> Quick answer: A used KUKA LBR iiwa 7 sells for £18,000 to £28,000 in the UK, versus £55,000 or more new. Its 7-axis architecture and joint torque sensors make it uniquely capable for force-controlled assembly, research, and contact-rich applications. The most critical inspection items are the torque sensor calibration and the Sunrise controller licence status.
The KUKA LBR iiwa is unlike any other cobot on the market. Where most collaborative robots estimate contact forces from current measurements, the iiwa has dedicated torque sensors in all seven joints. Where most cobots have 6 axes, the iiwa has 7, providing kinematic redundancy that allows the arm to reconfigure around obstacles without moving the tool. These design choices make the iiwa the dominant platform in academic robotics research and in precision automotive assembly worldwide.
In the UK, used iiwa units appear from decommissioned research projects, automotive plant upgrades, and laboratory clearances. For buyers who need genuine impedance control or who are building research infrastructure, a used iiwa at £18,000 to £28,000 is one of the most compelling value propositions on the secondhand robot market.
This guide covers both the iiwa 7 and iiwa 14 variants, what makes them worth the premium over standard cobots, how to inspect a used unit, and how to navigate the Sunrise controller and licence transfer process.
KUKA LBR iiwa Specifications
| Specification | iiwa 7 R800 | iiwa 14 R820 |
|---|---|---|
| Payload | 7 kg | 14 kg |
| Reach | 800 mm | 820 mm |
| Axes | 7 | 7 |
| Repeatability | ±0.1 mm | ±0.1 mm |
| Weight | 22.3 kg | 29.9 kg |
| Joint torque sensors | All 7 joints | All 7 joints |
| Torque resolution | 0.06 Nm (typical) | 0.1 Nm (typical) |
| Controller | KR C4 compact | KR C4 compact |
| Programming | Sunrise OS (Java) | Sunrise OS (Java) |
| External control | via Sunrise.Connectivity | via Sunrise.Connectivity |
| IP rating | IP54 | IP54 |
The 7-axis kinematic chain is the iiwa's most distinctive structural feature. Standard 6-axis robots have a unique solution (or limited solutions) for any given end-effector pose: moving the end-effector requires moving all joints in a defined way. A 7-axis robot has an infinite family of solutions for any given pose, allowing the robot to reconfigure the elbow position while keeping the tool exactly in place. This is genuinely useful in cluttered workspaces and in applications where specific joint configurations must be avoided.
iiwa 7 vs iiwa 14: Which to Buy Used?
| Factor | iiwa 7 R800 | iiwa 14 R820 |
|---|---|---|
| Payload | 7 kg | 14 kg |
| Typical used price (UK) | £18,000–£28,000 | £22,000–£34,000 |
| Primary market | Research, light assembly | Automotive, industrial assembly |
| UK availability used | More common | Less common |
| Weight | 22.3 kg | 29.9 kg |
| Application fit | Laboratory, inspection, light manufacturing | Medium-payload assembly, testing |
The iiwa 7 is more common on the UK used market because it has been more widely deployed in universities and research centres, which generate used units as projects end or equipment is refreshed. For research applications, the iiwa 7 is almost always sufficient. For industrial applications requiring the full 14 kg payload, the iiwa 14 is the appropriate choice.
Both variants use the same KR C4 compact controller and run Sunrise OS. Programs written for one variant require adaptation for the other (the kinematic model and joint limits differ), but the programming environment is identical.
Used KUKA LBR iiwa Price Guide: UK 2026
| Condition | iiwa 7 R800 | iiwa 14 R820 |
|---|---|---|
| Excellent (low hours, full docs, recent calibration) | £25,000–£28,000 | £30,000–£34,000 |
| Good (moderate use, functions correctly, documentation present) | £20,000–£25,000 | £24,000–£30,000 |
| Fair (higher use, some documentation missing, calibration due) | £14,000–£20,000 | £18,000–£24,000 |
| For inspection / uncertain history | £8,000–£14,000 | £12,000–£18,000 |
These prices assume the KR C4 compact controller and teach pendant are included. A controller-only used sale is unusual for the iiwa; arm-only sales are more common from research lab clearances where controllers are retained. Budget £8,000 to £15,000 for a used KR C4 compact controller if purchasing separately.
