KR 120 R3900-2 K vs Liujiang 331R
Side-by-side comparison of KR 120 R3900-2 K (KUKA Robotics) and Liujiang 331R (Dongguan Rongan Electromechanical Equipment Co., Ltd.) — specs, pricing, Robo Index, and verified deployments. Updated daily.
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Optimized for Cleaning & Facilities buyers. Priority specs lifted to the top and marked with a target.
Layer 1: Identity & Trust
Manufacturer Country
- KR 120 R3900-2 KGermany
- Liujiang 331RChina
Year First Available
- KR 120 R3900-2 K2015
- Liujiang 331R—
Verified Deployments
- KR 120 R3900-2 K0 Deployments
- Liujiang 331R0 Deployments
Layer 2: Operational
Price
- KR 120 R3900-2 K$19,000–$84,900 USD
- Liujiang 331R$3,800 USD
Availability Status
- KR 120 R3900-2 KACTIVE
- Liujiang 331RACTIVE
Arm Mechanics
Robot Weight
- KR 120 R3900-2 K42 kg
- Liujiang 331R55 kg
Payload
- KR 120 R3900-2 K146 kg
- Liujiang 331R8 kg
Reach
- KR 120 R3900-2 K3,904 mm
- Liujiang 331R300 mm
Degrees of Freedom
- KR 120 R3900-2 K6
- Liujiang 331R3
Repeatability
- KR 120 R3900-2 K±0.04 mm
- Liujiang 331R±0.2 mm
IP Rating (Arm)
- KR 120 R3900-2 KIP65
- Liujiang 331R—
IP Rating (Wrist)
- KR 120 R3900-2 KIP67
- Liujiang 331R—
Performance
Duty Cycle
- KR 120 R3900-2 K—
- Liujiang 331Rnot specified
Safety
Dual Check Safety
- KR 120 R3900-2 K—
- Liujiang 331RNo
Controller & Programming
Controller Model
- KR 120 R3900-2 KKR C5, KR C5 micro
- Liujiang 331R运动控制卡
Teach Pendant Type
- KR 120 R3900-2 K—
- Liujiang 331Rtouch screen control
Digital Twin Support
- KR 120 R3900-2 K—
- Liujiang 331RNo
Connectivity
ROS-Industrial Support
- KR 120 R3900-2 K—
- Liujiang 331Rnone
End-Effector
Tool Changer (ISO)
- KR 120 R3900-2 K—
- Liujiang 331Rnone
Internal Cable Routing
- KR 120 R3900-2 K—
- Liujiang 331Rexternal only
Commercial
Price (USD)
- KR 120 R3900-2 K$19,000–$84,900 USD
- Liujiang 331R$3,800 USD
Warranty
- KR 120 R3900-2 K2 yrs
- Liujiang 331R—
Service Network
- KR 120 R3900-2 Kglobal
- Liujiang 331Rregional
| | |
|---|---|---|
| Layer 1: Identity & Trust | ||
| Manufacturer Country (values differ) | Germany | China |
| Year First Available (values differ) | 2015 | — |
| Verified Deployments | 0 Deployments | 0 Deployments |
| Layer 2: Operational | ||
| Price (values differ) | $19,000–$84,900 USD | $3,800 USD |
| Availability Status | ACTIVE | ACTIVE |
| Layer 3: Category Specific | ||
| Arm Mechanics | ||
| Robot Weight (priority for Cleaning & Facilities buyers) (values differ) | 42 kg | 55 kg |
| Payload (priority for Cleaning & Facilities buyers) (values differ) | 146 kg | 8 kg |
| Reach (values differ) | 3,904 mm | 300 mm |
| Degrees of Freedom (values differ) | 6 | 3 |
| Repeatability (values differ) | ±0.04 mm | ±0.2 mm |
| IP Rating (Arm) (values differ) | IP65 | — |
| IP Rating (Wrist) (values differ) | IP67 | — |
| Performance | ||
| Duty Cycle (values differ) | — | not specified |
| Safety | ||
| Dual Check Safety (values differ) | — | No |
| Controller & Programming | ||
| Controller Model (values differ) | KR C5, KR C5 micro | 运动控制卡 |
| Teach Pendant Type (values differ) | — | touch screen control |
| Digital Twin Support (values differ) | — | No |
| Connectivity | ||
| ROS-Industrial Support (values differ) | — | none |
| End-Effector | ||
| Tool Changer (ISO) (values differ) | — | none |
| Internal Cable Routing (values differ) | — | external only |
| Commercial | ||
| Price (USD) (values differ) | $19,000–$84,900 USD | $3,800 USD |
| Warranty (values differ) | 2 yrs | — |
