Quick Tool Changes with Shrink-Fit Technology

With a good shrink-fit system, you can change tools quickly, simply, and reliably using various tool holders. Here, we’ll explain in more detail how this works and what benefits it offers.

What happens during tool shrink fitting?

Shrinking a tool does not mean that the size of the tool itself is reduced. Instead, the tool holder—into which, for example, a drill or cutting tool is inserted—is heated briefly, precisely, and consistently so that it expands.

This creates enough space in the tool holder to insert the tool. As it cools, the material of the holder contracts consistently on all sides. This ensures that the tool is clamped with high rigidity, maximum clamping force, and proper centering.

Why are specialized shrink fit holders needed?

Specialized tool holders—known as shrink fit holders—are usually used for shrinking. They are specifically designed to retain their shape despite repeated heating and cooling cycles. For example, they contain no moving parts, ensuring that their balance grade is maintained; it is also important that the concentricity of the shrink fit holder is very high, because otherwise even a very precisely centered tool will be of no use.

Compared to conventional chucks, shrink fit holders have the minor disadvantage that a separate chuck with the appropriate diameter is required for each shank diameter. However, this is offset by the significantly higher concentricity, which is of great importance for high-quality machined workpieces.

What is a shrink-fit machine, and how does it work?

A shrink-fit machine heats the shrink fit holder—the tool holder—consistently and quickly using inductive current (i.e., via a magnetic field). With the appropriate accessories and measuring devices, it not only ensures that the new tool is precisely centered when inserted, but can also ensure correct length accuracy and measure—and, if necessary, correct—it before the shrink fit holder cools down. Appropriate sensors also prevent the shrink fit holder or the tool from overheating.

Automated Tool Heat Shrink Technology ensures, for example, that the overhang length and all other parameters important for machining the workpieces are automatically measured and correctly set—while still making the tool available again in the shortest possible time. This results in short setup times and low overall costs.

High-quality shrink-fit devices also feature their own cooling unit, in which the shrink fit holder is cooled with a consistent level of cooling. Contact cooling is used, for example, while some devices also employ water cooling. This cooling system, which complies with safety standards, also eliminates the risk of burns, which are possible if the heated tool holder is accidentally touched.

Adjust, Shrink, and Measure—the Fully Automatic All-in-One Solution

With ZOLLER »redomatic«, shrinking your tools is a stress-free and fully automatic process. Our all-in-one solution for presetting, shrinking, and measuring tools—with all processes automated within a single workflow—features 4-axis CNC control, autofocus, a tool turret, an induction coil, a tailstock, and a cooling system.


Safe, economical, and precise

With the patented automatic length stop system (»asza«), it offers the option of shrink-fitting tools to their target length simply, quickly, and precisely, with an accuracy of ±10 µm.

ZOLLER »redomatic« supplies only as much energy as is absolutely necessary when heating the tool chucks, thereby also protecting your chucks; the heat-shrink guiding system we designed and the patented fume extraction unit ensure greater safety for your employees.

Learn everything about our successful shrink-fitting solution here

What are the advantages of shrink-fitting and unshrinking?

Shrink-fitting and unshrinking tools offers a number of advantages:

  • It is possible to center the tool before the shrink process, which prevents misalignment and ensures high concentricity.
  • The tool is held with consistent clamping forces in the shrink fit holder.
  • Specialized chucks provide high balance quality and do not deform even after numerous heat-shrink processes.
  • With a high-quality shrink-fit device and a suitable shrink-fit holder, the heating and cooling processes take less than a minute.
  • For high speeds and tools with long overhangs, no other clamping method allows for similarly precise tool utilization.

Everything in One Place

With our ZOLLER »powerShrink« shrink station, you have everything you need for a quick heat-shrink process in one place. Thanks to its modular design, you can easily adjust the workplace to your needs and requirements.

The station is universally compatible with all HSS and carbide tools ranging from 3 to 32 mm in diameter and is also suitable for extremely long tools.

Learn more about the ZOLLER »powerShrink« shrink station

Tool Heat Shrink Technology: Your Advantages

Read how we have achieved significant increases in energy efficiency, process speed and ergonomics. Use perfection for your production.


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Christoph Zoller

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