Having just committed to invest in the company’s first fully automated, energy-efficient mass production injection moulding cell, Broanmain Plastics explores the various externalities (positive and negative) that arise when manufacturing components of any size, on any scale.
Broanmain Plastics
After five decades of mass application, the volume of imperishable plastic waste and the detrimental impact this has on the environment inevitably raises cause for concern among scientists, governments, society and activists. Many blame the mass manufacturing of plastics for these environmental issues. However, it is often omitted how integral plastic is to daily lives and wellbeing, and that the root cause of plastic waste, carbon emissions and pollution can more often be attributed to inefficient production methods and waste mismanagement.
‘The zero-impact agenda’, ‘achieving net-zero’ and ‘zero-impact manufacturing’, are all terms frequently discussed when tackling topics surrounding sustainable production processes. However, any form of production uses resources, whether biodegradable, made of recyclate materials, carved from wood or printed on hemp. So, how do we make plastic production more sustainable? Operations Manager at Broanmain Plastics, Thomas Catinat shares his views and mass-manufacturing insight.
The sustainable value of plastics
Although an unpopular opinion, plastics remain essential.
Plastic packaging mitigates food waste attributed to spoiled product. Healthcare plastics are essential to patient and health worker safety and medical diagnosis and treatment plans. Plastics are lightweight and therefore a more fuel-efficient way to transport food and liquids, reducing energy consumption, emissions of CO2 and transport costs. Plastic also makes vehicles, aircrafts and boats lighter, meaning they do not consume as much fuel, nor release as much CO2 compared to other materials.
For plastics produced via injection moulding in particular, the scale of the sustainability challenge is focused on reducing waste, minimising the impact on the environment and being more energy efficient. The European Strategy for Plastics in a Circular Economy supports a production model that minimises waste by encouraging innovation to ensure productivity from each unit of raw material is maximised.
Producing more using less
Injection moulding for plastic manufacturing is far more energy-efficient and produces less waste than other methods. However, the type of production volume can affect the sustainability, efficiency and overall cost-effectiveness of a product’s manufacturing process.
Typically, low-volume production runs, also known as small-batch or limited-run batch, involve fewer than 10,000 pieces of a component. There are many benefits to this method, as lower initial costs and shorter turnaround times make it easier for new or smaller companies with tight budgets to produce their parts and products.
In comparison, high-volume production runs generally involve several hundred thousand to millions of parts. Mass production may have been cast as the environmental enemy, but when appropriately managed, can often be more sustainable for the environment than low-volume, batch production runs due to reduced plastic waste, fewer start-ups and optimised energy usage.
Tooling is often a key part of the economics in plastic injection moulding and is the biggest one-time expense. For many production runs, no matter the volume, the tooling cost remains the same. Some small batch or limited batch runs may utilise aluminium tooling rather than hardened steel tools. However, these are hard to scale up if a company wants to expand production as they lack durability and often require replacing.
Amortisation of the tooling cost is an essential part of the equation. Dividing the number of parts that are made by the injection moulding tool over its useful life can help to reduce the cost per part. These measurements can also assist with understanding how other processing variables, for example energy consumption, are impacted by tool quality.
Moreover, mass manufacturing can actually have less of an impact on the environment than batch manufacturing. It’s all about having a clear plan and managing plastic waste effectively. When utilised well, economies of scale, high volume production runs, secure storage facilities and Kanban can help OEMs fully maximise their costs savings, boost profitability and be more environmentally conscious.
Economies of scale
As well as creating cost advantages per unit, the transition to efficient, cleaner production is another way to spur economies of scale. Deployment of more efficient injection moulding machines can lead to less energy consumption, fewer product defects and consequently less material waste. This can induce cost reductions, which incentivises more deployment of cleaner technology.
Additionally, once a cleaner, more efficient moulding machine is switched on and is running, it has the potential to become more efficient and productive.
Putting this into context, Thomas explains: “Think of it like your domestic washing machine. You could put in four pairs of socks or run a full cycle. The energy and water consumption will be the same, the output very different. Providing manufacturers aren’t over-producing and generating excessive waste, mass-production, when utilised with good storage logistics and Kanban systems, can be more resource efficient and get you closer to zero impact.”