What Makes the iiwa Different: Joint Torque Sensors
The core technical differentiator of the LBR iiwa is joint torque sensing at all seven joints. This is not an add-on or an approximation: the iiwa has a dedicated strain-gauge torque sensor in each joint, providing direct measurement of the torque applied at that joint.
This matters because it enables:
Gravity compensation: the robot can hold its current configuration with minimal effort, making it safe to physically guide by hand. The force required to backdrive the robot in gravity compensation mode is typically 5 to 10 Newtons at the end-effector, compared to 20 to 50 Newtons for torque-estimated cobots.
Impedance control: the robot can be programmed to behave as if connected to virtual springs and dampers. It will compliantly deflect when an external force is applied, making it suitable for assembly tasks where parts must be guided into position with controlled compliance, such as peg-in-hole insertion.
Contact detection: the iiwa can detect and react to unexpected contact forces with far greater sensitivity than cobots relying on motor current estimation. This enables safe interaction in close proximity to humans.
Force-controlled applications: polishing, grinding, sealing, and assembly operations where the robot must maintain a specified contact force can be implemented directly with the iiwa's torque sensors, without an external force-torque sensor (though external sensors can be added for higher precision).
For buyers evaluating the iiwa against lower-cost cobots with estimated force sensing, the critical question is whether the application genuinely requires the accuracy and bandwidth of joint torque sensing. For straightforward pick-and-place or machine tending, the iiwa's capabilities exceed requirements and a lower-cost cobot is the better choice. For precision assembly, research, or compliant contact tasks, the iiwa's capabilities are not matched by any alternative at a comparable price.
KUKA Sunrise OS and Licence Transfer
The KUKA LBR iiwa runs on KUKA's Sunrise OS, a Java-based operating system specifically designed for the iiwa. Programming is done in Java using KUKA's Sunrise Java API. This is a departure from the teach-pendant-based programming of most industrial robots and from the graphical interfaces of cobots like Universal Robots.
For experienced software developers, Sunrise Java is powerful and familiar. For users without Java experience, the learning curve is steeper than PolyScope or similar graphical interfaces.
Sunrise.Connectivity is an optional package that enables external control of the iiwa from an external PC (for example, via ROS or a custom C++ application). This is the most common way the iiwa is used in research settings. Confirm whether this package is installed and licensed on any used unit you are considering.
Licence transfer process: Sunrise OS base licences are tied to the controller hardware and transfer with the physical controller. Additional option packages (Sunrise.Connectivity, torque sensing options, application-specific packages) may require reactivation. The procedure:
- Contact KUKA UK or a KUKA system partner with the robot's serial number and controller details
- Request a licence state audit to identify what is installed and what requires transfer/reactivation
- Arrange reactivation of any options that need it
KUKA UK can be reached through their Coventry office. Several UK KUKA system partners (e.g., KUKA Industrial UK, specialist system integrators) can also assist with this process.
Research vs Industrial Use: Different Priorities
The LBR iiwa is used in two quite different contexts in the UK, and the inspection priorities differ between them.
Research and university use: Units from research environments have typically accumulated moderate hours, often with varied and experimental use cases. Documentation from research installations is often more thorough than from industrial use. Software configuration may be research-specific (ROS nodes, custom external control setups) rather than standard Sunrise applications. The key questions for research-sourced units are: are the torque sensors reading cleanly, is the software licence complete, and is the physical condition acceptable?
Industrial use (automotive, manufacturing): Units from industrial installations have typically accumulated higher hours on more repetitive cycles. Documentation may be less accessible, as it is embedded in the host facility's production system documentation. The key questions for industrial-sourced units are: what were the operating conditions, are the joint cycle counts and error logs available, and has the robot been regularly maintained?
For both contexts, a pre-purchase test of the torque sensor calibration is the single most important inspection item.
Pre-Purchase Inspection: What to Check
Torque Sensor Calibration
Power on the robot and run the gravity compensation calibration routine in Sunrise (this is a standard startup procedure). The calibration should complete without errors. With the robot in gravity compensation mode, manually guide all 7 joints through their range: the force required should be consistently low. Any joint that feels significantly stiffer than others, or that exhibits irregular resistance, warrants further investigation.
Review the Sunrise log for any torque sensor fault history. Repeated torque overload faults on a specific joint indicate heavy use or potential sensor damage.
