#pcb pcbs pcbmanufacturing pcbmaterial mokotechnology

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The Basic Properties of PCB Material

This is perhaps the most crucial aspect you need to pay attention to. As we mentioned at the outset, you need to be careful while selecting the PCB material, and being acquainted with the properties is so crucial. In this section, we are going to look at thermal, electrical, and chemical properties. So let us begin

Thermal Properties

As the title suggests here, we examine the effect of temperature. Pay attention to the following.

The Glass Transition temperature. Temperature ranges affect PCB material significantly. Generally, the substrate softens if subjected to a temperature beyond the required threshold. But again, the substrate will harden when taken back or when the temperature is readjusted to normal. The range where transformation can possibly occur is called glass transition temperature (Tg). This unit is determined in degrees celsius.

The Decomposition temperature. This is a temperature within which decomposition of the PCB material takes place. Generally, when the substrate is in temperature beyond a particular threshold, it decomposes. Unlike in glass transformation, the effects of substrate decomposition are irreversible. Why does this imply? People work in different environments with different temperature ranges. When selecting a PCB substrate, you need to ensure it is really compatible with your working environment.

Coefficient of Thermal Expansion. The expansion rate of any PCB substrate is the CTE. Whenever a material his subjected to a temperature beyond its Tg, the CTE rises, and this is quantified in parts per million (ppm). A PCB material often has a greater CTE compared to a copper layer. In most cases, this deviation in temperature is the leading problem of interconnection issues when heated. However, because of the constraints in the PCB material as a result of the glass woven, CTE is generally within 10 to 20 ppm in the X and Y axes. In case the temperature goes beyond the Tg limit, the CTE does not change.

Thermal conductivity. The heat conductive characteristics of PCB material is called thermal conductivity (k). The thermal conductivity of a substance is directly related to the potential of a PCB material to transfer heat. The thermal conductivity is determined in in watts per meter (w/m), expressed in kelvin (k)

In light of the above, the thermal properties of a PCB substrate is a vital factor for consideration. PCB materials are significantly affected by temperature ranges, and so you should pay attention to the conditions in your working environment. What about the electrical properties?

Electrical Properties of PCB material

There are several electrical characteristics you need to consider when it comes to the choice of a PCB material. The following is a brief overview of some of them.

Dielectric constant. This feature is Relative Permittivity. Impedance and integrity are the two most significant factors for consideration when it comes to the electrical performance of a PCB substrate. The dielectric constant of a PCB material range from 3.3 to 5.5. This value is affected by frequency. Specifically, it is inversely related to the frequencies. Nevertheless, Er changes differently in different materials. It changes less in others and more in others. For a substrate to be safer for use in high-frequency applications, it should have a stable dielectric constant in wide frequency ranges.

Dielectric Loss Tangent (Tan δ). It is also the Dissipation Factor (Df). If a material has a low loss tangent, it actually loses less power. The loss tangent applied in the PCB materials often varies from 0.02 to o.oo1. The higher value applies to most of the materials, while the latter one is used in the high-end materials. Besides, the loss tangent is also affected by the frequencies. It increases with a rise in frequencies. However, on the basis of digital circuitry, the loss tangent is not very significant.

Volume Resistivity (ρ). This is the resistance of any dielectric substance to insulation or perhaps electricity. If a PCB substrate has a great resistivity, it is not likely to expedite electric charges. The resistivity of any dielectric substance is measured in ohm-meters (Ω-m) or ohm-centimeters (Ω-cm). Just like in the dielectric insulators, all the materials on the PCB needs to have high resistivity. The preferred resistivity value range between 103 and 1010 Megaohm-centimeters. Nevertheless, external factors such as significant temperature variations and humidity influence the resistivity of a substance.

Surface Resistivity (ρS). This is the surface resistance of a dielectric substance to insulation as well as electricity. Just like the volume resistivity of a material, surface resistivity needs to be high. It should range between 103 and 109 megaohms per square. Also, differences in temperature and moisture influence surface resistivity.

Electrical Strength. Throughout the Z direction of a PCB substrate, the potential of a dielectric substance to withstand electrical breakthrough is called electrical strength. This is determined in volts/mil. Most PCB substrate’s electrical strength falls between 800 V/mil and 1500 V/mil.

Indisputably, the electrical characteristics of a PCB material is a vital factor for consideration. From the above discussion, it is crucial to pay attention to these properties when making your choices. Let us now look at other aspects of PCB material properties.

Chemical Properties

The following are the critical properties for consideration in this regard.

Flammability Specs (UL94)

Moisture Absorption. This is the capacity of a dielectric substance to resist exposure to a liquid. The moisture absorption figure for many PCB materials ranges from 0.01% to 0.2%. In general, moisture absorption affects both the electrical and thermal characteristics of dielectrics.

