Machinist

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Machinist
Dreher an einer Drehbank.jpg
Machinist, operating a metal lathe
Occupation
Occupation type
Vocational
Activity sectors
Industrial manufacturing
Description
CompetenciesPatience, steady hand, ability to read plans, attention to detail, physically strong
Education required
Industrial Training Institute, Apprenticeship
Fields of
employment
Industrial manufacturing
Related jobs
Millwright
Machinery repairman creates helicopter part aboard an aircraft carrier US Navy 030227-N-9403F-006 Machinery repair aboard USS Abraham Lincoln CVN 72.jpg
Machinery repairman creates helicopter part aboard an aircraft carrier

A machinist is a tradesperson or trained professional who operates machine tools, and has the ability to set up tools such as milling machines, grinders, lathes, and drilling machines.[ clarification needed ]

Contents

A competent machinist should have a well-developed mechanical aptitude, the ability to correctly use precision measuring instruments, interpret blueprints, and a working knowledge of the proper parameters required for successfully utilizing the various tools commonly used in machining operations.

Nature of work

The machine trade is an extremely broad field with a wide variety of workplaces, job duties, and types of work. Most machinists work in machine shops and factories where they operate machinery that produce precision component parts. In general, the occupation is exacting, and requires extensive knowledge of the tools and processes in order to achieve the tight tolerances and surface finishes that these parts specify.

Many machinists make mass-produced parts using highly automated computer numerical control machines which are common today, but still require such professionals to set up and calibrate the machines. Other more specialised machinists produce custom-made parts for prototyping, repair, or research. A machinist may work on manufacturing something relatively simple like a bracket, or a shaft, or something extraordinarily complex, such as aerospace components accurate to 5 micrometres.

Good machinists are highly sought after and respected skilled trades persons and are generally well-paid. In utility, medical, and military use companies, experienced machinists can earn over $100 000 per year.

Some titles reflect further development of machinist skills such as tool and die maker, patternmaker, mold maker, programmer, and operator. A machinist is one who is called on to fix a problem with a part or to create a new one using metals, plastics, or rarely, wood. Depending on the company, a machinist can be any or all of the titles listed above.

other related fields include Millwrights, quality assurance, and mechanical engineers.

In Australia, a related profession is a fitter and turner. A fitter and turner is the tradesperson who fits, assembles, grinds and shapes metal parts and subassemblies to fabricate production machines and other equipment. [1]

Under the machinist title are other specialty titles that refer to specific skills that may be more highly developed to meet the needs of a particular job position, such as fitter (assembles parts), turning hand, mill hand, and grinder.

Role in manufacturing

Many women worked as machinists in the United States during World War II, sometimes referred to as 'Rosies'. WomanFactory1940s.jpg
Many women worked as machinists in the United States during World War II, sometimes referred to as 'Rosies'.

A machinist is usually called upon when a part needs to be produced from a stock material by cutting. Such a part may be unique or may be needed in the thousands. The part could be anything made from metal or plastic, though machined parts are usually ones that require high precision and cannot be produced by other means. Machinists generally start with a saw cut length of stock or a casting. Producing a part will often require several steps and more than one machine tool. Each machine tool plays a specific role in cutting away excess material. When large numbers of parts are needed, production planning is required to plan the most logical workflow through a series of machines. Computer numerical controlled (CNC) machines are computer-driven tools that can machine a large variety of shapes, and whose use in the workflow depends on the part to be machined. [2]

CNC machines are becoming the standard due to their speed, precision, flexibility, repeatability, and reduced downtime while changing jobs. Production runs consisting of large numbers of parts are more cost effective and commonly referred to as production work in the trade. Conversely, small production runs are sometimes referred to as prototype or jobbing work.

Production engineers use blueprints and engineering drawings to produce detailed specifications of the part, especially its geometry (shape), then decide on a strategy to make it. Machine tools are then configured by the machinist and production commences. The machinist works with the quality department to ensure the specifications are maintained in the finished product. [2]

Machinist inspecting a CNC lathe Cnc lathe.png
Machinist inspecting a CNC lathe

Large commercial organizations often staff machinists on site in a maintenance mode to ensure continuing operations of the production machinery. Such machinists can often make replacement parts the same day. Because of this, the labor cost for this role are significantly lower than costs involved with production shutdowns.

Additive machining

Additive machining means 3D printing to create industrial components, prototypes, tooling, and end-use production parts. Additive machining comes into its own in the manufacturing of very small intricate parts, which could not be produced through any other manufacturing process. There are several processes in additive manufacturing which include direct metal deposition: electron beam melting, fused filament fabrication, select laser sintering, and variations of them.

