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Waste reduction to lower CO₂

By: Austin Watkins

Waste is an inevitable part of the manufacturing process; one that can take a hit on a company’s bottom line. But when businesses prioritize waste reduction at the source, they save time, money and resources that can easily be measured to show efforts in lowering CO₂.

Defining waste reduction

Waste reduction is the practice of using fewer materials and energy to minimize the amount of waste generated. This leads to lower CO₂ emissions with less materials and products that need to be recycled, incinerated or put into landfills.

Ways to reduce waste 

When considering the waste hierarchy, “reduce” is the first strategy and waste reduction is an approach to achieve it. There are many ways to reduce waste, including scheduling colour changes, proactive maintenance plans, reusing scrap waste in plants, and the use of a purging compound.

Schedule colour changes

When you schedule colour changes from light to dark, this lowers the number of long runs with streaky, unacceptable parts between colors. It's a straightforward tactic that can be implemented into the production schedule.

Scheduling colour changes only works when you have the luxury of planning production runs in advance. With just-in-time production or when only using a few colours, this is not often a feasible approach.

Proactive maintence plans 

Proactive maintenance plans are critical to preventing contamination from accumulating over the long-term and then causing unexpected, long-running delays such as black specks.

Well-timed screw pulls, routine maintenance purges, and even regular heater-band checks can ensure that burned material and other contaminants don't accumulate within your machine.

Screw pulls or extended cleans normally require a lot of time and labour from the manufacturing or maintenance team, so plan accordingly.

Reuse waste in the plant 

When waste is reused in the plant, it can be placed back into black parts, used as a post-purge, or used as startup material. This is a great way to reduce the need for transportation between producer and recycler and back.

To achieve this, preprocessing equipment such as grinders are typically required onsite. Additionally, this process involves the reintroduction of degraded or contaminated materials back into machines; something to consider as customer requirements may not allow reprocessed polymers.

Use purging compounds

A high-quality purging compound can be used for many different applications and should more than pay for itself by saving material and time.

With many different types of compounds on the market, the task of finding one could feel very daunting. Our purging solutions experts are at the ready to support your journey in implementing purging compounds. Contact us today to receive a free sample to see the benefits of this process firsthand in your facilities.

Designing for waste reduction

Designing for waste reduction means thinking of the product's finish before it is even moulded. By thinking of the full life cycle (and post-life) for a product at the design phase, challenges that may emerge later in the product for feasible recycling can be easily overcome up front. For this to be successful, both the customer and producer need to openly discuss this goal from the onset.

While product purpose, shape and durability are key factors in the decision-making process as well, in this initial phase, it’s critical to consider the products end-of-life goal. Certain polymers have a much larger demand in the post-consumer market than others due to reprocessing feasibility as well as customer demand.


PET and olefinic resins are the most common re-processed materials. Sensitive or engineering resins can be harder to reprocess and also have a lower demand.

Measuring waste reduction

graphic clipboard with production and waste evaluation text
Waste reduction can be an easier metric to measure and monitor; it can be less complex when compared to calculating machine time or the cost of labour.

Let’s break it down with a very simplified example:

   -  You need 1 kilo per part and in the next run, you need to make 1,000 parts.

   -  In a perfect production, you would make 1,000 parts with 1,000 kilos.

   -  Rather, you find that you’ve used 1,300 kilos to make your 1000 parts.

   -  Then the answer is clear. You had 300 kilos of waste in that production run.

The benefits of waste reduction

Waste reduction lowers CO₂ emissions. How? By lowering the amount that needs to be recycled. And while recycling is a critical part of the waste hierarchy, it still has its own carbon footprint (transporting, sorting, reprocessing, transporting back). By focusing on reducing waste at the source, it’s possible to reduce the carbon footprint from the top down.

Additionally, less waste means fewer raw materials needed for production. As we saw earlier this year, large resin demands cannot always be met and it is only expected to rise in the coming years.

Lastly, less waste also means more running time for your machines; therefore, machines can be optimally used to produce money-generating products rather than wasted material. Additionally, with machines running optimally, the energy that was needed before to achieve the same level of clean is reduced. Combining these two factors is the ultimate CO2 and cost reduction strategy.

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Austin Watkins

Austin Watkins International Product Manager Advanced Materials IMCD Group
For nearly 10 years, Austin Watkins has worked in the field of commercial purging compounds with the world’s leading thermoplastic moulders. He has conducted more than 100 purging trials across the globe, tackling a vast range of downtime-causing issues and helping to reduce time and material waste due to machine contamination. With IMCD, he continues his work collaborating with local engineers and plant managers to help make moulding plants as efficient as possible.