Common material of connector insulator

Usually there are: PBT, Nylon, ABS, PC, LCP and other materials as shown in Attached Table 1, but in principle, the material with better fire resistance is adopted.

Amy polumbo BT material:

PBT material is commonly used with 20-30% glass fiber, anti-crack, anti-impact, anti-electric ability, good wear resistance, low friction coefficient, good lubrication effect, good oil resistance and chemical resistance. Has good dielectric strength under heat and humidity. Its shrinkage rate between 0.6%-3.0%, its temperature resistance is about 230℃. Good formability and fire resistance. It is a common adhesive material for connector products.

B. NYLON66, NYLON6T, PC, LCP material:

Its shrinkage rate of 1.0%-0.3%, high temperature resistance than PBT, commonly used YLON66 temperature 260℃--280℃, YLON6T temperature 280℃--300℃, LCP temperature 290℃--320℃. But its water absorption is large, generally used in high temperature and PITCH less products (such as SMD, Housing, PLCC and other products)

C. Abs material:

It has good impact toughness, oil resistance, wear resistance, easy to form, good rigidity, good temperature resistance of about 100℃, generally used in auxiliary products in connectors.

Common defects of injection molding and their causes

Common forming defects are the following: plastic parts have black spots or black liquid, surface is not smooth, overflow, plastic forming is incomplete, bubble or burning, deflated, patchwork stitching or plastic parts in the mold and so on. The main reasons can be divided into three parts: the factors of injection molding machine, the factors of mold and the factors of plastic material.

The composition and performance of connector contact parts

Material of connecting body: the plug is made of metal connecting body, generally brass is the main material, but the special requirement is very high times of inserting and removing, and phosphorus bronze, beryllium copper and other games can be used in the long life period. The following to the current industry on the type of copper and sex for the introduction

1. Brass -- An alloy of copper and zinc, the colour varies according to the zinc content.

A. brass ----- containing zinc 25~35%, the most suitable room temperature processing.

B. Brass ----- containing 35%~45% tin, the most suitable for normal temperature processing, copper plate sold on the market, copper bar are.

2. Bronze ---- alloys of copper and tin vary in colour according to the content of tin.

The general term for copper alloys other than brass is bronze.

Phosphorus bronze ----- in bronze with phosphorus, friction resistance, but too much phosphorus, it is difficult to cast, it is divided into tin 8~12%, phosphorus 0.5~1.5%.

Contact material selection

Contacts can be made from any of several alloys, depending on the type of contact, the frequency of insertion and extraction, and the electrical and environmental conditions under which the connector operates. Some commonly used materials and their applications are as follows:

Brass -- although brass is a good conductive material, but after repeated bending is easy to deformation and rapid fatigue. It is usually used as stationary contacts in inexpensive connectors, or as other metal parts within connectors. Connectors with brass contacts should not be used where excellent elasticity is required. Of course, due to its low cost, brass can still be used competently as a contact in many places.

Phosphor bronze -- Phosphor bronze has a higher hardness than brass, while maintaining a longer period of elasticity. It is often used as an operating temperature below 300? The material of the contact part of F. For most connectors with low insertion frequency or normal bending contacts, the use of phosphor bronze ensures good reliability.

Beryllium bronze - - beryllium bronze has mechanical properties far better than brass or phosphor bronze. Beryllium bronze parts shape and harden upon annealing, effectively retaining their shape forever, and are the most resistant material to mechanical fatigue. Beryllium bronze is recommended for frequent insertion and removal applications where high reliability is required.

Local plating of copper sheet

Surface processing of the joint (electroplating) : the surface of the joint is generally treated with electroplating in order to prevent corrosion and oxidation, make the contact surface smooth and ensure the mechanical properties of the raw materials.

A. The thickness of gold plating is 30μ ", and the thickness of Ni in the gold plating area is 50~80μ ".

B. The thickness of gold plating is 3μ ", and the thickness of Ni in the gold plating area is 30~50μ ".

C. the other:

Size: acceptance according to the order material size.

