Shaped turning tool

Overview A turning tool, also known as a pattern knife, is a special tool whose edge shape is designed according to the profile of the workpiece. It is mainly used on ordinary lathes, hexagonal lathes, semi-automatic and automatic lathes to process revolving body forming surfaces.

Type (1) The flat-shaped turning tool has a flat bar shape and is similar to an ordinary turning tool. The blade shape has a certain profile, the structure is simple, the manufacturing is easy, and the cost is low. However, there are only a few regrinds. For the machining of simple external forming surfaces such as thread turning tools and shovels made of milling cutters.

(2) The cutter head and cutter bar of the prismatic turning tool prism are separately manufactured, which greatly increases the number of re-grinding along the rake face, and the cutter body has good rigidity, but the manufacturing process is more complicated than that of the round body turning cutter. Less, and can only machine outer forming surfaces.

(3) Round-shaped turning tool It is formed by a long prismatic turning tool wrapped around a cylindrical surface. It allows for the greatest number of regrinds, is easier to manufacture than a prismatic turning tool, and can machine internal and external forming surfaces on parts.

Front and rear corner turning tools must have reasonable front and rear corners to work effectively. Due to the complex blade shape of the turning tool, the orthogonal directions of the points on the cutting edge are inconsistent. At the same time, the measurement and regrinding are convenient. Both the rake angle and the relief angle are not measured in the orthogonal plane, but are specified on the tool's assumed working plane ( Measurements are made perpendicular to the section of the workpiece axis and the assumed operative rake angle and the assumed working relief angle at the outermost edge of the cutting edge and the center of the workpiece are used as the annotation values.

(1) Prism forming tool The flank of the turning tool forming tool is a shaped prismatic surface, and the rake surface is a flat surface. The flank face is parallel to the dovetail KK, and the rake face is inclined by 90°-(rf+af) with KK. When manufacturing a prismatic turning tool, the angle between the rake face and the flank face is ground to 90°-(rf+af). When cutting, the flank is installed with af corner, so that the front corner rf and the rear corner af are formed.

(2) Round body forming tool The rake face of the lathe turning tool edge grinds out rf, and the flank surface is a forming turning surface. During cutting, the reference point is installed at the same height as the center of the workpiece, so that the center of the forming knife is higher than the center of the workpiece H, so that the desired back angle af is obtained.

When H=Rsinaf

After af, rf is determined, the distance between tool center O' and rake face hc

Hc=Rsin(af+rf)

With O' as the center, a circle with radius hc is called sharpened circle. When making and regrinding the round body forming knife, make the rake face tangent to this circle.

The clamping prism forming turning tool is based on the dovetail as the positioning reference, and is fitted in the dovetail groove of the tool holder. The back plane of the cutter dovetail is the clamping reference. During installation, the cutter body is erected and tilted. The screw at the bottom of the tool holder can be used to clamp the position of the calculated reference point to the center of the workpiece and clamped with bolts. At the same time, the lower end of the cutter can receive some cutting forces to enhance the rigidity of the cutter.

The round body forming turning tool uses the cylindrical hole as a positioning reference and is set on the screw of the tool holder. The shaping turning tool is connected with the end surface tooth block by means of a pin, and the end surface tooth block meshes with the sector tooth to prevent the force surface from rotating when the shaping turning tool works, and at the same time, the position of the reference point of the turning body forming turning tool can be roughly adjusted. Use fan segments and worms to fine tune the height of the datum point. After adjustment, tighten the nut to clamp the forming tool in the tool holder.

Grinding sharpening tool turning tool is relatively simple, as long as the use of a simple two-way universal sharpening fixture in the tool grinder, the tool flank and the grinding wheel surface perpendicular (rf + af) angle can be sharpened.

When the end of the circular turning tool is engraved with a sharpening test circle, apply a layer of red oil on the end face, draw a tangent to the test circle with a nail, then install the tool on the mandrel and adjust the tangent of the test circle to Grinding the work surface of the grinding wheel can be sharpened.