Methylene Chloride Resistance (MCR). This is the chemical resistance of any PCB substance. This measures the dielectric strength of methylene chloride absorption. The MCR often ranges from 0.01% to 0.20%.

Types of PCBs

As we stated at the outset, there are three main variants of PCB materials. Let us now review them in detail.

Single-layer PCBs

As the name suggests, this is a PCB made from one layer of the base substance. Usually,  a tinny metal layer covers one side of the base substrate. Since copper is the most fantastic electrical conductor, it is always preferred as a coating. Upon applying the copper base platting, a protective solder mask is often applied. Finally, the last silk-screen is used to mark out all the essential units on the board.

Single-layer PCBs are quite easy to create and manufacture. This is due to the fact that they have different circuits and units soldered on a single side. For this reason, single layer PCBs can be acquired at relatively lower prices, especially where one makes a large volume purchase. They are used for different applications such as calculators, printers, and power supplies, among others.

Double layer PBCs

Unlike single-layer PBCs, double layer PBCs are characterized by base material having a slim layer of a conductor, such as copper on both sides. Holes are often drilled on the board to enable circuits on one section of the board to link to the circuits on the end.

In the double layer PCB board, the circuit and the components are often linked in two ways. The first one can be using a through-hole and a second one utilizing a surface-mount. In general, a through-hole connection simply means the minor wires, also referred to as leads are always fed via the holes. Afterward, the leads are soldered to the appropriate component.

In contrast, the wires are not used in the surface mount as connectors. In this case, a lot of soldered small leads are directly linked to the board. This implies that the board itself is a wiring surface for various components. This permits the completion of the circuit with limited space. A lot of space is freed, and as a result, the board can carry out more functions at a faster speed and a lightweight compared to when through-board holes are used.

Usually, double layer PCBs are utilized in the applications demanding an intermediate degree of circuit complexity, including the following:

Industrial controls

Power supplies

Instrumentations

LED lighting

Automotive dashboards

Amplifiers

Vending machines

Multilayer PCBs

Multilayer PBC is made up of a series of either triple or a number of double-layered PBCs. A specialized glue is often used to secure these layers before they are sandwiched between insulation units to make sure too much heat cannot melt or soften any of the individual components. Additionally, these PBCs are always in a variety of sizes. They can contain only four layers, or as many as ten or twelve. The biggest multilayer PBC ever to be designed was 50 layers in thickness.

If a PBC has a lot of layers, developers can come up with quite thick, complex structure appropriate for a wide range of intricate electrical functions. Multi-layer PBCs can be pivotal in the following applications:

File servers

Data storage

GPS technology

Satellite systems

Weather analysis

Medical equipment

The Common types of PCB Materials

There are three common materials crucial in the fabrication of the PBCs. The following is a brief overview of each of the three.

FR-4      

This is the widely used material in the manufacture of PBCs. It is just a glass strengthened epoxy laminate sheet. The laminate that is utilized here flame retardant and also resistant to water. It also offers better strength when it comes to weight ratios. The material provides a very high tensile strength.

PTFE (Teflon)

This is basically a plastic substance with no resistance. For this reason, it is utilized for fast speed and frequency applications. This material has a lot of advantages. For instance, it is very flexible, making it priceless in applications having tight tolerances. Additionally, it is very lightweight, making it usable across different industries. Moreover, it is flame resistant, has great physical strength, temperature stability, and quite versatile in application.

Metal

This is a conventional material of copper and aluminum, among others utilized in PCBs. They permit the usage of Surface Mount Technology for the incorporation of components. They also have mechanical durability and, therefore, can be used for long.

The Future of PCB Material

The shrinking of the electronic devices will lead to the production of smaller and densely packed PCBs. These products will have significant electric potential. The development beyond the boards we just discussed here comprises of 3-dimensional molded plastic boards as well as the increased utilization of the integrated circuit chips. For this reason, the manufacture of PCBs is likely to be more dynamic in the years to come.

PCB MATERIAL GUIDE    

Before we talk about PCB material, let’s started with a PCB introduction.PCB is a self-contained component of interconnected units found in gadgets ranging from ordinary beepers or pagers to complex radar and computer programs. A thin layer conducting substance printed or deposited on the insulating board called the substrate is used to develop circuits. The specific electronic units are put on the substrate’s surface, which is then soldered to the interlocked circuits. It is common to have PCB performing one role, for instance, a signal amplifier or a number of functions. There are main types of PCB construction. These include:

Single-sided PCB

Double-Sided

Multi-layered

PCB is the most critical part component of electronics. You may have heard of the printed writing cards or printed writing board when individuals talk about PCB. Well, there is no difference between these terms; they mean the same thing. Due to their significance in all electronics, including computers and calculators, the board material for the PC is chosen with a lot of care and caution. The person making the selection must have knowledge of the electrical requirements of any type of equipment.

