The lights-sparse versus the lights-out factory — Part 1

Siemens Ltd

Wednesday, 06 July, 2022

The lights-sparse versus the lights-out factory — Part 1

The concept of a ‘lights-out’ factory — one in which the requirements for human activity are so minimal that the facility can operate in the dark — has been around for decades, but the digital and automation technologies needed to make it a reality at scale are just now maturing. At the same time, new market trends and perennial issues like questions about labour versus automation are making the realisation of the lights-out factory that much more challenging. Widespread deployment of lights-out factories globally across industries may be years or decades away, but forward-looking manufacturers may seize opportunities today to implement lights-out processes within their conventional and smart factories — making for a ‘lights-sparse’ facility or production line.

‘Lights-out’ concepts and real-world manufacturing

The global manufacturing community has long been intrigued by the notional concept of a completely self-sufficient factory in which the only human interactions are the placing of orders and receipt of finished products. Although this blue-sky version is unlikely to completely materialise on a large scale in the near term, it is reasonable to ask which concepts behind autonomous manufacturing might come to fruition. Importantly, any realisation of these concepts must move beyond novelty and prove truly beneficial to manufacturers — improving productivity, quality, sustainability, consistency, safety, profits and certainty. According to a Gartner study, by 2025, 60% of manufacturers will have more than two completely lights-out processes in at least one of their facilities. It is an ambitious expectation for lights-out production.

The lights-out factory or ‘dark factory’ made its way from the pages of science fiction (first popularised in the 1955 short story Autofac, by US author Philip K Dick) to the floors of actual manufacturing facilities in the latter half of the twentieth century. Called lights-out factories because they require so little human intervention that they can operate in the dark, such facilities were attempted in earnest beginning in the 1980s. These early efforts were unsuccessful, but several success stories beginning in 2001 have been widely publicised and discussed. Perhaps the most well known is the FANUC factory in Japan that uses robots to build robots, with no human intervention reportedly for a month or more.

FANUC and other manufacturing companies have demonstrated that the lights-out factory is both possible and profitable — for their particular applications. The question remains whether it makes sense for your company to build or convert to a lights-out factory, or more likely, convert certain processes within your facility to run lights-out.

Ambitious expectations for lights-out production in 2025.

Ambitious expectations for lights-out production in 2025. For a larger image click here.

For the foreseeable future, converting or building a factory for comprehensive lights-out operation depends on several factors and could become a costly endeavour. A complete lights-out factory must be outfitted with automated guided vehicles (AGVs) and the factory floor infrastructure and floor plan that support them; self-loading and unloading production equipment or robots to complete each of the production steps; self-configuring machines such as CNC machine tools and robots that change out their own end effectors; modular production stations that can be automatically resequenced depending on the particular product being manufactured; vision or other non-destructive automated systems for real-time quality inspections; reconfigurable conveyor belts; pick-and-place machines; advanced networks like 5G; sensors, sensors and more sensors; and perhaps most critical of all, the digital infrastructure and control software capable of scheduling and orchestrating the entirety of the production process, from receipt of raw materials and supplier-made components (which must be quality verified) to packaging and loading finished products onto delivery vehicles.

Traditionally, the type of manufacturing that lends itself to this type of factory is mass production on a fixed schedule. The smaller the lot or batch size a factory is producing, or the more frequently it is required to make new or modified products, the perception is that it is less likely to be a good candidate for full lights-out operation. Automation and digital manufacturing technologies can create this reality but must be incremental to reap the benefits (especially in brownfield facilities where large capital investments are already in place).

It is frequently noted that human beings are the most flexible of production resources. Human intervention remains the most efficient and economical way to implement production changes in a significant majority of manufacturing cases. Today, this human activity is supported by data-generated actionable insights and advanced technologies such as autonomous mobile robots, collaborative robots, edge computing and artificial intelligence/machine learning. Human-supported lights-sparse production, in which specific operations within the process are conducted at crewless locations within the factory or remotely outside the factory, is a scenario that could make the most of human, digital and automated resources.

Given the challenges of a fully automated factory for most manufacturing endeavours, what makes sense for a much larger segment of manufacturers is to identify specific processes or areas within a facility, or specific blocks of time during production, when crewless operation is both feasible and valuable.

Rather than targeting a complete lights-out factory, most manufacturers are better served to start with lights-sparse manufacturing within their otherwise conventional or smart factory.

At the same time, some manufacturers may want to consider the recently trending concept of the microfactory, with new business models of subscriptions (instead of upfront capital investments) — a small, highly automated manufacturing space that requires a smaller labour force and uses far less energy and materials than a conventional factory. An agile microfactory is capable of high-mix, low-volume business with low cost and high ROI.

