- Klein modular connector crimpers
- Klein Journeyman crimpers
- Crimping pliers, which can also strip and cut wire
- Crimping tool for F connectors and other hexagonal connectors
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Crimping is a method of joining two or more pieces of metal or other ductile material by deforming one or both of them to hold the other. The bend or deformity is called the crimp. [1] [2] Crimping tools are used to create crimps.
Crimping is used extensively in metalworking, including to contain bullets in cartridge cases, for electrical connections, and for securing lids on metal food cans. Because it can be a cold-working technique, crimping can also be used to form a strong bond between the workpiece and a non-metallic component. It is also used to connect two pieces of food dough.
A crimping tool or crimp tool is used to created crimps. [1] [2] Crimping tools range in size from small handheld devices to benchtop machines used for industrial purposes. [3] [2]
For electrical crimps, a wide variety of crimping tools exist, and they are generally designed for a specific type and size of terminal. Handheld tools (sometimes called crimping pliers) are most common, which may be ratcheting. Apart from Handheld Tools, Crimping Tools can also include sophisticated electrically powered hydraulic types and battery operated tools that cover the entire size range and type of conductors, designed for mass production operations. [4]
An electrical crimp is a type of solderless electrical connection which uses physical pressure to join the contacts. Crimp connectors are typically used to terminate stranded wire. [5] Stripped wire (often stranded) is inserted through the correctly sized opening of the connector, and a crimper is used to tightly squeeze the opening against the wire. Depending on the type of connector used, it may be attached to a metal plate by a separate screw or bolt or it could be simply screwed on using the connector itself to make the attachment like an F connector.
The benefits of crimping over soldering and wire wrapping include:
Crimping is normally performed by first inserting the terminal into the crimp tool. The terminal must be placed into the appropriately sized crimp barrel. The wire is then inserted into the terminal with the end of the wire flush with the exit of the terminal to maximize cross-sectional contact. Finally, the handles of the crimp tool are used to compress and reshape the terminal until it is cold-welded onto the wire. [4]
The resulting connection may appear loose at the edges of the terminal, but this is desirable so as to not have sharp edges that could cut the outer strands of the wire. If executed properly, the middle of the crimp will be swaged or cold-formed.
More specialized crimp connectors are also used, for example as signal connectors on coaxial cables in applications at high radio frequencies (VHF, UHF) (). These often require specialised crimping tools to form the proper crimp. [8]
Crimped contacts are permanent (i.e. the connectors and wire ends cannot be reused). [9]
Crimp-on connectors are attached by inserting the stripped end of a stranded wire into a portion of the connector, which is then mechanically deformed by compressing (crimping) it tightly around the wire. [10] The crimping is usually accomplished with special crimping tool such as crimping pliers. A key idea behind crimped connectors is that the finished connection should be gas-tight.
Effective crimp connections deform the metal of the connector past its yield point so that the compressed wire causes tension in the surrounding connector, and these forces counter each other to create a high degree of static friction which holds the cable in place. Due to the elastic nature of the metal in crimped connections, they are highly resistant to vibration and thermal shock. [11]
Two main classes of wire crimps exist: [12]
In addition to their shape, crimped connectors can also be characterized by their insulation (insulated or non-insulated), and whether they crimp onto the conductor(s) of a wire (wire crimp) or its insulation (insulation crimp). [13]
Crimped connections are common alternatives to soldered connections. There are complex considerations for determining which method is appropriate –crimp connections are sometimes preferred for these reasons:
Crimped connectors fulfill numerous uses, including termination of wires to screw terminals, blade terminals, ring/spade terminals, wire splices, or various combinations of these. A tube-shaped connector with two crimps for splicing wires in-line is called a butt splice connector.
Single-wire crimp terminals include:
Crimping is also a common technique to join wires to a multipin connector, such as in Molex connectors or modular connectors.
Crimp plug-and-socket connectors can be classified as rear release or front release, referring to the side of the connector where the pins are anchored: [20]
Crimp connections are used typically to fix connectors, such as BNC connectors, to coaxial cables [21] quickly, as an alternative to soldered connections. Typically the male connector is crimp-fitted to a cable, and the female attached, often using soldered connections, to a panel on equipment. A special power or manual tool [22] is used to fit the connector. Wire strippers which strip outer jacket, shield braid, and inner insulation to the correct lengths in one operation [23] are used to prepare the cable for crimping.
