Measuring waiting waste: machine downtime in a lean waste analysis

This article is for managing directors, plant managers, production managers and the people in charge of lean, continuous improvement and maintenance in small and medium-sized manufacturers (SMEs) who want to put a number on waste rather than just name it. It looks closely at one of the eight types of waste, waiting, in the place where it is easiest to measure objectively: the individual machine. How many minutes does a machine stand still because it is waiting for material, a release, an operator or maintenance, and what changes in a waste analysis once those minutes are measured instead of estimated?

What DIPS GmbH writes about waste

DIPS GmbH, a Vienna consultancy for digital transformation, processes and software development, published the article Lean Management: So reduzieren Unternehmen Verschwendung und verbessern den Wertstrom (“Lean management: how companies reduce waste and improve the value stream”) on 14 August 2026. It explains the lean principles, how mid-sized companies can introduce lean through a pilot value stream, and how to assess the results with KPIs. The definition everything else rests on reads: “Verschwendung ist jede Aktivität, die Zeit, Kosten oder Kapazität beansprucht, ohne den Nutzen für den Kunden zu erhöhen.” (Waste is any activity that consumes time, cost or capacity without increasing the benefit for the customer.)

DIPS GmbH maps eight types of waste to examples from production and logistics and from administration and services. For waiting, the production example is material or a machine waiting for a release. The article also makes a point that matters for any measurement: OEE alone says little about a whole customer order, and high machine utilization can even worsen flow when it creates overproduction and inventory. This article adds the measurement side to the method: how do you make waiting at the machine visible without falling into the trap of simply maximizing utilization?

Waiting runs in two directions: the material waits, the machine waits

In lean practice, waiting is usually seen from the material’s point of view: an order sits in front of a machine, a part waits for the next operation. That waiting shows up in inventory and lead time. The second direction is the machine that waits: it is ready to run, but it stands still because material is missing, the first-off approval is pending, no operator is available or maintenance has not arrived yet.

In SMEs this second kind of waiting is often invisible. It rarely appears in the shift log because it does not look like a breakdown. Nobody did anything wrong, the machine just “waited a bit”. Over a week, though, those minutes add up, and instead of entering the analysis as waste they disappear into a vaguely lower output. This is where measuring at the machine helps: every stop has a start, an end and a duration, and once a cause is assigned, “the machine was down” becomes a specific waiting reason the team can discuss.

The eight types of waste: what a machine measurement shows and what it does not

Measuring at the machine does not replace a waste analysis. It provides solid data for some types of waste, clues for others and nothing at all for some. The overview below helps set the right expectations.

The table shows why waiting is a good place to start: it is the type of waste that the machine itself reports most accurately. Inventory, transport and unused potential remain a job for the shop floor walk and the value stream mapping.

Making waiting time visible at the machine in six steps

1. Choose a pilot machine. DIPS GmbH recommends introducing lean through a pilot value stream. The same applies to measurement: start with the machine that limits the flow of that value stream, usually the bottleneck. One minute of waiting at the bottleneck is one minute of output lost for the whole value stream.
2. Define a stop clearly. From when is the machine considered stopped? Set a threshold and write it down. Without that rule, weeks and machines cannot be compared.
3. Capture every stop automatically. Start, end and duration come from the machine signal, not from memory. That is the only way the short waits of a few minutes, which nobody writes down, show up in the data.
4. Separate waiting causes from technical causes. Build a short list of causes with its own block for waiting: waiting for material, for release or inspection, for an operator, for maintenance, for an order. Technical failures and planned stops sit next to it, separately.
5. Review weekly by duration and frequency. A Pareto per cause shows which waiting reasons cost the most minutes and which occur most often. That leads to one action for the shop floor meeting, for example fixed material staging before the shift starts.
6. Compare before and after. DIPS GmbH stresses that a credible ROI assessment needs baseline values. The measured waiting minutes of the first weeks are exactly that baseline, against which every action is checked.

Not every machine has to run: waiting in relation to flow

The DIPS GmbH remark on utilization deserves a clear consequence: the goal is not to bring every minute of waiting on every machine down to zero. A machine that is not the bottleneck is allowed to wait. If it keeps running anyway, it produces for stock, and the waste simply moves from waiting to overproduction and inventory.

An example for illustration: in a value stream where a milling machine is the bottleneck and a saw feeds it, the measurement shows that both machines wait for material for a similar amount of time per shift. At the milling machine, every one of those minutes is lost output. At the saw, part of it may be an intended buffer. The same number therefore leads to different decisions. That is why measurement always belongs in the context of the value stream: measured stops show where waiting happens, the value stream shows where waiting actually costs customer value. Micro-stops, which often hide motion and small waits, deserve their own analysis (see below).

How TEEPTRAK measures waiting at the machine

TEEPTRAK captures stops and micro-stops automatically and in real time. A module is wired into the electrical cabinet and a sensor is placed at the line, with no connection to the PLC. Installation takes about one hour per machine and OEE is available within 48 hours. For an SME, that means no IT project and no changes to the PLC before the first data arrive. Every stop is recorded with its start, end and duration, operators assign the cause at the machine, and waiting causes can be analyzed as a block of their own. TEEPTRAK is used in more than 700 plants in over 30 countries, with 30% fewer unplanned stops on average.

Further reading

• DIPS GmbH: Lean Management: So reduzieren Unternehmen Verschwendung und verbessern den Wertstrom
• Micro-stops on packaging lines: where they start and how to reduce them
• Opportunistic maintenance: bringing preventive work forward during unplanned stops

FAQ

What counts as waiting waste in lean? Any time in which material, orders, people or machines wait for the next step without creating value for the customer. At the machine it shows up as a stop with a non-technical cause, such as missing material or a pending release.

Can all eight types of waste be measured at the machine? No. Waiting can be measured directly, overproduction, overprocessing and scrap partly. Inventory, transport and unused potential still need observation in the value stream.

Where should an SME start? With one machine, usually the bottleneck of the pilot value stream, a clear definition of a stop and a short list of causes with a dedicated block for waiting. After a few weeks you have a measured baseline against which every action can be judged.