G20-851S SCARA Robotic Arm (Manipulator)
SCARA Robot · Load capacity: 20 kg · Arm length: 850 mm
G20-851S specifications
The G20 SCARA series handles the highest payloads while delivering high-performance motion and speed. The G20 high-rigidity arm combined with our PowerDrive servo technology delivers the high performance Epson has long deserved. Combined with industry-leading ease of use, the G20 robot has become a favorite among customers.
Model introduction
The G20 SCARA series handles the highest payloads while delivering high-performance motion and speed. The G20 high-rigidity arm combined with our PowerDrive servo technology delivers the high performance Epson has long deserved. Combined with industry-leading ease of use, the G20 robot has become a favorite among customers. High performance: Maximum motion range, Max-E design achieves high space utilization; 0.37 seconds cycle time can increase the total throughput of components; Excellent acceleration/deceleration rates and smooth start/stop times; Higher speeds can reach nearly 11,500 mm/s, allowing components to operate quickly and precisely; Unique high-rigidity arm design, low residual vibration, high load, and high performance: maximum payload up to 20kg, rated payload of 10kg; Compared to competing products, it offers a higher duty cycle and overall performance. Diverse types and configurations of arms: two arm lengths, 850 and 1000 mm, are available, allowing customers to choose the optimal working arm; Models for countertop, ceiling, and sidewall installation; Models compliant with ISO Clean (ISO14644-1:2015) and ESD standards are suitable for semiconductor and electrostatic-sensitive applications, such as hard disk drive assembly; The Z-axis offers arm lengths of 180 mm (150 mm, clean type) and 420 mm (390 mm, clean type).
Exclusive highlights of the G20-851S
Maximum motion range, Max-E design achieves high space utilization; 0.37 seconds cycle time can increase the total throughput of components; Excellent acceleration/deceleration rates and smooth start/stop times; Higher speeds can reach nearly 11,500 mm/s, allowing components to operate quickly and precisely; Unique high-rigidity arm design with low residual vibration
Maximum payload capacity up to 20kg, rated payload of 10kg; Compared to competing products, it offers a higher duty cycle and overall performance
Available in two arm lengths, 850 and 1000 mm, allowing customers to choose the optimal working arm; Models for countertop, ceiling, and sidewall installation; Models compliant with ISO Clean (ISO14644-1:2015) and ESD standards are suitable for semiconductor and electrostatic-sensitive applications, such as hard disk drive assembly; The Z-axis offers arm lengths of 180 mm (150 mm, clean type) and 420 mm (390 mm, clean type).
Epson RC+ offers industry-leading ease of use, shortening development time; The dual-layer controller enables high-performance or low-cost G20 robot solutions; Integrated options maximize system performance and shorten overall development time; High-performance processing power is many times faster than competitors' products
Automotive—mirror/glass assembly, ignition module assembly, headlight and taillight assembly and testing, transmission assembly, clutch assembly, fuel injector assembly, dashboard assembly, engine hood and trunk lock assembly; Consumer products — home appliance assembly, paint brush assembly, electric toothbrush assembly, electric saw assembly, speaker manufacturing, weed trimmer assembly, connector assembly; Industrial products — loading/unloading casting equipment, smoke detector assembly, fiber optic connector assembly, light bulb assembly, hydraulic valve testing; Telecommunications — mobile phone assembly and testing, radio assembly and testing; Pharmaceuticals — customized prescription drug filling, tablet packaging, protein crystal structure analysis; Solar energy—panel assembly
G Series SCARA · Classic High Reliability · Series technical features
The G Series is Epson's classic SCARA product line, covering loads ranging from G1 to G20 weighing 0.5-20kg, known for its PowerDrive servo technology and high-rigidity arm design, and has long dominated precision manufacturing production lines.
Epson's self-developed servo technology enables high-speed, smooth start/stop and excellent acceleration and deceleration characteristics.
The G Series has large shipments and high inventory, with abundant maintenance documentation and spare parts resources.
Countertop, ceiling, and sidewall mounting models are fully available to suit different production line layouts.
High-performance or economical controllers can be selected as needed, balancing performance and cost.
Applicable industries
Typical applications of this model in the following industries (click to view industry solutions).
