Crimper for crimping terminals and tips: the complete guide

Poor contact in a car’s electrical circuit is most often due to a breach of wire connection technology, not a breakdown of the cable itself. If you try to squeeze the terminal with pliers or a hammer you get a flattened tip with cracks on the sides, then such contact will not live long and will cause heating or fire. Professional crimper solves this problem by creating uniform pressure on all sides, forming a reliable connection by cold welding. It is the correct choice of the matrix and the force of the tool that determines whether the wiring will withstand the vibration of the engine and temperature changes.

Poor connection of wires leads to a voltage drop and overheating of the contact site, which is especially critical for starter or generator chains. Using an inappropriate tool often causes the wires inside the insulation to remain free, and only the outer shell is squeezed. To avoid such errors, it is necessary to understand the principle of work. mechanical mites and strictly observe the correspondence of the caliber of the matrix to the cross-section of the wire.

Principle of operation and instrument design

The basis of any high-quality crimper is a mechanism that ensures synchronous convergence of the sponges of the matrix. Unlike simple passages, where the force is distributed unevenly, a specialized tool creates a pressure of several hundred kilograms per square millimeter. This allows the metals of the contact pair and the wire vein to penetrate into each other, forming a monolithic connection. The key element here is matrixwhich can be built-in or replaceable, depending on the device model.

Modern models are often equipped with a ratchet mechanism that prevents the sponge from being unclothed until the full crimping cycle is complete. This function eliminates the human factor and ensures that the connection is completed. If you try to unclutch the handles ahead of time, the mechanism simply locks, forcing the wizard to complete the operation. This is especially important when working with copper-headedwhich require considerable effort for plastic deformation.

⚠️ Warning: Never attempt to forcefully unclog a jammed snoring mechanism unless the clamp cycle is complete. This will lead to breakage of the teeth of the ratchet and loss of calibration of the tool.

The design of the sponges can be designed to form various profiles: square, hexagonal or in the form of petals. The choice of profile depends on the type of terminals used and the requirements of the manufacturer of electrical equipment. For car wiring, the most common is considered hexagonalThis provides maximum contact area and mechanical strength.

Snoring mechanism device

Inside the handles of the crimper is a system of levers and gear wheels, which blocks the reverse stroke until a certain angle of convergence of the sponges is reached. This ensures repeatability of the result regardless of the physical strength of the operator.

Types of Crimperes for Automotive Electrics

The tool market offers many modifications, each of which is designed for solving problems. To maintain a car, it is important to distinguish between tick types, since there are practically no universal solutions that work equally well with thin signal wires and thick power cables. The main division occurs by type of matrices and range of sections.

• 🔧 Fixed-matricular mites compact tools sharpened under one or more adjacent terminal sizes. They are ideal for frequent work with a specific standard, for example, only with type connectors. Deutsch or Molex.
• 🔧 Tool with swivel heads - allow you to switch between different clipping profiles without replacing the nozzles. This is convenient for a mobile crew, but such models are often bulky and less durable.
• 🔧 Krimperes with interchangeable sponges - professional solution, where a separate insert is used for each wire section. This ensures the highest accuracy and durability of the tool.

Separately, it is worth highlighting hydraulic models that are used to squeeze large-sized tips on power cables of batteries or winches. Such devices develop a huge effort and work with sections from 16 mm2 and above. For a thin on-board network of passenger cars, they are redundant and can damage miniature contacts.

When choosing a tool, pay attention to the material of the execution. Forged steel preferable cast alloys, as it better withstands cyclic loads and does not burst when working with solid veins. The handles should have an anti-slip coating, as the work is often done in gloves stained with oil or lubricant.

Selection of a matrix by wire cross section and type of terminal

The most common mistake in crimping is the discrepancy between the size of the matrix and the diameter of the wire. If the matrix is too large, the petals will not close tightly and the contact will be weak. If the matrix is small, it can cut the veins or deform the terminal itself, making it impossible to install it in the connector. On the housings of quality tools always a color or digital marking is applied, indicating the range of cross-sections.

Color coding usually meets the standards of terminal insulation: red for 0.5-1.5 mm2, blue for 1.5-2.5 mm2 and yellow for 4.0-6.0 mm2. However, you can’t rely on color alone, as insulation manufacturers may be deviating from the standard. Always check. cross-section wires and markings on the terminal itself. For uninsulated tips, it is important to consider not only the diameter but also the thickness of the sleeve wall.

