Reliable machining of demanding materials
Tools and processes have to meet high requirements when it comes to machining hardened materials. Their hardness and brittleness increase the risk of tool breakage, especially in case of thread production at the end of the manufacturing chain. In this stage of the process, errors are hard to correct and rework is time-consuming. However, these challenges can be overcome using the right procedure: modern thread milling technology enables reliable and precise machining, even in case of very hard materials.
Why is thread milling ideal for hardened materials?
Compared to conventional procedures such as tapping and EDM, thread milling offers decisive advantages: shorter machining times, high process reliability and excellent thread quality. Standard threads may even be efficiently introduced into hardened materials. Flexibility, process reliability and precision are guaranteed all through the process to the last machining step.
Process reliability
Thread milling ensures a reliable production process, also for demanding materials:
- In the event of a tool breakage, the workpiece is not damaged because the milling cutter is smaller than the thread diameter.
- Subsequent thread milling in already finished or hardened parts is also very reliable.
- Small cutting forces ensure an even force distribution on the workpiece.
- The minimal vibrations during CNC machining reduce the risk of tool breakage.
Thread quality
The procedure ensures a consistently excellent thread quality:
- Clean threads with high surface quality thanks to optimal chip removal
- Tight tolerances can be observed thanks to radius compensation, even in case of tool wear
- Precise thread geometry with high gauge conformity within DIN tolerances
- Nearly the full thread depth can be used because there is no lead-in
Flexibility
One tool, many options:
- One tool covers a broad range of materials, which means less effort for changeover.
- The same milling cutter may be used for producing left-hand and right-hand threads as well as blind and through holes.
- Different thread diameters with the same pitch can be realised very easily.
- Thanks to their high flexibility, these milling cutters are especially suited for individual manufacture and small series.
Efficiency
Thread milling also presents economic advantages:
- Much faster machining compared to EDM (up to 10 times faster)
- No core hole drilling necessary – one-step machining
- Low tool wear and long service life
- Reduced non-productive times and fewer tool positions needed
- Fewer steps in the process and thus less programming effort
Product highlight: thread milling cutter WZG 171518
- High wear resistance due to solid carbide with optimised coating
- Great variety of thread diameters, metric or inch versions available
- Optimised cooling through groove on the shank (inner coolant supply)
- Various applications: suitable for most materials (up to 67 HRC)
- Core hole and thread in only one work step
- Both dry and wet machining possible
- CNC programming example available
Cooling during thread production
The selection of the right cooling system impacts greatly on process reliability and tool life. Exterior cooling using air, emulsion or water is a common solution, where the coolant should be supplied as steeply as possible to ensure efficient chip removal.
However, even better results can be achieved with inner coolant supply, especially when it comes to thread milling. The coolant is supplied directly to the cutting edge, which improves chip removal and increases surface quality and tool service life. Moreover, downtimes are decreased because there is less need to change tools and lower cleaning effort involved, which is a clear economic advantage in the whole machining process.
Which tool holder is the right one?
Tool holders play an often underestimated, but nevertheless central role in achieving high quality, efficiency and process reliability in thread milling, especially with regards to high-precision applications and demanding materials. They ensure exact concentricity and reduce vibrations, and are thus vital for high-quality threads. Additionally, correct tool holders contribute to increasing tool service life and simplify the tool change.