Mirror/glass assembly, ignition module assembly, front and tail light assembly and testing, transmission assembly, clutch assembly, fuel injector assembly, dashboard assembly, engine hood and trunk lock assembly
Home appliance assembly, paint brush assembly, electric toothbrush assembly, chainsaw assembly, speaker manufacturing, weed trimmer assembly, connector assembly
Casting equipment loading/unloading, smoke detector assembly, fiber optic connector assembly, bulb assembly, hydraulic valve testing
Mobile phone assembly and testing, radio assembly and testing
Customized prescription drug filling, tablet packaging, and protein crystal structure analysis
Panel assembly
Typical application scenarios
Common application processes for this model (click to view process details):
G Series SCARA · Classic High Reliability · Other models in the same series
Compare load and reach to choose the model that best suits your process.
G20-851S model positioning and working condition adaptation
G20-851S Belongs to the Epson G Series SCARA · The classic highly reliable SCARA horizontal multi-joint robot model has a rated load of 20kg, a motion radius of 850mm, and repeatability of ±0.025mm. Epson's technological foundation is SCARA's global market leader: RS/GX/LS series with high speed and precision, SPEL+ development efficiency, and mature vision integration; The control platform is RC700-A, and the program ecosystem is SPEL+ language (BASIC style) + Vision Guide visual.
From the perspective of working condition adaptation, the typical use for medium-duty load (20kg) positioning is:Welding, machine tool wiring, medium-sized palletizing, and die-casting part removal。 The medium reach (850mm) meets the needs of conventional workstations, with flexible single-station layout. ± 0.025mm repeatability is the standard level for six-axis industrial robots, covering most working conditions such as welding, handling, palletizing, and loading/unloading. This level is the main stage for welding and loading; when selecting a positioner or dual stations, pay attention to the total cycle time and interference zone planning.
| Parameters | Engineering interpretation and usage recommendations |
|---|---|
| Rated load capacity: 20kg | It is recommended to reserve a load margin of 20%–30%; Verification is made by combining end self-weight + workpiece + imbalanced load inertia, especially sensitive to high-speed conditions |
| Movement radius: 850mm | Determine the radius of the workcell layout: bins, tooling, and fences are bounded by maximum arm span + safety distance; Verify the accessibility of each pick-and-place point during cross-station service |
| Repeatability: ±0.025mm | Repeatability ≠ absolute accuracy: Precision assembly requires external measurement closed-loop or visual guidance; Long-term accuracy trends rely on annual retest management |
| Main unit weight: 48kg | Installation base and foundation load-bearing check based on weight + dynamic load; Floor slab installation requires structural calculation, with heavy-duty models serving as independent foundations |
| Controller RC700-A | Decide on the process ecosystem, spare parts channels, and second-hand residual value; Currently, spare parts channels are smooth, and repair and upgrade paths are mature |
Control systems and common failure modes
The RC700-A controller paired with the G20-851S features a programming language and development environment of SPEL+ (BASIC style) + Vision Guide visual. Maintenance of this generation of control platforms focuses on three basic components: power, storage, and cooling—most "sudden downtime" can be detected in advance when preventive maintenance is in place.
