In an aluminium foundry, the energy bill is often an "invisible" cost item, with kWh accumulating rapidly as production flows. Energy efficiency is the most practical way to produce more parts in the same shift while maintaining more stable quality.

The largest share of energy consumption occurs during melting, accounting for up to 50 per cent of the total. Added to this are the costs of keeping the furnace hot during holding, transfer losses in ladles and lines, mould heating and auxiliary equipment (fans, pumps, compressors). Each step appears small on its own, but together they create a significant cost burden.

The critical point is this: Energy cost, capacity and quality are interlinked. Temperature fluctuations and long holding times increase the risk of oxidation and hydrogen pick-up, raising scrap levels; as scrap increases, the need for remelting arises and kWh consumption grows further. Therefore, energy management is not just about saving, but also about process control.

In this article, I will share ways to reduce kWh consumption and scrap rates with practical and measurable steps. We will also briefly outline the energy advantage of recycled aluminium, which offers significant savings potential of approximately 14 MWh per tonne compared to primary production. To better understand the approach and production perspective, you can also take a look at the Erapres page.

Make energy loss visible first: measure, target, track If you want to reduce energy consumption, you must first make it visible. In foundries, energy loss rarely occurs in one place; it trickles away at many points. Therefore, don't think of measurement as simply checking the electricity meter; the true picture emerges when electricity, natural gas, compressed air, and cooling water are monitored separately.

A practical starting point: keep the main input measurement, but at least add a sub-meter or flow measurement for the ovens, compressor line and cooling unit. That way, instead of the excuse "production increased, so the bill increased," you can discuss which equipment contributed how much. Measurement is the foundation of setting targets, and monitoring brings the target down to earth.

Basic energy map: melting furnace, holding, transfer, mould, auxiliaries
Think of the casting process as an energy map, with each station producing a different type of loss:

Melting furnace (electric or natural gas): This is where the greatest consumption occurs. The temperature of the charging material, the frequency of opening the furnace door, the insulation condition and the combustion setting directly affect kWh or Nm³ consumption. When furnace efficiency drops, not only energy but also melt quality fluctuates.
Holding: The phrase "We're just keeping it warm" is usually the most expensive phrase. Example: When the casting cell is idle for 45 minutes, the holding furnace continuously consumes energy to maintain the same temperature. On top of that, oxidation increases on the molten surface, the risk of hydrogen absorption rises, and scrap increases. In other words, holding silently erodes both energy and quality at the same time.
Transfer (pot, launder, ladle): Open transfer lines, poor insulation and unnecessary long distances create the need for "reheating". Transfer loss is generally compensated for by higher set values on the melting side, which inflates the bill.
Mould and mould heating: If the mould temperature is unstable, the cycle lengthens, the first part's waste increases, and reheating cycles begin. Here, energy loss generally manifests as time loss.
Yardımcı ekipmanlar (hidrolik ünite, chiller, kompresör): Bunlar “küçük ama sürekli tüketim” kaynağıdır. Kompresör gece kaçakla çalışır, chiller kısmi yükte verimsiz döner, hidrolik ünite boştayken bile yağ soğutması ister. Tek tek bakınca küçük görünür, 7 gün 24 saat eklenince ciddi bir taban yük oluşturur.
kWh/ton, çevrim süresi, hurda oranı: doğru KPI’lar nasıl seçilir?
KPI seçerken amaç, sahada aksiyona dönüşmeyen veri üretmek değil, neden-sonuç ilişkisini yakalamaktır. Dökümhane için pratik 5 KPI çoğu zaman yeterlidir:

Total energy intensity (kWh/tonne): If you track electricity and natural gas separately, report both per tonne. You can make comparisons even if production quantities change.
Melting and holding energy intensity (kWh/tonne of melt): Large deviations generally indicate waiting time, incorrect set values or insulation problems.
Cycle time (seconds/piece): This is directly related to energy. As the cycle lengthens, furnaces, chillers, and hydraulic systems run longer.
Scrap rate (percentage): Scrap is the most severe form of energy loss, as it means remelting.
Specific compressed air consumption (kWh or Nm³/tonne): Leaks and incorrect pressure settings are quickly apparent here.
Always monitor KPIs alongside quality. If energy decreases while porosity increases, you are actually shifting the cost elsewhere. A simple target example: "Reduce the total kWh/ton value by 7 per cent within 8 weeks, keep scrap below 3 per cent, and shorten the cycle time by an average of 2 seconds."