Appearance: a. Unplated surface: no oil stain, flat material strip, not deformed, bent or stretched.

B. Plating surface: smooth luster, fine particles, no pollution deformation.

C. Baking: frozen --55±3℃*30 'at room temperature 10' ~15 '→105±2℃*30' at room temperature 10 '~15.

D. Heat resistance: 85±2℃*2hr.

2. Copper plate tinned

A. Salt spray testing as agreed by both parties.

B. Baking test such as (Item I. 3) and less than 90% stained with tin.

C. More than 90% of direct tin contamination.

D. Heat resistance: 85±2℃*2hr.

E. Copper bottom copper plating 30~50μ "thick plating.

F. Tin-lead ratio Sn/ PB90:10 or 95:5

G. Thickness of tin plating as per order requirement.

V. Electrical performance

A. Voltage and current rating: The voltage rating relates to the spacing, while the current rating relates to the contact area and the tip section area. It shall be used in accordance with the specifications and standards (please refer to the attached table).

B. Contact resistance: when the connector is properly engaged, A current of DC 0.1A is applied between each terminal and PIN. The contact impedance should be as shown in the table.

C. Insulation resistance: a voltage of DC 500V shall be applied between the terminals and between the terminals and the connection point, and the insulation resistance value shall be shown in Schedule 6.

D. The voltage time test shall be the same between the withstand voltage terminals and between the terminals and the connection points as shown in the schedule.

Mechanical properties

A. Inserting force: 25mm±3mm/min at the speed of binding. The resulting insertion force shall be in accordance with the specifications of the insertion and extraction force.

B. Pull-out force: the pull-out speed is 25 mm±3mm/min. The resulting pull-out force shall conform to the specifications of the pull-out force.

C Durability: the following requirements shall be met after the insertion and pull-out test of 30 points at the speed of (10 points/min). A: Contact impedance is within two of the initial value. B: The pull-out force shall meet the specification value.

D terminal holding force: the terminal is pulled out from the HSG at a speed of 5 mm±3mm/min, and the tension shall meet the tension specification value.

E.PIN Retaining Force: Pin is pushed out from BASE at a speed of 5 mm±3mm/min, and its thrust shall meet the thrust specification value.

F. Riveting force of terminals: pull the terminals out of WIRE at a speed of 5 mm±3mm/min, and the tension shall meet the riveting specification value.

7. Environmental performance

A. Temperature rise of terminals: the temperature rise shall be less than 30℃ after applying the maximum rated current of AC to any joint to thermal equilibrium.

B. Shock resistance: at DC 0.1A on condition test with amplitude of 1.5m/m and frequency of 10Hz-55Hz/Min, and X, Y and Z axes three times each time after two hours, shall meet the following requirements: A: contact impedance shall be less than two of the initial value, B: discontinuous conduction time shall be less than 1μsec, C: appearance shall be the same.

C. Impact Resistance: Test X,Y,Z axis 3 times at 50g acceleration at DC 0.1A on, after test, it shall meet the following requirements. Below, B: The appearance shall be the same.

D. Tin-loading: from the terminal to the base level of 1.2mm, immersed in 230±50℃ tin tank for 3±1 seconds, the surface should be more than 95% tin adhesion.

E. High temperature resistance: it should be abnormal after 96 hours in a temperature tank of 85±2℃ and the contact resistance should be less than twice of the initial value.

F. Heat resistance of solder: from the terminal body at the base level of 1.2mm, immersed in the tin tank at 260±50℃ for 5±1 seconds, the insulator should have no crack deformation and other abnormal state, and the terminal strength should be within the specification.

G. Humidity resistance: placed in a constant temperature and humidity tank with temperature of 85±2℃ and humidity of 90%~95% for 96 min. The test shall meet the following requirements within 30 minutes after the drop is wiped.

