A few decades ago, industrial robots were extraordinary because they could place heavy parts with centimetre-level accuracy. Today, the competitive benchmark has shifted by several orders of magnitude.
Modern precision robots routinely achieve ±5 µm repeatability, with some specialist motion stages achieving sub-micrometre accuracy. To put that into context:
- 1 micrometre (µm) equals one-thousandth of a millimetre, often called a micron. Put another way, 1 micrometre is one-millionth of a metre.
- A human hair is roughly 70 to 100 µm thick.
- An advanced SCARA robot can place components with an error margin smaller than one-tenth of a human hair’s diameter.
- High-end photonics assembly systems use motion stages with a command resolution of 0.1 µm – too fine for the average human eye to see, even when aided by most optical microscopes.
This level of performance is a key reason why precision robotics is seeing wider adoption. Electronics assembly and medical device manufacturing may be very different sectors, but they now share a common constraint: humans cannot reliably assemble or inspect anything at these tolerances. Precision robotics is filling the gap as devices become smaller, more complex and far less forgiving of variability.
In this article, we explore how accuracy, repeatability and precision differ; what types of robots excel at such work; and which applications, particularly in electronics and medical manufacturing, are pushing the boundaries of what automated precision can achieve.
Innovation in high-precision robotics
To illustrate the innovation currently taking place in the sector, here are a couple of recent examples of products by well-known companies that claim to attain unprecedented levels of precision.
Yamaha Robotics: new high-precision SCARA systems
Yamaha’s updates to its YK-XG and YK-TZ SCARA robot ranges claim ±5 µm repeatability for micro-assembly, semiconductor handling and optical device production. Some documentation cites a standard specification of ±0.01 mm (±10 µm) in the X-Y axes, which is still within the micrometre-class requirements of advanced electronics and photonics manufacturing.
Zimmer Group’s medical-grade end-effectors for catheter and stent assembly
Zimmer Group has been expanding its line of cleanroom-certified grippers and micro-handling tools designed for extremely delicate medical devices – such as catheters, soft tubing, stents and drug-delivery components. These end-effectors enable sub-millimetre placement without deforming soft materials.
And in electronics…
Fanuc’s SCARA and SR series systems, marketed for PCB micro-assembly and component placement, emphasise high-speed precision for sub-millimetre electronics work.
Technical explainer: Accuracy, repeatability, precision and other jargon
Understanding how robots achieve such high performance requires clarity on terminology.
Accuracy
Accuracy measures how close a robot gets to the commanded position.
If a robot is told to move to X = 100.000 mm and actually reaches 100.007 mm, its accuracy error is 7 µm.
Repeatability
Repeatability measures how consistently the robot returns to the same position, even if that position is not perfectly accurate relative to an absolute coordinate system.
Industrial robots are typically optimised for repeatability, because most assembly tasks use fixed reference points, jigs or machine vision systems to correct offsets.
Precision
Precision is often used as an umbrella term describing both accuracy and repeatability. However, in standard metrology, precision is the degree to which repeated motions or measurements show the same results (it is the formal synonym for repeatability).
However, in robotics, it is often used as a practical umbrella term describing how “tight” the robot’s motion envelope is under real conditions, reflecting the overall quality of both its accuracy and repeatability.
Metrology
Metrology is the scientific discipline of measurement. It defines how accuracy, precision, repeatability and uncertainty are quantified, and it establishes the standards against which all measurements must be traceable.
In industrial robotics, metrology governs everything from encoder calibration and thermal compensation to how positioning tolerances are validated. I
n standard metrology (as defined in ISO and international measurement vocabulary), precision refers strictly to the closeness of repeated measurements – whereas in robotics, the term is often used more loosely as a practical umbrella for accuracy and repeatability combined.
Resolution
Resolution typically refers to the smallest unit of movement the motion stage can command or detect (the encoder step size). It is not the same as the system’s actual positioning accuracy or repeatability.
A system can have a high resolution (for example, 0.1 µm) but poor repeatability (for example, ±1 µm) due to thermal drift or vibration. This conflation is common but misleading.
Tolerances
In engineering, tolerances define the acceptable range of variation in a part’s dimensions or a process’s output. No manufacturing system can achieve a perfect, exact value every time, so tolerances specify how much deviation is permissible without affecting function or quality.
For example, if a component is specified as 10.00 mm ±0.05 mm, it may measure anywhere between 9.95 mm and 10.05 mm and still be considered correct.
Micrometres and microns – a reminder
- 1 micrometre (µm) = 0.001 mm
- The term micron is commonly used instead of micrometre.
- Sometimes written as “um” when the µ symbol is unavailable.
- Engineers often refer to precision classes informally as “micron-level”, “sub-micron”, or “nanometre-level”.
Why repeatability matters more than absolute accuracy
If a robot always returns to the same point within ±2 µm, it can compensate for its absolute inaccuracy by calibrating against a known reference.
Regardless of the sector – PCBs or stents – consistent repetition is more important than absolute position.
Environmental influences
Ultra-precision systems must control:
- Thermal drift
- Vibration
- Tool wear
- Payload-induced deflection
- Airflow disturbances (especially in cleanrooms)
These factors significantly affect sub-10 µm performance.
Electronics assembly: Where precision robotics first took hold
Electronics manufacturers were among the first to automate tasks requiring micrometre-scale positioning. Some of the most intricate tasks include:
Chiplet placement in advanced packaging
Chiplets need alignment within ±1 to 3 µm before bonding. Robots assist wafer-level placement, die attach and underfill operations.
Wire bonding at 25 to 50 µm pitch
Wire bonding machines are semiautomated robots capable of placing thousands of bonds per second with astonishing consistency.
