Cutting by use of rotating axially moving tool – Tool or tool with support – Having stepped cutting edges
Patent
1997-06-09
1998-09-01
Howell, Daniel W.
Cutting by use of rotating axially moving tool
Tool or tool with support
Having stepped cutting edges
407113, 408230, 408713, B23B 5102
Patent
active
058001000
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a drilling tool for drilling in solid metal, with a base body with chip flutes for the chip removal, with two cutting inserts each located in respective recesses on the end of a respective chip flute, which inserts are interchangeable, have the same shape and size, and are preferably realized in the form of reset inserts. Each insert has a different radial distance from the drill axis, the working areas of which inserts are adjacent to one another with some overlap, and two cutting edges are in contact with one another to form an obtuse point angle to form a blade.
2. Background Information
Conventional drilling tools of the prior art are generally equipped with "neutral" reset inserts, which means that they can also be used in a similar manner for turning or milling tools. But precisely when they are used in drilling operations, they cannot be used to achieve optimal results.
The most widely used drilling tools are trigon reset inserts (German Patent No. 27 30 418 C2, German Patent No. 40 18 843 A1, European Patent No. 54 913 B1). The indexable inserts described in these prior art documents have been found to be useful for larger drilling tools which have a drill diameter of more than 25 mm, and they are economical. Given a correct positioning of the inner and outer blades, the use of these reset inserts guarantees a stable, balanced cutting action with only low drift forces. The inserts can be positioned at almost any angle in the base body. With drill diameters of less than 25 mm, the interchangeable trigon inserts of the prior art have the disadvantage of a very small carbide volume, as a result of which they cannot be subjected to high thermal and mechanical loads. Therefore drilling tools for smaller drill diameters generally have a longer, more rectangular shape (European Patent No. 181 844 B1). The blade geometry of the trigonal reset inserts of the prior art has been transferred largely unchanged to these essentially rectangular inserts, resulting in a significant increase in stability. One disadvantage of drilling tools which use such rather rectangular reset inserts, however, is that when the inserts are used in drilling tools which have helical chip flutes, the portion of the drill which holds the reset insert interferes with the chip removal. For the removal of the chips formed during drilling, a low-friction separation between the chips and the blade edges is necessary, for which purpose large angles of twist are advantageous. On account of the amount of space available, reset inserts which have a rectangular outline are more difficult to install than the trigon inserts of the prior art. A repositioning of the insert to balance the cutting force is therefore difficult. On such inserts, and at high speeds, an equalization of the cutting force which has been achieved by unequal distribution between the inner and outer blade causes a major imbalance, and thus has a negative effect on the result of the drilling operation. On the drilling tool of the prior art, the chip space of the outer blade is also relatively small, although this space is required to handle approximately three-quarters of the volume of the chips.
OBJECT OF THE INVENTION
The object of the invention is to combine the improved stability of rectangular reset inserts with the favorable centering characteristics of trigon inserts, and to guarantee a favorable chip removal from the drilling area.
SUMMARY OF THE INVENTION
The invention teaches that this object can be accomplished by a shape of the inserts which is extended in a longitudinal direction of the inserts, with a channel like trough which runs essentially in the longitudinal direction of the cutting surface sides of the inserts and with blades located on the ends of the channel; whereby the channel contains a base surface which has the approximate outline of a parallelogram and, with regard to the longer sides of the parallelogram, forms an acute angle with the longitudinal axis of the ins
REFERENCES:
patent: 4367991 (1983-01-01), Grafe et al.
patent: 4946318 (1990-08-01), David et al.
patent: 5454671 (1995-10-01), Qvarth
patent: 5466097 (1995-11-01), Wallstrom
patent: 5503509 (1996-04-01), Von Haas et al.
patent: 5622461 (1997-04-01), Tukala et al.
Howell Daniel W.
Kennametal Hertel AG Werkzeuge + Hartstoffe
LandOfFree
Drilling tool with reset inserts does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drilling tool with reset inserts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drilling tool with reset inserts will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-262406