1. The second contact resistance should be early, within a 2. The insulation resistance should be in more than 10 m Ω, 3. The appearance should be no different, 4. It should meet the requirements of voltage resistance.

H. Saline spray test: the sample was placed in 35±2℃ with a ratio of 5±1%, 16 hours ON, 8 hours OFF as a cycle, after 3 cycles with clean water, should meet the following requirements: a: contact impedance should be less than two times of the initial value, c: appearance without cracks or obvious corrosion phenomenon.

I. Sulfide gas test: after the sample is placed in 40±2℃ with a concentration of 50±5ppm for 24 hours, the contact impedance should be less than two times of the initial value.

Copper conductor related test items

1> wire diameter tolerance:

0.10mm≦d≦0.40mm, allowable deviation ±0.004mm;

0.40mm < d≦1.0mm, allowable deviation ±1%d (d denotes outer diameter of wire)

2 Difference between maximum and minimum outside diameters of > (F)

0.10mm≦d≦0.40mm, allowable difference F < 0.004mm;

When 0.40mm < D ≦1.0mm, allowable difference F < 1% DMM (D represents the outer diameter of the line).

3> elongation (soft state) : the total length of the wire is 20mm.

When 0.10mm≦d≦0.25mm, elongation ≧12%; 0.25mm < d≦0.40mm, elongation ≧15%; 0.40mm < d≦1.0mm, elongation ≧20%;

----- Elongation =(breaking time -20)/20

Related properties of copper conductor

The most commonly used conductor in wire and cable is copper, which has a combination of properties, such as high electrical and thermal conductivity, high ductility, good strength, and can be alloyed with or coated with a variety of other metals.

Copper conductors used at temperatures up to 300 ° F (or for short periods 400 ° F) shall be coated with tin, tin lead, or pure lead to a thickness of 40 to 70 micro inches. In addition to minimizing oxidation, these coatings are used to increase solderability and corrosion resistance.

Copper wires used continuously at 400℉ (or for short periods at 500℉) are plated with a minimum of 40 micro inches of silver, which withstands higher temperatures well. When the frequency is high enough for the skin effect to become apparent, the conductivity of the silver coating is better than that of the tin coating.

Copper alloy or copper-clad steel conductors are used to increase strength, but these materials are always used at the expense of electrical conductivity. Cadmium copper, for example, a copper alloy containing 0.5-1.0% Cd, has a tensile strength of 150% of copper, but an electrical conductivity of only about 80% of copper. In addition, copper-clad steel conductors have a tensile strength of 150-200% of copper, but their electrical conductivity is usually only 30-40% of copper's.

Aluminum alloy is lighter than copper conductor of the same specification, but its electrical conductivity is only about 60% of copper. In addition, when exposed to air, aluminum forms a surface oxide that forms undesirably high resistance connections. Therefore, conductors in wires and cables are often made of copper. According to the current classification of conductors in the industry, there are roughly the following kinds: solid conductors, stranded conductors and braided conductors.

1 - > solid conductor in electric wire electric cable 掁 is small and does not require flexural cases, using solid conductor (single strand). It has the advantage of low cost compared to the equivalent stranded wire. Wires and cables with solid conductors are usually used for mounting lines for small instruments, floor wiring, or any similar fixed equipment.

> Stranded Conductors ----- Stranded conductors are used in most wires and cables to provide better softness and longer flexure life. From a practical point of view, stranded conductors have a longer service life than solid conductors. If there is a small V-shaped crack or similar damage, it only takes a few bends to break. However, in the same operation, only a few of the stranded conductors are nicked or damaged, and the rest of the last damaged stranded wires can still provide a reasonable service life.

2> braided conductors ---- - Flat or round (tubular) braided conductors are sometimes used in some applications where they are more suitable than round solid or stranded cables. Braided conductors rarely have insulation because the insulation prevents high deflection and the ability to stretch the length slightly due to the axial push and pull of the cable.

