In the plastic manufacturing industry, the durability and longevity of a plastic injection mould or mold are crucial for cost-effective production. Moulds are expensive and represent a significant investment. Mould life expectancy can range from less than 500 cycles to over 1 million depending on aspects like the quality of the mould and the material being moulded. Understanding the lifespan of these moulds can help plastic manufacturers plan for maintenance and replacements as well as allow them to anticipate production capacity. In this article, we’ll explore how long plastic injection moulds are expected to last and the factors that can contribute to their longevity.
How Do Injection Molds Wear Out?
Several factors can affect the durability and longevity of plastic injection moulds, including material selection and working environments. One significant factor is abrasion from the plastic being moulded, particularly when using glass-filled plastics. Additionally, chemical attack or corrosion from aggressive plastics like PVC or those containing flame retardant additives can cause moulds to wear out quickly. Fatigue from thermal cycling and the wear and tear of moving components, such as slides, lifters, and cores can also impact the mould’s lifespan. This is especially significant for unscrewing mechanisms that create screw threads in parts.
Plastic Injection Mould Material
Aluminium can be used for moulds processing low melt temperature plastics and low demand, simple parts or prototypes. Aluminium was more popular for these applications before modern mould-making machinery reduced the machining time of steel to be comparable with aluminium. This eliminated much of the cost advantage. More recently aluminium moulds have been made by 3D printing but these are less durable.
Various steels are the most popular mould materials. Pre-hardened or “P20” steels are the least expensive but difficult to machine and refurbish. They do not maintain highly polished surface finishes well. Most plastic injection moulds are made in fully hardened steel “H13” which is more durable and can be refurbished several times. This helps to increase serviceable life and maintain polished surfaces.
Stainless steel or “Stavax” is used for moulds processing chemically aggressive plastics such as those having flame retardant additives. It is relatively expensive but a prudent investment.
The materials used for both the mould and the plastic being moulded play a big role in how long the mould lasts. Steel molds for plastic injection are a common choice for their durability in high-volume production and can exceed one million cycles. Aluminium moulds for plastic injection are cheaper but they wear out faster making them suitable for low-volume production.
The type of thermoplastics used during manufacturing also matters as some plastics are more abrasive than others. Corrosive resins like PVC for example can damage aluminium moulds.
Plastic Injection Mould Design and Construction
A well-designed and precisely constructed mould will last longer. This is why investing in high-quality engineering is crucial. Higher-quality moulds have a much longer tool life and can last over 1 million cycles. Complex moulds can be more susceptible to wear and may require more maintenance due to their intricate parts. The way the components within the tool are arranged and the overall mould design can also dictate how long the mould will last.
Plastic injection Mould Maintenance
Poorly maintained moulds not only cause defects and production delays but also significantly shorten the mould’s lifespan. This is why regular maintenance practices such as cleaning, lubricating, and inspecting are essential. With regular inspections, you can help identify any early signs of damage and extend the injection mould life expectancy with a minor repair.
Production Volume
The number of cycles plastic injection mould tools are put through directly impacts their longevity. High production volumes mean more frequent use, which accelerates wear and tear. Manufacturers should ensure their production demands are combined with increased mould maintenance to avoid overworking the moulds and compromising their durability.
Operational Conditions
Plastic injection moulding operational conditions, including injection pressures, temperatures, and cycle times, also affect mould lifespan. High pressures and extreme temperatures can cause stress on the mould materials, while fast cycle times and increased production speed can also increase the rate of wear. By adjusting these parameters to optimal levels, manufacturers can help prolong the mould longevity.
How Long Does An Injection Mold Last?
Injection moulding tools can have varied life expectancies depending on the factors mentioned and the injection moulding plastic materials. Here are some general estimates for different types of moulds and production volume levels.
- Prototype Moulds – These typically last for a few hundred to a few thousand cycles and are used for low-volume production or testing.
- Medium production moulds – These moulds are built for medium production volumes and can last around 500,000 cycles
- High-Production Moulds – Usually made from hardened steel, these moulds can last for over a million cycles if properly maintained.
Plastic Injection Moulds from Fern Plastic
When it comes to effective plastic manufacturing, a well-designed and maintained plastic injection mould is essential. At Fern Plastics we offer plastic injection mould services that ensure your moulds are durable and efficient. Whether you need new moulds, repairs and maintenance or reshoring support for mould transfers, we can help.
For more information about our plastic injection mould manufacturing, contact us online or call 01902 758282.