Injection moulding is a widely used manufacturing process for producing complex, high-precision components such as the Caplugs plastic product protection solutions. It is an efficient and cost-effective method, making it a popular choice in various industries. This blog post provides a short overview of injection moulding, and provides a step-by-step process for applying an injection-moulded cap.

A short history of injection moulding

Injection moulding is a manufacturing technique that involves injecting molten material, typically thermoplastics, into a mould cavity. The material solidifies inside the cavity to produce the desired shape. It is a highly versatile process used to make plastic products of a precise design and size.

Injection moulding was invented in the 19th century by John Wesley Hyatt, who was searching for a substitute for ivory billiard balls. He discovered that celluloid, a type of plastic, could be moulded into various shapes. This breakthrough paved the way for the development of injection moulding as we know it today.

Injection moulding revolutionised how products were made and is now an integral part of the manufacturing industry.

The importance of injection moulding in manufacturing

Injection moulding plays a critical role in the manufacturing industry for several reasons. It allows for mass production of parts with consistent quality and reduced costs while ensuring product uniformity. This is possible due to automated machinery that can rapidly manufacture significant volumes of components. Producing parts in high volumes is especially beneficial for industries such as automotive, gas and oil, aerospace, construction, electronics, and medical devices.

The process also enables flexible design and the creation of complex shapes with a high level of detail. The mould cavity can be customised to create parts with varying thicknesses, textures, and surface finishes. This versatility allows engineers to design innovative solutions to suit the requirements perfectly.

The exceptional precision, consistency, and accuracy of injection moulding is crucial, especially in industries requiring tight tolerances, such as aerospace and telecommunications.

The fast production cycles of injection moulding enable efficient turnaround times. Once the mould is set up and the initial parameters are established, the injection moulding machine can produce parts at a rapid pace. This efficiency is essential for meeting tight deadlines and meeting consumer demands. Further benefits of the process are laid out in the blog post about the advantages of injection moulding.

The role of the moulding cap in injection moulding

In injection moulding, the moulding cap keeps the mould secure during injection. It seals and encloses the molten material within the mould, ensuring it solidifies into the desired shape, and averts potential leaks that might cause flaws in the end product. It also regulates material flow, prevents material waste, and enhances accuracy, quality, and efficiency in the injection moulding process. Finally, the smooth surfaces and contours of the moulding cap enable the easy release and ejection of the moulded part from the cavity. This feature enhances productivity and minimises the risk of damage to the part during the ejection process.

Different types of injection moulding caps

Moulding caps come in various types, each designed for specific applications. In order to select the most suitable one for a particular injection moulding project, it is helpful to understand the different types.

• The standard cap is widely used in general injection moulding applications. It offers a good balance of performance, cost-effectiveness, and versatility. Standard caps are available in different sizes and configurations to accommodate various mould designs and material requirements.

• The hot runner cap is used for high-volume production and complex part designs. Hot runner caps feature a heating system that keeps the material in a molten state as it enters the mould cavity. This eliminates the need for re-heating the material with each injection cycle, resulting in faster production cycles and reduced material waste.

• The multi-cavity cap is often used for projects that require multiple cavities, allowing for the simultaneous injection of multiple parts within a single mould. It improves productivity and efficiency by producing multiple components in each injection cycle.

The choice of moulding cap depends on the material used, the desired part design, and production requirements. Selecting the appropriate cap to ensure optimal performance and product quality is crucial.

Safety measures for applying the moulded cap

Safety is of the utmost importance when preparing to apply the moulding cap. Make sure to wear suitable protective gear such as gloves and safety goggles to shield against contact with heated materials and moving components. Know the emergency shut-off protocols and keep fire extinguishers easily accessible. Adhere to equipment warning signs and labels, confirm proper ventilation, and assess machinery for signs of wear. These precautions provide a secure environment, minimise accident risks, and facilitate a seamless application of the moulding cap.

Applying a moulded cap

Step 1: Research and preparation

Before starting the cap application, it is important to understand the types and purposes of the caps, as different caps have specific functions. Instructions or guidelines from the manufacturer can be helpful. Samples from the manufacturer also help to physically evaluate the cap’s suitability and size. Collect the tools needed and work in a clean, well-lit space.

Step 2: Clean the part

To ensure a strong bond, begin with a clean surface. Clean the area where the cap will be placed. Dust and dirt hinder adhesion, so use a suitable cleaning solution and a dry cloth. The surface should be completely dry before moving on.

Step 3: Positioning the cap

With the part clean, hold the cap over the designated area, aligning it carefully. Visual indicators or markings guide proper positioning. Double-check to ensure that the cap’s placement matches the product’s intended look and function.

Step 4: Applying the cap

Gently press the cap onto the part’s surface. Start with light pressure to allow adjustments. Gradually increase pressure as the cap adheres, ensuring a secure bond. Avoid excessive force to prevent damage. Follow the manufacturer’s instructions if adhesive is needed.

Step 5: Final check

After applying the cap, inspect it thoroughly. Check the alignment for evenness and symmetry. Look for gaps or irregularities indicating an improper fit. Verify that any locking mechanisms or features are engaged correctly. A meticulous final check ensures a successful application and a finished product that meets expectations.

FAQs

View all the products in our catalogue or contact us for additional information and advice on selecting, ordering and fitting plastic caps.

The Caplugs range of plastic protective products is created by injection moulding and dip moulding. Not all types of plastic are suitable for injection moulding. This article explains why thermoplastics are suitable as an injection moulding material.