Insulation materials for wires and cables

Insulating materials for wires and cables can be divided into the two basic groups thermosetting and thermoplastic, but the variety, compounds, and mixtures within each group are so vast that there is virtually no limit to the number of insulating materials available. Most insulating materials in the industry currently consist of compounds made from synthetic rubber polymers (thermosetting) and compounds made from synthetic materials to provide exceptional physical and electrical properties.

1. Thermosetting insulation materials:

Thermosetting materials are characterized by their ability to be stretched, compressed, or otherwise deformed (within reasonable limits) under mechanical stress, and then "bounce" back to their initial state and shape when the mechanical stress is relieved. Because thermosetting insulating materials are not susceptible to heat softening, they do not drip, flow, or deform during thermal and electrical overload (which causes internal heating).

2. Thermoplastic insulation materials

Thermoplastic insulating materials are known for their excellent electrical properties and low cost. Thermoplastics are widely used as insulating materials, especially in high-voltage cables, because they have excellent electrical properties due to their very thin insulation thickness. In addition, cables with a thinner insulation layer are usually smaller in size than cables made of thermosetting insulation material with the same electrical properties.

Several modified thermoplastic insulating materials can be prepared from various basic thermoplastic materials. Sometimes the main variation is color, but most thermoplastics are graded in order to meet specific requirements for temperature, strength and environmental resistance. Naturally, these materials are thermally formed, thermally softened and flowed under mechanical pressure, and then, after cooling and/or removing the mechanical strain, maintained their deformed shape and state.

PVC insulating materials are widely used in wire and cable because of their high dielectric and mechanical strength, high softness and flame retardant, water resistance, oil resistance and wear resistance. They also have the advantage of low cost and ease of processing. This makes it attractive to cable manufacturers and users alike. But recent data suggest that PVC processing is harmful to health.

Nylon is used primarily as a cover or sheath over other insulating materials to provide mechanical, thermal, and chemical protection. These jackets are usually very thin because even thin-walled nylon is tough. Thick nylon or insulation can make the cable stiff. Nylon is generally not used as primary insulation because of its poor moisture resistance, which reduces electrical performance in high humidity service conditions.

Polyethylene and polypropylene are used in many cables that require excellent electrical properties, such as low dielectric strength and low power loss factor. Other advantages of polyethylene include the ability to bend at low temperatures without cracking (even when very hard), water resistance, and general chemical inertia. Polypropylene has excellent wear and heat resistance, but poor softenness at low temperatures. Because this insulating material performs well even when it is thinner, it is possible to miniaturize wires and cables (with a smaller total diameter).

3. Insulation material and outer cover

According to the need to choose the best insulation materials, the selection factors include different performance characteristics, the following introduction:

1> General conditions:

Shrinkage: To become soft and flowing when heated, usually with a fixed melting point, and to harden again when cooled. Such materials can be molded into a shape (by heating and cooling), a process that can be repeated to melt the flowing polymer out of the line is one example.

Thermosetting: the material becomes soft and pliable during processing, and can be injected and extruded after solidification. After curing (cross-linking), it does not become soft even after reheating, thus improving the thermal properties and solubility of the heat-shrinkable material.

Insulation: good insulation properties, used for cable components, directly covering the conductor.

Outer cover: with good structure and chemical properties, directly covered on the cable for protection. Material selection to meet installation and environmental requirements, it is very important, more than electrical requirements.

2. General characteristics of > insulating compounds:

Mixing characteristics of insulation and outer coat (normal)

Insulating compounds constitute an insulating layer, and the important position of the insulating layer in the cable is mainly based on the following points: a. Dielectric characteristics when the surface of > conductor discharges at a higher voltage;

> high frequency signal cable low loss material;

C > high temperature heat resistance;

D > wear resistance, wrinkle resistance, not easy to cut off.

