Diamond drill bit for drilling stone parameters

 Drilling in stone, because of relatively high speed movement between

the diamond drill and stone complex tribological phenomena arising in

the contact interface. Friction  GUISHI metal grinding wheel between diamond drill and stone, as the

stone poor thermal conductivity, most of the heat transferred diamond

segment, making diamond drill surface temperature, resulting in diamond

graphite, diamond cutting capacity reduced, which leads to the bit

matrix thermal fatigue, lower strength and stiffness, increased noise

when processing stone, increased vibration, reduce bit life, serious

diamond head off, causing injury to the operator, but also affect the

processing quality and efficiency. Research diamond bit drilling

parameters affecting its surface temperature to identify factors that

influence the relationship between surface temperature and the law,

determine a reasonable processing parameters, help to improve the

diamond drill bit life and reduce GUSHI stone polishing pads  processing costs, improve processing

quality.
   Experimental conditions
  Using Cu-diamond tip metal powder, diamond particle size of 60 to 80

mesh, using pressing sintering method, the high speed steel cylinder

head welding. Diamond drill diameter φ37mm, high-5.6mm, width 2mm,

base diameter φ35.6mm, height 45mm. Processing equipment used XK5032C

type CNC milling machine, the device implements the X axis, automatic

feed three directions Y and Z axes, spindle cooling method using water

-cooled. The temperature measured with an infrared temperature

measuring surface of the tool, the measurement temperature range of -50

~ 650 ℃. Direct l2 ℃ measured at room temperature conditions. Stone

were selected marble, sandstone and granite. This experiment studies

the spindle speed, feed rate and stone impact performance parameters

such as surface temperature of the diamond drill bit. Experiment was

conducted under dry cutting conditions, machining state shown in Figure

1.
  Analysis
  3.1 feed temperature affects the speed of
  When processing stone diamond drill, impact drill surface temperature

of many parameters, including diamond properties, performance bond,

stone physical and mechanical properties, processing parameters,

cooling parameters. Effect on the surface temperature of the diamond

drill bit experimental study of  GUSHI concrete polishing pads stone processing parameters and

performance. Figure 2 is the spindle speed is 300r/min, the feed rate

was 10mm/min, 15mm/min, 20mm/min, 25mm/min, when the surface

temperature of the pre-drill drilling marble drilling time curve. As

can be seen in Figure 2, in the four kinds of conditions of feed rate,

the surface temperature of the diamond drill bits are increased with

the increase of the processing time. In the early stage of processing,

the temperature increases relatively slowly, when the processing time

exceeds 4s, sharp increase in temperature. When the processing time

reaches 10s, the diamond drill is the initial surface temperature 5

times. Figure 3 feed rate versus temperature curve for the processing

of marble. From the figure can be seen in the feed rate l0 ~ 20mm/min

the temperature rises slowly, the feed rate of 20 ~ 30mm/min, the

temperature rise is most obvious, the most heat in this interval drills

stone processing generated. As the drilling process, the diamond drill

bit with a large stone surface friction, resulting in diamond drill

surface temperature rise. Due to the low thermal conductivity of

marble, and a high thermal conductivity of the tool, a large part of

the heat conducted to the diamond drill bit, diamond drill causes the

surface temperature. Since the feed rate increases, the cutting face of

the contact per unit time increases, the number of cutter contact with

the stone, the surface temperature increases.
  3.2 Effect of the number of revolutions of the spindle temperature
 The feed rate of 15mm/min, spindle speed was 300rpm, 400rpm, 500rpm,

diamond drill bits and drilling the surface temperature of the time

when drilling marble curve. Overall, the temperature rises with

increasing linear time. Also can be seen from Figure 5, the temperature

increases with the spindle speed. However, the temperature rise is not

obvious. When the spindle speed reaches 500r/min, the maximum

temperature of 143 ℃. Increased spindle speed. Diamond particles to

increase the number of friction per unit time and stone, long exposure

time, thereby resulting in the surface temperature increases.
Effect of temperature on the surface properties of the stone
Spindle speed of 300rpm, when the feed rate is 15mm/min. Processing of

different stone diamond drill surface temperature averages. As can be

seen from Figure 5, when the diamond drilling granite surface

temperature reached a maximum of l50 ℃, while the lowest surface

temperature processing of sandstone, is 30 ℃; temperature during the

processing of marble is 70 ℃. Stone learned through performance,

granite density 2.5 ~ 2.7kg/cm3, the compressive strength of 120 ~

250MPa, marble density of 2.5 ~ 2.7kg/cm3, compressive strength of 47 ~

120MPa, sandstone density 2.2 ~ 2.5kg/cm3, compressive strength of 47 ~

120MPa. Three stone density basically the same, but far greater than

the compressive strength of granite, marble and sandstone, almost twice

the marble and sandstone. Stone intensity increased, the cutting forces

increase, diamond tool wear serious, leading to diamond drill the

surface temperature. Can be seen from Figure 5, the surface temperature

of the diamond tool machining granite processing time is 2 times

marble, sandstone five times. You can see from the processing of the

experiment, when dry cutting granite, diamond tool surface temperature

rises rapidly, while the high temperature, resulting in a diamond

cutter head off. Granite thermal conductivity 3.49W/mK, while the

thermal conductivity of copper is 370.49W/mK, it can be seen for most

of the heat is the heat conduction through the diamond drill, which led

to a sharp increase in the surface temperature of the diamond drill

bit, Diamond badly worn.
 Conclusion
 When using diamond drill bits manufactured stone, spindle speed and

drilling speed machining parameters a great influence on the tool

surface temperature. Tool surface temperature increase with spindle

speed and feed rate increases. Diamond drill surface temperature

increases with increasing drilling time, while time is proportional to

the drilling.