Heat shrink tooling is considered one of the best methods for high-performance machining. The mold and die industry was the first segment of the manufacturing market to look for more precise toolholder options, due to the need for a slim nose and long reach. Today, every segment of manufacturing can benefit from the advantages of shrink fit tooling.
At Triumph Tool, we believe in the importance of offering superior technical support and customer service to our clients. Our team has written this article as a basic introduction to heat shrink tooling, to be used as a resource for our clients and their teams. We hope you find it helpful! Please leave a comment below or contact us if you have any questions or feedback.
When looking for toolholder solutions for any type of machining, it is always good to focus on the three main features that a toolholder must bring you:
Rigidity comes from sufficient taper contact and proper clamping of the toolholder in the machine tool spindle.
Accuracy comes from minimal run-out at the cutting edge of the cutting tool when clamped in the holder.
Balance comes from a balanced assembly of the toolholder (including all accessories such as pull-studs) and cutting tool combination.
You may also often think about the following:
Geometry of toolholder
Geometry is important to avoid collisions with the workpiece. In regards to the EDM process, electrodes must be machined accurately and efficiently. Oftentimes, deep ribs are required in the part process and may present challenges. Also, deep cavities such as large door panel or bumper molds require deep reach with extreme clearances.
Cleanliness of the toolholder
Cleanliness is required to avoid excessive run-out, especially when machining graphite.
Extending cutting tool life
Since high-end cutting tools are needed to obtain the best performance in the shortest time possible, a toolholder that extends cutting tool life can be advantageous. These cutting tools often have exotic coatings that lend to an expensive price.
Surface finish at higher speeds and feeds
Some toolholders are used with lower depth-of-cuts, which translates into better surface finishes. This makes balance even more important to minimize vibration at the cutting edge of the cutting tool. Also, proper chip evacuation provides better finishes.
Shrink Fit Advantages
There are 10 inherent benefits that a good shrink fit chuck can offer:
1. Unsurpassed accuracy
A properly produced shrink fit chuck should be able to guarantee 0.00012″ (3 microns) maximum run-out at three times the cutting tool diameter.
2. Availability of slim profiles
Shrink fit chucks are available with three-degree draft angles and very slim profiles. They can also be modified to be straight walled, if needed, in order to prevent toolholder collision with the workpiece.
3. Gripping torque
A shrink fit chuck grips the cutting tool 360 degrees around the shank. This leads to a very high gripping torque that prevents the cutting tool from moving during roughing or finishing operations.
4. Extended reach options
Shrink fit chucks can use shrink fit extensions that provide the user with many options with standard products. When machining deep cavities, one can place shrink fit extensions into standard shrink fit chucks, getting unsurpassed toolholder lengths with very little run-out.
5. Balance repeatability and balanceable options
Shrink fit chucks can offer some of the best balance repeatability of any tool holding system on the market, since there are no moving parts. In many cases, if a shop purchases a properly balanced shrink fit chuck with correct accessories (such as pull-studs) and uses good cutting tools without inherent unbalance (such as flats or unequal spacing), then they can often have good balance characteristics for running at high speeds without doing an additional fine-tune balancing.
6. Reduction of tool changing time and less toolholder accessory inventory
Nothing beats the tool change time of shrink fit chucks if the process is joined with a capable inductive shrink fit machine. Tool changes can be done in 5 to 10 seconds, and most importantly, consistently. This allows the toolholder assembly to be in the machine making chips more of the time, rather than out of the machine waiting to be changed. Also, a shop needs very little additional toolholder accessory inventory (i.e., collets, nuts, seal disks, etc.). This simplifies the process.
7. Cleanliness of setup
A shrink fit chuck typically is a sealed system by design. Therefore, the introduction of contaminants in the bore are minimized. If contaminants are introduced to the bore of a toolholder, oftentimes run-out accuracy is compromised.
8. Coolant options
Shrink fit chucks have convenient methods to deliver coolant down to the cutting edge of the cutting tool. This helps with the proper removal of chips and can also aid in providing better finishes.
9. Consistency of setup
Shrink fit holders provide the great repeatability from toolholder setup to toolholder setup. This is especially beneficial for those shops running lights out. For example, all toolholder setup operators set the toolholders the same with shrink fit holders. There are no variables—such as over-tightening or under-tightening a collet nut or not cleaning out a chuck sufficiently.
10. Availability of shrink chucks
Most of the major toolholder builders in the world now offer shrink fit chucks as a standard. See a full standard offering at Haimer: Full Product offering at Haimer
To see the full article by Haimer: Top 10 Reasons to use Haimer Shrink fit Technology
To learn more about the advantages of heat shrink tooling, contact the team at Triumph Tool today.