Planing Tools: Definition, Structure, Classification and Application

1. Definition of Planing Tools and Operational Requirements

A planing tool is a cutting tool for planing operations. Its quality directly affects the accuracy, surface roughness, and production efficiency of the workpiece. Therefore, planer operators must master the geometric angles of planing tools and proficiently sharpen and select them.

Planing tools are cutting tools for planing operations, which is a widely used, simple method to machine flat surfaces and grooves.

2. Structure Characteristics of Planing Tools

The structure of a planing tool resembles that of a turning tool. However, planing tools perform discontinuous cutting and bear impact loads. For the same cutting area, manufacturers make the cross-sectional dimensions of the planing tool shank 1.25 to 1.5 times larger than those of a turning tool.

They also often use negative rake angles (-10°~20°, note: corrected from -100° as an error) to enhance the cutting edge’s resistance to impact loads. To prevent the planing tool shank from bending under cutting force, operators usually use bent-head planing tools.

3. Advantages of Bent-Head Planing Tools

Manufacturers generally produce planing tools in a bent-head form, which is another significant characteristic. When a bent-head planing tool bears large cutting force, the bending deformation of the tool shank makes it spring upwards and backward around point O, so the tool tip will not dig into the workpiece.

In contrast, a straight-head planing tool tends to dig into the workpiece when deformed, damaging the cutting edge and the machined surface.

4. Classification of Planing Tools by Use

We can classify planing tools into six types based on their use:

(1) Machinists use flat planing tools to rough and finish plane flat surfaces.

(2) Machinists use offset tools to machine planes, inclined surfaces and vertical surfaces that form an angle with one another.

(3) Machinists use cutting tools to cut grooves, sever workpieces and plane stepped surfaces.

(4) Machinists use bent-head grooving tools to machine T-slots, side grooves and analogous structures.

(5) Machinists use internal bent-head planing tools to machine internal surfaces (e.g., internal keyways).

(6)Machinists use form planing tools to machine special-shaped surfaces; the shape of the tool’s cutting edge matches the workpiece surface, allowing machinists to achieve one-pass forming.

5. Classification of Planing Tools by Structure

Based on their structure, planing tools fall into three categories:

(1) Integral planing tools: The tool shank and tool head are made of the same material. Most small and medium-sized planing tools adopt this integral design.

(2) Welded planing tools: The tool head and tool shank are welded together from two different materials, with the tool head usually being a cemented carbide insert.

(3) Assembled planing tools: Most large-sized planing tools use this design. The tool head and tool shank are made of different materials, and workers fasten the tool head to the shank with clamping plates, bolts, etc.