Unit 5 Machine-cutting Tools
Vocabulary Notes
alloy – сплав
alloy metal – легований метал
alloy steel tool
alloy steel cutter
alloy steel turning tool
alloy metal part
boring tool – розточувальний різець
boring tool use
boring tool treatment
alloy steel boring tool
planing tool – стругальний різець
planing
tool application planing
profiling tool – фасонний (профільний) різець
profiling tool treatment
profiling tool removal
flat drill – перове свердло
twist drill – спіральне свердло
gun drill – свердло з одним лезом, гарматне свердло
flat drill revolution
twist drill chip removal
gun drill application
effective cutting edge – робоча ріжуча кромка
effective cutting edge wear resistance
effective cutting edge strength
effective cutting edge shape
single-point cutting tool – різець із дуже вузьким ріжучим лезом
multiple-point cutting tool – різець із декількома ріжучими кромками
solid tool – цілісний різець
solid tool cutting edge
single-point cutting tool shank
multiple-point cutting tool wear
inserted tool – державка із вставним різцем
inserted tool wear
inserted tool wear resistance
to weld on – приварювати
to braze – паяти твердим припоєм
to weld the cutting edge
to braze the cutting edge
surface (syn. face) – поверхня
solid tool surface
boring tool surface
workpiece surface
to grind, ground, ground – шліфувати, заточувати
to grind the cutting tip ground cutting tip
to grind the part surface ground part surface
to grind the effective cutting edge ground effective cutting edge
ground tool surface
ground chisel cutting edge
Translate the text.
Machine-cutting Tools
Machine-cutting tools are that part of a cutting machine which serves for removing material from revolving work.
Cutting tools are made of hardened steel or alloy metals. All the cutting tools are used to perform work most efficiently. The cutting tools are subdivided into turning tools, boring tools, planing tools, profiling tools. etc.; flat and twist drills, gun drills, etc.; reamers, (milling) cutters, thread-cutting tools and abrasive tools.
The cutting tools having one effective cutting edge along which chips from the workpiece are removed are called single-point cutting tools.
The tools removing chips on two or more cutting edges simultaneously are called multiple-point cutting tools.
Each cutting tool consists of a shank for holding the tool in the machine and a cutting edge (a tip) for removing chips from the work.
The single-point cutting tools are subdivided into several types, such as:
solid tools;
solid tools having a steel shank and a cutting edge made of high alloy steel, welded on to the shank;
solid tools with a tip brazed on to the shank;
inserted tools having a small piece of the cutting edge made of carbide steel.
The various types of the cutting tools differ in shapes and angles to which the surfaces of the tools are ground. The cutting tip should be ground by hand or by machine with correct angles.
The shape of the tool and the proper angles depend on the material to be cut and the material from which the tool is made. The proper angle is from 6° for soft material to 15° for steel.
Additional Reading
Task I. Translate the text using the dictionary. Give a summary of the text.
Turing Tools
Cutting tools used for longitudinal turning are subdivided into roughing tools and finishing tools. Roughing tools are applied for roughing or removing excessive material from the work. Such tools have a long cutting edge. Angular roughing tools are used for turning surfaces of the parts in the chuck cams, as well as for facing.
Finishing tools are used after the piece was turned with a roughing tool to give accurate size and clean surface for the work being machined.
Side tools are used for cutting faces. The side tool has a long cutting edge set at an angle of 5° to the surface of the work to be cut, and a short cutting edge.
Necking tools are used for grooving. The cutting edge of the necking tool is narrow and may be easily broken. That is why the tool head is made several times larger than the width of the cutting tool.
Cutting-off tools are similar to necking tools, but they have a head longer than that of the necking tools.
Task II. Give the main idea of the texts.
I. Lathe Tools
Lathe tools are made of carbon steel, high speed steel and alloys.
Alloy steel tools are most widely used in metal cutting. High speed tools are also widely used in metal-cutting industry.
The cutting tools should be ground by hand or on machine to ensure the proper operation of the lathe. If the tool is not ground correctly it does not cut well.
In machine-grinding the tool is clamped rigidly in a chuck or tool holder and ground semi-automatically.
In grinding by hand the tool should be clamped on the work rest (опора, подставка) and moved back and forth across the entire face of the grinding wheel. The accuracy of the cutting tool ground by hand depends on the skill of the operator.
Lathe tools are subdivided into various types depending on the operation they perform.
Facing is performed by facing tools.
Turning of outside cylindrical surfaces may be done by roughing or finishing tools.
Cutting-off tools are used for cutting off excessive material from the workpiece.
Grooving is done by means of necking tools. Necking tools are similar to cutting off tools but the cutting edge of the necking tool is narrow for the width of the grooves is usually very small.
II. High Production Tools
A new range of tools is tipped with a special wear resistant cobalt-chromium-tungsten alloy which gives long life between regrinds. The alloy is tough: it takes in its stride stainless or high tensile steels, work hardening materials and interrupted cutting. High feed rates are obtained as the tips do not soften with heat. Regrinding is easily carried out with conventional grinding wheels.
Task III. Translate the text. What types of cutting tools are used for planing, shaping and slotting? Describe them.
Shaper- and planer tools like slotter tools are single-point cutting tools employed for generating flat surfaces.
Planer tools are similar to shaper tools but are usually larger and stronger. In many cases gang planer tools carrying three or more tool bits closely adjacent are used. As each chip removed is comparatively small, a planer equipped with a gang tool will carry a greater total feed and depth of cut than it is possible with a single-point planer tool.
Large-size planers are provided with two cutter heads mounted on the cross-rail. The heads serve for holding two tools which may cut the material simultaneously.
Planer- and shaper tools are used for machining surfaces to a high degree of accuracy and require less power per cubic inch of metal removed than machine tools employing multi-toothed cutters. In planers, shapers and slotters either the tool or the work is fed in a direction perpendicular to the cutting stroke.
The cutting action of slotting differs from planing or shaping as the end face of the tool is the cutting face. Tools of the normal planer type can be used with special type tootholders, but the tools have shorter shanks.
Two popular forms of the slotting tool are available, one is of square form with rounded corners, and the other is circular. In operation a hole is drilled through the component and the component is traversed in relation to the reciprocating tool so that the hole required is profiled.
Task IV. Translate the text using the dictionary.
Broaches
Broaches are classified according to the type of movement - push or pull; type of operation - internal or external; construction – solid, built-up or inserted tooth; purpose - production of hole, spline, spiral, surface broaching, etc.
Most of internal broaches are of pull type. When the internal broach is used the component is often completed in one pass by one broach only. Internal push broaches are useful for sizing operations. The stock removal is small compared with pull broaches.
Push broaches are used in sizing, correcting or burnishing holes in previously heat-treated components such as gears.
The essential features of a broach are a pull or push end, roughing teeth, finishing teeth, the front and the rear pilots.
The number of roughing teeth depends on the material to be cut and the amount of stock to be removed; the number of intermediate teeth depends on the material and finish required; the number of finishing teeth depends on the length of the workpiece, the finish and accuracy required.