How You can Reduce Energy Costs in Plastic Processing in 5 Steps - Part 2

The plastics injection moulding industry has advanced dramatically over the past couple of decades, but it continues to be an energy-intensive one. This, in turn, can lead to considerable costs.

Injection moulding plants can reduce their energy consumption, however, by developing a structured strategy comprising practical management, maintenance and investment actions. If done well, it could lead to energy consumption savings by up to 30%!

There are a number of ways to do so – including picking the right hydraulic oil, which was highlighted in our earlier article.

Below are 5 other ways:

  1. Understand what your ‘energy fingerprint’ is

In an injection moulding plant, energy use is variable, controllable and directly related to production. The key to understanding energy consumption is the Performance Characteristic Line (PCL), which provides a unique ‘energy fingerprint’ of a plant.

Armed with this, injection moulders can predict plant energy usage for any period based on actual or anticipated production volumes and integrate that data into their business accounting system for reporting and monitoring purposes.

They can also compare their PCL result against other plants, to monitor and benchmark their performance against global averages.

  1. Optimise your injection moulding machines

The base load (i.e. the energy used at zero production) can account for 75% of a standard injection moulding machine’s energy consumption.

By examining the moulding cycles through a machine’s power draw, the base load can be optimised through slight adjustments of the injection speed, clamp force, hold and cooling time.

Additionally, it is important that businesses pay attention to the technological advancements and adapt accordingly.

Today’s injection moulding machine technology is far more energy efficient than 20 years’ ago with the arrival of all-electric and hybrid machines. At a conservative estimate, modern hydraulic injection moulding machines are 25% more energy efficient than those manufactured in 1997. Meanwhile, the best all-electric machines may be up to 80% more energy efficient than their hydraulic predecessors.

By investing in more energy efficient machines and methods, it will not hinder but instead increase production rates too. It’s an all-round win-win situation.

  1. Don’t forget about the peripherals

Plastics processors should pay attention to their peripherals too. Often ignored, peripherals can provide significant energy savings in an injection moulding plant.

Simply fitting insulation to barrel heaters (which account for up to 25% of the energy input of an injection moulding machine) can cut heating costs by 50%!

  1. Minimise and boost moulding plant services

Elements such as compressed air, chilled water and dryers are essential in any injection moulding plant, and can be effectively managed and optimised to reduce energy use. These alone account for an approximate 30-35% of energy used.

Reducing leaks, dropping pressures and improving pipework for compressed air can cut compressor energy consumption by up to half. Additionally, installing insulation and variable speed drives (VSDs) to cooling tower fan can cut the cost of chilled water by up to 25%.

Similarly, the energy use during the drying process can be minimised too. Limit drying to the materials that truly need it and store them properly in a warm and dry environment.

Motors should not be overlooked as well. Turn off motors that are not contributing to production – every kW of fully loaded motor costs around $1,000 a year. Plants should ideally install VSDs to match motor speeds to demand, practice good maintenance and upgrade to new technology when possible.

  1. Manage energy usage

Energy efficiency is not all about hardware; the way a moulding plant operates plays a major role too. Staff can be trained and empowered to switch off machines, processes and services, which can lead to energy reductions of up to 20%!

Buildings and their associated services account for around 8% of total energy use in a typical injection moulding operation. It might be a small percentage, but there is room for improvement. For instance, LED lamps can be used instead as they are highly energy efficient, offer a long life, provide high quality illumination and require very little maintenance.

And heating – traditionally a low energy priority for injection moulding sites as process losses provide considerable amounts of space heating – can also be optimised. Improvement measures include air leakage reductions, better insulation as well as optimised setting and control.

To find out more and develop your own edge in today’s competitive industry, download the free ‘Energy Saving Guide for Injection Moulding Companies’.

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Anonymous
  • ES ASOMBROSO VER COMO HA IDO EVOLUCIONADO LA INDUSTRIA DEL PROCESAMIENTO DEL PLÁSTICO, HACE ALGUNOS AÑOS CUANDO EMPECE MI VIDA LABORAL , ESTUVE EN UNA EMPRESA DONDE LA INYECCIÓN DE PLÁSTICO SE REALIZABA EN MOLDES PIEZA POR PIEZA DONDE HABÍA QUE INYECTAR EL PLÁSTICO CALCULANDO LA FUERZA Y LA VELOCIDAD CON QUE SE INYECTARA EN EL MOLDE PARA QUE NO SE HICIERAN GRUMOS Y BURBUJAS A LA PIEZA, ERA TODAS UN ARTE LA MANUFACTURA , Y LAS MAQUINAS TAN RUDIMENTARIAS QUE SE ENGRASABA LA MANIVELA  CON CUALQUIER GRASA QUE SE TENIA A LA MANO, Y LA CANTIDAD DE ENERGÍA QUE SE USABA PARA TENER ENCENDIDAS LAS RESISTENCIAS DE LA MAQUINA CON LA QUE SE DERRETÍA LOS PELLETS DE PLÁSTICO A INYECTAR, IMAGÍNENSE , LLENAR CONTENEDOR CON PELLETS(que alcanzaba aproximadamente 10 descargas), ESPERA QUE SE DERRITIERA , PONER EL MOLDE , HACER LA LABOR DE INYECCIÓN, SACAR EL MOLDE , ABRIRLO , VOLVERLO A CERRAR( era una gran labor abrir y cerrar los moldes), volver a meter molde y de nuevo el mismo proceso, las manivelas que había que bajar y subir con la fuerza de uno mismo , eran muy duras  por la falta de una grasa adecuada, la energía eléctrica para obtener una pieza era exagerada,  ahora con las nuevas tecnologías y con las grasas adecuadas la labor se simplifica y el consumo energético.  

  • Excelente información sobre los pasos para la reducción de costos de energía , en el proceso de moldeo.