A reliable connection is essential in almost every metal product. However, each application requires a different solution. The material, wall thickness, load, production speed and available machinery all play a role.
Blind rivet nuts, weld nuts and press-in nuts have been used for many years. Friction drilling can be an alternative in many applications. This process creates a bushing directly in the base material. You can then form a thread in this bushing.
This means you do not need to add a separate insert, reducing the number of parts and process steps.
During friction drilling, a solid carbide tool rotates against the material at high speed. The combination of friction and axial force generates heat. This makes the material formable and causes it to flow around the tool.
Part of the material forms a collar on the upper side. The remaining material forms a bushing on the underside. A thread can then be formed in this bushing.
No chips are produced because the material is displaced rather than cut away.
The formed bushing increases the available thread length. This allows you to create a usable thread in thin-walled tubes and profiles.
The final strength depends on factors including:
It is therefore important to assess and test each application in advance.
With friction drilling, you do not need a separate nut or insert. This reduces the risk of missing parts and the number of production operations.
You also do not need to feed, position or weld a fastening element into place.
Friction drilling and roll tapping can be integrated into a drill press, CNC machine, robotic cell or purpose-built production machine.
With the correct parameters, you can create a stable and repeatable process. This can reduce production time, especially for larger production volumes.
During friction drilling, the material is displaced rather than removed. As a result, no chips can remain inside a tube, profile or product.
This can be an important advantage for closed structures or products where contamination is undesirable.
Friction drilling is not automatically the best solution for every application. The right choice depends on the product and the production process.
| Feature | Traditional fastening | Friction drilling |
|---|---|---|
| Additional fastening component | Usually required | Not required |
| Number of process steps | Depends on the method | Friction drilling and roll tapping |
| Chips | Possible | None |
| Suitable for automation | Yes | Yes |
| Suitable for thin-walled tubes and profiles | Depends on the method | Often |
| Validation required | Yes | Yes |
Blind rivet nuts, for example, remain suitable when you cannot apply much axial force to the product. Welding may be required for specific structures or material combinations. Friction drilling is particularly relevant when you want to create a thread directly in a tube or profile.
Friction drilling works with many formable metals, including steel, stainless steel, aluminium, copper and brass. The correct process parameters vary for each material.
The wall thickness and shape of the product are also important. Thin sheet metal, for example, must be properly supported to prevent deformation.
Brittle, hardened or very low-melting-point materials are generally less suitable. Flowdrill therefore assesses each application based on the material, geometry and required connection.
A reliable friction-drilling process involves more than selecting a tool. The machine, tool holder, lubrication, spindle speed, feed force and workpiece clamping must also be correctly matched.
Flowdrill helps you determine:
In addition to standard tools, Flowdrill also supplies solutions for applications with non-standard dimensions or specific production requirements.
Before introducing an application into production, it is advisable to test it using representative parts.
During these tests, you can evaluate factors including:
Flowdrill can assess applications internally and support durability and strength testing on certified machines. This gives you a better understanding of the performance before implementing the process in your production environment.
Friction drilling can reduce the number of parts and process steps. Whether friction drilling is suitable depends on your product, material and production process. A reliable solution therefore always starts with a technical assessment.
Would you like to know whether you can replace blind rivet nuts, weld nuts or press-in nuts? Ask a Flowdrill engineer to assess your application.
