- Three series: LS (large, belt-driven, 3–20 kg), RS (compact, direct-drive, 1–6 kg), T-series (all-in-one, no external controller box).
- Best-in-class repeatability: ±0.005 mm on RS3 and RS4 models — tighter than any SCARA competitor.
- T-series integrates the controller inside the robot arm — eliminates a separate control cabinet, reducing cell footprint.
- Epson RC+ software is free — no per-seat licence fees; point-and-click programming without writing code for simple tasks.
- Robot-only pricing: LS series $8,000–$18,000; RS series $12,000–$22,000; T-series $9,000–$16,000 (September 2026).
Overview
Seiko Epson entered industrial robotics in 1983, building assembly robots for their own watch and printer manufacturing. That background explains their strength in precision assembly — their robots were designed to meet the same tolerances required for watch movement assembly, which is among the most demanding precision work in manufacturing.
Today, Epson Robots is a separate business unit within Seiko Epson Corporation. Their SCARA robots dominate in electronics assembly (PCB, semiconductor packaging), medical device assembly, and pharmaceutical diagnostics — applications where ±0.01 mm repeatability is needed at speeds faster than a 6-axis arm can achieve.
Model Series Explained
LS Series (Large SCARA, belt-driven)
The LS series covers payloads from 3 kg (LS3) to 20 kg (LS20) with reaches from 400 mm to 1,000 mm. Belt-driven joints allow the motors to be located in the base and upper arm rather than at each joint — reducing arm weight and improving dynamics. The LS series is the choice when payload or reach requires a larger robot, with the trade-off of slightly lower repeatability (±0.01–0.02 mm) than the RS series.
RS Series (Compact SCARA, direct-drive)
The RS series (1–6 kg, 225–550 mm reach) uses direct-drive motors at the first two joints, eliminating backlash from belt/gear transmission. This gives ±0.005 mm repeatability — the tightest in the SCARA category. The RS series is designed for the most demanding precision tasks: watch assembly, medical diagnostics instrument assembly, and semiconductor packaging.
T-Series (All-in-One)
The T-series integrates the controller electronics inside the robot arm itself — there is no separate control cabinet. The robot connects directly to a 24V power supply and Ethernet; the controller is accessed via a web browser or tablet. This dramatically reduces the size of the control panel and is particularly valuable for space-constrained cells, multi-robot lines, and OEM integrations where a clean installation is required.
Specification Table
| Model | Series | Payload | Reach | Repeatability (XY) | Z Stroke | Cycle Time (T2 path) | Price (Sep 2026) |
|---|---|---|---|---|---|---|---|
| LS3-B401S | LS | 3 kg | 400 mm | ±0.01 mm | 150 mm | 0.42 s | ~$9,000–$13,000 |
| LS6-B601S | LS | 6 kg | 600 mm | ±0.01 mm | 150 mm | 0.38 s | ~$11,000–$15,000 |
| LS10-B1000S | LS | 10 kg | 1,000 mm | ±0.02 mm | 200 mm | 0.52 s | ~$14,000–$18,000 |
| RS3-351S | RS | 3 kg | 350 mm | ±0.005 mm | 150 mm | 0.32 s | ~$12,000–$16,000 |
| RS4-551S | RS | 4 kg | 550 mm | ±0.005 mm | 200 mm | 0.34 s | ~$14,000–$19,000 |
| T3-401S | T | 3 kg | 400 mm | ±0.01 mm | 150 mm | 0.40 s | ~$9,000–$13,000 |
| T6-602S | T | 6 kg | 600 mm | ±0.01 mm | 200 mm | 0.42 s | ~$11,000–$15,000 |
Cycle time is measured on the T2 path (ISO 9283): a 25 mm up, 300 mm horizontal, 25 mm down move at rated payload. Real-world cycle times at lower payload are typically 15–25% faster. All models are 4-axis (2 rotational arm axes + Z translation + Z rotation).
Controller and Programming
Epson robots use the RC700 controller (LS and RS series) or the T-series internal controller. Programming is done in SPELplus — a BASIC-derived language with motion, I/O, and vision commands. Epson RC+ (the development environment) is free to download and use — no per-seat licence fee, which is unusual in the industrial robot market.
Key controller features:
- Epson RC+: Free IDE with 2D/3D simulation, point-and-click teaching mode (jog and record), and SPELplus code editor. Most simple applications can be taught without writing code — the operator jogs the robot to each position and records it.
- Vision Guide: Epson's integrated 2D vision system (optional add-on). Locates parts using pattern matching, measures dimensions, and guides pick/place offsets. Configures through RC+ without separate vision software.
- Multi-robot: Up to 8 Epson robots can be controlled from one RC700 controller — significant cost saving in multi-robot assembly cells.
- T-series remote control: Browser-based RC+ 7.0 Remote interface — full programming, monitoring, and I/O control from any device on the network.
