The Library of Thread Rolling - 7/9

Thread rolling with knowledge and awareness

Specialist topic: An exciting overview of thread rolling... The basics, processes, tools, and applications of rolled high-tech threads

 

Why are thread rollers sought-after specialists?

As the company name says, the core competency of Eichenberger Gewinde AG is thread rolling. The thread profiles of the threaded spindles are manufactured exclusively using the thread rolling process. Both users of Eichenberger standard and customer-specific products and all manufacturing companies that want to have threads produced efficiently can benefit from our knowledge of this method of rolling.

In machining – e.g., milling or turning – shapes can be reliably reproduced to a thousandth of a millimeter by stopping the machine when the final dimension is reached, checking the dimension, and continuing machining if necessary. Not so with thread rolling. Because the tremendous pressure continues to act, the rolling process must be stopped before the intended form is reached, which happens at different times depending on the base material. Although steel only changes its form very slightly – the lattice structure of the material is put in order, so to speak – it does change noticeably.

Ending the rolling process

Estimating the point at which thread rolling "stops" is purely a matter of experience. If the pressure is too long or too short, the required shape is no longer correct. The only way to indicate the thread shape is faulty is my measuring it There is no second chance. The trick is to hear the expert say: "the material purrs". That’s when the process needs to be stopped. If this moment is missed, flaking can occur as the material is "rolled to death".

Rolling noise

The experienced machine operator can also tell whether the forming behavior is in the "green zone" simply by the sound of the rollers and rolling. If the sound changes, the form also changes. The sound depends on the base material: rolling unalloyed steel produces a different sound than rolling low-alloy or high-alloy chrome steel.

eich-produzieren

Fig. 1: Thread rolling – here, rolling tool profiles cut into the workpiece surface

Workpiece temperature

Special sensibility is required for self-heating. The following rule of thumb applies: If the threaded spindle is cold (or only very slightly heated) when it leaves the machine, it can be assumed that the parameters of the forming process were within the permitted range.

Example: thread to be hardened

For spindles with a steep thread, thread rollers rely on their awareness. They must notice when the material is “quiet”. In concrete terms, this means that they wait until the core temperature of the workpiece is the same as the ambient temperature. The thread dimensions must now be within the permitted limits. Too much heat in a spindle with a steep thread is synonymous with excessive tolerances.

The properties of the base material must be taken into account for both the hardened threaded spindle and the spindle with a steep thread. This requires experience, which cannot be learned, but can only be gained over a long period of time.

Example: Steep thread

For spindles with a steep thread, thread rollers rely on their awareness. They must notice when the material is “quiet”. In concrete terms, this means that they wait until the core temperature of the workpiece is the same as the ambient temperature. The thread dimensions must now be within the permitted limits. Too much heat in a spindle with a steep thread is synonymous with excessive tolerances.

The properties of the base material must be taken into account for both the hardened threaded spindle and the spindle with a steep thread. This requires experience, which cannot be learned, but can only be gained over a long period of time.

Example: Safety thread

The rolling of high-alloy steel for safety threads requires even more expertise. The growing, stretching, and shortening of the workpiece must be "felt" and "seen".

All these examples explain why experienced thread rollers are sought-after specialists whose work cannot be copied so easily.

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Fig. 2: Thread rolling tools with rolled threaded spindles

Eichenberger – your service provider right from the start

With Eichenberger, you can implement your individual requirements for a screw thread right from the start of development. Don't hesitate to contact us before you even know what you need. We will be happy to work with you to develop a customized solution for your thread system. Contact one of our experts directly, we are there for you right from the start.
> Contact us now without any obligation and find out more

With state-of-the-art production methods, many years of expertise and a tool inventory of over 1,000 rolling tools, we produce rolled screw drives that meet even the most unusual requirements:

  • Gradients up to 6x in diameter
  • Slope accuracy class G5
  • Spindle lengths up to 6 meters
  • Spindle diameter from 2 to 160 millimeters
  • All standard profiles (M, Tr, UNC, UNF, UNEF, Whitworth)
  • Multi-start threads, also as right/left-hand threads
  • Steep thread profiles
  • Ball screw profiles
  • Special profiles
  • Worm thread profiles (special quality and price advantages!)
  • Serrations and knurling
  • Conical thread
  • Threads on prefabricated and/or bulky parts, e.g., also on forged parts
  • Freely designed thread geometry
  • Responding to customer requirements, such as tailored nut geometry

Eichenberger leaves nothing to chance and places the highest value on quality. This is what has been impressing our customers since 1953. See for yourself!

> 100% Swiss Quality
> Thread specialist since 1953

To blog overview

 

Schnecken-Profil

Fig. 3: Worm profiles according to basic profile DIN 3976
Single and multi-start worms can be rolled.

 

Literature and sources

Apel, H. (1952). Gewindewalzen: Kaltverformen von Präzisionsgewinden und Spindeln. Hanser.
DeWiki (2022, 3.August). Lexikon Gewinde. https://dewiki.de/Lexikon/Gewinde
Kübler, K. & Mages W.J. (1986). Handbuch der hochfesten Schrauben, (1. Aufl.). Girardet
.
Peters, H. (2003). Mathematisch-Technisch-Algorithmisch-Linguistisches Sammelsurium. http://www.hp-gramatke.de
Trösch, B. & Husistein, K. (2007). Bibliothek der Technik -, Band 286, Gewinderollen. Moderne Industrie.
Verein Deutscher Eisenhüttenleute (1984) (Hrsg.). Werkstoffkunde Stahl, Bd. 1. Springer,
Wikipedia (2022, 3. August). Metrisches ISO-Gewinde. https://de.wikipedia.org/wiki/Metrisches_ISO-Gewinde


©
2007 Alle Rechte bei sv corporate media, D-80992 München http://www.sv-corporate-media.de
Abbildungen: Nr. 1, 23-25 RWT Rollwalztechnik GmbH, Engen; Nr. 2 Foto Deutsches Museum, München; Nr. 3 Musée du tour automatique et d'histoire de Moutier, Moutier (Schweiz); Nr. 16 Fette GmbH, Schwarzenbek; Nr. 18 Meinrad Plaz, Staufen (Schweiz); Nr. 26 Habegger SA, Court (Schweiz); Nr. 34-36 FBT Fahrzeug- und Maschinenbau AG, Thörigen (Schweiz); Nr. 37, 38 Schleuniger AG, Thun (Schweiz); Nr. 39, 40 Max-Planck-Institut für Physik (Heisenberg-Institut), München; Nr. 41 Saurer AG, Arbon (Schweiz); Nr. 42 Line Tech AG, Glattbrugg (Schweiz); alle übrigen Eichenberger Gewinde AG, Burg (Schweiz). Satz: abavo GmbH, D-86807 Buchloe. Druck und Bindung: Sellier Druck GmbH, D-85354 Freising. Printed in Germany 889030.

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