Custom Plastic Molding

Inox Custom Plastic Molding

Inox Casting is a trustworthy custom plastic molding provider which has worked and operated in this industry for over 20 years. We are engaged in custom plastic molding and producing a quality design in different molding industries.

With Inox casting custom plastic molding, it provides you with fast production and high efficiency. This process can bring an incredible amount of parts per hour. It is perfect for those who want to bring a high speed in production.

In Inox Casting custom plastic molding, it is performed by the latest technologies and machines which enable it to work by itself without having a lot of labors. So this method is ideal to save labor and at the same time to save more cost to spend.

Inox Casting custom plastic molding will extremely provide an enjoyable benefit in your production. It is one of the recommended and preferable processes due to its unique features and benefits.

Inox Casting is always happy to provide a custom plastic molding service for you. We always achieve the best result and quality in making custom plastic molding methods. You can also expect that our custom plastic molding services can be available at competitive rates.

Inox Casting works together with the professional and skilled worker to make sure the best result of the production. As an expert provider, we are committed to providing outstanding and satisfying services for every client.

For any clarifications, please don’t hesitate to contact us through email!

Custom Plastic Molding: The Ultimate Guide

Even as you want to make your unique custom plastic molded parts – you should know type of plastic material, molding technique, parts to make and even tooling, just to mention a few.

That is exactly what this guide is all about.

So, keep reading to learn more.

1.  What Is Customs Plastic Moulding?

Customs plastic moulding is the production of plastic products according to specific aesthetic or mechanical features.

In customs plastic moulding, the success of the end product depends on the specified requirements.

custom plastic molding

The custom features include; material type, colour, design, finishing, parts, quantity, etc.

2.  Benefits Of Custom Plastic Moulding

• Enhanced performance
• Detailed features
• Quantity control
• High efficiency
• Design flexibility

3.  Choosing Mould For Custom Plastic Moulding

A mould is a hollow cavity that gives shape to final product is known as a mould. Therefore, choosing a custom mould should focus on;

Lead Time

Time taken to build a mould varies depending on the type of a mould you are building.

While prototype and research and development (R&D) mould take weeks to produce, production-ready mould takes months.

In some instances, you can use an R&D mould and modify as you go along to avoid longer waiter time.

Cost Implications

The average cost of a mould ranges between USD 5000-100,000 depending on different factors such as mould class, materials, complexity.

Simple parts cost less than multi-cavity production mould.

When on a tight budget an R&D mould will be affordable, the only challenge is that it is not durable.

Complexity And Part Geometry

Certain features like part geometry, e.g. corners can be achieved by use of certain materials like hard steel, etc.

Using materials like soft aluminium may making achieving similar part feature challenging.

Secondly, mould materials also influence the final outcome of a plastic moulding product through interaction.

Some plastic materials do not interact well with certain mould material hence influencing the final product appearance.

Quantity To Produce

The number of parts you wish to run through the mould will determine the material and type of mould to build.

High volume mould handling up to millions of parts should have durable design and features.

This can be achieved by using hard steel inserts which is expensive but durable and flexible.

R&D and prototype mould can low plastic mould volume thus can be made using a cheaper material but won’t be durable.

Project Development Stage

Project development stage is divided into; design, prototype, pre-production, production and high volume stages.

In early project development stages, low cost prototype moulds are used due to several mould design modifications and changes.

As the project advances, higher volume and complex parts are likely to be run thus needing a production-ready mould.

Customers who do not wish to spend money and time on prototype can jump directly to production-ready mould.

4.  How Custom Plastic Moulding Process Works

Plastic moulding is a standard process consisting of four distinctive cycle or stages for all moulded products or parts.

Customs plastics moulding process focuses on clients’ specific requirements like raw materials, colour, design, dimension, quantity, shape, etc.

Single units take seconds to complete a whole process while complex and multiple units take minutes per complete cycle.

Clamping

A mould consists of two halves; fixed part and a moving part which must be pieced together and closed.

Clamping prepares the mould for injection process.

Injection

Plastic polymers are placed in a container part of the machines and heated to specific melting temperatures.

Once in liquid form, a hydraulic system then injects the molten plastic into the mould at certain pressure and held.

The pressure ranges from 35MPa to 140MPa at a controlled speed depending on the injection machine.

Holding pressure ensure that the mould cavity is completely filled to avoid deformities in the end product.