Prior to the establishment of PCB, the materials used for early boards were often covered by shells of knotted overlapping wirers, which could fail at particular junctures. When used for relatively long, they could as well short circuit, and some wires could start cracking. Expectedly, the manual process used in making these boards was so demanding, confusing, and meticulous.

Since many electronics started depending on circuit boards, it became increasingly necessary to come up with modest, more compact options, and this is precisely what led to the emergence of PCB material. Importantly, the metal, which enhances the flow of current between the board and the components attached, is referred to as solder. This substance has dual roles considering its adhesive features. This blog covers all the details you need to know about PCB materials. So read to the end, and you will enrich your knowledge and perhaps make the right choice when required.

The Bottom Line

PCB materials have a lot of characteristics. It is essential to consider all these characteristics are essential, and you have to consider them when selecting the materials for use in this regard. Some characteristics, such as decomposition temperature and glass transition temperature, are significantly affected by temperature variations. For this reason, you are supposed to consider the temperature of your working environment when selecting PCB materials. If you need help in choosing PCB material, try seeking help from Moko Technology.

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Difference between Copper PCB and Standard PCB

Difference between Copper PCB and Standard PCB

Standard PCBѕ uѕе a diеlесtriс and сорреr аѕ thеir mоѕt рrоminеnt mеtаl соnѕiѕt of different lауеrѕ оf material. They fеаturе a ѕubѕtrаtе, оr bаѕе, made frоm fiberglass, роlуmеrѕ, ceramic or аnоthеr nоn-mеtаl соrе. Mаnу оf thеѕе PCBѕ uѕе FR-4 for thе substrate. Thiѕ fibеrglаѕѕ mаtеriаl has a rеlаtivеlу affordable price аnd mоdеrаtе durability. Additiоnаl layers of copper, ѕоldеr mаѕk and ѕilkѕсrееn make the bоаrd conductive and outline соmроnеnt lосаtiоnѕ. These lауеrѕ may appear оn оnе side оf thе bаѕе, both ѕidеѕ оr in a multilауеr stack up while сорреr PCB hаѕ a similar lауоut tо аnу other PCB. It hаѕ a layer оr lауеrѕ оf сорреr, solder mask and silkscreen layered оvеr it.

Inѕtеаd оf hаving a fibеrglаѕѕ оr рlаѕtiс ѕubѕtrаtе, though, a сорреr circuit bоаrd hаѕ a mеtаl ѕubѕtrаtе. Thiѕ bаѕе mаinlу contains a соmbinаtiоn оf сорреr. Thе metal core саn соnѕiѕt еntirеlу оf mеtаl or hаvе a соmbinаtiоn of fibеrglаѕѕ аnd сорреr. Сорреr PCBs tурiсаllу аrе ѕinglе ѕidеd but can bе dоublе ѕidеd аѕ wеll. Multilayer сорреr PCBѕ аrе highly difficult to manufacture.

Yоu can find standard PCBѕ used in a nеаrlу infinitе numbеr of аррliсаtiоnѕ. Thеir capabilities dереnd оn thеir mаtеriаlѕ аnd соnѕtruсtiоn, ѕо thеу power low-end and high-еnd еlесtrоniсѕ аlikе. Singlе-ѕidеd PCBs арреаr in less соmрliсаtеd devices ѕuсh аѕ саlсulаtоrѕ, whereas multilayer bоаrdѕ have the роtеntiаl tо ѕuрроrt ѕрасе equipment аnd ѕuреrсоmрutеrѕ differing frоm сорреr bоаrdѕ gеt thе mоѕt uѕе in LED аnd роwеr соnvеrting еlесtrоniсѕ. Thе intеnѕе light produced bу LEDs creates high level оf heat, which сорреr dirесtѕ away frоm соmроnеntѕ.

A сорреr PCB еxtеndѕ thе lifespan of аn LED device аnd provides mоrе ѕtаbilitу. Yоu саn find сорреr ѕubѕtrаtеѕ in ѕtrееt lights, stop lightѕ аnd hоuѕеhоld lighting. Thеу аllоw роwеr соnvеrtеrѕ tо сhаngе сurrеntѕ аnd rеgulаtе electronics. Crеаtоrѕ in mаnу other induѕtriеѕ аlѕо find uѕе in аluminum PCBs, but thеу don’t implement thеm аѕ оftеn.

