Towards a new generation of coated hobs

• Research unit: EU RFP
• Project number: 97.0526-1

Key words (English)

Cutting tools; hobs; PVC coatings; dry HSC machining

Alternative project number (English)

EU project number: BES2-5273

Research programs (English)

EU-programme: 4. Frame Research Programme - 2.1 Industrial and materials technologies

Short description (English)

See abstract

Partners and International Organizations (English)

Genta (I), Saazor (D), Ensam (F), Vergnano (I), Diarc (F), PSA (F), ILM-CNR (I), Seram (F), IEG (CH)

Abstract (English)

The objective of the study was to bring reliable information so as to design new HSS hob for the dry and high speed cutting.
- The experimental investigations have shown that the dry and high speed hobbing needs a substrate with a high hardness and a high oxidation resistance at high temperature. The sintered high speed steel, as the S390, seems to be adapted to this kind of applications.
- The TiN has the better wear behaviour at low cutting speed and with oil lubricant. The (Ti,Al)N is more dedicated to the use in dry and high speed hobbing (40% more workpieces machined than with the TiN) but can not solve the apparition of the crater wear which is the main kind of wear at this high level of thermomechanical loads.
- The MoS2 can improve the life duration of the hob in dry and high speed hobbing (40% more workpieces machined than without MoS2) by its low friction coefficient at high temperature which limits the apparition of the crater wear.
- TheCrC/C brings a benefit effect in the removal of the chips (less chip jamming in the flutes) but doesn't bring anything in the improvement of the tool life duration in any tested cutting conditions.
- The Diamond doesn't bring anything in any tested cutting conditions.
- The TiCN has a good wear resistance in conventional hobbing but it looses its properties at high temperature, so the TiCN hasn't improved the tool life duration in high speed and dry cutting.
- The cMoTiN hasn't brought anything better than the TiN in conventional hobbing and than the TiAIN in high speed cutting.

The general goal of the study had been reached. The laboratory milling tests have been successfully performed which enabled as to recommend a dedicated substrate and coating for dry cutting.

In addition to the original program, industrial tests with conventional and recommended substrates and coatings have been performed and brought quantitative results for industry.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 97.0526-1