|
84.62 Machine-tools (including presses) for working metal by forging, hammering or die forging (excluding rolling mills); machine-tools (including presses, slitting lines and cut-to-length lines) for working metal by bending, folding, straightening, flattening, shearing, punching, notching or nibbling (excluding drawbenches); presses for working metal or metal carbides, not specified above.
The heading covers certain machine-tools, listed in the heading text, which work by changing the shape or form of metal or metal carbides.
In general machine-tools are power-driven but similar machines, worked by hand or pedal, are also covered by this heading. These latter types can be distinguished from the hand tools of heading 82.05 and from the tools for working in the hand of heading 84.67, by the fact that they are usually designed to be mounted on the floor, on a bench, on a wall or on another machine, and are thus usually provided with a base plate, mounting frame, stand, etc.
The heading includes :(1) Hot forming machines for forging, die forging (including presses) and hot hammers. Broadly speaking forging includes all processes for working heated metal by impact or by pressure, either to eliminate puddling slag (shingling) or to shape the metal. Except in the case of shingling where the metal is worked in the form of balls, the metal to be shaped is either in the form of semi-finished products such as blooms, billets or sheet bars, or in the form of bars and rods, usually of circular section.
In the process of die forging, the dies completely enclose the workpiece. In certain cases, however, a single metal die operating on only one part of the unworked piece is used. This is called open-die forging.
Die cutting machines can eliminate the "flash" produced during die forging. This trimming operation is carried out with the aid of special cutting dies.
The finishing operation to produce the necessary precise dimensions of the workpiece, carried out with a precision die, is described as "sizing" or "calibrating".
The following are examples of machine-tools specially designed and built for carrying out the operations described above : (a) Closed die forging machines :
Closed die forging is the process in which dies move towards each other and cover the workpiece in whole or in part. The heated raw material, which normally is a sawed or cropped round or square billet, is placed in the bottom die. The shape of the forging is incorporated in the top or bottom die as a negative image. Coming from above, the impact of the top die on the raw material forms it into the required forged form. (b) Open die forging machines :
Open die forging is the process of deforming a piece of metal between a hammer or ram and a single open die in a multiple step forming procedure until the final shape is achieved. (c) Hammers, drop forges and drop hammers (mechanical, hydraulic or pneumatic hammers and steam hammers), which operate by a series of short, sharp shocks. (d) Metal working presses, which operate by continuous pressure. However, general purpose presses not specially designed for metal working are excluded (heading 84.79). (2) Bending, folding, straightening or flattening machines (including press brakes) for flat products.
These products include, inter alia : (a) Profile forming machines are machines that are used for the automated and continuous production of metal profiles from flat products. A flat metal sheet is passed through several roller sets mounted on consecutive stands. The flat sheet is gradually cross-folded by each of the roller systems until the desired section profile is obtained. Profile forming machines modify the cross section of the metal sheet, while the longitudinal axis remains linear. (b) Numerically controlled press brakes for flat products are machines for bending metal sheet and plate in an automated and programmable manner. Typically, two C-frames form the sides of the press brake, connected to a table at the bottom and a moveable beam at the top. The bottom tool is mounted on the table and the top tool is mounted on the upper beam. The sheet is curved by a controlled lowering of the press beam. The flat sheet is pressed into a lower tool by an upper tool in a V-die and re-modelled in a straight line. (c) Numerically controlled panel benders for flat products are machines for the cold forming of flat metal sheets, designed to produce metal products from blanks in an automated and programmable manner. Panel benders are machines loosely similar to press brakes in concept but with a high level of automation, used to mass produce products from sheets of metal. They are capable of bending the metal sheet in two directions without having to move it, which is impossible for press brakes where the piece has to be inverted. (d) Numerically controlled roll forming machines for flat products are machines for bending operations in which a metal sheet or plate is passed through a set of three or more rolls, until the desired path (arc, circle, oval) of the longitudinal axis of the sheet or plate is obtained in an automated and programmable manner. Roll forming machines modify the curvature of the longitudinal axis of the metal sheet, while the cross section is left unchanged. Roll forming machines, passing products through roller systems, give them the required profile, in which the change in the structure of the metal occurs not over the entire area of the metal, but in places of deformation only as a result of bending. (e) Folding machines, the working of flat products consists of giving a sheet (or strip) in a straight line a permanent deformation of small radius, without rupturing the metal. This operation is carried out, either on a universal folding machine, or on a folding press. (f) Straightening machines and flattening machines for remedying imperfections in flat products, such as sheets or strip, arising during their manipulation after manufacture. For example, flattening machines of the roller type, which consist of a series of parallel rollers (or cylinders), either small in number (5 to 11) but of relatively large diameter and great rigidity, or large in number (generally 15 to 23) but of small diameter, great flexibility, and supported by an equal number of counter rollers. (3) Slitting lines, cut-to-length lines and other shearing machines (excluding presses) for flat products, other than combined punching and shearing machines.
