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How a shrink fit machine can save you money while improving tool performance

How a shrink fit machine can save you money while improving tool performance

Posted by All Industrial Tool Supply on Oct 20, 2021

How do shrink fit machines work?

Shrink fit machines and shrink fit toolholders work instead using the properties of thermal expansion as an alternative to mechanical clamping. The toolholder is manufactured with a bore that is slightly smaller than the diameter of the cutting tool. The holder is heated, causing it to expand a few thousandths of an inch, which allows the shank of the tool to slip into the toolholder. The holder is then cooled, causing it to contract, holding the tool with massive clamping force (10,000 lbs of force or more) that is applied with uniform pressure, surrounding the entire surface of the tool shank.

Concentricity of shrink-fit tools can be 0.0002" or better, with accuracy persisting through tool changes. The tool is centered automatically after each change via the contraction process.

To remove the tool, you simply reverse the process.

Shrink fit vs. collets or set screws

Shrink fit toolholding can provide roughly double the clamping force of a collet chuck or set screws. Compared with collet chucks, shrink fit tool holders offer exceptional balance and rigidity, preventing chatter and poor finishes. There are no set screws that require balancing on a shrink fit setup.

Who manufactures shrink fit machines and shrink fit toolholders?

Well-known brands like Techniks offer shrink fit machines and compatible tool holders. The Techniks 00400 SHRINKStation, for example, is one of the most popular shrink fit machines on the market. In general, you can mix-and-match shrink fit toolholders across brands, i.e. a Haimer shrink fit toolholder can be used in a Techniks machine, and so on.

Benefits of shrink fit toolholding

  • Very high grip force on the cutting tool
  • Tool changes can be handled in just seconds
  • Works great in low-clearance, tight spaces
  • Very rigid connection between the cutting tool and the holder
  • No moving parts
  • Increased tool lifespan and spindle life
  • Significant long-term cost and time savings

Downsides of shrink fit toolholding

  • More upfront costs to get started - the popular 00400 Techniks SHRINKStation, for example, sells for $6,900, but those costs can be recovered over time through increased efficiency, accuracy, and longer tool life.
  • Shrink fit machines have higher power requirements, which may dictate where they can physically be placed in a shop.
  • HSS and Cobalt Tooling can not be used with shrinkfit holders. They will go in, but due to the rate of thermal expansion of both HSS & cobalt being near the same as the holder, they may not be able to reliably be removed in the future.

What sizes and options exist for shrink fit toolholders?

Just about all common sizes exist in shrink fit options to suit your requirements, including CAT40, CAT50, BT30, BT40, ISO30, HSK40, 50, 63 and 100, C4, C5, C6 toolholders.

How long do shrink fit holders last?

One of the benefits of shrink fit technology is reduced wear and tear on toolholders and cutting tools. Some estimates state a 30% increase in tool life after switching to heat shrink technology from mechanical toolholding.

Other considerations

Shrink fit technology is recommended for use only on carbide cutting tools and generally isn’t used on HSS tools.

Shrink fit machines have higher electrical power requirements, which may constrain where they can be placed in a shop, so you should consider the available electrical power when selecting a shrink fit machine.

Finally, because of the heat involved, it’s important to note that shop staff should be trained on safety procedures when shrink fit machines are in use. Heated toolholders can typically be handled by operators with leather or clean, dry cotton gloves. Since electricity is used to heat the coils in a shrink fit machine, users should stand on rubber safety mats when in use.

Get in touch with All Industrial

For guidance on the use of shrink fit machines and toolholding, call, email, or chat with our team here at All Industrial Tool Supply. We’ll discuss the pros and cons and help you select a solution that saves you money and helps you operate more efficiently.

For a limited time, you can get free ShrinkFIT toolholders when you buy a Shrink Fit machine from Techniks. Learn more.