Flow-punch Hotdrill

With flow punch forming bushes or eyelets can be produced in thin-walled metals (for example sheet steel, non-ferrous metals, or stainless steels) without cutting up to a wall thickness of 12 mm. Bushes or eyelets can be obtained with up to 4 times the original thickness of the material in diameters of 1.8 mm to 32 mm.

The Advantages of Flow Punch Forming:

Benefit in practice :

• High precision and reproducibility
• Less material and lower weight due to the use of thin profiles
• Counterpieces (e.g. punches / dies, etc.) are not required, thus even profiles with difficult to access interiors can be processed.
• Flow punch forming in inclined position
• Increase in the drawing forces of threads (thread forming)
• Tightness of the clearance holes
• Increase in hardness - for example less wear with multiple connections
• No reinforcing welding, riveting down, or welding screw nuts necessary
• Only one basic material, thus avoidance of electrochemical corrosion
• High load capacity of bearing bushes
• Material hardening
• Easy to learn and affordable entry into a new technology

Economic Benefits :

• Chipless forming process : no connecting elements needed
• A single operation for the manufacture of eyelets
• Process can be automated
• A column drill is sufficient : no additional equipment costs
• Minimum setup times

Ecological Benefits :

• High-strength connections can be produced using the centerdrill process without additional materials. The basic material remains unalloyed and easy to recycle! Chip removal is not necessary.
• Centerdrill connections are detachable and offer significant advantages for subsequent dismantling compared to other processes.

Which materials can be processed with hotdrill?

Flow punch forming can be used with virtually all thin-walled metals (excluding tin or zinc); for example all welding steels, stainless steels, aluminium, copper, brass, bronze, magnetic materials and special alloys.

Some application examples:

Requirements for Flow Punch Forming:

Any column drilling machine with sufficient power or NC/CNC machining center, etc., with the required speed and kilowatt output is basically suitable for flow punch forming.

For secure clamping of the centerdrill, a special collet chuck with cooling ring was developed with which the heat can be dissipated ideally. For optimal concentricity a special collet is used for locating the centerdrill.

Which centerdrill for which application?

The standard versions include the short and long models of the hotdrill. They differ only in the length of the cylindrical part; the angle of the conical part is identical. When using these versions the material displaced against the direction of feed remains on the surface of the workpart and forms a collar. Both models are also available in the flat version, with cutters ground into the belt that remove the collar in the same operation, resulting in a smooth surface.

Centerdrill short or long version	Result : Bore with collar
Centerdrill Short Flat / Long Flat version	Result : Bore without collar

Process Data

Reference values for material S235JR (St37/2) with 2 mm wall thickness. Depending on the application and mechanical equipment, the process speeds can also be increased significantly.

Thread Forming with CenterTap:

Thread forming with centertap offers the exact same advantages as flow punch forming. It is a chipless process in which the material is rendered flowable and displaced from the thread root into the crests. It is similar in principle to the rolling of external threads. Because the material on the thread flanks is compressed during the process, the drawing forces of the formed threads are greater than for cut threads!

CenterTap

Fiber orientation of the formed thread

Advantages of Thread Forming

• Non-cutting manufacturing process
• Reinforced orientation of the material fibers results in threads that can withstand high drawing forces
• Highly accurate threads, therefore miscutting is not possible
• Low wear after multiple connections due to increased hardness
• 3 to 10 times faster than thread cutting
• increased life due to special TiN coating
• reduced friction, less burr formation and scoring
• Can be automated.

Please note :