Professional wiring installation, whether it is maintenance of car starters, generators or assembly of industrial cabinets, requires high reliability of connections. The basis of high-quality contact is not only the wire and the tip, but also the tool that unites them. Matrixes for squeezing They play a crucial role here, since it is their geometry that determines the density of the metal adhesion and the absence of air gaps. Incorrectly selected form of the working body of the press can lead to weakening of contact, overheating and even fire.
In modern practice of electrical installation, various pressing systems are used, each of which requires a specific approach to the choice of consumables. Hydraulic presses, working with interchangeable heads, allow you to process a wide range of cross-sections, from thin multicore conductors to massive tires. An understanding of the working principles of matrices is necessary for every specialist working with electricians to avoid marriage and ensure the longevity of connections.
In this article, we will discuss in detail the types of matrices, their marking, compatibility with different types of tips and the criteria for choosing a quality tool. You will learn why the profile form is so important and how to avoid common hydraulics mistakes. The right approach to the choice of equipment is a guarantee of safety and stable operation of the entire electrical circuit.
The design and operation of matrices
The matrix is a replaceable working part of the press, consisting of two halves, which close when lowering the punch. At the moment of compression, they form a predetermined profile around the sleeve or tip, providing the necessary deformation of the metal. Instrumental steelThe nucleus from which these elements are made must have high hardness and wear resistance to withstand thousands of compression cycles without loss of geometry. Any deformation of the edges of the matrix will immediately affect the quality of the crimping.
There are two main types of molding: hexagonal and bushing. Hexagonal crimping is used for copper and aluminum sleeves, providing uniform pressure on all sides. The bushing type, often referred to as "square" or "trapezoid", is designed for tinted tips of the type Nshwi and NSHVI2. The choice between them depends on the type of conductor being connected and the requirements of the standards.
⚠️ Note: The use of matrices with damaged or blunted edges is unacceptable. This results in an “impossible” contact zone, which in vibrating conditions (e.g. in a car) will cause rapid heating and breakdown of the connection.
Quality matrices have accurate size calibration, corresponding to international standards DIN or GOST. The gap between the closing halves in the closed state is strictly regulated for each section. If the matrix "does not reach" to the end or, conversely, compresses the conductor too much, violating the integrity of the veins, this is a sign of marriage or wear of the tool.
Technology of tempering matrices
Modern matrices undergo multi-stage heat treatment. The surface layer is hardened to high hardness (HRC 58-62) to resist wear, and the core remains more viscous to avoid chipping under impact loads.
Profile types and their purpose
The geometry of the working part of the matrix is a key parameter that determines the scope of its application. For copperhead The most common type of sleeve is a hexagonal profile. It provides maximum contact area and uniform pressure distribution around the sleeve perimeter, which is critical for large current loads. This type of crimp prevents the wire from turning inside the sleeve.
For the termination of multi-core wires, matrices with a bush profile are used. They form a square or rectangular cross section that is ideal for installation in terminal pads and automatic switches. There are also specialized matrices for aluminum-shell, which take into account the plasticity of this metal and often have a wider working surface.
- 🔹 Hexagonal matrices are a universal solution for copper and aluminum power connections, providing high mechanical strength.
- 🔹 Sleeve (square) matrices are the standard for finishing multicore wires before installation in shield equipment.
- 🔹 Trapezoid matrices - are used for specific types of tips and provide a tight squeezing without damaging the insulation at the edge.
When working with automotive electrics, where space is limited and vibrations are high, combined sets are often used. They allow one tool to perform power squeezing of the starter wires, and installation of signal lines.
When squeezing tin tips (NSHVI), use only matrices designed for tinted copper. Cracking "to break" (excessive compression) can lead to cracking of the tin coating and oxidation of the contact.
Marking and compatibility with the tool
Each professional matrix has a clear marking, applied by laser or engraving. The working surface is usually indicated by the range of cross-sections (for example, 16-25 mm2), profile type and sometimes compatibility with the tool brands. Compatibility This is a critical point, since the seats from different manufacturers (Klauke, Knipex, IEK, KVT) may differ in height and width of the tailing.
Some manufacturers use color coding for quick identification. For example, red may denote a range of up to 10 mm2, blue up to 25 mm2, and yellow may denote larger sections. However, you can’t rely on color alone, as the standards may vary. Always check the numerical values on metal.
| Type of tip | Matrix profile | Sectional range (mm2) | Application |
|---|---|---|---|
| NSHVI (single) | Busting (Square) | 0.25 - 10 | Signal chains, shields |
| NSHVI2 (double) | Bussing (Right angle) | 2x1.5 - 2x6 | The jumpers in the vending machines |
| TM (copper) | Hexagonal | 16 - 240 | Power cable lines |
| HA (aluminum) | Hexagonal (deep) | 16 - 240 | Introductory distribution |
Using third-party matrices in the original brand tool is possible, but requires fitting. Gaps in the seat can lead to skewed punch and breakage of an expensive hydraulic pump. For mass use, it is better to purchase original equipment or certified analogues.
