Since its introduction, Vergnano has actively participated in the development of the dry hobbing method. The rationale behind this choice has been confirmed by consistent investments made by major manufactures of speed gears and transmissions in this hobbing method.

      The combined use of powder metallurgy high speed steel (HSS-PM) substrates and state-of –the-art hard coating, such as TiAIN and AICrN, make it possible to reach cutting speeds exceeding 200m/min. Until recently, these values were thought impossible for steel hobs.

      PM steel often represents an economically advantageous alternative to solid carbide. Although solid carbide allows for higher cutting speeds, the high toughness of HSSPM permits greater feed rates and therefore similar or higher productivity compared to solid carbide.

      The high toughness also lowers the risk of accidental fracture. In addition, hobs made from HSS-PM have lower initial, re-sharpening and re-coating costs. HSS-PM hobs also yield excellent results using traditional wet hobbing methods, allowing for reduced process times and longer tool life.

      In certain particular applications the use of solid carbide hobs is advantageous compared to PM steels hobs. For example, when it is necessary to use cutting speeds higher than to 350 - 400 m/min, when small modules are required or in other extreme applications which cannot be covered by steel hobs. In particular, when hobbing  tempered steel components solid carbide hobs are the only possible choice.

      In order to broaden the product range and satisfy the customer's needs, Vergnano has installed a dedicated production line for solid carbide hobs. Carbide substrate type and coating can thus be optimised in relation to each specific application.

      For hobs, two different solid carbide types are employed: grade “K” and grade “P”, both of which offered by Vergnano. Each grade can have different compositions  depending on its final use.

      Grade “K” hobs, mostly used for large scale production, must be recoated after being  resharpened, whereas grade “P” hobs can be used after resharpening without recoating and are therefore more suitable for numerous, small production lots.

Vergnano’s new production site has enabled the introduction of an in-house recoating department and the extension of the resharpening service.       The direct control of such services by a hob Manufacturer like Vergnano has numerous advantages: resharpening and recoating are carried out by qualified personnel and can be tailored to the customer’s needs.       This results in hobs as good as new. In addition, Vergnano offers a complete reprofiling service for recovering damaged hobs and for modifying hob profiles.