Rotary cutting tool

Abstract

The invention provides a rotary cutting tool. Compared with a conventional rotary cutting tool with a constant helical angle cuttings chute, the rotary cutting tool keeps good cutting machining for a long distance and has very excellent practicability. A plurality of spiral cuttings chutes (3) towards the proximal end side from the end of the tool are formed on the cirumference of the tool main body (1) and after the front tool surface of the cuttings chute (3) is crossed with the cirumferential surface of the tool main body (1) or the front tool surface of the cuttings chute (3) is crossed with the cirumferential back tool surface formed at the cirumference of the tool main body (1), a cirumferential cutting edge is formed at the crosses edge part and the helical angle (alpha) of the cirumferential cutting edge gradually increases from the end of the tool towards the proximal end side.

Description

technical field [0001] The present invention relates to a rotary cutting tool. Background technique [0002] Generally, a printed circuit board is produced by cutting a green sheet into a plurality of small-sized printed circuit boards of the same specification. For example, it is produced by stacking a plurality of green sheets and processing holes, then performing etching or plating on each of the green sheets to form a pattern, and then performing the above-mentioned processing again on a plurality of sheets. The blank sheets are overlapped, and the blank sheets are cut into small-sized printed substrates of the same specification by using a rotary cutting tool. This cutting process is generally referred to as profile processing. In addition, when performing hole processing or contour processing, a method of overlapping substrates on a backing plate is generally used so that processing can be performed through a predetermined substrate, and the purpose of stacking multi...

AI Technical Summary

Problems solved by technology

[0008] If the skew amount δ is too large, not only the dimensional accuracy required for the printed circuit board cannot be satisfied, but also when the milling cutter is pulled upward at the end of the contour processing, the machined side surface becomes skewed, so the outer peripheral cutting edge (especially The outer peripheral cutting edge on the tip side of the tool) is easily in contact with the machined side surface, and there is a problem that the durability of the tool is deteriorated due to chipping of the outer peripheral cutting edge

[0009] In addition, since a plurality of blank sheets are piled up for contouring, if the chips cannot be discharged smoothly, there is also a problem that the tool may be damaged due to chip jamming even if the contouring is carried out only for a short distance.

[0010] Furthermore, the inventors of the present invention found that, with regard to the helix angle of the outer peripheral cutting edge (flute) that actually performs the cutting action, only when the helix angle on the tool base end side is larger than the helix angle on the tool tip side, Chip removal is improved under the influence of the helix angle of the chip flute on the base end side, but on the other hand, there is a problem that the cutting resistance is bounded by the change point of the helix angle due to the difference in the helix angle of the outer peripheral cutting edge. Due to this, the accuracy of the machined surface deteriorates, or the outer peripheral cutting edge is damaged or the tool itself is broken.

Images