Applications
| Application | Best Model | Why Epson SCARA |
|---|---|---|
| PCB handling and component placement | RS3, T3 | ±0.005 mm repeatability; fast cycle at low payload; compact footprint |
| Screwdriving in electronics | LS3, T3 | Speed + precision; integrates with Epson screwdriver module |
| Liquid dispensing (adhesive, solder paste) | LS6, RS4 | Consistent Z-axis approach critical for dispense volume; rigid Z axis of SCARA |
| Medical diagnostics cartridge assembly | RS3, RS4 | ±0.005 mm required; clean room options available |
| Watch movement assembly | RS3 | Epson's original application; submicron-precision tooling |
| Semiconductor packaging | RS4 | High speed, precision, cleanroom-compatible |
| Light palletizing / case loading | LS10 | 10 kg payload, 1000 mm reach — SCARA for fast light-case stacking |
Epson vs DENSO and FANUC SCARA
| Feature | Epson (RS/LS/T) | DENSO (VS series) | FANUC (SR series) |
|---|---|---|---|
| Best repeatability | ±0.005 mm (RS) | ±0.01 mm | ±0.01 mm |
| Cycle time (T2 path) | 0.32–0.52 s | 0.29–0.40 s | 0.32–0.44 s |
| Controller cost | Free software (RC+) | WINCAPS3 (licence) | iHMI (included) |
| All-in-one option | T-series (no external cabinet) | No | No |
| Vision (integrated) | Vision Guide (add-on) | Separate system | iRVision (add-on) |
| Global market share | #1 (est.) | #2–3 | #4 |
| Best for | Precision electronics, free software, T-series compact | Fastest cycle time (automotive) | FANUC ecosystem users |
Strengths and Limitations
Strengths
- Best-in-class repeatability (±0.005 mm RS series) — unmatched in SCARA category
- Free RC+ programming software — significant lifetime cost saving
- T-series all-in-one eliminates control cabinet — smallest cell footprint
- Up to 8 robots per controller — cost-effective multi-robot cells
- Epson's precision manufacturing heritage translates to robot quality
- Vision Guide integrates seamlessly with RC+ without separate software
Limitations
- SCARA limitations apply: limited reach above arm plane, no full 3D workspace of a 6-axis robot
- Max payload 20 kg (LS20) — not suitable for heavy parts
- SPELplus language is not widely taught outside Epson user base — training required
- Smaller global service network than ABB, FANUC, or Yaskawa — may have longer service response times in some regions
- Less suited to welding, dispensing paths requiring tool-angle variation (SCARA fixed tool orientation in XY plane)
Pricing
| Configuration | Typical Installed Cost |
|---|---|
| T3 (all-in-one) — small pick-and-place cell | $25,000–$50,000 |
| LS6 — PCB assembly or dispensing cell | $35,000–$70,000 |
| RS4 — precision assembly with Vision Guide | $45,000–$90,000 |
| Multi-robot LS6 × 4 on one RC700 | $80,000–$150,000 |
Installed costs include robot, controller (or T-series internal), EOAT, integration labour, and fixturing. SCARA cells are generally less expensive to integrate than 6-axis robot cells for equivalent tasks — fewer degrees of freedom means simpler programming and less complex EOAT.
Frequently Asked Questions
What is the difference between the LS, RS and T-series?
LS (Large SCARA): belt-driven, payloads 3–20 kg, reaches 400–1000 mm. Best for general assembly and handling tasks requiring more payload or reach. RS (Rigid SCARA): direct-drive, payloads 1–6 kg, reaches 225–550 mm. Best for highest-precision tasks — ±0.005 mm repeatability. T-series: all-in-one controller inside arm, payloads 3–6 kg, specs similar to LS. Best when a clean compact installation is required. For most assembly applications, start with the LS series (cost-effective, flexible) and specify RS only if you need ±0.005 mm repeatability.
Can Epson SCARA robots be used in clean rooms?
Yes — Epson offers clean room variants of the LS and RS series certified to ISO Class 3–5 depending on the model. Clean room variants have sealed joints, low outgassing materials, and filtered exhaust. The T-series does not have a clean room variant. For semiconductor and pharmaceutical clean room applications, specify the LS-B or RS-B clean room variants. Pricing is approximately 20–30% higher than standard.
How does Epson Vision Guide compare to a standalone vision system?
Vision Guide is a 2D vision system that runs on the robot controller — no separate PC or vision processor. It uses a single fixed or robot-mounted camera, performs pattern matching and measurement, and sends offset corrections directly to the robot motion planner. For applications requiring part location, presence/absence checks, and simple measurements, Vision Guide eliminates the cost and integration complexity of a standalone system ($5,000–$20,000 saved). For 3D vision, barcode reading on the fly, or multi-camera setups, a standalone system (Cognex, Keyence) is still required.
Sources
- Epson Robots LS Series Datasheet (2025)
- Epson Robots RS Series Datasheet (2025)
- Epson Robots T-Series Overview (2025)
- Epson RC+ 7.0 Programming Manual (2025)