Selection of matrices for different sections
The correct choice of matrix size depends not only on the wire cross section, but also on the type of insulation and number of veins. If you take a smaller matrix, you risk eating a part of the veins or deforming the tip tail, which will make it impossible to install it in the terminal. A matrix that is too large will not provide the required compression force, and the contact will be weak.
For polyconductor It is important to consider the filling rate. The 10 mm2 wire may have a different outer diameter depending on the number and thickness of the individual veins. Therefore, before crimping, it is always recommended to make a test sample on the cable trimming. It takes a minute, but saves you from reworking the whole work.
- 🔸 Thin cross-sections (0.5-2.5 mm2) require high accuracy and often use bushing matrices to form a neat "hemp".
- 🔸 Middle sections (4-35 mm2) are the most running group, where both hexagonal and bushing profiles are used depending on the task.
- 🔸 Large cross sections (50 mm2 and above) are processed only with hexagonal matrices using powerful hydraulic presses.
⚠️ Warning: Never try to squeeze a 16 mm2 wire with a 10 mm2 array, even if it "seems to fit in." This will lead to flattening of the contact platform and the inability to connect.
There are universal matrices with adjustable stops that allow you to vary the degree of compression. They are convenient in mobile work when there is no possibility to carry a full set of interchangeable tools. However, for stationary jobs and large volumes, it is better to have a separate pair for each popular size.
☑️ Checking before squeezing
Materials and durability of equipment
The quality of the metal from which the matrix is made directly affects the tool’s resource. Cheap Chinese counterparts are often made of soft steel, which quickly “floats” under load. After several dozen cycles of clenching, such a matrix begins to give an ellipse instead of a circle or hexagon, which is unacceptable for the human body. force-joint.
Professional equipment is made of alloyed tool steels with subsequent hardening and vacation. The surface of the working elements is often covered with an anti-corrosion composition or has a grinding that reduces friction. This is especially important when working in conditions of high humidity or dust, typical for car service stations and construction sites.
The resource of a quality matrix is from 5000 to 10,000 compression cycles. However, when working with aluminum shells, wear occurs faster due to the adhesion of metal on the working surfaces. Regular cleaning and lubrication of working edges with a special spray prolongs the life of the tool.
Savings on matrices of questionable quality lead to a defect of compounds, which can cost much more than the cost of the tool kit itself, especially when eliminating the consequences on an industrial scale.
Frequent errors in working with matrices
One of the most common mistakes is to try to squeeze two tips simultaneously in the same matrix, unless this is provided by the design. This leads to uneven distribution of force and deformation of both sleeves. Also, there is often an ignoring of the need to completely close the matrix - the operator stops the pressure ahead of time, believing that "and so will come down."
Another problem is the use of matrices for other purposes. For example, an attempt to squeeze a steel stud or a metal rod that is not designed for this leads to the painting of the edges. Hydraulic press develops a huge force, and the hardness of the material must correspond to the parameters of the tool.
- ⛔ Cracking over the insulation (if the matrix is not designed for this) leads to poor contact.
- ⛔ The use of damaged equipment - gives an unstable result and spoils the tips.
- ⛔ Ignoring the backlash in the tool - can lead to distortion and breakage of the punch.
Always check the condition of the tool before starting work. The presence of chips, cracks or strong production on working surfaces is a signal for immediate replacement. Careful attitude to the matrices and storage in a special case protects them from mechanical damage during transportation.
Can one brand’s matrices be used in another’s press?
In most cases, it is not, or it needs improvement. The landing dimensions (tail height, groove width) from different manufacturers (for example, Klauke, Greenlee, KVT) often differ. Installing an incompatible matrix can lead to tool jamming or hydraulics breakage. There are adapters, but they reduce accuracy.
How often do I need to change the matrices?
The service life depends on the intensity of operation and material of the clenched sleeves. In daily work on an industrial scale, replacement is carried out once a year or as a marriage occurs (infirmity, ellipsity). For periodic use in the garage, quality matrices can serve for decades.
What is dangerous when you are not squeezing?
The slug creates a gap between the wire and the sleeve, where there is a transitional resistance. When the current passes, this place begins to warm, oxidize, and the resistance grows even more. As a result, heating to the melting temperatures of insulation and fire are possible, especially in conditions of vibration characteristic of transport.