Known rotary cutting tools for performing reaming operations, such as a reamer, typically comprise a cutting head having an axis of rotation. The cutting head has a forward end and a peripheral surface extending rearwardly therefrom. The peripheral surface includes at least two cutting inserts or blades extending rearwardly from the forward end and separated by a chip flute for the evacuation of chips produced during the cutting operation.
Some conventional cutting head designs push the chips forward, through the hole using radial coolant in the flutes directed toward the cutting edges. However, the natural chip flow of the material, combined with the cutting geometry, causes the chip to want to flow backward directly into the chip flute during the cutting operation. This is not ideal because the chips may become tangled on the tool shank and/or remain in the machined holes during the cutting operation, thereby blocking any coolant from reaching the cutting edge.
The problem of inadequate coolant flow to the cutting edges in a cutting tool performing a reaming operation is solved by providing a reamer head with a flute geometry having three core regions: a front core region, a middle core region and a rear core region.
In one aspect, a reamer comprises a shank portion and a cutting portion extending from the shank portion. The cutting portion includes one or more blades separated by flutes. Each flute comprises a front core region proximate a front end of the cutting portion, a rear portion proximate a rear end of the cutting portion and the middle core region therebetween. The front core region has a thickness, T1, the middle core region has a thickness, T2, and the rear core region has a thickness, T3. The thickness, T2, of the middle core region is greater than the thickness, T1, of the front core region and the thickness, T3, of the rear core region.
In another aspect, an annular reamer head for a reamer comprises one or more blades separated by flutes. Each flute comprises a front core region proximate a front end of the cutting portion and a rear portion proximate a rear end of the cutting portion, wherein the rear core region includes an angled wall for directing coolant within each flute.
In yet another aspect, a method of making a reamer head comprises:
grinding a cylindrical blank to form a middle core region of a flute;
grinding the cylindrical blank to form a front core region of the flute after grinding the middle core region; and
grinding the cylindrical blank to form a rear core region of the flute after grinding the middle core region.
While various embodiments of the invention are illustrated, the particular embodiments shown should not be construed to limit the claims. It is anticipated that various changes and modifications may be made without departing from the scope of this invention.
Below are illustrations and explanations for a version of a cutting tool, such as an orbital drill, and the like, with both right-handed helical or spiral flutes and left-handed helical or spiral flutes for machining a workpiece (not shown) made of multiple materials. However, it is noted that the cutting tool may be configured to suit any specific application, such as reaming, end milling, and the like, and is not limited only to the example in the illustrations.
The description herein of specific applications should not be a limitation on the scope and extent of the use of the cutting tool.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
Throughout the text and the claims, use of the word “about” in relation to a range of values (e.g., “about 22 to 35 wt %”) is intended to modify both the high and low values recited, and reflects the penumbra of variation associated with measurement, significant figures, and interchangeability, all as understood by a person having ordinary skill in the art to which this invention pertains.
For purposes of this specification (other than in the operating examples), unless otherwise indicated, all numbers expressing quantities and ranges of ingredients, process conditions, etc are to be understood as modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired results sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Further, as used in this specification and the appended claims, the singular forms “a”, “an” and “the” are intended to include plural referents, unless expressly and unequivocally limited to one referent.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements including that found in the measuring instrument. Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10, i.e., a range having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.
In the following specification and the claims, a number of terms are referenced that have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Referring to
The cutting portion 14 includes a plurality of blades 18 separated by flutes 20 extending the length of the cutting portion 14. In the illustrated embodiment, the reamer 10 has a total of eight blades 18 and flutes 20. However, it will be appreciated that the invention is not limited by the number of blades and flutes, and that the invention can be practiced with a fewer or a greater number of blades and flutes, depending on the design geometry of the cutting tool.
The shank portion 12 of the reamer 10 includes a coolant header 22 in fluid communication with the longitudinal coolant cavity 13 that provides coolant, lubricant, and the like, to a plurality of coolant outlet channels 24. In the illustrated embodiment, there is a one-to-one correspondence between the number of flutes 20 and the number of coolant outlet channels 24. Thus, the reamer 10 of the illustrated embodiment has a total of eight coolant outlet channels 24 for providing fluid, such as coolant, lubricant, and the like, to the blades 18 of the reamer 10 (as indicated by the arrow in
Referring now to
As seen in
By comparing
As shown in
It should be noted that the rear core region 20c has a thickness, T3, that is relatively smaller than the thickness, T2, of the middle core region 20b. Thus, the middle core regions 20b has a thickness, T2, that is greater than both the front core region 20a and the rear core region 20c. The purpose of the relatively larger thickness, T2, of the middle core region 20b is to provide relatively stronger blades 18, as compared to blades having a smaller thickness. The magnitude of the thickness, T3, of the rear core region 20c may not vary as a function of the diameter of the reamer head 10, especially if the reamer head can be mounted in the same machine tool holding chuck (not shown). It should also be noted that varying the thickness, T2, of the middle core region 20b, while maintaining a constant thickness, T3, of the rear core region 20c will result in a change in the angle in which the coolant is delivered to the cutting zone. Thus, the coolant angle can be optimized by varying the thickness, T2, of the middle core region 20b, while maintaining the thickness, T3 of the rear core region 20c constant.
Referring now to
The flute 20 of the reamer head 14 of the invention is basically formed using a single path grinding process in which the grinding wheel 52 is driven about the rotational axis 54 of the grinding wheel 52 at a relatively high speed of about 3,500 rpm to about 5,000 rpm, while the grinding wheel 52 is moved along a line parallel to the axis, X, of the cylindrical blank at a linear speed of about 1-2 inches per minute. Linear movement of the grinding wheel 52 may begin at the front end 28 of the cylindrical blank 100 and advances to the rear end 30 of the cylindrical blank 100, as shown in
Next, the grinding wheel 52 is tilted upward at an angle between about 5 degrees and about 35 degrees with respect to the plane 40 that is substantially parallel to the axis, X, of the cylindrical blank 100, as shown in
Then, grinding wheel 52 is tilted downward at an angle between about 5 degrees and about 35 degrees with respect to the plane 40 that is substantially parallel to the axis, X, of the cylindrical blank 100. Linear movement of the grinding wheel 52 begins at the front end 28 of the cylindrical blank 100 and advances to the middle core region 20b formed in the earlier step. As a result, the front core region 20a of the flute 20 is formed in the cylindrical blank 100. At this point, the flute 20 with the front core region 20a, the middle core region 20b and the rear core region 20c is completely formed using a single grinding wheel 52. As a result, the cost of manufacturing the reamer head 14 is greatly reduced.
It should be appreciated that the invention is not limited by the order in which the rear core region 20c and the front core region 20a are formed, and that the invention can be practiced with forming the front core region 20a prior to forming the rear core region 20c.
The patents and publications referred to herein are hereby incorporated by reference.
Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.