Thomas Industrial Library

THERMAL (SHRINK FIT) SYSTEMS

While end mill holders and collet chucks are the main toolholders used in industry, they lack the accuracy and rigidity required for high-speed or high-precision machining. The thermal system is precise, rigid, and free of moving parts, offering complete concentric gripping and superior stiffness of an integral unit.

Fig. 3-3-14 The expansion and contraction of the toolholder provides clamping and releasing of the cutting tool. (Kennametal)

The thermal toolholder’s inside diameter is designed to be slightly smaller than the shank diameter of the cutting tool. When the toolholder is placed into the separate induction heating system, Fig 3-3-14, the inside diameter of the clamping end is heated and expands. The tool shank can then slip easily into the holder. As the holder cools, the resulting thermal contraction exerts a tremendous, uniform pressure around the entire surface of the tool shank, Fig.3-3-15. To remove the tool, the process is repeated.

Fig. 3-3-15 Induction heating system heats the toolholder, allowing the cutting tool to easily fit into the holder. (Kennametal)

Benefits

High precision and repeatability
High rigidity and gripping power
High balancing capability
Simple one-piece, symmetrical design
Easy tool assembling and disassembling
Short tool-changing time
Low maintenance cost and efforts
Increased cutting tool and spindle life
Increased chip removal rate and parts accuracy

Applications

High-speed machining applications
High-power machining applications
High-precision machining applications
Complex, contour, hard-to-reach applications
All rotary tooling applications
All metal and non-metal machining applications

The shrink fit system increases cutting tool life, chip removal rate, workpiece accuracy, and spindle life while reducing tooling preparation time. This means productivity can be greatly increased, and production costs can be reduced.

MODULAR TOOLING SYSTEM

COROMANT CAPTO™ Modular Tooling System Coromant Capto™ modular tooling system is effective for turning, milling, and drilling regardless of the machining operation or type of machine. The unique feature of this system is the tapered polygonal-shaped coupling, Fig.3-3-16, capable of transmitting considerable torque without losing its high precision and repetitive accuracy. It does not require keys, driving pins, balls, or interlocking teeth that have built-in disadvantages for turning at high speeds or in milling with high torque and radial forces. Coromant Capto works equally well in lathes with rotating spindles, in mill-turn centers, machining centers, and in flexible manufacturing systems.

Fig. 3-3-16 Coromant Capto™ modular tooling system provides high precision, repeatable accuracy tool-changing. (Sandvik Coromant)

The tapered polygon is tensioned in the clamping unit with a pre-load force of several tons, which produces an extremely stable joint. However, the tool can be quickly and easily removed manually or automatically. The length of the taper and the precision contact surfaces counteract bending of the cutting toolholder, and at the same time contribute to the coupling’s capacity to handle large torques.

The high precision of the coupling ensures a repeatable accuracy of ± .00008 in. (0.002 mm) in the X and Z axes. This repeatable accuracy applies when using the same external cutting unit and the same edge of an insert in the same clamping unit. When different cutting units are used, the tolerance of the insert seat in relation to the coupling, plus the tolerance of the insert, must be taken into consideration.

For tool changes, pre-measuring can be carried out to measure variations from nominal values. These differences can be compensated for by the tool-offset function of the machine control system. The versatility of Coromant Capto allows the system to be used on most machine tools and for many types of machining.

It forms the cornerstone for Just-in-Time production.

It is a viable solution for turning centers and FMS, and can also be used to advantage on conventional machines.

It allows tool system standardization and reduces inventory costs as well as simplifying administration and handling of tools.

Tools are prepared for through-tool coolant supply as a standard feature.

It is equally suitable for manual or automatic installations.

Driven tools for rotating tool applications change the scope and the efficiency of workpiece production in turning machines. Turning, milling, tapping, reaming, and drilling operations are combined in a single setup. The Coromant Capto adaptable range of driven toolholders can be fitted in almost any type of standard or special turning machine. The system has two basic types of driven toolholders: axial and radial. Each unit consists of standard modules for easy adaptation to different machines and turrets. To extend their application range, each one can be modified.

For more information on MODULAR TOOLING see the Websites: www.lyndex.com www.cormorant.sandvik.com/us www.kennametal.com