Different Characteristics of Copper PCB And Standard PCB

Stаndаrd PCBs аrе well-rounded аnd аdарtаblе. Yоu hаvе multiple ѕubѕtrаtе орtiоnѕ thаt dеtеrminе thе bоаrd’ѕ рriсе and durаbilitу. If уоu hаvе a lоw budget аnd lоw-intеnѕitу рurроѕе, you can сhооѕе соѕt-еffесtivе fibеrglаѕѕ. On thе other hаnd, you can invеѕt mоrе in a ѕtrоngеr bаѕе material thаt hаndlеѕ highеr lеvеlѕ оf ѕtrеѕѕ. Radio-frequency substrates аnd flеx substrates ѕuit ѕресiаltу аррliсаtiоnѕ.

However, FR4 сirсuit boards rеԛuirе еxtrа components tо withѕtаnd high-temperature applications. Nоn-mеtаl ѕubѕtrаtеѕ do nоt hаvе thеrmаl conductivity, so you have tо аdd a mаtеriаl thаt dоеѕ. If уоur device has a high-роwеr or high-dеnѕitу design, the сirсuitѕ bесоmе рrоnе tо ѕtrеѕѕ аnd dаmаgе. Yоu muѕt add hеаt ѕinkѕ, сорреr-fillеd viаѕ оr forced аir tо dirесt heat away frоm thе circuits.

In additiоn, сорреr boards are оnе of the most thеrmаllу conductive PCB options. Thеу kеер as muсh heat аwау frоm vitаl components as роѕѕiblе tо еnѕurе minimal сirсuit dаmаgе. Thanks tо thеir high hеаt tolerance, thеу саn handle higher dеnѕitу сirсuitѕ аnd lаrgеr power levels. Subѕtrаtеѕ сrеаtеd frоm Сорреr alloys hаvе a high lеvеl of рhуѕiсаl durаbilitу thаt lowers thе risk of brеаkаgе. Cоmраrеd tо other mеtаlѕ, Сорреr has a lower еnvirоnmеntаl impact in addition tо a reasonable соѕt.

On thе other hаnd, Сорреr PCBs tend tо hаvе more niche uses thаn ѕtаndаrd bоаrdѕ. Whilе thеу соѕt less thаn аdding conductors tо a standard board, they hаvе a highеr рriсе thаn standard PCBѕ withоut thоѕе соmроnеntѕ. Invеѕting in аn Сорреr соrе mау nоt рау оff if уоur application doesn’t invоlvе high temperatures. If уоu plan оn сrеаting a flеx сirсuit, a Сорреr flеx PCB саn оnlу flеx intо itѕ initiаl роѕitiоn. It will bеnd to fit into smaller electronics, but it wоn’t withѕtаnd thе stress оf vibrаtiоn.

The Feature of Copper PCB

Thе number оnе benefit of сорреr iѕ that it is highly соnduсtivе. This means that it can еаѕilу trаnѕmit signals withоut lоѕing еlесtriсitу along thе wау. It аlѕо mеаnѕ thаt mаnufасturеrѕ dоn’t have tо uѕе tоnѕ оf сорреr. Even just a ѕmаll amount will gеt thе jоb done. In the mоѕt соmmоn configuration, an ounce оf сорреr can bе turnеd intо 35 miсrоmеtеrѕ аbоut 1.4 thоuѕаndthѕ оf аn inсh thiсk, which саn соvеr an entire ѕԛuаrе fооt оf the PCB ѕubѕtrаtе. Cорреr iѕ also readily available аnd relatively inexpensive.

Elimination оf соmрlеx wirеd buss соnfigurаtiоnѕ

Inсrеаѕеd current саrrуing сарасitу

Increased еndurаnсе to thеrmаl strains

Optimized uѕе оf exotic high-temperature materials with lоwеr рrоbаbilitу оf сirсuit fаilurе

Abilitу tо inсоrроrаtе multiple copper weights on thе ѕаmе lауеr оf circuitry (lауеr count reduction)

Addеd сорреr plating in thе hеаt vias (thеrmаl rеѕiѕtаnсе rеduсtiоn)

Sеlесtivе areas plated with hеаvу copper саn function аѕ a hеаt sink оr intеrfасе tо соld рlаtе (built-in hеаt ѕinkѕ)

Intеgrаtiоn оf high-сurrеnt сirсuitѕ and соntrоl сirсuitѕ оn a ѕinglе PCB

Application of Copper PCBs

Dеmаnd fоr hеаvу copper-clad circuits in automotive, соmрutеr, industrial controls, аnd militаrу iѕ grоwing vеrу fast. More than 80% of the еxiѕting PCB mаnufасturеrѕ are limitеd оr nоt сараblе оf рrоduсing rеliаblе heavy copper рrintеd сirсuit bоаrdѕ.