These microfactories have the advantage of embracing digital tools from the very beginning. But easy and cost-effective digital technology can be leveraged both by contract manufacturers setting up microfactories (which are small-scale by their very nature) and by corporations with centralised design and geographically dispersed manufacturing — and for that matter, by manufacturers whose operations fall somewhere in between these two models.

Lights-out: new opportunities but also new challenges

Before delving into the means of implementing lights-out manufacturing, it is important to understand the goal — the value of lights-out operations to the manufacturer. Obviously, for a cost-benefit analysis to weigh in favour of lights-out implementation, the benefits must extend well beyond savings on the utility bill and lightbulb purchases. Examples of some of the benefits enjoyed by those implementing lights-out manufacturing or processes include:

  • Reduced labour costs: An example of a full lights-out factory, the Chinese e-commerce company operates a 3700 m2 lights-out warehouse with 20 robots and five technicians instead of the 500 workers a non-robotic operation would require. Implementing lights-out manufacturing in select areas of a factory would also reduce labour costs, just on a smaller scale.
  • Less reliance on a labour force: In some parts of the world and in certain industries there are more jobs than there are workers with the requisite skills to perform them. When lights-out manufacturing takes over tedious, repetitive tasks, workers can be trained and reassigned to those tasks better handled with the flexibility and creativity human beings offer.
  • Reduced error rates: Machines are simply better than human workers at performing repetitive tasks consistently. Machines never get fatigued or distracted, and they perform tasks with very little variation for long stretches.
  • Material management efficiencies: The application of lights-out technologies to the movement of materials has the potential to shorten dwell time between steps as well as replenishment time. The result is reduced inventory costs and higher production rates.
  • Accelerated product lifecycles: Lights-out operations have the potential for accelerated transitions from design to producing the finished goods. Lights-out machinery can be designed to receive digital product design and processing information, self-configure and begin production operations much more rapidly than attended machinery.

On the other side of a cost-benefit analysis is the lifecycle of automated equipment and end-of-life disposition towards sustainability. Once automated systems become obsolete or break down beyond repair, what happens to them? In a world pursuing sustainability and working towards a circular economy, manufacturers must consider whether automated equipment enables ‘reduce, re-use, recycle’ benefits while in use, and whether retired equipment can be re-used or recycled itself. Greenfield factories and microfactories can be designed from the very beginning with sustainability taken into consideration.

Enabling technologies

Enabling a lights-sparse facility to be considered today, since a number of technologies have gained capabilities essential to lights-out manufacturing.


Robotics has advanced on numerous fronts, including synchronisation with machines and work-in-progress components, increased range of motion, new gripping technology and much more. In addition to autonomous robots, advancements in cobots do not eliminate human labour, but they make workers more efficient and productive, potentially reducing the number of workers needed on the production floor.

Processing innovations

Process innovations such as 3D printing and other additive manufacturing (AM) techniques, plus hybrid manufacturing technologies that combine additive techniques with fully automated computer numerical control (CNC) equipment, make net-shape or near-net-shape production of components and products possible, with process steps guided through a direct interface with the digital factory. Additive manufacturing often begins with a high degree of automation and a reduced number of production steps or production stations — making it more amenable to lights-out operation than some conventional manufacturing operations.

Operational technology

Operational technology (OT) such as PLCs, edge devices, drivers, sensors, 5G and the IIoT offer accelerated processing speeds that enable automation equipment to rapidly respond to manufacturing conditions. Unattended machines can therefore initiate, proceed, adjust and stop operations that previously required human intervention. Critical enabling technology is the 5G mobile wireless communication standard, which is able to support a wireless data infrastructure within the factory.

Enhanced data-driven operational orchestration technology opens the door to reduced human intervention at the production line. A centralised orchestration control room with a multi-experience user interface, for example, may empower a single operator to oversee multiple machine operations, possibly from a remote location. Conversely, distributed user access to a centralised digital platform means that any authorised stakeholder can remotely access in a secure way the operational insights for decisive actions about any dark process in the manufacturer’s facility.

Virtual commissioning

Virtual commissioning also enables debugging of automation control logic and PLC code in a virtual environment before download to real equipment. The associated simulation and virtual validation help confirm that automation equipment will work as expected in autonomous mode.

AI and ML

Artificial intelligence/machine learning enables machines not only to learn process steps but also to improve performance, so that productivity and quality are both enhanced without human intervention.

Extended reality

Extended reality (XR) technologies, including virtual reality (VR) and augmented reality (AR), enable manufacturers to reduce the tasks an operator must accomplish, and the time spent doing them at the production line.

In Part 2

In Part 2 of this article, the challenges of achieving lights-out or lights-sparse manufacturing will be discussed, along with the digitalisation technology required to achieve them.

Top image: ©

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