Materials commonly encountered by machinists

The most common materials that machinists make parts from are steel, aluminium, brass, copper, and various alloys of these materials. Other less common materials such as vanadium, zinc, lead, or manganese are often used as alloying elements for the most common materials. Materials that machinists work with occasionally are plastics, rubber, glass, and wood products. Rarely, machinists also work with exotic and refractory metals. The term exotic metals is a general term describing out of the ordinary, rare or special purpose metals. A synonym might be space-age. A list of exotic metals might include, but is not limited to, titanium, beryllium, vanadium, chromium, molybdenum and tungsten, as well as special high-temperature metal alloys like Inconel or Hastelloy (superalloys). Very often the meaning of the term suggests the need for specialized handling and/or tooling to machine them effectively. [3]

While the foregoing were primarily the materials that a machinist would be cutting, the cutters that the machinist uses must be harder and tougher than the materials to be cut. The materials in the cutters a machinist uses are most commonly high-speed steel, tungsten carbide, ceramics, Borazon, and diamond. [3]

Machinists usually work to very small tolerances, usually within 0.010" or 0.25 mm (more commonly expressed as ±0.005" (Plus or minus five thousandths of an inch) or ±0.13 mm), and sometimes at tolerances as low as +/-0.0001" (plus or minus one tenth of a thousandth of an inch – or 0.0025 mm) for specialty operations. A machinist deals with all facets of shaping, cutting and some aspects of forming metal, although forming is typically a separate trade. The operations most commonly performed by machinists are milling, drilling, turning, and grinding. There are other more specialized operations that a machinist will less frequently be called upon to perform such as honing, keyseating, lapping, and polishing, to name a few.

Tools of the machinist

A machinist operating a drill press in 1917 Woman operating boring machine; boring wooden reels for winding barbed wire.jpg
A machinist operating a drill press in 1917

The tools that a machinist is expected to be proficient with fall into broad categories:

See also

Related Research Articles

<span class="mw-page-title-main">Lathe</span> Machine tool which rotates the work piece on its axis

A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, threading and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.

<span class="mw-page-title-main">Machine tool</span> Machine for handling or machining metal or other rigid materials

A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All machine tools have some means of constraining the workpiece and provide a guided movement of the parts of the machine. Thus, the relative movement between the workpiece and the cutting tool is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or "freehand". It is a power-driven metal cutting machine which assists in managing the needed relative motion between cutting tool and the job that changes the size and shape of the job material.

<span class="mw-page-title-main">Metalworking</span> Process of making items from metal

Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry.

<span class="mw-page-title-main">Machining</span> Material-removal process; manufacturing process

Machining is a manufacturing process where a desired shape or part is created using the controlled removal of material, most often metal, from a larger piece of raw material by cutting. Machining is a form of subtractive manufacturing, which utilizes machine tools, in contrast to additive manufacturing, which uses controlled addition of material.

<span class="mw-page-title-main">Numerical control</span> Computer control of machine tools

In machining, numerical control, also called computer numerical control (CNC), is the automated control of tools by means of a computer. It is used to operate tools such as drills, lathes, mills, grinders, routers and 3D printers. CNC transforms a piece of material into a specified shape by following coded programmed instructions and without a manual operator directly controlling the machining operation.

<span class="mw-page-title-main">Metal fabrication</span> Creation of metal structures

Metal fabrication is the creation of metal structures by cutting, bending and assembling processes. It is a value-added process involving the creation of machines, parts, and structures from various raw materials.

<span class="mw-page-title-main">Grinding machine</span> Machine tool used for grinding

A grinding machine, often shortened to grinder, is a power tool used for grinding. It is a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece via shear deformation.

<span class="mw-page-title-main">Speeds and feeds</span> Two separate velocities in machine tool practice, cutting speed and feed rate

The phrase speeds and feeds or feeds and speeds refers to two separate velocities in machine tool practice, cutting speed and feed rate. They are often considered as a pair because of their combined effect on the cutting process. Each, however, can also be considered and analyzed in its own right.

<span class="mw-page-title-main">Tool and cutter grinder</span>

A Tool and Cutter Grinder is used to sharpen milling cutters and tool bits along with a host of other cutting tools.

<span class="mw-page-title-main">Turning</span> Machining process

Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helix toolpath by moving more or less linearly while the workpiece rotates.