In an earlier article, the injection moulding process,  in which plastics become liquid when heated, without losing flexibility, homogeneity and colour fastness, was explained. This group of plastics is also known as ‘thermoplastics’. Polypropylene and high density polyethylene (HDPE) are plastics commonly used for injection moulding. 

Plastic injection moulding from granulate to end product

Unlike thermosets, thermoplastics take on the shape of the product precisely. Under high pressure, the liquid plastic fills the injection mould, creating a product that is precise down to the smallest product detail. This accuracy is essential to achieve the exact geometry and dimensions of injection-moulded products. It also enables the sustainable use of plastic products, as there is little waste, and eliminates the need for further finishing. This saves considerably on production time and costs.

Plastic with a high moulding capacity

Thermoplastics can also be formed in liquid form and under high pressure in the cavity of an injection mould. This is necessary to achieve a high-quality plastic product that exactly meets all product requirements in terms of geometry, dimensions, and level of finish. The material used influences the choice of heating, cooling and removal from the mould. Polyethylene retains the same properties, from the granules at the beginning of the process to the injection moulded product at the end.

Plastic injection moulding: light and robust

Thermoplastics are lightweight materials that can take severe knocks and are not affected much by weather and environmental conditions. This makes Caplugs’ plastic protection and masking products ideal for the aviation, petrochemical, electrical engineering, and automotive industries, among others.

Plastic granules are reusable

A significant advantage of thermoplastics is its reusability through re-shredding and heating. Thermoplastics can be completely reused for injection moulding, or used for dip moulding or other production methods for numerous other applications. Thermoplastics can be used multiple times over.

Would you also like to have your product injection moulded? Or are you looking for a plastic moulded protective or masking product? View the product range in our catalogue or contact us for more information or a customised solution.

Caplugs uses injection moulding to manufacture plastic protection and masking products. As mentioned in the blog post, injection moulding is used in industrial production to make three-dimensional plastic parts at scale. This blog post goes into more detail about the advantages of injection moulding for plastic protective products.

Precision moulding for a high level of detail

In injection moulding, liquid plastic is injected into a mould under high pressure. This process can produce complex parts with a high level of detail. This precision in the sizing and geometry of the components makes a difference for high-quality products.

Customisation and design freedom

It may appear that injection moulding is only used to produce large numbers of standard plastic products. However, injection moulding is also used to make custom-made protective solutions. An injection mould can be designed and created to exactly meet the desired geometry, size, and specifications required. Caplugs has a baby injection moulding machine for small runs.

Cost-efficient mass production

The quality of the mould (jig) used in injection moulding is critical. Once this has been created, large quantities of identical plastic products can be produced quickly, using the same mould and a very low error rate. For the production of several identical products in one go, multiple moulds can be used.

Additional cost-savings

In addition to the ability to produce a large number of identical products, injection moulding benefits from high production speed, minimal material wastage, and a highly automated production method that requires little manual work or post-processing.

Caplugs, the specialist in plastic injection moulding

For more information on customised injection moulding products or to order our standard protective and/or masking products, please contact us.

Many protective products in the Caplugs range are made by injection moulding, including fully-customised products. This blog post explains the injection moulding process, and introduces its advantages.

What is injection moulding?

Injection moulding is commonly used in industrial production to produce three-dimensional plastic parts and products on a large scale. Molten plastic is injected into a mould before it cools and solidifies to take on the desired shape. Injection moulding is used in several industries, including automotive, electronics, packaging and medical.

The plastic injection moulding

Each stage of the injection moulding process helps make a robust, high-quality plastic product. This affects the geometry, dimensions, colour, and the level of finishing of the product.
The injection moulding process consists of four stages:

1. Plasticising

Plastic pellets (granules) are the base material for injection moulding. The material goes from a storage hopper through a large loader. From there, the granulate is transported further via a screw. During this process, the plastic is heated until it melts. At the end of this step, the granulate has turned into a liquid and homogeneous mass. 

2. Dosing

The molten plastic is transported through the screw and measured. The final dosage is determined by the size of the desired product. 

3. Injecting

After the accurately dosed liquid plastic has been made from the granulate, about 95 to 98% of the cavity in the injection mould is filled with the liquid plastic under high pressure from the screw. The injection mould is not filled completely to enable venting and cooling. The high injection pressure ensures that the liquid plastic takes on the shape of the mould precisely – and thus the form of the finished product.

4. Cooling/pressing 

After injection, the cooling process starts immediately. The plastic is gradually reduced to a solid form through cooling channels in the mould. Any air present is also squeezed out of the injection mould during cooling. To complete this phase, the final spaces in the mould cavity, created by air bubbles and plastic shrinkage during cooling, are filled with additional liquid plastic. This is called emphasising the injection mould. The solidification temperature can vary depending on the type of plastic, and is programmed before the injection moulding process begins. After the product has cooled sufficiently, the mould opens, and a robot gently removes the product. The injection-moulded products are placed in a tray or a box via a conveyor belt. 

The advantages of injection moulding

Injection moulding offers several advantages:

• It is possible to produce highly accurate and detailed parts.
• Complex shapes with minimal deviations can be made, ensuring consistent quality.
• The injection moulding process is a very efficient method of producing large numbers of identical plastic parts and products.
• Once the parameters are optimised, the injection moulding process can be repeated many times, making it highly cost-effective.
• High production speed, minimal material wastage and automated processes also contribute to cost savings.
• Due to the precision and finishing quality of the injection-moulded products, only minimal post-processing is required.

Find out more about these advantages in our blog on the advantages of injection moulding for protective and masking products or contact us.