These products include, inter alia : (a) Slitting lines for flat products are processing lines where two cylindrical rolls with matching ribs and grooves are used to cut a large roll of metal into a number of narrower rolls or rolls with cut edges. The basic parts of a slitting line are: an uncoiler, a coil flattener, a slitter and a recoiler. The material is fed from the uncoiler, and is first flattened and then fed through the nip between the two cutting wheels (one on top and another underneath). The slit pieces are then taken up by various recoilers at the end of the line. (b) Cut-to-length lines for flat products are processing lines where a shear is used to cut long flat rolled or coiled metal into multiple sheets. Cut-to-length lines consist of three main parts: an uncoiler, a coil flattener, and a shear. The material is fed from the uncoiler through the coil flattener and cut by a shear into flat sheets of metal. (c) Shearing machines. The shearing process involves two cutting tools with faces in the same plane applied vertically to the metal to be cut. These tools penetrate the metal which is subjected to plastic deformation and the fibres of which, under progressively more and more pressure and penetration, rupture along the line of the blades.
Machines of this type include : balance shears, lever shears and guillotine shears which use blades; rotary shearing machines which, instead of blades, use tools in the form of discs or frustums of cones. (4) Punching, notching or nibbling machines (excluding presses) for flat products including combined punching and shearing machines.
These products include, inter alia : (a) Punching machines used for perforating, notching or cutting metal by means of two tools adjusted one inside the other. The punching tool is called the punch while the other is called the die. Rupture of the metal is effected as in shearing and the shape of the hole obtained depends on the shape of the tools.
The different machines of this type include machines for making gears by punching.
A punching machine works very differently than a press. Punching machines operate incrementally, along a given trajectory in cutting a piece of sheet metal, a process also known as nibbling. In contrast to this, punching as part of a die forging or die cutting operation cuts sheet metal with a single stroke of the dies. (b) Notching machines are small machines used for working various sections (L, T, I or U sections) and half-rounds, either to prepare them for assembly (for example, grooves, slots, tenons and dovetails), or simply to cut or pierce them. (5) Machines for working tube, pipe, hollow section and bar (excluding presses).
These products include, inter alia :
Machines that perform operations on metal tube, pipe, profile, hollow section and bar in order to alter the shape of the processed material without chips removal. Such operations may include bending, folding, end-finishing, straightening, flattening, punching (without the removal of meatl), and tube hydroforming, as well as the working of tube, pipe, profile, hollow section and bars (excluding presses), other than draw benches (heading 84.63).
Bending machines work either by means of forming rollers, by press bending or, for tubes (and, in particular, oil pipes), by drawing their ends while the main section is held by a fixed cylinder.
Folding machines work by folding bars, rods, tubes, angles, shapes and sections in a manner akin to forming (see item 2 (c) above).
Wire bending machines add curvature to single planes. Wire bending machines that carry out more complex operations (for example, spring manufacturing machines) do not constitute simple folding machines and fall in heading 84.63. (6) Cold metal working presses :
These products include, inter alia : (a) Hydraulic presses :
Hydraulic presses are machines using a high pressure fluid to drive, by a piston, the moving element of the machine to generate the force needed to move the beam of the press, to which the tools or die are mounted that change the shape of the material.
Hydraulic presses can be controlled either numerically or non-numerically. In contrast to mechanical or servo presses, the travel of a hydraulic press is freely adjustable and any intermediate position of the press beam can be realized without changing the kinematic setup of the machine. (b) Mechanical presses :
Mechanical presses are machines using an electrical motor to generate a compressive force through a kinematic chain. These presses are designed or intended to mechanically transfer energy from a primary motor to a tool using a clutch mechanism that transmits torque to generate movement from the wheel to the runner. The shape of the metal workpiece is changed by the substantial pressure placed on it.
Mechanical presses can be controlled either numerically or non-numerically. They have an electrical motor and use a clutch-based mechanism to reverse the motion. (c) Servo-presses :
Servo-presses are machines using, typically, a kinematic system driven by a servo-motor to generate a compressive force to change the shape of a metal workpiece. These presses are designed to mechanically transfer energy to a tool by means of a servo-drive, without a clutch mechanism, to generate torque to power the device.
Servo-presses are a special type of mechanical presses (usually screw driven). Their main characteristic is related to the management of the motion, which is performed directly by the servo-drive, while in certain other mechanical presses, the motion is controlled by the setup of the mechanical hardware, resulting in lower flexibility with respect to adjusting the travel of the press beam. (d) Extruding presses for extruding bars, rods, angles, shapes, sections, tubes, etc. These presses are designed to force a mass of metal through an extrusion die with the help of a punch. (e) Presses for compressing metal scrap into bales
PARTS AND ACCESSORIES
Subject to the general provisions regarding the classification of parts (see the General Explanatory Note to Section XVI), parts and accessories (other than the tools of Chapter 82) of the machine-tools of this heading are classified in heading 84.66.
The heading also excludes :(a) Hand tools (heading 82.05). (a) Rolling mills (heading 84.55). (c) Machining centres, unit construction machines (single station) and multi station transfer machines, for working metal (heading 84.57). (d) Tools for working in the hand, pneumatic, hydraulic or with self contained electric or non electric motor (heading 84.67). (e) Machines for stamping address plates (heading 84.72). (f) Pig iron breakers and special stamping mills for breaking up cast iron scrap (heading 84.79). (g) Machine-tools for bending, folding and straightening semiconductor leads (heading 84.86). (h) Testing machines and apparatus (heading 90.24).
|
제16부 기계류·전기기기
> 제84류 기계류
> 제8462호 프레스 
clhs@clhs.co.kr 
070-4214-8300