Patent Application
20080145158
1. Field of the Invention
The present invention relates to a milling cutter, especially to a milling cutter for processing a metal substrate.
2. Description of Prior Art
The printed circuit boards (PCB) used for electronic products are generally made of plastic material or glass fiber. The PCB also uses metal substrate with aluminum and copper as the manufacture technology is improved and cost is reduced. For example, street lamp and headlamp generally uses PCB with substrate having enhanced strength and hardness. It becomes research issue to explore the relationship between metal substrate and milling cutter.
The conventional milling cutter, for example, Taiwan Utility Model No. M280878, comprises a handle and a cutting portion, where the cutting portion extends outward from one end of the handle. The cutting portion comprises two corresponding spiral guiding grooves. Cutting knife is formed on one side of the guiding groove. The spiral angle of the cutting knife is between 20°˜30°.
However, the conventional milling cutter can only be used for PCB with plastic or glass fiber substrate. The conventional milling cutter has small spiral angle such that the cutting knife has poor strength, large cutting resistance and poor scouring removing ability. The lifetime of milling cutter is reduced. Moreover, the surface hardness and lubrication of the conventional milling cutter are not enough because the surface of the conventional milling cutter is not coated with coating layer. Abrasion and heat pile may occur during the milling process of the milling cutter.
The present invention is to provide a milling cutter with a cutting knife of specific spiral angle and at least one coating layer on surface thereof. The hardness, lubrication and scouring removing ability of the milling cutter are enhanced. The friction coefficient between knife and metal substrate, and heat pipe can be reduced to prolong the lifetime of the knife.
Accordingly, the present invention provides a milling cutter for processing a metal substrate. The milling cutter includes a handle and a cutting portion. The cutting portion extends outward from one end of the handle. The cutting portion includes at least two opposite spiral guiding grooves. A cutting knifes is provided on one side of the guiding groove. The cutting knife has a spiral angle with range between 35°˜45° and the cutting portion is coated with a coating layer on surface thereof.
The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself however may be best understood by reference to the following detailed description of the invention, which describes certain exemplary embodiments of the invention, taken in conjunction with the accompanying drawings in which:
With reference to
The other two factors influencing the properties of the milling cutter are front gap angle 26 and a rear slant angle 27, where the front gap angle 26 is in the range 20°˜30° and the rear slant angle 27 is in the range 7°˜15°. Moreover, to facilitate the entering of the knife into the metal substrate 5, the inner angle 28 of the cutting knifes 23 and 24 is in the range 150°˜160° and the inner angle 28 of the cutting knifes 23 and 24 is preferably 154°.
Moreover, a coating layer 30 is coated on the surface of the cutting portion 20, where the coating layer 30 can be a nano coating layer and is coated on the surface of the cutting portion 20 by physical vapor deposition (PVD). The coating material can be Zr, Cr, Ti or other material of high hardness.
With reference to
The milling cutter according to the present invention has following advantages. The cutting knifes 23 and 24 have high strength, low cutting resistance and good scouring removing ability because the spiral angle is in the range of 35°˜45°. Therefore, the lifetime of the milling cutter is enhanced. Moreover, the surface of the milling cutter is coated with a nano coating layer 30 to render it with high surface hardness and good lubrication. The abrasion and heat pipe for the cutting knifes 23 and 24 can be eliminated.
Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.