The following introduces several common properties of the outer cover material:

PVC----PVC has good dielectric, according to the type of existence, dielectric constant 3~6, types including PVC resin, plasticizing Qi, stable Qi, flame retardant Qi, filler and special addition Qi. The highest temperature of PVC application is 105℃, the lowest is -40℃, and the plasticizing can be transformed into brittle materials by chemical combination, especially at low temperature.

Polyethylene ---- density is divided into three categories (low, medium and high), with good electrical and physical properties, widely used. Electrical characteristics are high dielectric, low consumption, strong insulation, frequency and temperature stability. Physical characteristics have good flame retardant and UV resistance, adding all can improve its performance.

Polypropylene ---- and high density polyethylene the same, such as electrical and chemical resistance, has a strong physical properties, such as wear resistance, cut resistance, heat resistance, but low density; Combustible, but the heat resistance is better, suitable for rupture resistant occasions, mostly used in telecommunications cables, with ideal physical and dielectric properties.

XI. Design and selection of wire and cable performance requirements

In the practical design and selection of wires and cables, there are generally three aspects: physical requirements, environmental requirements and electrical requirements.

1> physical requirements:

Physical properties to be considered are: tensile strength, flexibility, wear resistance, impact, extrusion, deformation, cold flow, softening and breakdown resistance, size, weight, color marking, ending method, and peelability.

Bending life is a measure of how long a cable can be bent, or how many times a wire or cable can be bent without breaking a wire or shield. The bending life can be improved by stranding a thin single conductor for greater flexibility. Stranded copper - clad steel wires also increase bending life, but reduce softness.

The other method to be considered is the end joint method of cable, which generally include screw end joint, plain welding, compression joint, winding joint, fusion welding and so on. Because this will affect the choice of conductor and cable structure.

2 > environmental conditions:

The normal operation and life of cable often depend on the environment. What's the ambient temperature? Will the wiring be indoor, outdoor or underground? Exposure to moisture, dust, chemicals, oils or ozone? In addition to the physical environment, the surrounding electrical environment is also an important consideration. Will the cable be affected by static electricity? Can be affected by magnetic field radiation? And environmental conditions.

Cable users often only specify the maximum temperature, not realizing the minimum temperature, and how the cable is used at the lowest temperature may be equally important. At -40℃, there are many differences between cables suitable for fixed use and those suitable for mobile use. Knowing our customers' special needs, we are in a better position to advise them to take care of the environmental impact.

The maximum temperature may need to be tested to determine. Calculations of heat exchange take into account conductors, insulators, current strength, operating cycle, ambient temperature, ventilation rate, and additional conductors in the cable or cable duct.

3 > electrical requirements:

When choosing an electronic cable, the electrical requirements should be considered extensively. You should consider voltage, current, frequency, attenuation, capacitance, propagation speed, inductance, power supply and load impedance, characteristic impedance, corona, static and electromagnetic interference protection, electrical requirements also determine the wire or cable must be constructed. Changing electrical requirements can lead to confusion in the product line.

Voltage safety factor ------ An item that is often overlooked by technical conditioners is voltage safety factor. (dielectric breakdown voltage divided by working voltage) The highest safety factor shall be specified for conductors of multi-core cables subject to significant bending and movement. With high maintenance and replacement costs, and a large number of potential failure points inside, the safety factor for each conductor is defined to be between 70 and 100.

For mounting lines, the voltage safety factor is reduced to between 10 and 20, because such lines are commonly used in the chassis and are rarely bent. The recommended safety factor for testing the probe wire is only 3 to 5 because it is used intermittently. The minimum safety factor is between 2 and 3, which is used for high voltage cables because it is impractical to make high voltage cables with a high safety factor.

Frequency ------- More care must be taken in the selection and fabrication of cables for signals with higher frequencies because of their high insulation loss and the need for impedance matching.

The production of cables operating under a wide band has to be more sophisticated because of the difficulty of matching the impedance of a wide band.

