Moulding a better product, everything about mold design  

If you’ve ever wondered how most products are manufactured, the answer is moulds. Moulds are a type of tool used in product design to form and shape components into different shapes and sizes. From the simplest of products, such as a cell phone case, to the most complex items like a car engine, moulds are used to bring the desired design to life. Let’s take a look at what goes into making a mould, what they cost and why they are so important for product design.

6. Plastic injection mold design

Different types of moulds

There are many different types of moulds used in product manufacturing. Depending on the complexity and shape of the required parts, our design engineers may choose to employ injection moulding, pressure casting, blow moulding or another of dozens of different manufacturing techniques. Injection moulding is used to create highly detailed parts with intricate shapes, while blow moulding can be used to create hollow objects like bottles or containers. Pressure casting is best suited for producing large quantities of small parts such as screws or nails. A properly made mould ensures that components have consistent dimensions and require minimal finishing work after production. Without a proper mould, it would be impossible to mass produce components. The main types of manufacturing techniques and their mold design and manufacturing are explained below.

Plastic injection mold design

One of the most common manufacturing processes for plastic mold design is injection molding. This automated process involves injecting molten plastic into a mold cavity. The mold is then cooled down until the material solidifies, resulting in a finished product with a consistent shape and size. This method is often used for creating many high volume, affordable plastic components from toothbrushes to TV housings. It’s very quick and cost effective compared to other production methods. And to make the production process of high-volume items even more cost effective multi cavity mold design can be utilized to make many of the same components in one shot simultaneously. Such multi cavity molds obviously are a lot more expensive than single cavity molds and only interesting if annual production volumes are upwards of a million.

Plastic and aluminum extrusion

Extrusion is another common method used in product design and manufacturing. With extrusion, molten plastic or aluminum is forced through a die with a specific shape to create solid parts such as rods, tubes, and sheets. Unlike injection moulding, which produces intricate parts, extrusion produces continuous lengths of profiles that can be cut to size. Think of it as large playdough toys to push clay through in a certain shape. Extrusion is ideal for creating long parts with consistent wall thicknesses and complex cross-sections. It is often used for creating items like window frames, pipes, hoses, tubes, rods, wires, cables, etc. The dies (moulds) only cost a fraction of injection moulding tool design.

Rotation molding

Rotation molded parts are created by molds filled with plastic granules, moving around two axes whilst being heated from all angles. This method results in large hollow parts that are extremely durable in a process that creates a minimal amount of waste. Rotation molded parts are often found in outdoor equipment such as kayaks, water tanks or lawn furniture due to high resistance to extreme temperatures and environmental conditions like UV exposure or saltwater corrosion. Rotation molding is most suitable to create large hollow objects in series of hundreds to a few thousand units. Moulds are a lot less expensive than plastic injection mold design but the manufacturing process is a lot slower, hence components are much more expensive to manufacture.

5. Plastic part design for injection molding

Blow molding

This is another widely used production method that involves inflating molten plastic inside a mold in order to create hollow objects like bottles or jerrycans. The blow molding process is basically a more automated process of rotation molding more suitable for higher volumes of smaller hollow objects to be made fast. Do take into account that for blow molding it might be required to have a plastic part design for injection molding as well. For example, most bottles start as an injection molded part and are then heated and inflated by the automated blow molding machine to final bottle shape.

Metal casting

This involves pouring molten metal into a casting mold design made out of sand, ceramic, or plaster to create parts ranging from small jewelry pieces to large engine blocks. This process has been around since ancient times but continues to be an important part of modern manufacturing due to its versatility — almost any object imaginable can be cast using this method!
Within metal casting many variations exist, if your product requires intricate metal parts the design engineers from ManGo can advise the most suitable casting mold design and create your components accordingly.

7. Plastic injection mold design

Costs of moulds

The cost of a mould mostly depends on its size and complexity, as well as the type of material used for its construction. Moulds made from hard metals like stainless steel are more expensive than those from soft materials like aluminum. Hard moulds last longer enabling you to make more components before they wear out. The costs (or investment if you will) also very much depend on where the moulds are made. Range in price anywhere from € 500,- to well over € 1.000.000,-. In plastic mold design it is injection molding of which the tools are the most expensive because of the high pressured they need to withstand during production. ManGo has a large network of manufacturers all over the world that can be utilized to request prices for mold design and manufacturing. At the beginning of each project, we discuss with you the maximum mould budget to enable selecting the most suitable manufacturing method and design all parts accordingly.

Who owns the moulds?

Generally speaking, the company or individual who had the mould or moulds made is the owner unless specified otherwise in a contract between the parties involved in its creation. It’s important to consider this before opening the moulds to avoid discussions later on. Moulds remain at the factory where they are stored until a new order is placed. Mostly for practical reasons as moulds are heavy and vulnerable to move around and outside the factory there is no practical use for them. The custom-made mould is used again and again for future production orders – until it expires. Wear and tear of moulds is a normal process and a shot guarantee on moulds has to be given by the mould maker. These could range from a few thousand units using soft tools made from aluminum to more than a million with more expensive hardened steel moulds. In any case at ManGo we only work with manufacturers with clear terms and conditions and advise our clients within the process of industrialization of their product design.

Injection mould design Who owns the moulds
15. Plastic part design for injection molding how long does it tale to make moulds copy

How long does it take to make moulds? 

The time it takes to manufacture a mould varies greatly depending on its complexity and size; however, it typically takes between three weeks and three months for a mold to be completed by an experienced craftsman or mould factory. Additionally, some molds may require extra steps such as polishing or plating before they’re ready for use in the manufacturing process.

Steps in the mould making process

Making a mould requires several steps: design of the mould based on the delivered 3D CAD product design, machining the production-grade tools from steel blocks (or other materials like aluminum) and then testing/inspecting of the moulds before they are cleared to be used in the production process.

First Out of Tool (FOT)

Once your plastic injection mold design has been manufactured, you will typically get the first out of tool—that is, the first item that comes out when your mould is put to use. We at ManGo, the manufacturer and our clients judge these FOT components and most often improvements have to be made to take out small imperfections. This could mean that the plastic mold design needs some slight adjustments or machine settings need to be optimized. Then the Second Out of Tool (SOT) component is made and inspected again, this process is repeated until all parties are satisfied with the results.

Surface finish: perfection from every angle

Once the plastic injection mold design has gone through the process of FOT , SOT and the parts have been approved, the mould as a final step is processed to receive the surface finish. This surface finish is required to give the manufactured parts their desired look and feel. Which for example could be a matte or glossy surface but also a leather or dimpled pattern for example. Certain complex surface finishes can only be applied by specialized companies with laser technology and can cost as much as the mould itself.

Mould making steps


Mold design and manufacturing is an integral part of product design because moulds enable an efficient way to produce components in large quantities with precision accuracy while keeping costs low. No matter what type of product you’re looking to manufacture, chances are there’s an existing production method that will fit your needs perfectly. From plastic injection mold design to metal casting mold design, each technique has its own strengths and drawbacks. With proper research into your project’s needs as well as budget considerations taken into account ManGo always advise cabout the most appropriate manufacturing methods for your product design.

More information

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