel Mold

You can fabricate your mold using either hardened or pre-hardened steel.

Hardened steel is steel that has been machined then heat-treated and is characteristically stronger, more resistant to wear, and lasts longer compared with pre-hardened steel.

Hardened steel is ideal for fabricating injection molds for use in systems designed for long-term, high-volume production.

It is the ideal choice for manufacturing steel to mold glass-reinforced products as it is highly resistant to wear.

However, harder steel is also more brittle and will easily crack when you use it to fabricate injection molds that are susceptible to impact or side loading.

You can use pre-hardened steel if you want to sacrifice some strength for formability.

The malleability of pre-hardened steel allows you to use standard tooling for shaping into more complex designs.

The strength of pre-hardened steel can still support high-volume production for a considerably long time compared to aluminum and other materials other.

Aluminum Mold

Contradictory to steel, selecting aluminum significantly reduces the costs of your injection molds but at the expense of volume capacity and longevity.

This material is only suited for injection molds that you would use for prototyping or low-volume production.

It is highly preferred for malleability and ease of machining for part fabrication. Aluminum is also very light in weight and cools considerably fast.

For this reason, you can also use it to manufacture tooling.

The ease of aluminum workability also fastens the process of manufacturing molds due to faster production cycles and turnaround time.

However, the softness of aluminum also makes your molds more difficult to weld and highly prone to wear and tear.

You can also fabricate hybrid molds that incorporate both steel and aluminum for better heat transfer in less demanding applications.

6.  Clamping Mold In Plastic Injection Molding Machine?

Depending on your application, you may need to turn the pump on and off multiple times in the process.

Manual instructions come in handy in the course of clamping a plastic mold.

You can clamp the mold into the injection molding machine following these steps:

• Lift the mold using a suitable crane and place it in the molding area. Fix the alignment holes to the locating rings.
• Adjust the moving platen until it contacts the back of the mold’s then level the mold with its gates open.
• Loosely fix the fixed-platen to the clamps then engage the soft-die cast platen with grade 8 bolts.
• Fix the ejector bars. This process may require you to considerably retract the moving platens.
• Fix the ejector bars into the mold holes then slowly retract the moving platens to about 4 or 6 inches from the mold.
• Tightly thread the knockout bars onto the mold’s back.
• Remove the tension by lowering the chain host after the upward advancement of the moving platen.
• Appropriately set the clamp pressure to the size of the mold.
• Clamp the moving platen then appropriately torque the clamp bolts.
• Retract the safety straps and hoist off the molding zone.
• Open the mold and tighten the knockout rods with hex nuts or screws.
• Ascertain the proper function of the ejectors then clean up your working area.
• Clean your working area.

7.  Plastic Molding Techniques?

Different molding technique follows a specialized manufacturing process to produce unique parts and components for distinct application needs.

Determining an appropriate plastic molding technology is the first step toward manufacturing your plastic components with desirable characteristics for your application.

The most widely used plastic molding techniques include:

Blow Molding

Blow molding closely resembles the glass blowing process and involves heating a bulk of plastic into a tube-like structure and then inflating it by pumping air through it.

Pumping air into the plastic structure forces the plastics to adopt the shape of the mold into whose walls it has been pushed.

blow molding

The subsequent steps involve cooling and ejection of completed parts.

Compression Molding

It involves heating the mold and the plastic and then compressing the heated plastic into shape.

Heating, the curing process, strengthens the structure of the plastic part.

The finished part is discarded from the mold.

compression molding

However, you have to trim the material before discarding it from the mold if your original material was a plastic sheet and not plastic bulk.

Extrusion Molding

This type of plastic molding is what you would consider if you want to manufacture parts or items like straws, pipes, or tubing which are long and hollow.

In extrusion molding, the melted plastic is directly extruded into the die unlike other types of molding where the plastic resins are subjected to extrusion.

extrusion molding

To manufacture a plastic into the desired shape in extrusion molding, you have to first melt the plastic and then force it through a die.

The die produces a plastic shape having a fixed cross-section.

Once the tubing has been extruded, it has to undergo cooling and clipping into the ideal length before the shipment.

You can produce diverse shapes using this plastic molding technique.

However, you can only use extrude thermoplastics because the process starts with melting a soling plastic and the final product also require resolidification.

Injection Molding

You can select injection molding for versatile production of high throughput production of high-quality plastic parts.

The size of parts produced by the injection molding technique depends on the press sizes hosted in molding machines.

The tonnage and pressure of the press also depend on its size.

You can use small press machines to produce precise, tiny plastic components and parts ideal for microscopic applications.

injection molding

Large press machines are also vital in the production of large plastic parts.

Injection molding also supports high engineering flexibility in plastic parts designs because it can utilize a wide array of additives and plastic resins.

The manufacturing process of injection molding is quite simple, you could customize the technique for the production of specialized products.

The parts are formed on the cavities of the injection mold.

Consequently, your injection molding system melts the plastics and fills them in the mold cavities. After cooling, the parts are pin-removed from the mold.

Though the overall cost of manufacturing a plastic part through injection molding is relatively high, the cost per plastic part is comparatively economical.

Rotational Molding/Rotomolding

The rotational plastic molding technique is a highly suitable technique for the manufacture of large, hollow, isolated part structures like tanks.

Structures are formed by subjecting the plastic bulks to high temperatures and coating the mold’s interior by constant rotational movements.

A centrifugal force resulting from the constant mold rotation creates a product with even walls. The finished product is dislodged from the mold once it is cooled.

rotational molding

 This plastic molding technique is slower than most plastic molding techniques and can also be cheaper in specific applications.

It is highly customizable and can be used to manufacture assorted product lines such as car parts, bulk and storage containers, marine buoys, etc.

You can set the mold to imprint logos, insert slots, contours, curvatures, etc.

The techniques of rotational mollding produce comparatively low levels of scraps which can further be recycled back into the production system.

8.  Plastic Mold Cavities

This is the hollow chamber that contains molten plastic. There are two types of mold cavities, single and multiple cavity molds.

Each of these types of mold cavities has type-specific advantages and disadvantages.

For instance, single cavities molds will offer you high plastic molding precision at a low tooling cost. However, their volume capacity is limited and costlier in producing a single product unit.

On the other hand, multiple cavity molds have a high-rate, and high-volume capacity and can support simultaneous molding of assorted parts in a single cycle.

Further, unit costs of products manufactured through multiple cavity molds are lower.

However, multiple cavity molds are also not the most ideal for the manufacturing process that requires multi-level engagements.

Multiple cavity molds cannot maintain supply levels and correctly match production conditions in multi-stage manufacturing.

More Resources:

Injection Mold Tooling

Plastic Injection Mold

Steel Mold

Aluminum Mould

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