What is Trepanning – Drilling large Holes in sheetmetal

Trepanning is a manufacturing process used to produce holes or circular grooves by using one or more cutters and revolving them around a center.

What is trepanning ?
Trepanning is a technique used for drilling larger hole diameters where machine power is limited as it is not as power consuming as conventional drilling where the entire hole is converted into chips. The trepanning tool does not machine the whole diameter, only a ring at the periphery. Instead of removing all the material in the form of chips, a core is left at the centre of the hole. Consequently, this method is for through-hole applications.

Trepanning machining is used to produce the following features and parts:

Low volume disks from flat stock. Disks can be fabricated up to .25 (6.35mm) thick and 6 (152mm) in diameter. Large diameter through holes in flat stock. Trepanning is limited to creating holes that are not greater than five times the material thickness. Machining internal and external circular grooves or o-ring glands.

Deep holes 2 (50.8mm) or more in diameter. This process is similar to gun drilling where the cutter is centering at start, and forced lubrication and cooling is used. Straightness and diametric tolerances are almost comparable to gun drilled holes.

See also

trepanning process
trepanning process
  • Trepanning is the process for making large holes in sheet metal.
  • A small diameter hole is drilled in center for drilling large diameter hole.
  • The pilot of trepanning tool is fitted into this hole and the length of the adjustable arm is set to the radius of the hole to be cut.
  • Holes up to a diameter of 350 mm can be cut by this arrangement

Trepanning. It is the operation of producing a hole by removing metal along the circumference of a hollow cutting tool. This operation is performed for producing large holes. Fewer chips are removed and much of the material is saved while the hole is produced.

Trepanning can be utilized in:

  • Machinery and Heavy Equipment
  • Manufacturing and Rebuild
  • Oil and Gas
  • Aerospace and Defense
  • Metals Production and Distribution
  • Forging

Can be utilized when holes may be required in:

  • Finished Parts for Weight Reduction
  • Clearance
  • Fluid Flow
  • Working Cavities
  • Machining Blanks
  • Piston and Cylinder Features
  • Seals
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