7-Axis Joint Check
Move each of the 7 joints through its full range, checking for:
- Smooth, consistent resistance throughout the range
- Absence of grinding, clicking, or irregular sounds
- No visible binding or skipping
The iiwa's gearboxes are strain-wave type (harmonic drives). These are precision components; they do not typically fail suddenly, but wear does increase backlash and reduce torque accuracy over time.
Cable Routing
The iiwa uses an internal cable routing system. Inspect the external portions of the cable harness, particularly at the base entry and the wrist exit. Any chafing, compression, or bending beyond the minimum bend radius indicates potential internal damage.
Sunrise Controller Condition
Inspect the KR C4 compact controller for:
- Physical damage to the cabinet
- Cooling fan operation (power on and listen: all fans should run quietly)
- No moisture or contamination inside the cabinet
- All cable connections seated correctly
UK Applications and Ecosystem
The LBR iiwa is used across several sectors in the UK:
- Automotive assembly: KUKA's original industrial target for the iiwa, deployed in precision assembly at several UK and European automotive facilities
- University research: widely deployed across UK robotics research groups (Imperial, UCL, Edinburgh, Birmingham, Sheffield, Bristol, and others)
- Medical devices: precision assembly and testing of medical components where compliant manipulation is required
- Electronics assembly: high-precision insertion tasks that benefit from impedance control
- Non-destructive testing: moving sensors over complex surfaces with controlled contact force
For ROS users, the iiwa_stack ROS package provides a well-maintained interface to the iiwa via Sunrise.Connectivity. The ROS 2 ros2_iiwa package is also available. Community support through research groups and online forums is more active for the iiwa than for most industrial cobots.
Where to Find Used iiwa Robots in the UK
Used KUKA LBR iiwa units appear through:
- Robot AutoTrader: browse current listings at /browse and check the resale index for price benchmarks
- University equipment disposal: UK universities sell surplus equipment through channels including JANET (academic network) surplus lists, university estates sales, and specialist academic equipment resellers
- KUKA system partners: some UK KUKA system partners offer refurbished iiwa units with limited warranties
- Industrial auctions: less common than for standard industrial robots, but iiwa units appear in automotive and precision manufacturing auctions
For a broader comparison of the used cobot market in the UK, the used cobot buyers guide covers all major brands. The Robot AutoTrader robot database includes full specifications for the iiwa 7 and iiwa 14.
Frequently Asked Questions
How much does a used KUKA LBR iiwa cost in the UK? A used KUKA LBR iiwa 7 R800 in good condition typically sells for £18,000 to £28,000. The iiwa 14 R820 commands a premium at £22,000 to £34,000 used. New pricing is approximately £55,000 to £70,000 depending on configuration.
What is the difference between the KUKA LBR iiwa 7 and iiwa 14? The iiwa 7 has a 7 kg payload and 800 mm reach; the iiwa 14 has a 14 kg payload and 820 mm reach. Both share the 7-axis architecture and joint torque sensor specification. The iiwa 7 is more common in research contexts; the iiwa 14 is more common in automotive and industrial assembly.
What makes the KUKA LBR iiwa different from other cobots? The LBR iiwa has torque sensors in all 7 joints, enabling genuine impedance control and contact-rich manipulation that is difficult or impossible for force-estimated cobots. Its 7-axis kinematic chain provides redundancy for obstacle avoidance without moving the end-effector. These features make it the standard choice in research robotics and precision assembly.
How do I transfer a KUKA Sunrise licence for a used iiwa? Sunrise OS base licences are tied to the controller hardware and transfer with it. Additional option packages may require reactivation through KUKA UK or a KUKA system partner. Request a licence state audit from KUKA UK with the robot's serial number before completing the purchase.
Is the KUKA LBR iiwa suitable for research use in UK universities? Yes. The LBR iiwa is the most widely used robot in academic robotics research globally, with extensive ROS support and a large community. Many UK universities run iiwa units. A used iiwa represents significant value for research groups given the performance gap versus lower-cost cobots.
What should I look for when inspecting a used KUKA LBR iiwa? Prioritise the joint torque sensors: verify they read cleanly in gravity compensation mode without offset drift. Check the Sunrise log for joint fault history. Test all 7 joints through full range. Confirm the Sunrise controller and all required licences are included.