Sоlаr роwеr соnvеrtеrѕ

Sаfеtу аnd ѕignаl ѕуѕtеmѕ

Rеnеwаblе еnеrgiеѕ аnd ѕtоrаgе рumрing рlаntѕ

Tоrԛuе соntrоlѕ

High роwеr rectifiers

Ovеrlоаd relays

Pоwеr соnvеrtеrѕ fоr rаilwау ѕуѕtеmѕ

Power linе monitors

Trасtiоn converters fоr rail applications

UPS systems

Elесtriс vehicle charging (commercial and induѕtriаl)

Prоtесtiоn relays

Exсitаtiоn ѕуѕtеmѕ fоr роwеr rеgulаtоrѕ

Position соntrоl ѕуѕtеmѕ

Pоwеr grid ѕwitсhing ѕуѕtеmѕ

HVAC ѕуѕtеmѕ

Enеrgу ѕtоrаgе and power grid bасk uр

Nuсlеаr роwеr applications

Linе reactors

Hydro-electric рlаntѕ

Surgе рrоtесtоrѕ

Fuѕе blосkѕ

Wеlding Equipment

Wеароnѕ control ѕуѕtеmѕ

Rаdаr ѕуѕtеmѕ

The driver bеhind thе dеmаnd оf copper PCBs iѕ еvеr inсrеаѕing power, реrfоrmаnсе, аnd соѕt rеԛuirеmеntѕ. Knоwn in the induѕtrу аѕ the PCB thеrmаl mаnаgеmеnt еxреrtѕ, Amitrоn hаѕ been manufacturing PCBѕ with hеаvу copper рlаting ѕinсе 1994 аnd wе are capable of producing 20 рluѕ оunсеѕ of finished сорреr аnd rеliаblу ѕрrау coat a protective and consistent solder mаѕk with imаgеd nomenclature. An еxtrеmе сорреr circuit соuld utilizе 6 оz. in thе hоlе walls and 20 оz. surface copper.

Copper Specification

Cорреr iѕ a mеdium strength, non-magnetic mеtаl. It hаѕ еxсеllеnt еlесtriсаl аnd thеrmаl conductivity рrореrtiеѕ аnd hаѕ a соmраrаtivеlу low cost. In itѕ рurеѕt form it is ѕоft аnd mаllеаblе but the intrоduсtiоn оf аllоуing еlеmеntѕ рrоvidеѕ many industrial аnd commercial uѕеѕ.

It iѕ аlѕо often a by-product оf ѕilvеr production. Sulрhidеѕ, оxidеѕ аnd саrbоnаtеѕ аrе the most imроrtаnt оrеѕ. Copper аnd сорреr alloys аrе ѕоmе оf thе mоѕt vеrѕаtilе engineering materials аvаilаblе. The combination оf рhуѕiсаl рrореrtiеѕ such as ѕtrеngth, соnduсtivitу, corrosion rеѕiѕtаnсе, mасhinаbilitу аnd duсtilitу makes сорреr suitable fоr a widе rаngе оf аррliсаtiоnѕ. Alsо, these рrореrtiеѕ саn be furthеr enhanced with variations in соmроѕitiоn and mаnufасturing methods.

Yiеld Strеngth оf Copper: Thе уiеld роint fоr сорреr alloys is not sharply defined. Aѕ a rеѕult it tеndѕ tо bе reported аѕ еithеr a 0.5% еxtеnѕiоn under lоаd оr as 0.2% offset. Mоѕt соmmоnlу thе 0.5% еxtеnѕiоn уiеld strength оf annealed mаtеriаl registers аѕ аррrоximаtеlу one-third thе tensile ѕtrеngth. Hardening bу соld wоrking mеаnѕ thе material bесоmеѕ lеѕѕ duсtilе, аnd yield ѕtrеngth аррrоасhеѕ thе tеnѕilе strength.

Mеlting Pоint оf Cорреr: Thе mеlting роint fоr pure Cорреr iѕ 1083ºC.

Struсturе оf Cорреr: Copper hаѕ a fасе сеntrеd сubiс crystal ѕtruсturе. It iѕ уеllоwiѕh red in physical арреаrаnсе and whеn роliѕhеd dеvеlорѕ a bright metallic luster.

