Hollow Boring Bar

Abstract

To provide a hollow boring bar which leaves no cutting chips inside a steel pipe and does not scratch the inner surface when machining the inner diameter of the steel pipe material. [Solution] The hollow boring bar does not have a breaker on the tip of the tip, but has only a few degrees of upper rake face 7a, a slight front relief angle 7c, and a slight side relief angle 7b. This naturally results in chips that are generally inappropriate, becoming elongated wire-like objects, and these wire-like chips penetrate the center of the boring bar and are discharged from the opposite exit of the boring bar.

Description

[Technical field]

[0001] This invention relates to a boring bar that is attached to the tool post of a general-purpose lathe to perform deep hole boring. [Background technology]

[0002] When using a general boring bar, care must be taken to remove the chips and avoid the resulting scratches on the inside surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication 2007-185765 Sandvik Intellectual Provider AG [Patent Document 2] Patent Publication 2014-184496 JFE Steel Corporation Summary of the Invention [Problem to be solved by the invention]

[0004] Chip disposal is considered to be a problem in the internal machining of steel pipes. [Means for solving the problem]

[0005] Conventional boring bar cutting edges have been designed with various types of breakers to reduce the amount of chips, but this can cause chips to get caught between the steel pipe and the boring bar, scratching the inside of the steel pipe and damaging the tip of the tip. The tip of the boring bar we have devised does not have a breaker, but only has a few degrees of upper rake face, front relief angle, and a few degrees of side relief angle. This naturally results in chips that are generally inappropriate, long and thin wire-like objects, but if these wire-like chips are passed through the center of the boring bar and discharged from the opposite exit of the boring bar, no chips will remain inside the steel pipe and the inside will not be scratched. Only one chip is produced per machining pass. Effect of the Invention

[0006] As mentioned above, the hollow boring bar of this invention is attached to a general-purpose lathe, so it can be used for small lots without using a dedicated boring machine. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is an explanatory diagram of the boring bar body and the brazed cutting edge. [Diagram 2] FIG. 1 is an explanatory diagram of processing a steel pipe using a boring bar. [Diagram 3] This is a photo of the processing process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Attach the boring bar to the lathe and align the height of the cutting edge to the center of the diameter of the steel pipe workpiece. The optimal direction of lathe rotation is reversed. Select the appropriate peripheral speed and feed speed based on the steel pipe material, tip material, and other conditions. Also, pre-machine the inlet and outlet of the steel pipe to a C-surface of about the finished diameter. This is to prevent damage to the tip of the tip due to the reaction of the bar bending when the boring bar is removed. At the start of cutting, use a chip leading puller. EXAMPLES

[0009] Figure 3 [Industrial Applicability]

[0010] This invention relates to a hollow boring bar with a brazed tip for cutting the inner diameter of a turning tool. [Explanation of symbols]

[0011] 1 Boring bar body 2 Boring bar holder 3 Holder set screw 4 Lathe mounting bracket 5 Upper and lower tool holders 6 Bite set screws 7 Tip Brazing Tool 7a Upper scooping face 7b Side clearance angle 7c Front clearance angle 8 Triangle for chip guide 9. Chip front puller rod 10 steel pipe material 11 Wire-like chips 12 Chip inlet 13Cutting waste outlet

Claims

[Claim 1] The boring bars used for deep hole machining of steel pipes, cylinders, etc., are prone to scratching the inside of the workpiece due to the chips produced during boring. However, the hollow boring bar is designed to prevent scratches on the inside of the workpiece by passing the chips produced during cutting through the boring bar and discharging them from the other side of the bar.

Images