The weekly inspection routine also makes your job easier: On Monday, obtain last week's energy and production report; on Tuesday, check the furnace insulation and heat leakage points; on Wednesday, perform a compressor leak test; on Thursday, verify the chiller and water flow rates; on Friday, close the KPIs along with the scrap and quality reports.

MES and automation for real-time monitoring: where is the waste, and how can it be identified?
In an automated casting cell, most waste appears as "idle time," but the root cause is often different: the mould is not ready, the robot cannot pick up the part, the temperature is not maintained, the operator is waiting for approval. When these stoppages are recorded with their cause codes using MES or centralised monitoring, recurring losses immediately become apparent.

Real-time monitoring ensures the following: When the line stops, the holding furnace does not run hot for no reason, the chiller is scaled according to need, and robot and press cycles remain synchronised. As a result, repeated heating is reduced, transfer delays are shortened, and the cycle becomes more stable. This approach relies less on technical terms and more on a simple habit: making decisions based on data, not guesswork.

At this point, correct configuration and operator habits in the field are crucial. Service and training support ensure that the team's measurement discipline is established and process settings are standardised, preventing targets from remaining on paper.

Melting and holding savings: the biggest share is here If you want to reduce energy consumption in the foundry, you should focus on where the largest share lies: melting and holding. Every "small" improvement made here pays off twice. Firstly, fuel or electricity consumption is reduced directly. Secondly, metal loss (oxides, slag, dross) is reduced; less loss means less re-melting.

Think of this part as heat management. If you keep the heat in the right place, the metal remains calm, the temperature band remains stable, and waiting times are not prolonged. If the heat gets out of control, oxide builds up on the surface, slag increases, more "cleaning" is done in the pot, and ultimately you lose both energy and net metal.

Charging plan and recycling: energy consumption decreases with the right material mix
Recycled aluminium offers a significant energy advantage. Compared to primary metal production, you can process the same mass with much lower energy consumption. The key issue on site is this: energy savings are only sustainable without compromising quality if the right charging plan is implemented.

Random cold charging creates temperature fluctuations in the furnace. As the metal melts, the bath temperature fluctuates, the burner operates more aggressively, and the time increases. This fluctuation increases the following two risks: increased oxidation and deviation of casting parameters. The result is increased energy consumption, increased scrap, and the start of a remelting cycle.

Set up the charging plan using simple logic: fixed quality target, fixed temperature band, fixed flow. When determining the mixture, pay attention to the following:

Classification: Sort scrap according to alloy groups. If the mixture is uncertain, correction alloys and reprocessing increase.
Dry charging: Moist material expends heat to evaporate water. It also creates splashing and safety risks.
Material cleanliness: Paint, oil, dirt and plastic residues increase both fumes and emissions, as well as slag formation.
To clarify the melting process, you can also refer to the melting furnace operating principle content as a useful reference on site; establishing the correct loading rhythm is the fastest point of gain in most plants.

January settings and maintenance: burner, refractory, cover, leaks
Oven adjustment is often seen as a "job for the expert", but it can be managed with a simple framework. In burner systems, the goal is this: burn the fuel completely, keep the heat inside, and avoid letting in unnecessary air.