Cooling

Here, the molten mould begins to harden and solidify taking the shape of the mould. The temperature drops significantly at this stage.

Ejection

Once cooling time is reached, the mould opens and the part is ejected from the mould cavity.

It then closes ready for another process.

Mould made of aluminium material transfer heat faster compared to steel reducing cooling time and cooling channels.

custom plastic molding process

5.  Techniques In Customs Plastic Moulding

There are five techniques that can be used in custom moulding techniques;

Extrusion Moulding

Extrusion moulding involves pressing molten plastic through a shaped hole known as a die to form a desired shaped product.

The outcome product has the same shape along its length. This technique is common in the manufacture of straws or PVC pipes, in high volumes.

extrusion molding

The limitation of this technique is that the die is limited to making particular plastic parts.

Compression Moulding

Begins with raw liquid plastic material which is fed into a heated mould and compressed together to form a shape.

Cooling is then done and the end product trimmed before it is ejected from the mould.

This technique produces strong and durable plastics parts due to high temperatures involved.

Compression moulding plastic parts are used to replace metal parts in automotive, hoods and fenders, etc.

compression molding

Injection Moulding

The technique uses molten plastic which is injected into a custom mould at a given pressure.

It is then left to cool and solidify into desired shape before ejection.

injection molding

Injection moulding is used for making car parts, medical devices, bottle tops, electric switches, etc.

Blow Moulding

Blow moulding process is used for the production of custom plastics that require uniform wall thickness.

Raw plastic material is melted and air blown into it like a balloon till it presses against the custom mould walls.

This is then left to cool into its shape before it is ejected.

blow molding

Some of the products made from this technique include, plastic bottles, watering cans, drums, etc.

It is a fast and economical way of mass producing hollow and thin-walled custom moulded plastics.

Rotational Moulding

Rotational moulding involves the use of resins or liquid plastic material poured into custom mould and rotated at high speed.

The liquid then forms a hollow part with its walls pressed against the mould.

The mould is left to cools and the customized shape formed with evenly thick walls.

This technique is economical and fast compared to blow and injection moulding techniques.

Rotational molding

 It is used for making storage tanks, kayak, road cones, among others.

6.  When To Choose Customs Plastic Moulding

• When you want to add value to plastic moulded product to increase efficiency.
• To improve product design and aesthetic appearance.
• To satisfy market demand for particular product requirement.
• To create a market niche with your custom moulded product brand.

7.  How To Reduce Cost Of Custom Plastic Moulding?

• Eliminate unnecessary features
• Reduce undercuts
• Limit cosmetic finishes and appearance
• Modify and recycle moulds
• Apply core cavity approach in the process
• Use a family or multi-cavity mould for multiple identical parts

8.  Custom Plastic Moulding Defects

These are simply the normal defects during plastic injection moulding or plastic moulding.

They can be as result of raw material used, process quality or moulding machine, etc.

Luckily, some of these defects can be corrected during process to produce high quality products.

Flow Marks

These are common near gate areas and join lines of in narrow sections of products.

Flow marks can be considered serious or minor defects depending on component thickness.

To correct flow marks during moulding process, mould temperature, injection speed, pressure and material temperature need to be increased.

Lastly, the location of the gate area can be shifted if the above fail.

Burn Defects

Burn marks appear as yellow or black discoloration on finished plastic products.

They are characterised by high melting temperature or increased inject speed.

This can be corrected by lowering melting temperature and reducing injection speed.

Deformation (Warped Area)

Warped area are common in long plastic mould products due to the size.

This defect is hard to correct and sometimes leads to design modification or machine parameter adjustments as the available solution.

Some of the solution for common deformation defects area:

Warping caused by residual stress is corrected by increasing mould temperature and reducing injection pressure.

Part sticking deformation is rectified by adding daft angle, while poor cooling defects are corrected by increasing cooling time or cooling channels.

Deformation due to shrinkage can be solved by adjusting mould design or changing the raw material used.

Sink Marks

Are sunken spots on the moulded plastics due to uneven plastic shrinkage due to thickness and lack of cooling system.

To correct this, increase cooling time and cooling channels, add holding time and add inserts in thick areas to reduce thickness.

9.  Choosing Material For Custom Plastic Moulding

There are several plastic materials that you can choose for custom plastic mould process.

This should be guided by application requirement of the plastic product as well as its working environment.

