Heat maps in factories
What a heat map reveals about a hall, what it is good for, and why the road to one holds six hurdles the finished picture never shows.
What is a heat map in a factory?
A heat map is a picture in which values are shown as intensities of colour: areas of high activity or load stand out more strongly than quiet ones. In a factory it can show, among other things:
- material movements
- forklift and tugger train traffic
- the walking routes of the staff
- machine utilisation
- how often things break down or stand still
- storage movements
- energy consumption
- temperature distribution
- safety incidents
- how the floor is used
Complex relations become visible directly on the hall layout.
Why heat maps matter in a factory
Production systems produce a great deal of data. In tables and conventional reports, though, spatial relations are hard to see.
A heat map ties the data to the place it occurred. What becomes visible is not merely that a plant runs many journeys, but where they concentrate. That spatial perspective is what makes it valuable to factory and production planning.
What hotspots a factory has
One of the main things a heat map does is expose hotspots: areas where an activity happens especially often or especially intensely. In production those might be:
- busy crossings
- overloaded material supply areas
- storage areas approached again and again
- machines running at high utilisation
- areas with frequent breakdowns
- particularly heavy transport corridors
Such concentrations are hard to find in a large table. On a heat map they jump out.
Which material flow questions it answers
Heat maps bear especially on material flow analysis. Material movement often consists of thousands, sometimes millions, of individual journeys. Laid over a factory layout, a heat map shows which areas carry them. It answers questions such as:
- which traffic routes are used most?
- where do the densities build up?
- which areas are driven through more often than they need to be?
- where does traffic cross?
- which material supply areas carry the heaviest load?
- which machines generate the most transport?
That makes it a foundation for improving both layout and material flow.
What it contributes to space planning
It plays a part in space planning too. A production area should not be judged by its geometric size alone; what counts is how intensively it is actually used.
A heat map can show that some areas are heavily frequented while others are barely touched. Out of that come starting points for:
- layout improvements
- rearranging machines
- adjusting storage areas
- changing traffic routes
- new material supply concepts
- better use of the existing production area
It thereby ties quantitative data to the spatial plan of the factory.
Where it becomes a matter of safety
Another field is safety at work. In many factories staff, forklifts, tugger trains and other vehicles share the same traffic areas. A heat map shows where the most movement happens and where the streams cross. Those places are potential hazards.
From the analysis, footpaths can be rerouted, traffic separated, crossings defused, safety zones set up and transport processes adjusted. A heat map therefore exposes not only efficiency but risk.
Why it is so laborious despite looking simple
A finished heat map looks plain: a hall layout with some areas picked out in colour. The work happens long before the picture.
For it to mean anything, large amounts of data have to be captured, cleaned and placed in space. That is where the effort sits, and the six hurdles below are what it comes down to.
First hurdle: the data lies scattered
A heat map can only be as good as the data beneath it. In many plants the necessary figures are spread across several systems:
- ERP systems
- MES systems
- warehouse management systems
- transport control
- machine data
- GPS or indoor tracking
- RFID systems
- scanners
- sensors
- records kept by hand
Those sources differ in format and structure. Before a heat map can exist, they have to be brought together.
Second hurdle: the data does not know where it came from
The larger problem is placing it in space. An ERP system records that material went from workplace A to workplace B. Where those workplaces stand in the hall, it usually does not know.
A heat map needs precisely those coordinates. Machines, storage places, workplaces, supply areas and waypoints have to be located first. Only then can production data be drawn on a layout.
Third hurdle: the hall plan is on paper
The layout itself is often a hurdle as well. In some companies the hall plan exists only as a PDF, a CAD file, an image, an outdated drawing or a printed sheet.
To calculate on it, the plan has to be prepared and carried into a coordinate system. If it is out of date, checking machine positions and areas comes on top. In a plant that has grown over decades, that is considerable work.
Fourth hurdle: a straight line is not an aisle
A journey should not be drawn as a straight line between two points. In reality forklifts, tugger trains and people move along the routes that exist.
A realistic heat map therefore needs a digital way network describing aisles, footpaths, crossings, one-way sections, blocked areas and clear widths. The movements then have to be carried onto it. That step is the most demanding one computationally.
Fifth hurdle: millions of single movements
At a large site, enormous volumes build up quickly. At several thousand journeys a day, evaluated over weeks or months, millions of individual movements have to be processed.
For every journey the start has to be found, the destination, the route across the network and the load on each segment. Only the sum of that becomes the heat map. At that volume it takes real computing power.
Sixth hurdle: a colour is not yet a cause
A heat map shows a distribution, not an explanation. A heavily loaded area may arise because many machines stand there, because a main route runs through it, because a store sits there, because transport is poorly organised, or because the layout has a problem.
It should therefore never be read on its own, but together with process data, material flows and the layout.
What it gains once it knows the period
A static heat map shows one period. More powerful are dynamic ones, where periods and scenarios can be picked. That reveals the differences between:
- early and late shift
- individual weekdays
- production programmes
- product groups
- different months
A picture thereby turns into an instrument of analysis.
Where it fits into a digital factory model
The greatest potential appears when heat maps are joined to digital factory models. Production data can then be tied straight to the digital layout.
Planners see not only how a factory is built, but how intensively its parts are actually used. That connection is a foundation for digital factory planning and for work around the digital twin.
What heat maps are worth
The main points at a glance:
- heavily loaded areas found quickly
- better analysis of material and traffic flows
- bottlenecks made visible
- support for layout planning
- better use of the existing production area
- greater safety at work
- large volumes of data made legible
- decisions founded on data
- complex relations easy to communicate
A heat map condenses complex production data into a picture that is understood without deep analysis.
When the effort pays off
The worth of a heat map lies in tying data to the real layout. Material flows, traffic, utilisation and breakdowns become visible in space, and that perspective is what yields the decisive clues.
Making one, though, is considerably more laborious than the finished picture suggests. Data has to be gathered, cleaned, joined and located; an up-to-date layout, coordinates and usually a digital way network come on top. The heat map is only the visible end of a long preparation.
Whoever masters that effort holds a powerful instrument for material flow analysis, factory planning and continuous improvement.
Common questions
What does a heat map show in a factory?
It shows how a particular figure or activity is distributed in space, for example transport movements, machine utilisation, walking routes or breakdowns.
Why are heat maps useful for material flows?
They show where in a factory the most material movement happens, which exposes heavily loaded routes and inefficient transport structures.
Why is making a heat map so laborious?
Production data rarely carries spatial information. Machines, storage places and routes have to be given coordinates first, and the data then joined to a digital factory layout.
What data does a material flow heat map need?
The start and destination of each journey, quantities or frequencies, the positions of machines and stores, and ideally a digital way network of the factory.
Can heat maps be produced automatically?
Yes. Where production data, coordinates and the factory layout are structured, heat maps can be generated automatically and refreshed regularly.
What is the difference between a heat map and a material flow visualisation?
A material flow visualisation shows individual connections between source and sink. A heat map condenses many movements and shows which areas carry the most overall.