In brief
A material flow investigation covers more than transport movements. It links the objective and system boundary with goods, routes, equipment, people, organisation, times and costs before feasible alternatives are evaluated and their effect is verified.
What is a material flow investigation?
A material flow investigation systematically records and evaluates all relevant operations in which goods are processed, inspected, handled, transported, stored or provided. It also considers the information and control rules that initiate, prioritise or prevent those movements.
The current VDI 2689:2019-02 covers methods, checklists, project management and implementation approaches. Earlier editions remain useful as methodological history, but current recommendations must be checked against the latest edition.
Separate the trigger from the measurable objective
A new product variant, high inventory or a planned conversion is a trigger, not yet an objective. The objective describes the decision and the intended, measurable effect: shorter lead time, lower transport effort, higher supply reliability or evidence that the planned capacity is sufficient.
| Trigger | Decision question | Useful measures |
|---|---|---|
| Growth or new variants | Can the existing structure handle the future volume? | Movements per shift, peak load, buffer demand |
| High inventory | Where do waiting and unnecessary intermediate storage arise? | Inventory, coverage, dwell time, lead time |
| Conversion or new layout | Which allocation shortens critical relationships? | Transport intensity, distance, crossings, space |
| Disruptions and bottlenecks | Which dependency limits system performance? | Utilisation, waiting, backlog, performance availability |
Define the system boundary and investigation objects
The study must state whether it covers a workstation, segment, building, plant or multi-site chain. The boundary can be widened if an initial analysis shows that a relevant cause lies outside it.
For each transported item, the team records quantity and frequency, dimensions, weight, load carrier, source, destination and time requirement. Routes, handling equipment, people, organisation, dispatching and costs complete the picture. This prevents a visible vehicle issue from being treated when the actual cause is a batch-size or release rule.
Seven practical work steps
- Define the decision and objective: specify what decision the investigation must support.
- Set the boundary: document processes, areas, time horizon, products and exceptions.
- Prepare the investigation: assign data sources, methods, owners and quality checks.
- Capture the current state: reconcile system data with observation, measurements and layout.
- Evaluate the current state: assess quantities, routes, times, stocks, capacities and costs together.
- Develop and compare options: evaluate technically feasible alternatives using common criteria.
- Implement and verify the effect: record baseline, target, measurement date and responsibility.
Which representations help?
A material flow matrix condenses relationships between sources and destinations. A Sankey diagram makes strong and weak flows visible, while a route diagram places those intensities in the real layout. Time and inventory analyses add the operational dimension.
Static analysis is the starting point. A simulation study becomes useful when variability, queues, control rules or shared resources determine the outcome.
Combine system data and observation
ERP, MES and WMS records provide scale, but do not automatically describe physical reality. Missing timestamps, changed master data, collective postings and manual transports require validation. A short observation, in turn, may not represent product mix and peak demand. Reliable analysis reconciles both perspectives.
Technical basis
- VDI 2689:2019-02, guide for material flow investigations.
- VDI 3595:1999-06, material-flow-oriented allocation of operating areas and equipment.
For application, see our material flow analysis, simulation and optimisation and the guide to data capture for factory planning.