Introducing the Surfacing Center SCG 250
Working with larger optics in the 250 mm range you are confronted with various geometries and demanding specifications that require sophisticated grinding solutions.

The SCG 250’s unique mechanical design combines ideal axis configurations for excellent grinding of large spherical, aspherical, and freeform optics in one machine. Its innovative kinematics and spindle setup allow for both cup and peripheral wheel grinding in one process cycle resulting in superb form accuracy and minimized surface roughness.

The optional packages include fast automation and sophisticated in-process measurement technology for higher productivity and process stability.

Innovative frame concept
The SCG 250 has been designed with your requirements for perfect grinding in mind. The new frame concept is the basis for completely independent vertical and horizontal spindle arrangements as well as tool configurations. It unites perfect preconditions for the very different grinding tasks like spherical and aspherical machining in one innovative mechanical design. An independent placement of the working positions allows high flexibility in tool size and process design – with virtually no limits.

Optionally, the versatile surfacing center can be equipped with a freeform package. Two highly dynamical axes with small moving masses enable high accelerations and processing speeds.

Advanced spindle technology
The spherical version of the SCG 250 comes with up to three independent tool spindles offering higher flexibility in defining the grinding steps and corresponding grain sizes of the tools.

The version S2/1 enables automated multistep processing. One spindle does the rough grinding including centering and beveling. A second spindle takes care of the fine grinding.

With the version S3/1 the grinding is brought to the finest level. The additional third tool spindle meets the highest quality requirements. It also increases your flexibility in small batch processing – reducing the need for disruptive tool changes.

All tool spindles are direct-driven, allowing for smooth processing with minimal subsurface damage.

Automated processing
The spherical SCG 250 versions (S2/1 and S3/1) come with an optional fast automation which includes, automatic setup cycles, automatic lens detection and multi-purpose workpiece magazines. This retrofitable automation assures fast handling, minimum auxiliary times, and maximum cost-effectiveness.

Version SCGA250 – spheres and aspheres processed in one machine
As the companion of the SCG 250 for spherical grinding, the SCGA250 has full grinding capabilities of spheres and aspheres. The extended axis arrangement of the SCGA250 with two additional horizontal tool spindles allows optimized asphere manufacturing. Very precise contour processing of aspherical lenses is guaranteed.

The options for peripheral wheel or cup wheel grinding offer the freedom to select the optimal manufacturing process for convex and concave aspheres as well as for edge processing.

SCG 250 with freeform option – sophisticated freeform grinding capabilities
In addition to rotationally symmetric parts, the SCG 250 can process freeform optics when equipped with the freeform option. The peripheral wheels are mounted to fast X-axes enabling rough and fine grinding of non-rotationally symmetric optical components.

In-process metrology
The consistent high performance and tight process control is accomplished with an integrated metrology package.



CT Control automatically checks center thickness and performs the adjustments accordingly.



Tool Control recognizes the grinding tools and significantly reduces the set-up and correction times. Additionally process control compensates for tool wear.



Feed Control with its first touch technology minimizes the air cutting during tool approach to a minimum – saving valuable process time. Feed Control also optimizes the grinding process by adjusting the feed rate of the tool with respect to the cutting conditions.


Curve Control allows for measurement and correction of spherical geometry.



Balance Control allows the operator to control and optimize the balance of the tool run out resulting in significantly reduced subsurface damage.

Data communication
The system interfaces to an Ethernet network connection and to the SCHNEIDER Optical Technology (SOT) software enabling smooth and effective data exchange for setup and operation. The service is supported by an intelligent analysis system with remote diagnostic.

A graphical user interface assists the operator for simple and fast communication tasks.

The SCG 250 supports data exchange with external devices, e.g. measuring equipment.

When using the Surfacing Center SCG 250 you have the means to be better, faster, and more competitive. The processing capability and the widely automated operation of the SCG 250 make this machine a perfect mate for SCHNEIDER polishers like the SLP 301.

Technical Data

max. working range ø restricted (and unrestricted) spheres

SCG 250 S2/1: 250 mm (280mm)
SCG 250 S3/1: 250 mm (280 mm)
SCG 250 S4/1: 250 mm (280 mm)
– Edge processing up to 140 mm (250 mm only with restrictions and special tool)

max. working range ø restricted (and unrestricted) aspheres

SCG 250 S4/1: 250 mm (280 mm)

max. working range ø restricted (and unrestricted) freeform

SCG 250 S4/1: 250 mm (280 mm)

max. working range ø with automation

150 mm

working range radius

15 mm – flat

number of axes

3+3 (X, Z, B, optional fast X-axes, optional C-axis)

feed rate

X-axis: 0.01 – 30000 mm/min
Z-axis: 0.01 – 15000 mm/min
fast X-axes (FF): 0.01 – 30000 mm/min

positioning and repeat accuracy

X-, Z-axis: +/– 0.001 mm

feed rate

B-axis: 0.1 – 5400°/min

positioning and repeat accuracy

B-axis: +/– 4”

tool spindle connection

cup wheels: 25 x 42 HD, 40 x 80 HD
peripheral wheels: clamping sleeve

speed range

grinding tool spindle (cup wheel) max. 7000 min-1
grinding tool spindle (peripheral wheel) max. 5000 min-1

workpiece spindle connection flange ø

215 mm

speed range workpiece spindle

0.01 – 2000 min-1

power consumption

9 kVA avg.

compressed air supply

min. 6 bar (87 psi)


min. 0.6 bar (8.7 psi)

machine weight

approx. 4000 kg (8819 lb.)

dimensions without control panel (width x depth x height)

approx. 2450 x 1750 x 2150 mm (96 x 69 x 85 inches)

All data subject to change without notice. Please verify details with SCHNEIDER.


  SCG 250
PDF , 612 KB