Star SB-20R Type G CNC Swiss-Type Automatic Lathe with Iemca Steady 320 Bar Feeder – Year 2025

Brand: Star
Model: SB-20R Type G
Year: 2025
Specifications
Max Machining Diameter: 25/32″
Max Headstock Stroke: 8″
Number of Turning Tools: 6 tools (ø12mm) / 7 tools (ø10mm)
4-Spindle Sleeve Holder # of Tools: 4 Front Tools / 4 Rear Tools
4-Spindle Sleeve Holder Drilling Capacity: 1/2″
4-Spindle Sleeve Holder Max Tapping Capacity: M10 × P1.5
4 Spindle Cross Drill Unit # of Tools: 4
4 Spindle Cross Drill Unit Drilling Capacity: 9/32″
4 Spindle Cross Drill Unit Max Tapping Capacity: ER 16: M6×P1.0
4 Spindle Cross Drill Unit Spindle Speed: ER 16: max.6,000min-1
4 Spindle Cross Drill Unit Drive Motor: 1.0kW (continuous) / 1.2kW (5min./30%ED)
5 Spindle Cross Drill Unit # of Tools: 5
5 Spindle Cross Drill Unit Drilling Capacity: 3/16″
5 Spindle Cross Drill Unit Max Tapping Capacity: ER 11: M5×P0.8
5 Spindle Cross Drill Unit Spindle Speed: ER 11: max.10,000min-1
5 Spindle Cross Drill Unit Drive Motor: 1.0kW (continuous) / 1.2kW (5min./30%ED)
Catridge Type Cross Drill Unit # of Tools: 2
Catridge Type Cross Drill Unit Drilling Capacity: ER 16: 5-Spindle & 5-Spindle High Speed: ø7mm (9/32in), ER 11: 5-Spindle: ø6mm; 5-Spindle High Speed: ø5mm
Catridge Type Cross Drill Unit Max Tapping Capacity: ER 16: M6×P1.0, ER 11: M5×P0.8
Catridge Type Cross Drill Unit Spindle Speed: ER 16: max. 6,000 min-1, ER 11: 5-Spindle: max. 8,000 min-1; 5-Spindle High Speed: max. 10,000 min-1
Catridge Type Cross Drill Unit Drive Motor: 1.0kw (continuous) / 1.2kw (5min./30%ED)
Rapid Feed Rate: 35m/min (X1,Y1,Z1,X2,Z2)
Main Spindle Indexing Angle: C-axis control
Main Spindle Speed: max. 10,000min-1
Main Spindle Motor: 2.2kw (continuous) / 3.7kw (10min./25%ED)
Coolant Tank Capacity: 180L

Equipped With
Fanuc oi-TF Plus CNC Controller, Iemca Steady 320 Bar Feeder, Operation panel 8.4″ color LCD display, Pneumatic unit, Automatic centralized lubrication unit, Coolant level detector, Door interlock system, Broken cutoff tool detector, Parts ejection detector, Drive unit for revolving guide bush, Revolving guide bush unit, Main/Sub collet, C-axis control (Main/Sub), Spindle clamp unit (Main/Sub), Tool holder, 4-Spindle cross drilling unit, 4-Spindle sleeve holder, Back 4-Spindle unit, Air purge for revolving guide bush, Air purge for main spindle, Sub spindle air purge unit, Sub spindle air blow unit, Work light, Leakage breaker

Star SB-20R Type G CNC Swiss-Type Automatic Lathe with Iemca Steady 320 Bar Feeder – Technical Evaluation (Year 2025)
1. Technical Evaluation Overview

The Star Micronics SB-20R Type G is a CNC Swiss-type automatic lathe designed for high-precision, small-diameter turned parts. Manufactured in 2025, the machine supports a maximum machining diameter of 25/32″ and a maximum headstock stroke of 8″, placing it firmly in the small-part, high-accuracy production segment.

The machine is equipped with a main spindle capable of up to 10,000 min⁻¹, featuring C-axis control, and driven by a 2.2 kW continuous / 3.7 kW intermittent motor. Rapid traverse rates are specified at 35 m/min across all linear axes (X1, Y1, Z1, X2, Z2). Coolant capacity is 180 liters, supporting continuous production environments.

Tooling flexibility is a key aspect of the SB-20R Type G configuration. The machine includes multiple front, rear, and cross drilling units:

Turning tools: 6 tools (Ø12 mm) or 7 tools (Ø10 mm)

4-spindle sleeve holder: 4 front tools / 4 rear tools, drilling up to 1/2″, tapping up to M10 × P1.5

4-spindle cross drill unit: drilling up to 9/32″, tapping up to M6 × P1.0, spindle speed up to 6,000 min⁻¹

5-spindle cross drill unit: drilling up to 3/16″, tapping up to M5 × P0.8, spindle speed up to 10,000 min⁻¹

Cartridge-type cross drill units with ER16 and ER11 interfaces for flexible drilling and tapping configurations

Control is provided by the FANUC 0i-TF Plus CNC system, and bar feeding is handled by an IEMCA Steady 320 bar feeder. The machine is supplied with an extensive automation and monitoring package, including guide bush air purge, broken cutoff tool detection, parts ejection detection, spindle clamps (main/sub), and centralized lubrication.

Critical parameters such as maximum bar diameter (metric equivalent), achievable tolerances, and sub-spindle power are not explicitly stated and should be verified.

2. What to Check Before Buying

Although the machine is very recent, the following technical checks remain relevant:

Mechanical and kinematics:

Verification of headstock stroke accuracy over the full 8″ travel.

Smooth operation of the revolving guide bush and confirmation of guide bush air purge effectiveness.

Alignment and synchronization between main and sub spindles under C-axis interpolation.

Spindles and drive units:

Functional testing of the main spindle at high speed (10,000 min⁻¹), including thermal stability.

Verification of cross drilling unit spindle speeds and motor outputs under load.

Tooling systems:

Correct indexing and rigidity of multi-spindle cross drill and sleeve holder units.

Compatibility and condition of ER16 / ER11 cartridge tooling systems.

CNC and automation:

Verification of FANUC 0i-TF Plus options, backups, and alarm history.

Functional testing of safety and monitoring systems (door interlock, broken tool detection, parts ejection detection).

Integration and synchronization of the Iemca Steady 320 bar feeder with the lathe control.

3. Typical Industrial Applications

Based strictly on the stated configuration, the SB-20R Type G is technically suitable for:

High-volume production of small, high-precision turned components.

Parts requiring extensive cross drilling, tapping, and milling within a single setup.

Applications in sectors such as precision mechanical components, connectors, fittings, and similar small-diameter parts.

Material types, surface finish capability, and achievable tolerance classes are not specified and should be validated through process trials.

4. Common Risks in Used Machines

Even for relatively new Swiss-type lathes, typical risks include:

Tooling complexity, where incorrect setup of multi-spindle units can affect accuracy.

Guide bush wear or contamination, impacting surface finish and concentricity.

Control configuration errors, especially with advanced options and automation features.

Incomplete documentation, such as missing CNC backups or bar feeder parameters.

5. Maintenance and Service Considerations

With no service history provided, only general considerations apply:

Regular inspection of spindles, guide bush assemblies, and lubrication systems is essential.

Coolant quality and filtration should be closely monitored given the 180 L capacity and fine machining focus.

CNC parameters and option data should be backed up before any relocation or process changes.

Any long-term maintenance planning should be based on on-site inspection and operational testing rather than assumptions tied to machine age.

Final Note:
The Star SB-20R Type G, as specified, is a modern, highly equipped Swiss-type CNC lathe with extensive multi-spindle drilling and automation capability.