KEY ADVANTAGES
Bearing System:
1)Adopting the Floating Bearing Structure. The floating bearing design reduces the relative linear
speed of the bearing couple and decreases temperature rise on friction surfaces. The floating
elements are made of highly elastic materials with high temperature and abrasion resistance.
This design increases bearing life and reliability in high WOB or high RPM applications.
2). Implementing the Metal Face Seal (MFS). High precision metal rings are used to form the
bearing axial dynamic seal. Two elastic rubber energizers are separately located in the head
and cone sealing areas to form a static seal. This type of seal reduces the friction force on the
sealing surfaces by 70% to 80%. With the reduction of the friction heat and friction force,
compared with the conventional rubber seal bits, the average working life (total drilling hours)
can be increased by 35%. *Note: MD Series Bits are also available with the O-ring sealing
system in place of the Metal Face Seal.

Cutting Structure of rock roller bit:
1)Secondary Cutter Technology. Secondary cutter technology is the addition of a secondary row of
cutters between primary rows of cutters, forming a special cutting structure with twin bottom hole
break lines. This design significantly reduces cone shell erosion in directional and horizontal
applications.
2).Compact Technology. By examining the protrusion, tungsten grade, and overall shape of the
compacts, the JZ engineers have designed the MD Series Bits with compacts that are optimal for
high ROP in soft to medium hard formations. This design also effectively prevents cutter breakage
in transitional zones.

Gauge Protection:
MD Series Bits come with an enhanced gauge protection package. The hardfacing on the shirttail is
reinforced and covers a larger area for better protection of the sealing area. Compacts are fitted in
shanks with a certain exposure to reduce wear on tricone bit head and grease reservoir area. In
addition, the gauge protection is reinforced by utilizing double rows of buttons on the gauge rows
of the cone.

We also are large China PDC Drill Bits manufacure.