Combustion adjustment and excess oxygen: Excess air causes more hot gas to escape through the chimney. This means that some of the heat you pay for is being lost. If the flame colour and stability are compromised, the adjustment may be off.
Flame adjustment: The flame should not "beat" the top of the bath. Excessive turbulence can increase surface oxidation.
Refractory and cover leaks: Think of this as leaving a window open in your house. You burn more to heat the interior, but the heat escapes. Refractory cracks, lid misalignment, worn lid gaskets, or leaks around the observation window generally have the same effect.
A practical maintenance schedule implemented on-site can stop losses before a fault occurs:

Daily visual inspection: Check for cover seating marks, flame behaviour, unexpected smoke and hot spots.
Weekly cleaning and brief test: Burner nozzle and air line check, cover and hinge gaps, simple leak scan.
Monthly leak check: Cover perimeter, service covers, flue line joints, crack map on refractory surface.
Scheduled refractory maintenance: Repairing fine cracks early delays major overhaul.
Waste heat recovery: Recover energy from the flue gas. Hot flue gas is energy flying out of your pocket. The most practical scenarios for recovering this energy are: charge preheating, plant heating and domestic hot water heating. Recovery is particularly meaningful in continuously operating furnaces because the hot gas flow is regular.

Start your investment decision with these three questions, without getting bogged down in complex tables:

What is the current consumption (natural gas or electricity)?
How many hours per year does the stove operate?
What is the target payback period in months or years?
These three pieces of data provide a quick answer to the question "is it worth doing" in most projects. But don't overlook two considerations: safety and emissions compliance. Insulation for combustion products and hot surfaces, access safety and appropriate filtration are essential; otherwise, the gain creates operational risk.

Do not raise the melting temperature excessively: target temperature without compromising quality Excessive superheating silently inflates your energy bill. As the metal exceeds the target, two things happen: more heating is required during holding, and oxide formation on the surface accelerates. As oxide and slag increase, net metal decreases; when net metal decreases, more melting is required for the same number of parts.

Therefore, work with a target temperature band rather than a single set value. The purpose of the band is to tolerate mould and transfer losses while avoiding unnecessary heating. The measurement point and measurement time should also be standardised; different operators taking measurements at different times will lead to different decisions, even for the same batch.

Operator habit is the determining factor here. Example: Increasing the set value by 10-15 degrees before each casting to ensure the job is guaranteed results in both energy and dross being wasted at the end of the day. The most practical way to prevent this is to write a short and clear standard operating procedure: measure, verify the band, make minor adjustments if necessary, record. Once this discipline is established, you will experience less downtime, fewer remeltings, and more stable temperatures.

Casting cell efficiency: reduce cycle time, minimise rework
Energy is not only consumed in the furnace. When the cycle time increases, the press's hydraulic unit operates for longer, and the mould temperature control device, chiller, pumps, and robots remain in operation for extended periods. What we call efficiency in a high-pressure die casting (HPDC) cell is actually about controlling time. When you control time, both kWh/part decreases and the re-casting and re-melting cycle is broken because quality fluctuations are reduced.

Mould temperature control: stable heat, less scrap, less energy
If the mould temperature fluctuates from day to day, think of the cell as if you were "taking the same part out of a different mould each time". Temperature fluctuations increase the risk of shrinkage, porosity, and cold joints. The common result of these defects is this: the part either becomes scrap or requires reworking; as scrap increases, the metal must be remelted, and energy is paid for twice.

The quickest gain on the field is to maintain the mould temperature within a narrow band rather than varying it over a wide range. Practical points:

Temperature control unit (TCU) settings: Instead of "eyeballing" the settings, define a target temperature band for each mould. The mould's behaviour in the first part in the morning should be the same as its behaviour in the middle of the shift. Water circuit cleaning: Limescale and sediment narrow the water channels. Flow rate decreases, the mould overheats in one area and cools in another. This also extends the cycle, inflating lubrication and cooling times.
Correct flow rate setting: Excessive flow is not always good. Excessive cooling leads to premature solidification of the metal during filling and cold joining; you then try to compensate by increasing the injection speed and temperature, which again increases energy consumption.
Optimise dosing and metal transfer: waiting times consume energy
Waiting in the casting cell is an invisible energy drain. When there is unnecessary waiting during molten metal transfer, you experience losses on both sides: Holding time in the furnace increases, and presses, hydraulics, cooling, and auxiliary equipment in the cell run idle. On top of that, the temperature drops while the metal waits in the pot, and the operator increases the set value to compensate for this drop. This also feeds the risk of oxidation and gas absorption.

