• Rapid shrink-fit and expansion

• Maximum clamping forces can be applied

• Longer tool life and spindle life

• Good surface finish with high tool clamping rigidity

• Good bending and radial rigidity even with long extension

• Narrow chuck design

• Localized energy applied in clamping area means the energy transferred to the chuck is kept to a minimum

• Equipment is easy to handle

• Processor controlled adjustment to the amount of energy required

• Rapid cooling of tool and chuck by cooling units allow minimum warming of the thermal expansion tools

• Clamping of carbide and HSS tools for shank tolerance h6 to DIN 6335 and DIN 1835 can be accomplished with the same chuck

• By using special heat resistant steel and special hat treatment methods, the chucks are particularly durable and stable in form

• High production reliability achieved by shielding the hot components in the cooling adaptor

• Chuck concentricity greater than or equal to 3 um

• Can be used at high spindle speeds

Thermal expansion is generally well known as a way of making connections that cannot be released.  Over the last few years, however, systems have also become available for reversible clamping of cylindrical tools.  To ensure the successful use of this method in practice, it must also achieve short shrinkage and expansion times.

By applying heat inductively with a high level of energy, tool change can be accomplished in seconds.  The thermal expansion clamping of the tools for high speed machining and heavy duty cutting produces a value (concentricity better than 3 um) that indicates the technical advantages of this clamping method. 

In principle, clamping in a thermal expansion chuck is bases on a change in volume of stable materials in proportion to the temperature. 

In the thermal expansion chuck, an increase in temperature cases an increase in the internal diameter  After a cylindrical tool has expanded in this way, it is then inserted and cools down.  A radial clamping effect is produced while the chuck ha changed in its physical shape.  As long as this distortion occurs within the elastic area of the material used, the clamping process is reversible and can be repeated as often as required.

Decisive factors in the clamping process are the heating time, the temperatures and temperature patterns that occur within the heated chuck.  In this respect, warming in the medium frequency range clearly offers advantages.  The created electromagnetic field allows clamping area of the chuck to successfully warm up within a maximum of 10 seconds and allows the tool to be easily inserted.  The localized warming allows the energy applied to the chuck to be kept at a minimum.  After the tool has been inserted or removed, cooling takes place immediately so that the rest of the chuck and the tool itself are only warmed to a minor level.  By thermally expanding the tool, inductive heat produces important advantages in the transference of heat to the tool.  the effective time is optimized and the tool is heated less intensely than by heating with hot air or flame.  The higher temperature difference between the chuck and the tool allows the tool to be removed more easily.  The cooling time is approximately 60 seconds.