Shrink
Permanent connection via a thermal fit
Shrink fitting is a joining process in which two components are joined together by means of form-fit and force-fit using controlled temperature differences. The joint is formed solely through the thermal expansion and contraction of the materials involved—without the use of any additional joining aids.
During the shrink-fit process, the inner component is cooled significantly while the outer component is heated. This temperature difference causes the bore of the outer component to expand, while the inner component contracts. In this state, the two components can be fitted together manually or mechanically.
Once the parts are joined, the temperatures equalize again. The inner component expands while the outer component contracts, creating a very stable, backlash-free, and durable joint. This process is irreversible, as the joint is held together solely by the resulting press fit.
Shrink fitting is particularly well-suited for applications that require high torque transmission, precise alignment, and a secure, long-lasting connection.
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Silvio Stranek
Sales, Technical Consulting / Quotes (Upper Austria, Tyrol, Salzburg, Vorarlberg, Bavaria, South Tyrol)
Email. s.stranek@htr.at
Phone: +43 (0) 664 / 88 92 78 10
Thomas Stadlober
Sales, Technical Consulting / Quotes (Styria, Vienna, Lower Austria, Carinthia, Slovenia)
Email. t.stadlober@htr.at
Phone: +43 (0) 664 / 88 64 15 06
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Your Questions, Answered
We have compiled a list of frequently asked questions to help you better understand our services.
What is shrinkage?
Shrink fitting is a joining process in which two components are joined together by controlled temperature changes. The joint is formed by the components returning to their original shape as the temperature equalizes.
Why are the components cooled or heated?
As it cools, the inner component shrinks, while the outer component expands as it heats up. This is what makes the joining possible in the first place, and the desired fit is restored as the component cools.
Is the shrink-fit connection removable?
No, shrink-fit joints are not detachable. The joining process is permanent, as the joint is held together solely by the resulting press fit.
What are the benefits of shrinking?
This method enables a backlash-free, high-load-bearing connection without the need for additional fasteners. It also ensures excellent concentricity and alignment.
For which applications is shrink wrapping suitable?
Shrink fitting is often used for components that must transmit high forces or torques—for example, in shaft-hub connections or similar press-fit joints.
Does shrinkage affect the material properties?
The material properties are generally preserved, as no material-bonded connection is formed. However, controlled process management is essential to prevent unwanted stresses.