Some of the factors to consider during material selection are;

• Material hardness
• Material cost
• Flexibility and impact resistance
• Weight or density
• Material advantages and disadvantages

Armed with the above factors, you can select any of the below materials for your custom moulding process.

Polypropylene (PP)

Polypropylene plastic resembles PE in properties but is a little harder and heat resistant.

Acrylic (PMMA)

Acrylic also known as Poly (methyl methacrylate) is a thermoplastic with glass like properties. It is clear thus allows light to pass through it.

It is also strong, light and shatter-resistant.

Polycarbonate (PC)

Polycarbonates are naturally transparent plastics which are strong and tough.

They bear similar characteristics as PMMA, only that they retain their properties over a wide temperature range.

Acrylonitrile Butadiene Styrene (ABS)

This plastic material is mostly used for engineering purposes because it is easy to mould.

It is strong, opaque, has a low melting point and is available in various textures and surface finishing.

Polystyrene (PS)

This is a common material that can be used in either general purpose polystyrene (GPPS) or high impact polystyrene (HIPS) injection moulding.

Polyethylene (PE)

Polyethylene is the most used plastic material globally and is available in 3 types with varying density namely;

• Low density (LDPE),
• High density (HDPE)
• Polyethylene terephthalate (PTE)

PE is available in various ranges of hardness, flexibility, melting point and transparency.

Thermoplastic Elastomer (TPE)

Thermoplastic elastomer is a blend of plastic and rubber material which has elasticity.

TPE can be recycled as many as six times.

Thermoplastic Polyurethane (TPU)

Thermoplastic polyurethane is a type of TPE and is very popular. TPU is harder than TPE thus is used to replace hard rubber.

Polyoxymethylene (POM)

Polyoxymethylene material also known as acetal are naturally white and opaque plastic engineering materials. POM has excellent dimensional stability and is very stiff.

Nylon Polyamide (PA)

Polyamides are available in two forms, natural and synthetic with nylon being synthetic.

10.  Tooling For Custom Plastic Moulding

Tooling is the process of designing a mould and its various parts.

This is a highly technical tasks and requires technical expertise for a high quality precise mould parts.

Tooling engineers should therefore determine steel material grade parts that run together to avoid uneven wear and tear.

Secondly, they should check and ensure a steel hardness is balanced between wear and tear and toughness.

Another component to consider is the running size and gates to proper filling and cycle time.

Tooling stages go through the following stages to completeness.

• Manufacturability and feasibility
• Design and specification
• Construction of primary and secondary tools
• Tool in-house sampling
• Tool corrections

The commonly used materials in tooling of custom plastic mould are steel and aluminium depending on needs and application.

11.  Overmolding Vs Insert Moulding Customs Plastic Parts

Overmolding is a process of combine two or more distinctive materials or colours into a single unit by two-shot injection process.

Common materials used during overmolding are plastic over plastic substrate or rubber over plastic substrate.

insert molding custom plastic parts

overmolding

Overmolding enhance aesthetic features of a product and also eliminate secondary process.

Some of overmolding products include hand-held tools, robotics with rubber handles, etc.

Insert moulding process involves filling molten plastic polymers into a cavity and cooling it for a final product.

This method allows plastics to bond with their inserts normally metals as it solidifies into a final product.

Insert moulding eliminates the use of adhesives or fasteners which needs labour.

12.  Benefits Of Prototypes In Custom Plastic Moulding

Prototypes are samples or simulations of a real product that are released to test the functionality of the final product.

In custom plastic moulding, prototypes are common especially for complex designs and part.

Some of the benefits associated with prototype include:

Reduce Financial Risk

Building a prototype for complex plastic mould designs and parts will offer insight on the likely appearance problems on final product.

This will enable design engineers correct it beforehand.

Tests Precision

A prototype offers you a chance to test the functionality of the expected end product or design.

In other words, it accelerates proof of concept thus helping in buy-in of ideas.

It is a great way to collect customers’ feedback on a product and aid in decision making process.

Reduces Manufacturing Defects

If a mould has design or dimensional problem, it will appear in the end product as a manufacturing defect.

This can be corrected with prototyping before mass production begins.

Estimate Production Cost

Another benefit of prototypes in customs plastic moulding is the ability to calculate the cost of production, time and materials.

When making a prototype, you get a chance to estimate production time from start to delivery, material and production costs.

For all your custom plastic molding needs, Inox is here to help – contact us now.