For thin-walled, non magnetic materials vacuum clamping is preferable where machining of large, uneven parts is required.

Witte Gerätebau, manufacturer of different fixturing systems, specializes in the sector of vacuum clamping technology for difficult applications and special solutions.

The company has already designed and manufactured several large format vacuum clamping systems for the aerospace industry. They benefit from their own decades of experience as a subcontractor for aluminum aircraft parts as well as their equally long experience and extensive know-how in vacuum clamping technology.

One system for many parts thanks to grid plate technology
A special requirement is usually to incorporate a clamping fixture into an existing CNC machine and integrate its operation into the control process. In this case, Witte built a clamping system, which was integrated into a CNC-high gantry machining center.

Currently meter-long rough, uneven aluminium panels in thicknesses from 9 to 50 mm are being milled. To enable double-sided machining the heavy components must be evenly pre-processed. A unit was developed, comprising of a gantry with an hydraulic press and controls to create the force required to press these parts down on to the vacuum chuck, mounted on a base structure with linear units.

Because of the heavy cutting performance and uneven clamping surfaces involved, Witte designed a special vacuum grid chuck. This classic type of vacuum clamping technology offers the highest clamping forces and is predestined for parts with simple geometries and rough surfaces.

The 2000 x 7000mm large vacuum surface is divided into 50 sections, which can be operated independently via NC controls. A special slot and seal geometry enables clamping of parts even when they are extremely uneven.

Several small work pieces can also be clamped simultaneously using the same principle, thereby increasing the effectiveness of the system significantly.

Part loading also takes place using vacuum technology via crane. The uneven work pieces are pressed down hydraulically section by section. The gantry moves with up to 15 m / min feed rate to varying positions on the raw material where one segment at a time is pressed down onto the chuck with up to 2 tons force, resulting in full surface clamping of the part.

The complete system is now running reliably in three-shift operation.
All processes are automatically monitored and regulated. The complete system includes a sophisticated pump system with sufficient suction power and a built-in liquid separation unit to ensure safe operation should coolant be sucked in.