Milling cutters are cutting tools typically used in milling machines or machining centres to perform milling operations. They remove material by their movement within the machine or directly from the cutter's shape.

<span class="mw-page-title-main">Metal lathe</span> Machine tool used to remove material from a rotating workpiece

In machining, a metal lathe or metalworking lathe is a large class of lathes designed for precisely machining relatively hard materials. They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of applications, and a broad range of materials. In machining jargon, where the larger context is already understood, they are usually simply called lathes, or else referred to by more-specific subtype names. These rigid machine tools remove material from a rotating workpiece via the movements of various cutting tools, such as tool bits and drill bits.

<span class="mw-page-title-main">End mill</span> Milling cutter designed to cut axially

An end mill is a type of milling cutter, a cutting tool used in industrial milling applications. It is distinguished from the drill bit in its application, geometry, and manufacture. While a drill bit can only cut in the axial direction, most milling bits can cut in the radial direction. Not all mills can cut axially; those designed to cut axially are known as end mills.

<span class="mw-page-title-main">Machine shop</span> Room, building or company where machining is done

A machine shop or engineering workshop is a room, building, or company where machining, a form of subtractive manufacturing, is done. In a machine shop, machinists use machine tools and cutting tools to make parts, usually of metal or plastic. A machine shop can be a small business or a portion of a factory, whether a toolroom or a production area for manufacturing. The building construction and the layout of the place and equipment vary, and are specific to the shop; for instance, the flooring in one shop may be concrete, or even compacted dirt, and another shop may have asphalt floors. A shop may be air-conditioned or not; but in other shops it may be necessary to maintain a controlled climate. Each shop has its own tools and machinery which differ from other shops in quantity, capability and focus of expertise.

<span class="mw-page-title-main">Tool and die maker</span> Class of machinist in manufacturing

Tool and die makers are highly skilled crafters working in the manufacturing industries. Tool and die makers work primarily in toolroom environments—sometimes literally in one room but more often in an environment with flexible, semipermeable boundaries from production work. They are skilled artisans (craftspeople) who typically learn their trade through a combination of academic coursework and with substantial period of on-the-job training that is functionally an apprenticeship. They make jigs, fixtures, dies, molds, machine tools, cutting tools, gauges, and other tools used in manufacturing processes.

Gear cutting is any machining process for creating a gear. The most common gear-cutting processes include hobbing, broaching, milling, grinding, and skiving. Such cutting operations may occur either after or instead of forming processes such as forging, extruding, investment casting, or sand casting.

<span class="mw-page-title-main">Grinding (abrasive cutting)</span> Machining process using a grinding wheel

Grinding is a type of abrasive machining process which uses a grinding wheel as cutting tool.

<span class="mw-page-title-main">Spindle (tool)</span> Rotary unit of a machine tool

In machine tools, a spindle is a rotating axis of the machine, which often has a shaft at its heart. The shaft itself is called a spindle, but also, in shop-floor practice, the word often is used metonymically to refer to the entire rotary unit, including not only the shaft itself, but its bearings and anything attached to it. Spindles are electrically or pneumatically powered and come in various sizes. They are versatile in terms of material it can work with. Materials that spindles work with include embroidery, foam, glass, wood, etc.

In manufacturing, threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element. There are many methods of generating threads, including subtractive methods ; deformative or transformative methods ; additive methods ; or combinations thereof.

<span class="mw-page-title-main">Milling (machining)</span> Removal of material from a workpiece using rotating tools

Milling is the process of machining using rotary cutters to remove material by advancing a cutter into a workpiece. This may be done by varying directions on one or several axes, cutter head speed, and pressure. Milling covers a wide variety of different operations and machines, on scales from small individual parts to large, heavy-duty gang milling operations. It is one of the most commonly used processes for machining custom parts to precise tolerances.

References

  1. "Fitter and Turners – JobOutlook" . Retrieved 12 February 2022.
  2. 1 2 "Tool & Die Makers - Tooling Engineers | ESI Engineering Specialties Inc". ESI Engineering Specialties Inc. Retrieved 2016-02-04.
  3. 1 2 Fagerlund, Jaakko (2010-12-08). "Home Shop Machinist: Materials and their properties". Home Shop Machinist. Retrieved 2016-02-04.
  4. "Useful Tools". CNCCookbook. Archived from the original on May 6, 2016. Retrieved 2016-02-04.
  5. "10 Must-See Ideas for Cutting, Tooling, Programming, Machining, and Shop Management". americanmachinist.com. Retrieved 2016-02-04.