Gear hobbing is the most common manufacturing process for pre-machining of gears. The process is used for gears of almost all sizes. For example, gear hobbing is used in the production for fine mechanic components, like watches, and for heavy industry applications, like ship building, as well.

During the hobbing process, high thermal and mechanical loads affect the cutting edges of the hob. These high loads lead to damages on the hob, named tool wear. Tool wear occurs in different characteristics, see figure. Along the clearance faces, flank wear occurs. In the tooth tip area, this flank wear could be more extensive due to the high load of the multi flank chip formation. Furthermore, the interrupting load during hobbing can lead to chipping along the cutting edge.

Another wear phenomenon is crater wear on the cutting face of the tool. This phenomenon is related to the thermal load during chip formation.

gear hobs resharpening SAMP Blog

After a hob is used to produce a certain number of gears, the wear is high enough, that the gear quality decreases, or the risk of significant tool damage rises.

At that time, a hob needs to be reconditioned. For this job, it is important to rely on a reliable company. Samputensili and its joint-venture Star-SU operate several tool service centers worldwide. These tool service centers have the capability to resharp, recoat and even reprofile all types of gear cutting tools. The vast majority of its capacity is for the reconditioning of hobs as well as other types of gear cutting tools. 

Gear hobs resharpening SAMP Blog

Because of the many years’ experience, Samputensili and Star-SU generate an unbeatable expertise in hob resharpening using the newest machine tool technologies. Using our own developed hob grinders combined with the newest quality control equipment, all our customers can take advantages of having the same tool quality and performance on their reconditioned tools as a new one. If the regrinding is not executed with adequate precision and lacks quality control, geometry errors will occur. A low hob quality after resharpening will occur in a geometry deviation of the gear. Some possible examples for resharpening errors are shown below.

Gear hobs resharpening

It is extremely important that at service centers all reground tools are processed through a precise quality control procedure to avoid regrinding errors. This eliminates any quality losses in the gear production due to inadequate hob resharpening.

In addition to the cutting face regrinding, the reconditioning process consists of several additional processes to ensure a high tool performance over the whole tool life. As a last step, the recoating is a major step to prepare any hob for its next use. A huge advatange of Samputensili service centers is that coating centers are directly located within each service center, so that unneeded transport times can be eliminated and the turn around times for tools are reduced to an optimum.