KEEPING COOL WHILE FORMING THREADS

For obtaining a maximum component safety and profile accuracy of internal threads, users resort to thread forming more and more frequently. This becomes obvious in the double-digit growth rates at LMT Tools. A suitable cooling system increases the service life of these tools considerably, as illustrated by an example from Germany.

There’s a growing trend towards thread forming and with good cause: During the cold forming process, the structure of the material is not cut but molded and hardened. This has many advantages as the increased thread strength also enhances the component safety and the profile accuracy as well as the surface quality and the pitch strength. The process safety improves as well, in relation to no chips being generated that could result in obstructions.

HPF thread former with axial cooling system

For efficient production of internal threads without generating chips, LMT Fette developed the first of its kind in the High Performance Forming (HPF) series. What makes them special in comparison with other thread formers:

  1. The HPF has a (shock absorbing or forgiving) main body made of steel while still offering significantly higher torsional stiffness than solid carbide thread formers.
  2. The insert is made of a tough, highly wear-resistant, ultra-fine grain carbide substrate enhanced by a proprietary coating guaranteeing longer tool life.

September 2014 LMT added a axial cooling system to the HPF line. This offers the advantage for blind holes – and especially horizontal use and deep threads where the cooling is applied directly to the forming process. Thanks to this program extension, LMT Tools now offers tools with internal cooling for through holes (IKR, radial outlet) and for blind holes (IKZ, central outlet).

Quadrupled operating time for car socket forming

The HPF thread former with axial cooling has already proved itself at an automotive supplier in Germany. This company uses an HPF M8 x 1 to produce solid sockets for plug connections in motor vehicles (material 23MnB4). Due to the modular design and direct cooling during the forming process, they are now able to manufacture the internal threads in a safer and more efficient manner than their competitors. Tool life over previous tools increased 400 per cent while the cycle time decreased by 70 per cent. For the customer, this resulted in a total savings of 90,000 euro a year for an amount of 3.5 million components.

Overview of the cutting rates

Initial situation: Coated M8 × 1 HSS-E PM thread former

Vc: 6 m/min
n: 240 1/min
Cooling: Oil
Operating time: 15,000 threads
Cycle time: approx. 10 seconds

Solution: HPF-IKZ M8 × 1 6GX by LMT Fette

Vc: 25 m/min (maximum cycle of machine reached)
n: 1,000 1/min
Cooling: IKZ with oil
Operating time: 60,000 threads
Cycle time: approx. 3 seconds

Results:

  • Increased Tool life by a factor of four
  • Reduced cycle time by 70 per cent
  • Total Savings of approx. 90,000 euro a year

Contact

LMT Tool Systems GmbH
Bernd Günther
Grabauer Str. 24
21493 Schwarzenbek
Germany

HPF thread former

The HPF thread former by LMT Fette is optimally suited for producing internal threads without generating chips. The new axial cooling system guarantees that the cooling medium is directly applied to the forming process.

Solid sockets manufactured with the HPF thread former

When manufacturing solid sockets with the HPF thread former, an automotive supplier was able to quadruple the tool life and to reduce the cycle time by 70 per cent

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