| Service Network (values differ) | global | regional |
Insufficient data for full comparison
The following fields had no data for any of the selected robots: Battery / Shift Runtime, Path Accuracy, Max TCP Speed, Cycle Time (25/305/25), MTBF, Vibration Damping, Safety Category, Safety I/O Pairs, E-Stop Response, Safe Zone Count, Programming Languages, Offline Programming, Communication Protocols, IoT / Cloud Platform, Cybersecurity Certs, Predictive Maintenance, Tool Flange Standard, Pneumatic Lines, Electrical Lines, Spare Parts Lead Time, Expected Service Life
best in categoryweakest in categoryvalues differ
ROI Comparison
Same operating assumptions across every robot — the only difference is price. Set your numbers once to see which pays back fastest.
Annual labor displaced (per robot): $50,000
| Metric | KR 120 R3900-2 K | Liujiang 331R |
|---|---|---|
| Investment | $51,950 | $3,800 |
| Payback period | 12.5 mo | < 1 mo |
| Net savings (5 yr) | $198,050 | $246,200 |
| ROI (5 yr) | +381% | +6479% |
Estimates labor-cost displacement only — not a full total cost of ownership. Actual ROI depends on integration, maintenance, training, downtime, and task fit. Converted currencies are indicative; USD is the price of record.
Trade-offs at a glance
Frequently asked
Who makes KR 120 R3900-2 K and Liujiang 331R?
KR 120 R3900-2 K is made by KUKA Robotics, based in DE. Liujiang 331R is made by Dongguan Rongan Electromechanical Equipment Co., Ltd., based in CN.
How do KR 120 R3900-2 K and Liujiang 331R compare on the Robo Index?
KR 120 R3900-2 K grades AAA on the Robo Index. Liujiang 331R grades A. The Robo Index is a credibility grade (AAA … C) that blends commercial maturity, verified deployments, company standing, and independent coverage — see methodology for the full breakdown.
How does the reach of KR 120 R3900-2 K compare to Liujiang 331R?
KR 120 R3900-2 K has a reach of 3904 mm. Liujiang 331R has a reach of 300 mm.
Are KR 120 R3900-2 K and Liujiang 331R in the same category?
Both robots are classified as Industrial Arm on Robolist. Filters and ranking treat them as direct alternatives.
What is the realistic total cost of ownership for Industrial Arm robots?
Hardware cost is one input. Industrial Arm TCO also includes integration, training, downtime, and end-of-life. Our breakdown: TCO of a 6-Axis Arm Cell: Hardware, EOAT, Integration, Programming.
What should a buyer ask vendors when choosing between KR 120 R3900-2 K and Liujiang 331R?
Spec sheets only show part of the story. Useful vendor questions cover support, lifecycle, integration cost, and references. We have a buyer-focused checklist: Industrial Arm Vendor Selection: Capability Matrices and Proof Points.
Going deeper — picking the right robot
TCO of a 6-Axis Arm Cell: Hardware, EOAT, Integration, Programming
7 min readIndustrial Arms
Industrial Arm Vendor Selection: Capability Matrices and Proof Points
9 min readIndustrial Arms
Programming Approaches: Teach Pendant, Offline, AI-Assisted — What Each Costs You
8 min readIndustrial Arms
Build vs buy vs lease: which model fits a first deployment
8 min readChoosing Your First Robot
The hidden specs vendors hope you'll miss
10 min readReading the Spec Sheet
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About this comparison
KR 120 R3900-2 K vs Liujiang 331R compares two robots in the industrial-arm category. All data is sourced from manufacturer spec sheets, verified deployments, and third-party filings; see our methodology for how the Robo Index is calculated.