Here, discipline is not about "running fast" but keeping the flow synchronised. The following scenario is common in plants using metered feeding: When metal arrives in the same quantity and at the same rhythm for each stroke, filling becomes more stable, the parameter range narrows, and scrap decreases. When planning this approach, low-pressure metered furnace solutions provide a good reference framework for understanding the metering logic and cell feeding discipline.

Robotic and automated cells: achieving the same quality with less energy
The robot's contribution is not just labour. When the robot picks up the part at the same time, from the same point and at the same speed, the cycle time is reduced. Most importantly, the mould's open time is reduced. The longer the mould remains open, the greater the heat loss; then, to bring the mould back to the target temperature, you either extend the cycle or increase heating and lubrication. Both of these require energy.

We can summarise automation in terms of energy in two sentences: Less waiting, less re-melting. Because the robot consistently performs tasks such as picking, deburring, spraying (lubricating) and even simple controls, the process deviates less. As deviation decreases, scrap decreases, and as scrap decreases, the need for remelting decreases. If you would like to see examples in the field, the applications on the Aluminium injection robots category page provide an idea of how cell standardisation is established.

Break the scrap and remelting cycle: quality root cause analysis
The quickest way to reduce scrap is to stop viewing every defect as a "one-off". The most common causes of scrap in HPDC are generally: gas and air entrapment, oxide and slag carryover, mould temperature deviation, incorrect lubrication (excessive or insufficient), inadequate ventilation or vacuum, incorrect injection parameters (speed, pressure, phase transition).

There is no need for a complex system to address the root cause. A simple flow works in most facilities:

Define the problem: Error type, part area, which shift and which mould did it occur in? Collect data: Mould temperature trend, cycle time, metal temperature, lubrication time, is there vacuum, have the parameters changed? Conduct a controlled trial: Adjust a single variable and monitor the results using the same KPIs.
Standardise: Link the good result to the instruction and recipe, reduce operator variance.
This approach yields a net energy gain: remelting decreases, cell downtime shortens, and more sound parts are produced on the same line during the same shift. This is the most tangible manifestation of energy efficiency on the shop floor.

Quick wins in auxiliary systems: compressors, cooling, hydraulics, lighting
Significant savings in foundries often start with furnaces, but the base load that inflates the bill is usually the auxiliary systems. Compressors, chillers, hydraulic units and lighting operate around the clock, and small losses accumulate over time. The good news is that low-cost, quick-return measures are readily available in these areas. The bad news is that, if left unchecked, they silently erode production continuity and equipment lifespan.

Compressed air leaks and correct pressure: invisible energy waste Compressed air is one of the most expensive auxiliary energies in foundries. The most frustrating aspect is that leaks are often "invisible". Parts are removed during the shift, but leaks continue to run the compressor overnight.

Establish a simple routine that works in the field:

Leak detection tour: Once a week, walk along the line when production is low. Couplings, quick connectors, hoses and regulators are the first suspects. Ultrasonic leak detection: Detects even undetectable leaks. Scan once to generate a "leak map", then check the same points every week.
Shift closing check: Provide the operator with a clear checklist. Details such as an idle blow gun, an open purge line, or an unnecessarily left-open valve are caught here.
Increasing the pressure "just to be safe" translates directly into electricity consumption. As a general field rule, increasing the pressure by 1 bar can increase compressor energy consumption by approximately 7%. In most stations, the real need is not higher pressure, but proper regulation and leak-free lines.