Optical module assembly (smartphone cameras, LiDAR, AR optics)
Lens stacks in smartphone cameras require micron-level robotic alignment for optical calibration.
Micro-soldering on flex circuits
Flexible PCBs deform easily, requiring robots with force-controlled precision to anchor components and avoid damaging traces.
Insertion of miniature connectors and sensors
Wearables, hearing aids and IoT devices rely on extremely small connectors that humans can no longer reliably insert.
Suggested optimal robot architectures (electronics)
For extremely small-scale precision (1 to 10 µm), SCARA robots are typically the optimal compromise between rigidity, speed, and vibration control.
Delta robots excel when speed is prioritised, with moderate precision. Cartesian systems achieve the highest accuracy but are not always practical for free-form assembly.
SCARA robots are typically the optimal compromise because their planar 4-axis structure minimises stack-up error and reduces cumulative stiffness losses compared with 6-axis articulated robots.
Why medical device manufacturing now demands electronics-level precision
Medical devices are being redesigned around micro-electronics, microfluidics and flexible polymers. As the technology shrinks, the production techniques converge with those of electronics.
A modern disposable insulin pump or neurostimulation implant contains:
- Micro-pumps
- Sensors
- Bonded polymers
- PCB assemblies
- Wireless communication modules
- Laser-machined components
This level of integration demands sub-millimetre assembly and often sub-100 µm alignment – pushing manufacturers to adopt precision robotics similar to electronics factories.
Intricate medical tasks suited to precision robots
Catheter assembly
Robots thread micro-wires, place reinforcements, apply adhesives and guide tubing around delicate features.
Stent manufacturing and laser welding
Nitinol stents require micro-positioned welds often at 10 to 20 µm accuracy.
Assembly of drug-delivery systems
Injection systems, smart inhalers, and wearable pumps involve tiny gears, valves and chambers.
Bonding and sealing microfluidic chips
Diagnostics devices often have channels smaller than a human hair, requiring robots to align substrates with precision before bonding.
Inspection of surgical instruments
Vision-guided robots detect imperfections too small for the naked eye – down to 5 to 10 µm fractures or defects.
Which robots are most suitable for medical precision?
Applying the same engineering principles:
- SCARA robots are again the “sweet spot” – stiff, fast and cleanroom-compatible.
- Cobots with force-torque sensors excel at handling soft, flexible medical materials like silicone tubing.
- Delta robots are used in sterile kitting and packaging, where high speed is essential.
- Cartesian and piezo-based stages dominate microfluidics, photonics, and high-accuracy test equipment.
Suggested optimal robot architectures (medical)
For intricate medical assembly – especially catheter, stent and micro-device production – the balance of accuracy, stability and footprint makes SCARAs the most practical choice, with Cartesian stages used for ultra-fine sub-micron alignment tasks.
Challenges engineers must consider
Cleanroom constraints
Robots must meet ISO 5-7 standards, avoid particulate contamination and use food-grade or medical-grade lubricants. ISO 5 corresponds roughly to Class 100 (which means that the maximum allowable particles ≥0.5 µm per cubic foot is 100); ISO 7 to Class 10,000 (maximum allowable particles ≥0.5 µm per cubic foot, 10,000).
Speed vs precision
Micrometre-level precision often requires slower, more deliberate movement.
Tooling and grippers
Micrometre-class production depends on ultra-stiff grippers with tightly controlled surface friction.
Regulatory environment
FDA 21 CFR 820 and ISO 13485 require rigorous process validation – making repeatability more important than absolute accuracy.
Skill requirements
Companies need automation engineers trained in robotics, machine vision, metrology and cleanroom process control.
Market landscape – key robotics suppliers
Precision robotics suppliers to watch
- Yamaha Robotics
- Fanuc
- Epson
- Omron
- ABB
- IAI / Intelligent Actuator
- Codian Robotics (delta robots)
- Zimmer Group (grippers, tooling)
- Universal Robots
- Techman (force-controlled cobots)
Leading medical device manufacturers
These are not robotics companies themselves, but are major adopters of robotics technologies.
- Medtronic
- Johnson & Johnson (Ethicon, Biosense Webster)
- Abbott
- Boston Scientific
- Stryker
- Becton Dickinson
- Phillips-Medisize
- Jabil Healthcare
- Siemens Healthineers
- GE Healthcare
- Baxter
- Edwards Lifesciences
These firms increasingly integrate electronics and micro-modules into their devices, driving convergence with electronics-style manufacturing workflows.
The future: Sub-micron robotics and AI-driven precision
Within the next decade, we can expect:
- Sub-micron robot calibration using AI compensation models
- Active vibration cancellation built into robot arms
- Robotic assembly of optoelectronics and bio-hybrid devices
- Laser processes integrated into robot wrists
- Smarter vision systems able to compensate for thermal drift in real time
The industries will continue to overlap as medical devices become smarter, smaller and more electronic. Precision robotics will be the only way to build these products at scale.
Shrinking margins of error
Electronics assembly and medical device manufacturing may appear to be two separate sectors, but they are converging rapidly around a single constraint: the need for extreme, repeatable, micrometre-class precision.
As devices shrink and become more intricate, tasks once performed by trained human hands under a microscope are increasingly delegated to robots with the stability, speed and repeatability to meet demanding tolerances.
Whether placing semiconductor chiplets, threading catheter wires or aligning microfluidic channels, precision robotics is becoming the backbone of the next generation of manufacturing – and a major growth area for suppliers and investors watching the rise of miniature, high-value devices.
The companies that master micrometre-class automation could define the next decade of electronics, medical technology, and other sectors.
Main image courtesy of Prism Sustainability Directory