A crimped connection will only be reliable if a number of criteria are met:
Micrographs of the crimped connections can be prepared to illustrate good and bad crimps for training and quality assurance purposes. The assembled connection is cut in cross-section, polished and washed in nitric acid to dissolve any copper dust that may be filling voids leading to a false indication of a good crimp.
Insulation color | Wire gauge (AWG) | Comments |
---|---|---|
Yellow | 26–22 | |
Transparent | 24–20 | |
Red | 22–18 | |
Blue | 16–14 | |
Yellow/Black | 16–14 | Heavy duty |
Yellow | 12–10 | |
Red | 8 | |
Blue | 6 | |
Yellow | 4 | |
Red | 2 | |
Blue | 1/0 | |
Yellow | 2/0 | |
Red | 3/0 | |
Blue | 4/0 |
Crimping is most extensively used in metalworking. Crimping is commonly used to fix bullets in their cartridge cases, for rapid but lasting electrical connections, for securing lids on metal food cans, and for many other applications.
In jewelry manufacture, crimp beads, or crimp tubes, are used to make secure joints in fine wire, such as used in clasps or tie loops. A crimped lead (or other soft metal) seal is attached to secure wires used to secure fasteners in aircraft, or to provide visual evidence of tampering when securing a utility meter or as a seal on cargo containers.
In plumbing, there is a trend in some jurisdictions towards the use of crimped fittings to join metallic pipes, replacing the traditional soldering or "sweating" of joints. This trend is driven in part by increased restrictions or bans of processes involving open flames, which may now require costly special permits.
When joining segments of tubular sheet metal pipe, such as for smoke pipes for wood stoves, downspouts for rain gutters, or for installation of ventilation ducting, one end of a tube is treated with a crimping tool to make a slip joint into the next section of duct. The joint will not be liquid-tight but will be adequate for conveying low pressure fluids. Crimp joints may be arranged to prevent accumulation of dirt.
Crimping is often used around the edges of pies and filled pasta like ravioli to seal the insides by connecting the top and bottom dough layers. This can be done with fingers, a fork, or a crimping tool. A jagging iron, also known as a crimping wheel, or jagger, consists of a handle and a wheel with a wavy pattern. There are also crimping tongs.
The technique of soldering wires has remained common for at least a century, however crimp terminals came into use in the middle of the 20th century. In 1953, AMP Incorporated (now TE Connectivity) introduced crimp barrel terminals, and in 1957 Cannon Brothers experimented with machined contacts integrating crimp barrels. [28] During the 1960s, several standards for crimp connectors were published, including MS3191-1, MS3191-4 and MIL-T-22520. In 2010, the predominant standard for crimp connectors changed to MIL-DTL-22520. [29]
Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between parts of an electrical circuit, or between different electrical circuits, thereby joining them into a larger circuit.
An electrician is a tradesperson specializing in electrical wiring of buildings, transmission lines, stationary machines, and related equipment. Electricians may be employed in the installation of new electrical components or the maintenance and repair of existing electrical infrastructure. Electricians may also specialize in wiring ships, airplanes, and other mobile platforms, as well as data and cable lines.
A ferrule is any of a number of types of objects, generally used for fastening, joining, sealing, or reinforcement. They are often narrow circular rings made from metal, or less commonly, plastic. Ferrules are also often referred to as eyelets or grommets within the manufacturing industry.
The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.
Pliers are a hand tool used to hold objects firmly, possibly developed from tongs used to handle hot metal in Bronze Age Europe. They are also useful for bending and physically compressing a wide range of materials. Generally, pliers consist of a pair of metal first-class levers joined at a fulcrum positioned closer to one end of the levers, creating short jaws on one side of the fulcrum, and longer handles on the other side. This arrangement creates a mechanical advantage, allowing the force of the grip strength to be amplified and focused on an object with precision. The jaws can also be used to manipulate objects too small or unwieldy to be manipulated with the fingers.