Cooling water and chiller management: correct temperature, correct flow rate When the cooling system operates inefficiently, both the chiller and pumps consume more energy. The most common root causes are water quality and heat transfer surfaces. Scaling and dirty heat exchangers reduce heat transfer. The system runs longer to reach the target temperature, which increases kWh consumption.

Practical tips:

Heat exchanger and filter cleaning: If the pressure loss has increased or the water is returning hotter under the same conditions, it is time for cleaning. Adjust the set value according to the season: Insisting on the same low set value in winter creates unnecessary compressor load. The highest cooling water temperature allowed by the process is generally the most economical point.
Free cooling (if applicable): If outdoor air and process conditions are suitable, you can reduce the chiller compressor load during certain periods and lighten the load with a dry cooler or tower.
Do not view water leaks as "just water waste". A leak means that the lost water must be recooled and repumped, which means paying for energy over and over again.

Efficiency in hydraulic units and motors: maintenance, oil, driver settings
The hydraulic system is the heart of the pressure die-casting cell. If the oil becomes contaminated or the filter clogs, the pump is forced to work harder, heat increases, and the need for cooling grows. The result is both increased electricity consumption and a higher risk of failure.

Here are three points that yield quick results:

Filter and oil discipline: As the filter becomes clogged, flow decreases and pump load increases. If the oil's viscosity deteriorates, the system overheats. Leakage and bypass control: Internal leaks consume power without being visible. An increase in oil temperature often provides a clue.
VSD (variable speed drive) logic: The motor does not always need to run at full speed. When demand decreases, the speed drops, and power consumption also decreases. In suitable systems, this approach reduces the base load. For hydraulic efficiency-focused solutions, you can also look at equipment options such as inverters and Green Pump features: Technical specifications of cold chamber injection presses. Prioritise safety on this side. Do not perform adjustments or maintenance without following the manufacturer's instructions, pressure limits, and lockout/tagout (LOTO) rules.

Lighting and heating, such as "fixed loads": the cumulative effect of small steps Lighting, local heaters and open doors are loads that may seem small but operate daily. Here, the gain comes not from a single action but from the cumulative effect of numerous correct small steps.

Feasible moves:

Replace old light fittings with LEDs to illuminate the same area using less power.
Add motion sensors and timers to storage areas, corridors and infrequently used spaces.
Instead of heating large volumes, use localised heating at operator points.
Install strip curtains or high-speed doors on doors to reduce heat loss.
View these tasks not as "standalone miracles" but as part of an overall energy plan for the site. As leaks, incorrect settings, and unnecessary operating times decrease, it becomes easier to maintain the same production with more stable and lower energy consumption.

Conclusion Energy efficiency in aluminium casting not only reduces costs but also tightens process control. Unnecessary kWh during melting and holding, extended cycle times in the cell, mould temperature fluctuations, scrap, and remelting cycles feed into each other. By breaking this chain, you can produce more robust parts with the same or even more stable quality.

A practical summary that delivers quick results in the field:

No improvement without measurement; track kWh/tonne, cycle time and scrap in the same table.
Adjust the furnace, refractory, cover and hot spot leaks; retain heat inside.
Reduce holding and transfer delays, synchronise metal flow with the cell.
Keep mould temperature stable within a narrow band, reduce first piece scrap and cycle time.
Link scrap to root cause, convert every recurring error into a standard work instruction.
Eliminate base loads such as compressor leaks, incorrect pressure settings, dirty heat exchangers, and idling hydraulics.
Align the team towards the same goal, incorporate measurement and adjustment discipline into the daily routine.
Select a small pilot for the start, measure for 2-4 weeks in a single cell or single furnace, establish a standard, then roll out.

Do this today: calculate your current consumption, select the two biggest losses, and write a clear action plan. Which step is inflating your kWh the most?