High power levels combined with high frequencies (or even HF and UHF) can cause problems. Standard coaxial cables are unable to transmit UHF signals at high power levels due to excessive loss and overheating. It is better to choose waveguide when high power level and frequency exceed UHF.

Capacitance ------ For AC or pulse signals, the cable capacitance must be charged before the load can receive the full signal voltage from the signal. Sometimes the load voltage may never reach the full source voltage, and it may have different waveforms because the cable acts as a filter. In order to minimize the effect of capacitance, insulation with a low dielectric constant shall be specified; Conductors should be as far apart as possible and cables should not be longer than they need to be.

Attenuation ------- Attenuation is a property to be carefully considered in cables transmitting low level signals, or in applications where efficiency is an important property. The attenuation of a cable represents the loss due to heat during transmission of a signal. Conductors, by their resistance, are partly responsible for heating. The same is true of AC capacitance loss, which is proportional to the product of the dielectric constant and dielectric loss factor values for two cables of the same size.

Therefore, in order to minimize attenuation, the previous recommendation to minimize capacitance should be followed. Also be sure that the insulation has a low loss factor and that the conductor with the highest conductivity is useful. Care must be taken, however, because even in a constant diameter coaxial cable, where the thicker conductor leads to lower resistance losses, it generally leads to higher AC losses. This loss increase is caused by tighter capacitive coupling between conductors. At higher frequencies, losses also increase.

Propagation speed ------ Another important electrical characteristic is propagation speed. For structurally similar cables, this factor is inversely proportional to their insulating dielectric constant. As a result, the term is often used to indicate the relative superiority of cables from the point of view of insulation.

Propagation speed is a very important design factor in computers and precision timing circuits. If the propagation speed is slow, waveform distortion will occur, and such distortion is very important in pulse circuits. Differentiation between precise data signals and high amplitude noise is often caused by waveform distortion in the cable.

Characteristic impedance ------- Characteristic impedance is important in many electronic cable applications. If both reflection is not allowed and energy loss must be minimized, then the impedance must match. Otherwise the cable or equipment will be damaged due to overpressure.

XII. Insulation & Coating Material Properties.(UL444)

1. Wire diameter and core number

2. Strip length and use

3. Tin plating

4. Twisting and tin plating

The fit between the wire diameter requirements of the wire rod twist and the P.C.Board hole is as follows:

5. Wire rod design and specifications:

1. The material of the wire --------- general connector used wire material with better fire resistance for the principle. The general wiring shall meet the VW-1 grade required by UL, and the general isolation wire shall meet the VW-1SC grade. The temperature limit wire shall be used in the allowable temperature range from 60 ℃ to 250℃ according to the characteristics of the insulator material. The general use is based on 80℃, and the AC power supply temperature is based on 150℃.

Rated voltage:

3. Rated current

4. The wetting

1. Before heating the tin furnace, adjust the temperature to 230±5℃, adjust the tin furnace temperature according to the type of wire. For example, the temperature of the 1015 line can be higher than that of the 1007 line tin furnace.

2. If the temperature of the tin furnace is too high, it will cause PVC scald, and the time of dipping tin should not be too long.

3. Before dipping tin, it is necessary to gently scrape off the top oxide of the tin liquid (tin residue), and then dip the wire into tin. Otherwise, the oxide is easy to be stained on the core wire, and the color is gray.

4. The flux (tin water) should not be too much or too thick, because the excess tin water after heating is easy to stick to the PVC, it is difficult to remove, affecting the appearance, the height of the tin water and the depth of the tin liquid of the core wire directly affect the size of the tin.

5. The tin liquid in the tin furnace is about 80% full.

6. Pay attention to safety when using the tin stove at very high temperature.

7. The general action is to first clean the line to be stained, remove the foreign matter in the tin furnace, depending on the length of the tin stained with tin water, into the tin liquid for about 3 seconds, quickly lift and knock out the extra tin on the wire. The wire diameter requirement of twisted wire after tin dip and the compatibility of PCB holes