5S in micro actuator manufacturing: from organisation to reliability
Regner® Editorial Team
Aiguaviva -
05/10/2026
5S (Seiri, Seiton, Seiso, Seiketsu and Shitsuke) is a Japanese method of workplace organisation. In the manufacture and integration of micro actuators for laboratory robotics and medical instrumentation, order and cleanliness are not a matter of appearance or formal discipline: they directly influence precision, quality and process stability.
The method originated in Japan within the Toyota Production System and became one of the pillars of lean manufacturing, with the aim of eliminating waste and optimising the workplace. Applied to microengineering and custom automation platforms, its purpose goes further: it becomes a system for reducing variability, ensuring traceability and safeguarding the reliability of the final product.
A micro actuator packs a complex mechanical, electrical and electronic architecture into a very small volume: precision lead screws, gear trains, electric motors, position sensors, wiring, miniature fasteners, specialised lubricants and mechanical or plastic parts with tight tolerances. When the reliability of a robotic cell depends on the alignment and behaviour of such small components, the environment in which they are assembled and integrated is critical: any deviation at the workstation ultimately affects assembly, performance or product service life.
In precision assembly, 5S therefore serves as a tool for process control and error prevention. This is its role in each of the five stages:
| Stage | Meaning | What it prevents in micro actuator assembly |
|---|---|---|
| Seiri | Sort | Mixing up components with different part numbers and accumulating unnecessary material |
| Seiton | Set in order | Missing tools or incorrect components going unnoticed |
| Seiso | Clean and inspect | Particle contamination and undetected wear |
| Seiketsu | Standardise | Variability between operators, shifts and batches |
| Shitsuke | Maintain discipline | Standards slipping over time |
1. Seiri (sort): preventing the mixing of part numbers in micro actuator assembly
The first S involves identifying the items needed in the work area, separating them from unnecessary items and removing the latter to free up useful space and avoid distractions or confusion.
On an assembly line for micro actuators or mechatronic subassemblies with multiple variants and part numbers, the accumulation of non-essential material is a frequent source of error. A 12 V motor and a 24 V motor may have identical housings; two lead screws may differ only in their thread pitch; an encoder may have the same physical format as a different electronic version; an interconnection cable may differ only in length or terminal configuration. The smaller the component, the harder it is to spot a mistake by eye, and the greater the risk of fitting an incorrect part.
Applying Seiri with technical rigour requires materials to be classified according to how frequently they are used:
- Daily or frequent use: components, calibrated tooling and technical documentation for the active work order, within the operator’s immediate reach.
- Occasional use or batch changeovers: replacement tooling or secondary gauges, stored in labelled cabinets within the plant.
- Obsolete or surplus items: removed or transferred to quarantine areas before they can accidentally return to the line.
Eliminating unnecessary items is, in essence, a way of protecting the line against the mixing of part numbers and human error.
The difficulty is that a real machine never operates under ideal conditions. Loads change, syringes have tolerances, fluids present different levels of resistance, components deform slightly, and the process must remain repeatable after thousands or hundreds of thousands of cycles.
For an integrator, the question is therefore not simply ‘What resolution does the actuator have?’ The question is much broader: ‘How does this subsystem behave within the machine, under load, throughout its service life and when something stops working as intended?’
2. Seiton (set in order): a place for everything and everything in its place
Once the area has been cleared, Seiton assigns each necessary item a clearly designated, accessible and unmistakably labelled location, avoiding wasted time and effort.
Measuring instruments, tools for controlled tightening, assembly fixtures and component trays must occupy predetermined positions, marked using visual identifiers, labelled templates and colour coding. Component and material management also follows FIFO (First In, First Out), ensuring that batches of parts are used in a sequential and controlled manner.
The benefit goes far beyond reducing search times: the workstation itself reveals an anomaly before it affects the product.
- If a tool is missing, the empty space makes this immediately apparent.
- If a tray contains an incorrect component, the visual contrast highlights it.
- If a material is in the wrong area, it can be detected at a glance.
In this way, 5S turns the workplace into a real-time visual information and control system.
3. Seiso (cleaning and inspection): detecting anomalies before they reach the product
In the manufacture and integration of micro actuators for sectors such as biotechnology or clinical applications, cleaning involves more than simply removing dust. Machining swarf, plastic debris, excess lubricant or particles from packaging may be present during assembly and adjustment. In precision mechanical systems, certain particles can increase friction, generate unwanted noise or accelerate premature component wear.
