Products -SUPER ABRASIVE MATERIALS >> PCD & CBN INSERTS FOR TURNING, BORING AND MILLING

PCD & CBN INSERTS FOR TURNING, BORING AND MILLING

Superabrasive Materials

There are many different types of tip available in the market designed to cope with an array of workpiece materials but for simplicity these may be grouped as follows

  • Polycrystalline Diamond (PCD).
  • Cubic Boron Nitride (CBN).

PCD

PCD may be used for both roughing and finishing work, although it is usually most beneficial when tight tolerances or high surface finishes are required combined with the need for exceptionally long tool life. It is available in three grades of increasing crystal size and toughness but with an attendant decrease of edge quality. The finest grade is, therefore, only employed where superior surface finish is the main objective, the middle grade is the general purpose material giving long life with good component finishes; the coarse grade is used where maximum abrasive resistance is required and where finish is not critical.

We will be pleased to offer advice on the selection of the best grade of PCD and cutting geometry for your particular application





CBN

If polycrystalline diamond has a major disadvantage, it is that being carbon based, it has an affinity to the free carbon found in most ferrous materials and is therefore generally unsuitable for machining steels and iron based materials. For this reason a range of products has been developed based on polycrystalline cubic boron nitride which have been demonstrated to be extremely cost effective especially with the harder ferrous materials (45-65 HR). Examples of materials that may be considered for machining with these inserts are listed below.

  • Hardened Steels
  • Chill Cast Iron
  • Hardened Bearing and Tool Steels
  • Stainless Steels
  • Hard Facing Alloys which are Cobalt, Nickel and Iron based
  • Grey Cast Iron

CBN for Rough Machining:

Different types of PCBN exist for the rough machining of the materials listed above which are usually selected on the basis of the required amount of stock removal.

For roughing cuts in excess of 1mm depth the PCBN is usually supplied in the form of solid ISO tips for use in a clamp type tool holder, designed for use with negative top rake geometry. It is also usual to provide a strengthened cutting edge by means of a lapped or honed 'T' land.

Where roughing cuts up to 1mm only are to be taken or when the applications require positive tool geometry, a brazable type of PCBN may be employed. In these cases the inserts are fabricated in a similar manner to diamond tips but usually with a polished 'T' land.

CBN for Finishing:

A specific form of CBN with reduced CBN content is supplied for use on fine finishing of hard ferrous materials. This material is capable, given the correct machining parameters, of producing turned finishes equal to those of ground components. The attendant cost savings found from switching from grinding to turning are often very dramatic. Again, the inserts are fabricated in a similar manner to those in PCD.

Insert Shape:

We follow the normal ISO convention for describing insert shape and geometry, for example an 12mm triangle may be designated as follows

T P G B 12 02 02

T = Shape (triangular)

P = Insert clearance angle (11)

G = Tolerance class (G)

B= Type of insert, i.e., Hole and Chipbreakers

12 = Edge length (12mm)

02 = Insert thickness (2.38mm)

02 = Radius (0.2mm)

When ordering please specify PCD or CBN
We will be pleased to offer advice on the selection of the best grade of PCD and cutting geometry for your particular application.