Drilling Parameters

About Drilling Parameters

Parameters for drilling and slot drilling, conditions for Drilling in the chart are available.


  • Hits, number of repoints and stack heights are for general information. They should be determined by hole quality.
  • Where the board thickness and/or stack height are not shown in the table, please contact Union Tool's Technical support team
  • These parameters can be affected by the condition and performance of both the spindle and drilling machine.
  • The pressure foot and vacuum performance of the drilling machine can affect hole quality.
    Periodic inspection, maintenance and measurement is strongly recommended.
  • The thickness of the entry and back-up board, together with the material type can affect the drilling parameters and care should be taken to choose and appropriate product.
  • More detailed information can be found in each parameter file.


Maximum Spindle Speed

Slot Drilling Parameter

Terms for drilling parameter

Terms Major units Meanings and formula
Spindle speed rpm Number of revolution per minute
Velocity m/min
Velocity of periphery
V=π·D·N / 1000
V: Velocity [m/min]
D: Drill bit diameter [mm]
N: Number of revolution per minute [rpm]
SFM: Surface feet per minute
1m/min = 3.28 Feet/min
Infeed rate m/min
Vertical speed of drilling
Chipload µm/rev
Feed amount per revolution
f =F/N x 1,000,000
f :Chipload [µm/rev]
N:Number of revolution per minute [rpm]
F:Infeed rate [m/min]
Retract rate m/min
Retract speed after drilling
Depth into back-up board mm
Penetration depth into back-up board. Too Shallow causes a risk of not drilling through the PCB. And too deep can cause registration accuracy, roughness, and breakage problems.
Hits - Life of drill bit. This parameter table shows the general values inputted into drilling machine.
Repoint (Number of repoints) - Generally, the tip of drill bit is repointed after use, having deteriorated through wear. This parameter table shows the general information for repointing frequency.
Stack height - To improve productivity the PCB is often stacked up for drilling. This parameter table shows the general number of panels per a stack for each general PCB thickness.

Unit Conversion

Distance 1m = 1000mm = 39.37Inch
1Inch = 0.0254m = 25.4mm
Velocity, Infeed rate, Retract rate 1m/min = 16.67mm/sec = 39.37Inch/min = 3.28Feet/min(SFM)
1mm/sec = 0.06m/min = 2.36Inch/min
1Inch/min = 0.0254m/min = 0.423mm/sec
Chipload 1µm/rev = 0.0393Mil/rev
1Mil/rev = 25.4µm/rev

PRODUCT 01 PCB Drills / Routers / Ultra precision micro-hole drill

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