Type of terminal	Wire cross-section (mm2)	Colour of insulation	Profile type
NSHVI LAUGHTER	0.5 - 1.5	Red.	Square.
Ring non-isolator.	1.5 - 2.5	No.	Hexagonal
Scapular insulator.	4.0 - 6.0	Yellow	Oval.
DB-25 connector	0.3 - 0.7	Grey	Trapezia

Using an incorrect matrix profile can lead to the fact that the terminal simply does not enter the back part of the connector. For example, a square clip often gives larger dimensions than a hexagonal one with the same compression area. For the purpose of a tight fitting, such as OBD-II or engine control units, special accuracy of selection is required.

⚠️ Note: It is strictly forbidden to use matrices for copper wires on aluminum cables without special lubrication and appropriate tips, as this will lead to electrochemical corrosion and destruction of the contact.

Technology of correct crimping: step-by-step instructions

The process of creating a reliable connection begins long before the moment of compression of the handles of the crimper. The first step is to clean up the insulation. It is important to remove just as much insulation as the length of the terminal contact pad requires, usually 2-3 mm. If you clean too much, the bare part of the wire will remain outside and may cause a short circuit; if too little, the insulation will fall under crimp, disrupting contact.

After preparing the wire, it must be inserted into the terminal to the point. Make sure that all the veins are inside the sleeve, and the insulator of the wire is tightly adjacent to the end of the terminal (if double pressing is provided). When working with tin tips, make sure that the tin layer does not interfere with the tight fit of copper to copper, although in most cases this is not critical.

Place the terminal in the corresponding stream of the matrix. For ratchet tools, simply squeeze the handles until the characteristic unlock click. If the tool is simple, without a fixator, the compression should be single and powerful. Repeated compression of the already compressed terminal forbiddenBecause the metal loses its plasticity and can crack.

Typical errors and methods of their elimination

One of the most common problems is “unfavorable” when the petals of the matrix do not close completely. Visually, this may be imperceptible, but the pull test (the tear test) will show that the wire is pulled out easily. The reason is often the use of a worn matrix or an attempt to squeeze a wire of a larger cross section than is designed for the tool. In such cases, the connection must be remade, replacing the terminal.

The other extreme is “crushing” when the metal of the sleeve thins or bursts. This reduces mechanical strength and can lead to the breaking of the terminal tail. It's particularly dangerous. aluminum wirewhich are more fragile at the break. If you notice cracks in the metal after crimping, such a terminal should be disposed of immediately.

Often there is a mistake when the insulation falls under the clamp. This creates a barrier between the wire and the contact, increasing resistance. Over time, such contact begins to warm, the insulation melts, and a short circuit occurs. Always monitor the depth of the stripping and the position of the wire in the ticks before compression.

Quality control and connection verification

After the completion of the pressing, visual and mechanical control should be carried out. Visually, the connection should be smooth, without distortions and squeezed isolation. Metal sponges should fit tightly around the wire. Any gaps or protruding veins are unacceptable. For responsible nodes, such as starter wiring or ignition circuits, it is recommended to use a dynamometer tool to check the compression force, although in garage conditions this is rare.

The simplest method of checking is an attempt to turn the terminal around the wire with your hands or pull it out. If the wire is held dead and not scrolling, the connection is made qualitatively. You can also use a multimeter in vertebral mode to make sure there is no excessive resistance, although for short areas this is less informative.

⚠️ Note: Do not use an open fire to heat shrinkage on terminals already installed if they are near plastic wiring elements. It is better to use a building hair dryer with temperature adjustment.

Regular tool inspection is also important for maintaining the quality of work. Clean the matrices of metal shavings and lubricate the hinge joints. Dulled or deformed sponges must be replaced, as they will not provide the desired compression profile.

Can you squeeze the terminals with ordinary pliers?

Technically, you can compress the metal with pliers, but this will not give a guaranteed result. Flatheads do not create uniform pressure on all sides, which leads to deformation of the terminal and weak contact. For temporary repairs on the road, this is permissible, but for permanent operation, a specialized crimper is required.

Do I need to squirt the wire before squeezing?

In most cases, tinting (soldering) of a multi-core wire before squeezing is not recommended. Salt is a soft metal, and under pressure it “flows”, which over time leads to a weakening of the contact. The crimping should occur between the copper veins and the copper terminal. The slinging is allowed only if it is expressly indicated in the instructions for the connector.

How to choose a crimper for the house and garage?

For home use, the best choice is a universal crimper with a set of interchangeable matrices or a rotary head covering popular sections from 0.5 to 6 mm2. It is important to have a snoring mechanism that will help avoid mistakes for beginners. Expensive professional models with fixed matrices for the home are often redundant.