Seiso therefore treats cleaning as a preventive inspection:
- Early detection of anomalies: cleaning a workstation involves checking the condition of tooling, checking for mechanical play and identifying small leaks.
- Signs of wear: recurring material residue in a clamping area may indicate tool wear or a process deviation.
- Protecting the assembly: keeping the assembly surface clean prevents contaminants from entering lubricated areas or electrical contacts.
Cleaning at source and eliminating sources of contamination help keep machinery and assembly tooling in operational condition at all times.
4. Seiketsu (standardise): making good practice the standard
For precision products intended for automated platforms, the method cannot depend on the individual judgement of each operator or shift. The first three S stages only deliver value when they become an ongoing standard.
Seiketsu consolidates good practice through visual work instructions and clear control rules:
- Visual guidance on the shop floor: workstations documented with photographs showing the correct condition of the work area.
- Visual storage management: clear marking of storage areas, inventory limits (minimum and maximum quantities) and identification of calibrated tooling.
- Part number changeover protocols: standardised procedures for clearing the workstation and removing all residual items between batches, preventing components from different versions or configurations from being present together.
Standardisation reduces variability: when working procedures are clearly defined, the manufacturing process behaves predictably and consistently.
5. Shitsuke (discipline): maintaining the standard every day
The fifth S ensures the method is sustained and encourages a habit of rigour. Organising a plant for a one-off audit is relatively straightforward; maintaining that level of discipline in daily production requires an established industrial culture.
This stage closes the continuous improvement cycle (PDCA: plan, do, check and act): the system continually compares results with standards and applies corrective actions when deviations are detected. It is supported by regular internal audits, checklists and the monitoring of indicators.
The decisive factor, however, is team awareness: understanding that a tool out of place presents a calibration risk, that a poorly labelled tray can cause part numbers to be mixed, or that a small contaminant can alter an actuator’s mechanical behaviour.
When this understanding becomes ingrained, 5S is no longer seen as an additional compliance requirement and becomes part of the technical DNA of the production process.
5S in engineering and manufacturing at REGNER
At REGNER, custom electric linear actuators are engineered and manufactured in Aiguaviva (Girona), and 5S forms part of the way we work on the shop floor. It is not limited to maintaining order: it is applied as a process control system.
In practice, this means:
- Visual identification of workstations, trays, tooling and work areas, so that any deviation can be seen at a glance.
- Part number and batch changeover protocols that clear the workstation between one production run and the next.
- Control of tooling and tools, including calibrated items.
- Organised management of components and materials, following FIFO principles and separating surplus or non-conforming material.
- Cleaning and inspection of workstations as part of the working routine.
- Internal audits, checklists and monitoring of indicators.
In an environment producing custom actuators with many variants, this rigour helps ensure that what engineering specifies is exactly what is assembled.
Beyond organisation: the foundation of reliability
In the manufacture of micro actuators for robotics and instrumentation, the 5S methodology directly affects quality, traceability, safety and operational efficiency. It helps reduce set-up times, prevent assembly errors and detect problems before they affect the final product.
Above all, however, it requires an analytical view of the process:
- Why is there unnecessary movement in the assembly sequence?
- Why is lubricant appearing in an unintended area?
- Why are components with different part numbers present at the same workstation?
In an industry where a micro actuator must deliver precise, repeatable motion throughout its service life, reliability does not begin at final verification. It begins at the workstation where the actuator is manufactured.
Frequently asked questions about 5S in micro actuator manufacturing:
What is 5S?
It is a Japanese method of workplace organisation with five stages: Seiri (sort), Seiton (set in order), Seiso (clean and inspect), Seiketsu (standardise) and Shitsuke (sustain discipline). Its aims are to reduce waste and make problems visible.
Why is it important in micro actuator assembly?
Because the components are very small and many parts with different part numbers look alike. An organised, clean and standardised workstation reduces the risk of fitting the wrong part or introducing particles that affect friction and wear.
How does 5S relate to traceability?
A workstation with visual standards and controlled part number changeovers prevents batches and versions from being mixed, and makes it easier to identify which components have been fitted to each unit.
Does 5S replace final quality control?
No: it complements it. 5S prevents errors at the source of the process, so that final verification confirms quality rather than having to correct it.
Contents
2. Seiton (set in order): a place for everything and everything in its place
3. Seiso (cleaning and inspection): detecting anomalies before they reach the product
4. Seiketsu (standardise): making good practice the standard
5. Shitsuke (discipline): maintaining the standard every day
6. 5S in engineering and manufacturing at REGNER