| Failure mode | Typical performance | Disposal recommendations |
|---|---|---|
| SCARA synchronous belt tension attenuation and wear | SCARA Synchronous Belt Tension Attenuation and Wear (Main Cause of Precision Drift) | Included as a mandatory inspection item for annual maintenance, with spare parts stocked in advance |
| The encoder battery is depleted | Encoder battery depleted (loss of origin and calibration data) | Initial interpretation of alarm codes by reference with manuals, remote diagnosis allows for early positioning |
| Driver alarm | Driver alarm (high-speed overcurrent) | Daily inspection coverage, with abnormal trends (abnormal noises/temperature rise/errors) recorded |
| RC controller fan and power supply aging | RC controller fan and power supply aging | Quarterly dust removal maintenance and cabinet temperature monitoring |
| Maintenance projects | Cycle recommendations | Key points |
|---|---|---|
| Timing belt tension adjusted by periodic inspection (SCARA specific item) | By cycle | Timing belt tension adjusted by periodic inspection (SCARA specific item) |
| Annual battery replacement | Year | Battery replacement annually, calibration data backup |
| Guide rails and screw lubrication (LS/GX series) | According to the manufacturer's manual cycle | Guide rails and screw lubrication (LS/GX series) |
| Cable and drag chain inspection | every six months | Insulation, shielding, and bending radius inspection of power and encoder lines, as well as wear of cables inside the drag chain, are the main causes of intermittent faults |
| Zero point and accuracy retest | Every year | Repeatability measured by dial gauges or laser trackers, drift trend digitization—accuracy degradation can be seen six months in advance |
| Control cabinet dust removal and fans | Every quarter | Filter cleaning, fan speed and noise checks, cabinet temperature recording; Dust environments shorten the cycle |
Henghuan's service capabilities for the G20-851S
This site is a third-party robotics technology service provider. The eight major business supports related to the G20-851S are as follows (sorted by service frequency for each model):
- Maintenance and repair: For on-site diagnostics, board-level maintenance, and annual maintenance contracts for the G20-851S—such as periodic inspection and adjustment of synchronous belt tension (SCARA unique item), we implemented brand-exclusive items according to SOPs, and Sichuan-Chongqing responded on the same day.
- Used & in-stock robot sales: SCARA has a large second-hand circulation and is the preferred choice for 3C and electronic assembly conditions; Procurement focuses on inspecting belt and guide rail wear; In-stock G20-851S or equivalent models come with a full-function test report and a 12-month warranty.
- Sales of new industrial robots: When adding new production lines or replacing entire batches, we conduct cross-brand selection comparisons based on process requirements (including models of the same grade as Epson), and provide configuration and pricing plans.
- Applied technology services: Process programming, trajectory optimization, tap time potential, and mold change formula management for the G20-851S, with targeted commissioning according to welding, machine tool wiring, medium palletizing, and die-casting part pickup.
- Research and development of automation equipment: Custom fixture ends, peripheral tooling, and safety fences for the G20-851S, with interfaces designed according to Epson flange and IO standards.
- Robot rental: For short-term production capacity or process validation periods, G20-851S equivalent in-stock models can be rented, including transportation, installation, and commissioning, with flexible lease terms and repurchasing.
Common issues with this device
Is it easy to find spare parts for the G20-851S?
Epson: The spare parts channel for this generation is smooth; we have in-stock or short-cycle channels for standard parts such as drivers, power modules, batteries, and teach pendant components; It is recommended to allocate consumables for periodic inspection and adjustment of synchronous belt tension (SCARA specific items) according to the annual maintenance contract.
With a nominal load of 20kg, how much can it actually handle?
The rated load is the static load limit of the flange surface. In actual selection, three factors must be considered: the self-weight of the end fixture (vacuum suction cup groups or grippers often account for 2–5kg), the inertia generated by the workpiece offload (checked according to the inertia ratio when the center of gravity deviates from the flange center), and the dynamic load during high-speed movement. The conventional engineering practice is to keep the "end + workpiece" within 70%–80% of the rated value to ensure cycle time and service life.
If the equipment's accuracy deteriorates after several years of use, how can it be restored?
According to the inspection order: first check whether the zero point is drifting (common after collision or battery depletion), then perform zero calibration; Check the reducer's return error (actual measurement of forward and reverse positioning deviation; if exceeded, disassemble or replace); Then check the installation base fastening and foundation settlement; Finally, trajectory compensation parameter restructuring. Most accuracy issues can be mostly restored after calibration and maintenance, so there is no need to rush into major repairs—we first release the inspection data before deciding on the plan.
Is the used G20-851S worth buying?
SCARA has a large second-hand circulation and is the preferred choice for 3C and electronic assembly applications; Procurement focuses on checking for belt and guide rail wear. Three essential items for second-hand procurement: comprehensive inspection reports (axial accuracy, driver status, insulation and battery), maintenance history and operating hours, controller generation, and software license integrity. Every used machine we sell comes with inspection records and a 12-month warranty, and we can also accept third-party inspections designated by customers.
Need technical support or procurement for this model?
Whether it's model selection comparison, installation and commissioning, or maintenance of in-use equipment, you can contact Henghuan. Tell us about your processes, loads, and equipment status, and we will provide third-party technical support and solution recommendations.
Contact Henghuan Back to the full series