Cоrrоѕiоn Rеѕiѕtаnсе оf Cорреr: All copper alloys rеѕiѕt соrrоѕiоn bу fresh wаtеr аnd ѕtеаm. In mоѕt rurаl, mаrinе аnd industrial atmospheres copper alloys аlѕо rеѕiѕtаnt to соrrоѕiоn. Copper iѕ rеѕiѕtаnt tо saline ѕоlutiоnѕ, ѕоilѕ, nоn-оxidiѕing minerals, оrgаniс acids аnd саuѕtiс solutions. Mоiѕt ammonia, hаlоgеnѕ, ѕulрhidеѕ, ѕоlutiоnѕ containing аmmоniа iоnѕ аnd oxidizing асidѕ, likе nitriс асid, will attack Cорреr. Cорреr аllоуѕ also have рооr rеѕiѕtаnсе to inоrgаniс асidѕ. The corrosion rеѕiѕtаnсе оf сорреr аllоуѕ comes frоm the fоrmаtiоn оf аdhеrеnt films оn thе material surface. Thеѕе films аrе rеlаtivеlу imреrviоuѕ to соrrоѕiоn thеrеfоrе рrоtесting the bаѕе mеtаl from furthеr аttасk.

Moko Technology focuses on offering EMS service with Single-Sided PCBs, Double-Sided PCBs, Multilayer PCBs, Rigid PCBs, Flex PCBs, Rigid-Flex PCBs and Rigid-Flex PCBs, link in https://www.mokotechnology.com/ and contact us if you're looking for printed circuit board!

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Types of PCB

A Printed Circuit Board (PCB) electrically connects and mechanically supports various electronic components. We do this by using conductive pads or tracks. These are etched from copper laminated sheets. However, we also include a non-conductive substrate. There are various types of PCB boards and they have specific applications. Today we will take a look at some of them.

Single-sided PCB

A single-sided PCB is one of the types of PCB and is made from a single layer of a substrate. Only one side of this substrate is coated with copper. In single-layer boards, we solder various components onto one side. So, this makes it easier to design and produce a single-sided PCB. Therefore, they have a low cost and we can manufacture them in high volumes. Hence, we commonly use single-layer PCB in simple applications like calculators, printers, radio, and cameras.

Double-sided PCB

Double-sided PCB is also among the types of PCBs. They have a substrate material like single-layer PCB. However, the substrate is coated with copper on both sides. We can drill holes in double-layer boards to allow the connection between components on opposite sides.

We use these types of PCB in applications that have intermediate complexity. Therefore, the typical examples include LEDs, amplifiers, HVAC systems, vending machines, and car dashboards.

Multi-layer PCB

Multi-layer PCB has multiple layers of PCB. So, we have to use a specialized glue for securing them together. We need to place the layer of boards by sandwiching them between insulation layers. Therefore, we can ensure that excess heat won’t damage the components.

These types of PCBs are suitable for a wide range of advanced electronic applications. So, we often use multi-layer PCB in data storage, file servers, satellite systems, medical equipment, GPS technology, and weather analysis.

Rigid PCB

We manufacture rigid PCB from a solid substrate which prevents the twisting of the board. A computer motherboard is a common example of a rigid PCB. The motherboard is designed for allocating electricity from the power supply and facilitating communication between various computer parts such as GPU, RAM, and CPU. Rigid PCBs are the most abundant type of PCB. So, we use rigid PCB in those applications where we want to prevent the deformation of PCB and increase its lifespan.

Flexible PCB

Flexible PCB is the exact opposite of rigid PCB. As the name suggests, these PCBs are very flexible and can move freely. Since flexible PCB needs flexible manufacturing material, therefore, they have a high manufacturing cost.

Flexible PCB offers many benefits that rigid PCBs are unable to offer. We can fold flexible PCB over their edges and wrap them around the corners. Their flexibility allows them to have lightweight and hence we can use them in small spaces.

We can also use flexible PCB in those areas which are subjected to environmental hazards. However, to achieve this, we have to manufacture them by using waterproof, corrosion-resistant, and shockproof materials. This is something that the rigid PCB is not capable of.

Flex rigid PCB

These types of PCB combines the best of both worlds as they depict the properties of both the rigid and flexible PCB. These boards have multiple layers of rigid PCB attached to a number of flexible PCB layers.

These boards have more benefits than those offered by flexible or rigid PCB alone. Flex-rigid PCB has a lower parts count than the conventional flexible or rigid boards. This is because we can combine the wiring options for both of them into a single PCB. When we combine the properties of flexible and rigid PCBs in the flex-rigid board then we get a reduced size, streamlined design, and lighter weight.

We mostly use flex-rigid PCB in those applications where weight and space are of prime concern. This includes digital cameras, automobiles, cell phones, and pacemakers.

Materials for PCB Manufacturing

The dielectric substrate is a major part of PCB which is either flexible or rigid. We use a dielectric substrate with a copper coating. We will now discuss some of the materials which we frequently use for manufacturing PCB.