A crocodile clip or alligator clip is a plier-like spring-tensioned metal clip with elongated, serrated jaws that is used for creating a temporary electrical connection. This simple mechanical device gets its name from the resemblance of its serrated jaws to the toothed jaws of a crocodile or alligator. It is used to clamp and grab onto a bare electrical cable to a lead on a battery or some other electrical component. The clip's tapered, serrated jaws are forced together by a spring to grip an object. A Clothespin or Kelvin clip is a special form of crocodile clip whose jaws are insulated from each other, allowing two isolated wires to connect to a single test point. This enables 4-wire measurement of circuits with very low resistances. When manufactured for electronics testing and evaluation, one jaw of the clip is typically permanently crimped or soldered to a wire, or is bent to form the inner tubular contact of a ~4 mm (0.16 in) female banana jack, enabling quick non-permanent connection between a circuit under test and laboratory equipment or to another electrical circuit. The clip is typically covered by a plastic shroud or "boot" to prevent accidental short-circuits.
A banana connector is a single-wire electrical connector used for joining wires to equipment. The term 4 mm connector is also used, especially in Europe, although not all banana connectors will mate with 4 mm parts, and 2 mm banana connectors exist. Various styles of banana plug contacts exist, all based on the concept of spring metal applying outward force into the unsprung cylindrical jack to produce a snug fit with good electrical conductivity. Common types include: a solid pin split lengthwise and splayed slightly, a tip of four leaf springs, a cylinder with a single leaf spring on one side, a bundle of stiff wire, a central pin surrounded by a multiple-slit cylinder with a central bulge, or simple sheet spring metal rolled into a nearly complete cylinder. The plugs are frequently used to terminate patch cords for electronic test equipment such as laboratory power supply units, while sheathed banana plugs are common on multimeter probe leads.
A terminal is the point at which a conductor from a component, device or network comes to an end. Terminal may also refer to an electrical connector at this endpoint, acting as the reusable interface to a conductor and creating a point where external circuits can be connected. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener.
Twist-on wire connectors are a type of electrical connector used to fasten two or more low-voltage electrical conductors. They are widely used in North America and several European countries in residential, commercial and industrial building power wiring, but have been banned in some other jurisdictions.
Lineman's pliers, Kleins, linesman pliers, side cutting linesman pliers and combination pliers are a type of pliers used by lineworkers, electricians, and other tradespeople primarily for gripping, twisting, bending and cutting wire, cable, and small metalwork components. They owe their effectiveness to their plier design, which multiplies force through leverage.
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets.
The Western Union splice or Lineman splice is a method of joining electrical cable, developed in the nineteenth century during the introduction of the telegraph and named for the Western Union telegraph company. This method can be used where the cable may be subject to loading stress. The wrapping pattern design causes the join to tighten as the conductors pull against each other.
A screw terminal is a type of electrical connection where a wire is held by the tightening of a screw.
Tinsel wire is a type of electrical wire used for applications that require high mechanical flexibility but low current-carrying capacity. Tinsel wire is commonly used in cords of telephones, handsets, headphones, and small electrical appliances. It is far more resistant to metal fatigue failure than either stranded wire or solid wire.
F-Crimp is a type of solderless electrical crimp connection. It is not related to the F connector common in RF equipment.
MC4 connectors are single-contact electrical connectors commonly used for connecting solar panels. The MC in MC4 stands for the manufacturer Multi-Contact and the 4 for the 4 mm diameter contact pin. MC4s allow strings of panels to be easily constructed by pushing the compatible connectors from adjacent panels together by hand, but require a tool to disconnect them to ensure they do not accidentally disconnect when the cables are pulled. The National Electric Code (NEC) and the UL6703 standard for PV connectors specify that connectors have to be from the same type and brand to avoid the dangers of cross-mating. In addition, IEC 62548 ‘design requirements for PV Systems' require PV connectors to be of the same origin. Originally rated for 600V, newer versions of the MC4 connector are rated at 1500V, which allows longer series strings to be created.
Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor.
A swaged sleeve is a connector that gets crimped using a hand tool and die (swaged). This type of compressed sleeve is commonly used to make mechanical or conductive connections. These sleeves join or terminate wire rope, aircraft cable, synthetic cable, fibrous rope, or electrical conductor cables.
FASTON terminals or faston terminals are connectors that are widely used in electronic and electrical equipment. These terminals are manufactured by many companies, commonly using the terms "quick disconnect", "quick connect", "tab" terminals, "spade" terminals or blade connectors; without qualifiers, the first two could be mistaken for plumbing connections.
In telecommunications, a line splice is a method of connecting electrical cables or optical fibers.
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