VACUUM WORKHOLDING – HOW DOES IT WORK?

On all surfaces of an object there is an even pressure due to the surrounding atmosphere of approximately 1 bar (10.9kg per square metre or 14.5 pounds per square inch).

Using a vacuum pump, the air underneath the component is sucked away, so that the pressure load on these lower surfaces is partly removed; the clamping or holding force results from the difference in pressure between the upper and lower component surfaces.

The amount of one-sided pressure is dependent on the amount of under pressure or vacuum generated. Modern vacuum pumps will remove 98% of all the air under the component reducing the pressure there to 20mbar from the 1000mbar above the component.

The component is held by this difference between the upper and lower pressure.

The weather and position above sea level of the vacuum application affects the amount of atmosheric pressure available and this will affect the actual clamping force obtained for a specific application.

VACUUM WORKHOLDING – WHAT HOLD DOWN FORCE CAN I ACHIEVE?

The clamping force on a component is proportional to the surface area, therefore, for a component size of 20cm x 40cm and vacuum of 0.8 Bar, the clamping force can be calculated: (1 Bar = 100kN/m² or 14.5lbs/in²)

Clamping force in kN/m² is
0.20m x 0.40m x 0.8bar x 100kN/m² = 6.4kN

Clamping force in lbs/in2 is
7.87” x 15.75” x 0.8bar x 14.5lbs/in² = 1437.8lbs

APPLICATIONS AND ADVANTAGES

We offer Vacuum Workholding for the following:-
· Horizontal and Vertical Milling Machines
· Machining Centres with or without pallets
· Turning Machines – Manual or CNC
· Grinding Machines – Surface and Cylindrical
· Engraving Machines
· Measuring Machines
· Special purpose machines and applications

Vacuum workholding offers the following benefits:-
· Clamping with no distortion or clamping marks
· Very fast clamp and un-clamp cycle time
· Machining without vibration – thus preventing chatter marks
· Machining area free of clamps for possible multi-surface working
· Suitable for many materials
· Adaptable to many different processes