FR4

FR is an abbreviation for Fire Retardant. FR4 is the most common glass laminated material for all types of PCB fabrication. FR4 is a composite material that is based on woven glass-epoxy compounds. It is very useful because it gives us excellent mechanical strength.

FR-1 and FR-2

This material is based on phenol and paper compounds. We mostly use this material only for single-layer PCBs. Both FR2 and FR1 have the same properties. However, they have one difference which is glass transition temperature. FR2 has a lower glass transition temperature in comparison to the FR1. We further divide these materials in halogen-free, standard, and non-hydrophobic.

CEM-1

This material is a composite of phenol compounds, paper, and woven glass epoxy. We use this material only for single-layer PCB. We can use CEM-1 as an alternative to FR4. However, CEM-1 is more costly than FR4.

CEM-3

This material is white in appearance and we mostly use it in double-layer PCBs. It is based on glass epoxy compounds. CEM-3 is cheaper than FR4 so it is a good alternative. However, it has lower mechanical strength in comparison to FR4.

Polyimide

We mostly use this material in flexible PCBs. It is based on rogers, kepton, and dupont. It has good felicity, electrical properties, high chemical resistance, and wide temperature range. The operating temperature of this material is from -200 ͦC to 300 ͦC.

Prepreg

It is a kind of fiberglass that is impregnated with resin. These resins are pre-dried, so it sticks, flows and completely immerses when heated. The adhesive layer of the prepreg gives it a comparable strength to the FR4.

There are many forms of this material which have varying resin content. These include Medium Resin (MR), Standard Resin (SR), and High Resin (HR). We choose between these according to the layer structure, required thickness, and impedance.

MOKO Technology is a leading company in the field of Printed Circuit Boards (PCBs). We specialize in all types of PCB  manufacturing with multiple materials since 2006. Feel free to contact us if you have any queries or if you want a quote.

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Introduction of rigid PCB

Rigid PCB is an inflexible and solid Printed Circuit Board. We cannot bend them or force them out of shape. It is very difficult to fold them or modify them after their manufacturing. Rigid PCB is made from the solid substrate and they have copper tracks. They also include component layouts where we solder active & passive components through automated or manual techniques. The aim of this article is to guide you regarding Rigid PCB and tell you everything you need to know.

Features and Benefits of Rigid PCB

Rigid PCB offers many benefits when we use them for commercial and industrial electronic systems. We mainly choose them because,

We can manufacture them to fit into any device instead of designing a device according to the specifications of the PCB.

They are compact and lightweight. Therefore, they have a smaller size.

We can design them without contact crimps or connectors. So, they are reliable when it comes to high-end applications.

Since they have a lesser number of interconnects, hence they have a smaller chance of circuit failure.

They can withstand extreme temperatures because of their thermally stable structure. This advance property makes them a suitable option for aerospace and military applications.

They require lesser material for manufacturing. Therefore, expenses for material procurement and manufacturing are reduced.

Rigid PCBs offer good resistance to ultraviolet radiation, aggressive oils, and harsh chemicals. Hence, we can use them in marine applications.

We can design them such that we can easily surface mount them on both sides.

It is possible to customize a rigid PCBs to meet special industrial requirements.

We can manufacture them robustly to withstand vibrations, high impact, shock, and other aggressive conditions.

Applications of Rigid PCB

We tend to use Rigid PCBs when we are looking for maximum adaptability and reliability. If we don’t want the circuit to bend under the applied stress then we use Rigid PCBs. They have evolved at an enormous pace in the last few years and are now used in a variety of applications. This has led to an increased demand for Rigid PCBs, the likes of which are unprecedented.

Computer Electronics

Most of the computer components today rely on Rigid PCBs. For instance, computer hard drives revolve at very high speeds. Therefore, it is necessary that their adjoint circuit can withstand the consequent vibrations. Also, if the hard drive operates for a long time then it will get very hot. So, the PCB will have to face high temperatures. Therefore, we use Rigid PCBs because they can withstand these extreme conditions and the data is safely read and written on the hard drive.

These conditions are not subject to computers only. Rather, most of the electronic systems today like PlayStation, televisions, microwaves, refrigerators, and printers have these extreme conditions. Therefore, we have to use rigid PCB because their performance isn’t affected by extreme conditions.

Automotive Electronics

Most of the electronic hardware in modern automobiles rely on rigid PCBs. These include anti-lock braking systems, instrument panels, engine management units, airbag controllers, and dash systems.

We can design rigid PCBs to fit into small spaces or irregularly shaped craters. This provides us flexibility in the manufacturing process. We can sync the circuits with other electronic modules without using bulky connectors or cable ties. Weight is also a concern in many vehicles. Therefore, even a small addition can make a huge difference. Rigid boards allow us to effectively address these concerns as compared to conventional alternatives.

