Planing

planing [′plān·iŋ]

(engineering)

Smoothing or shaping the surface of wood, metal, or plastic workpieces.

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planing

A process for smoothing the surface of a material by shaving off small fragments.

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Planing 

the process of machining materials, accompanied by chip removal; it is performed by the relative reciprocal motion of a tool, such as a planing cutter or blade, or of the workpiece. Chip removal usually occurs during the cutting stroke.

In planing metal, the cutting speed is defined as the speed v_c (in m/min) of the straight-line motion of the cutter (on shapers, see Figure 1) or of the workpiece (on a standard planer) during the cutting stroke. The feed s (in mm per double stroke) is the lateral movement of the workpiece per double stroke of the cutter (on a shaper) or of the cutter per double stroke of the workpiece (on a standard planer). The depth of cut t (in mm) is the difference between the height of the machined surface and the height of the surface before machining. The production time for planing is defined as

where B is the relative movement (in mm) of the cutter or work-piece in the direction of feed, n is the number of double strokes per minute of the cutter or workpiece, and l is the number of passes of the cutter.

Figure 1. Diagram of the planing process on a shaper: (1) surface being worked, (2) cutting plane, (3) base plane, (4) bearing surface of the cutter, (5) machined surface, (6) cutting surface; (a) and (b) thickness and width, respectively, of the cut layer

Multitool planing makes better use of a planer’s capacity (Figure 2). High-output finish planing uses wide planing cutters with auxiliary cutting edges set at an angle φ₁ = 0^c. The cutters have lengths 1.2–1.8 times greater than the length of the feed, and they are equipped with hard-alloy faces. Large feeds—up to 20 mm per double stroke—are used. Efficient cutting conditions for planing are determined by the same procedures used for turning; the proper correction coefficients must be taken into account.

Figure 2. Diagram of multitool planing: (1), (2), (3), and (4) cutters; (s) feed

The principal drawbacks of planing are the impact of the cutting tool at the beginning of each stroke and the presence of a return stroke, which decreases the tool life and the productivity of the operation.

In woodworking, planing consists in the removal of material in the form of shavings by means of hand woodworking tools, such as planes, and the working of wood to produce planed, one-ply veneers.

REFERENCES

Obrabotka metallov rezaniem, 2nd ed. Moscow, 1962.
Rezante konstruktsionnykh materialov, rezhushchie instrumenty i stanki. Edited by P. G. Petrukha. Moscow, 1974.
Arshinov, V. A., and G. A. Alekseev. Rezanie metallov i rezhushchii instrument, 2nd ed. Moscow, 1967.

D. L. IUDIN