How to choose a microactuator for analytical instrumentation
Regner® Editorial Team
Aiguaviva -
20/08/2026
Choosing a microactuator for analytical instrumentation involves assessing resolution and repeatability; the operating profile, duty cycle and service life; the available space and system architecture; failure behaviour and sensing; the chemical and acoustic environment; quality and regulatory requirements; and whether to use a catalogue component or a purpose designed subsystem. The decision should not be based solely on force, speed or catalogue price.
Behind every reliable analytical result there is movement: a syringe drawing in an exact volume of sample, a valve switching at precisely the right moment or a flow cell being positioned with micrometre repeatability. In an analyser, the microactuador is the point where the instrument’s digital world meets the physical world of the sample. Its selection can have a significant impact on the accuracy, reliability and maintenance costs of the final equipment.
However, actuator selection is often addressed too late in the development process and using incomplete criteria. Force, speed and price are compared, while the factors that truly distinguish a robust instrument from one that will cause problems in the field are overlooked. After more than three decades working with OEM manufacturers of analytical instrumentation, REGNER has distilled this experience into seven key questions that should be answered before making a decision.
1. What resolution and repeatability does the application actually require?
This is the fundamental question, and the right answer lies not in the actuator itself, but in the analytical method. In a bomba de jeringa, motion resolution translates directly into volumetric resolution, while stroke repeatability translates into dosing repeatability.
The analytical specification, for example a maximum coefficient of variation in dispensing, should be translated into mechanical parameters such as lead screw pitch, motor resolution and allowable axial play. Overspecifying resolution adds unnecessary cost; underspecifying it can render the system unusable. The optimum solution can only be found when the instrument manufacturer and actuator manufacturer work together to make that translation.
2. What is the actual operating profile and how many cycles will the instrument complete over its service life?
A benchtop analyser in routine laboratory use may perform dozens of cycles every day for ten years. Multiplying the daily cycle count by the number of operating days and years can result in hundreds of thousands of strokes. This lifetime requirement, rather than catalogue force alone, should guide the selection of lead screw and nut materials, lubrication and bearings.
The operating profile also determines the duty cycle: the proportion of time the actuator is running within each period. This governs thermal behaviour and therefore the force actually available during sustained operation. Two instruments with the same total number of lifetime cycles can place very different thermal demands on the same actuator. One may dispense once every few minutes, while another performs repeated sequences of consecutive strokes. Force ratings should therefore be requested for a clearly stated duty cycle rather than as an isolated peak value.
Example calculation
55 cycles/day × 365 days × 10 years
= 200,750 operating cycles
If each cycle includes extension and retraction, the actuator will complete 401,500 individual strokes.
Four hundred thousand strokes without a maintenance interval: that is the figure that needs to be validated through testing, not the theoretical service life stated in the catalogue.
Always ask about life testing. Not theoretical calculated life, but accelerated testing under conditions representative of the actual application. In practice, the difference between the two is the difference between evidence and expectation.
3. What space and system architecture does the instrument allow?
The miniaturisation of benchtop, portable and cabinet mounted analysers makes every millimetre a valuable resource. What matters here is not only the size of the actuator, but also its architecture: whether the motor is arranged in line or in parallel, whether the lead screw is captive or non captive, and where the sensor is located.
A slightly longer but narrower actuator may make an instrument design feasible where the opposite geometry would not. It therefore makes sense to involve the motion system supplier during the product architecture phase, rather than waiting until the available space has already been fixed.
4. What happens when something goes wrong?
In instrumentation, safety has two sides. The first is mechanical: does the system need to hold its position in the event of a power failure? If so, a self locking lead screw can provide inherent holding capability without continuous power consumption. Its holding capacity must, however, be validated under the actual load, vibration, wear and environmental conditions of the application.
The second is functional: how will the system detect a blockage, a positioning deviation or an end position? The answer depends on the available sensing, feedback signals and control logic. A good microactuator does more than move accurately. It also provides the system with the information it needs.
5. Is it compatible with the chemical and acoustic environment of the application?
Analysers operate around aggressive reagents, condensation and frequent cleaning processes, so actuator materials, coatings and protective features must be selected accordingly.
There is also a factor that is consistently underestimated until the first prototype is built: noise. A laboratory instrument operates alongside people throughout the working day, and excessive noise or an unpleasant acoustic signature can undermine an otherwise technically excellent product. Low noise performance has to be engineered into the system, through the motor, gearbox and lead screw finish.
6. What quality and regulatory requirements apply?
If the instrument is a medical device or an in vitro diagnostic device, traceability requirements extend throughout the supply chain. A supplier certified to ISO 13485 as well as ISO 9001 provides change control, batch traceability and document management practices that are compatible with those of the equipment manufacturer.
Even outside regulated sectors, these practices translate into something very tangible: consistency from batch to batch and fewer unexpected issues after years of series production. You can find further details about our certifications and quality systems.
7. Catalogue component or purpose designed subsystem?
This is the fundamental decision. A catalogue actuator can solve the needs of a prototype quickly; a subsystem designed specifically for the application, with the motor, gearbox, lead screw, guidance and sensing engineered as a complete system, solves the needs of the product.
The second approach reduces the number of suppliers and places responsibility for integration with the specialist. It helps reduce the risk associated with poorly defined interfaces, which are among the most common sources of reliability problems. Our experience with custom actuators for OEM manufacturers is clear: the more critical the movement is to the analytical function, the greater the value provided by a subsystem approach.
The 7 criteria, at a glance
| Criterion | Key question | Risk if not assessed |
|---|---|---|
| Resolution | What is the minimum movement required by the method? | Dosing error |
| Operating profile | How many cycles, and at what duty cycle? | Premature failure or loss of force due to temperature |
| Space envelope | What geometry can the instrument accommodate? | Integration problems |
| Sensing | How are blockages or positions detected? | Lack of diagnostics |
| Environment | Are there reagents, condensation or noise constraints? | Degradation or poor user experience |
| Quality | What level of traceability does the product require? | Regulatory risk |
| Architecture | Catalogue component or subsystem? | Poorly defined interfaces |
Choosing a microactuator ultimately means choosing a partner
Selecting a microactuator for analytical instrumentation often goes beyond purchasing a component. It requires technical collaboration. The seven questions above have one thing in common: none of them can be properly answered from a catalogue, and all of them are better addressed with a technical partner who understands both precision mechanics and the requirements of analytical instrumentation.
This is the role REGNER Engineering has been fulfilling for OEM manufacturers worldwide for more than thirty years, with in house development and manufacturing under ISO 9001, ISO 13485 and ISO 14001 certification.