The electronic components in automobiles have to withstand extreme conditions. They experience extreme vibrations because of driving on the rough terrain. They are also exposed to extreme cold and heat from the air conditioner and the engine. Therefore, we must use rigid PCBs because they are the only ones capable of withstanding these conditions.

Smartphones

Smartphones are handheld, therefore we need to make them small, portable, and lightweight. So, we need a PCB which can perfectly sync the core components and hold them together. Therefore, rigid PCBs are an ideal candidate for smartphones.

We take our smartphones everywhere with us so their hardware must withstand the changing environment and temperature fluctuations. Therefore, we cannot use conventional PCB. So, we look towards a rigid PCB.

Nowadays, most smartphones are water-resistant and come with water-repelling cases. These allow a smartphone to work even when it is submerged in water or any other liquid. These service conditions are too demanding for conventional PCBs. Hence, we have to once again rely on rigid PCBs.

The material of Rigid PCB

The performance of rigid PCBs depends mainly on the substrate material which constitutes the adhesive and dielectric films. We mostly use Polyester for manufacturing low-end rigid PCBs. However, for manufacturing high-end rigid PCBs we use PTFE and Kapton. These are a bit expensive and are therefore deployed in aerospace and military applications.

When we compare these three materials, we come to see that Kapton has the highest dielectric constant. Therefore, it has superior mechanical and electrical properties. These properties sustain even in high temperatures. However, these are more expensive and readily absorb moisture. In comparison, polyester doesn't absorb moisture but it can't sustain its performance at extremely high temperatures. We mainly use PTFE in high-frequency applications that require low dielectric constant.

Manufacturing of Rigid PCB

There are different technologies for manufacturing rigid PCB and we choose between them according to our requirements. Now we will take a look at some of them.

Layer Stack up Technique

One way to manufacture rigid PCBs is by stacking up layers of rigid material in a selective and orderly manner. We can then use through-holes for establishing connections between the layers. We can easily reduce the volume of the finished electronic product by using the stack up technology. This will allow rigid PCBs to withstand extreme contact pressure and intense heat strokes. Therefore, we will get better performance and improved reliability.

Industrialists came up with the idea of rigid PCB in the 70s. Since then, the stack up technology is widely deployed for fabricating rigid PCBs. With the passage of time, many people came up with different innovations and the standard procedure was modified. Today, the most reliable variant is to apply glass epoxy resin (FR4) on a rigid board. Also, we apply a solder mask for protecting the circuit pattern on the rigid board.

Substrate Material

We mostly use Kapton as a substrate material for making the core. We use a mixture of Kapton and acrylic for making a film that protects the circuit pattern. In this case, the adhesion is dependent on the prepreg which has a low flow rate. We laminate all these elements so that we can fabricate the rigid PCBs.

Rigid substrate material allows for excellent dielectric properties which are suitable for impedance control and high-frequency signal transmission. Therefore, they can also withstand the extreme environment, radiations, and temperature shocks. Hence, we can ensure that the electronic product will run smoothly.

Quality Control

Rigid PCBs can solve the issue of thermal dissipation and loose contact by taking care of the connectors. Therefore, we can improve the overall reliability of the electronic product. Towards the end of the manufacturing process, we can try to bend the PCB. If it is successfully bent then it doesn’t meet the electrical and mechanical performance standards. This allows us to effectively perform quality control and modify the process if need be. Therefore, we can achieve the required degree of rigidity and consequently the required level of performance.

Shortcomings of the Stack Up Technique

When we manufacture rigid PCBs through the stack-up technique then they have comparatively high density and low yield rate. Therefore, it is difficult to repair them in case of a breakdown. We need to embed the rigid base within the substrate material during the manufacturing process. So, there is a large wastage of raw material and the manufacturing process becomes difficult. Therefore, we need some new technology for manufacturing rigid PCBs.

Embedding Technique

When we use the embedding technique, we integrate the circuit units into internal rigid boards. So, after that, we can go about the bottom-up approach. So, the interconnections are unavailable between the two layers and the connection is mainly dependent on the buried VIAS and blind VIAS. Embedding allows us to reduce the raw material wastage and improve the performance of the rigid boards.

Since we are layering up in the embedding technique, therefore the effective surface area is much larger. So, the usage rate of the substrate material is improved. We can further enhance this by using through-holes to establish a firm connection in the circuit.

Embedding technique also allows us to address the problems of high density. It also offers a relatively easier manufacturing process. Therefore, we prefer this technique over the stack-up technique.

If you are looking for a reliable and durable rigid PCB then you are in the right place. MOKO Technology is a renowned name in the PCB industries and we have a wide experience in manufacturing rigid PCB. Our products are of premium quality and our services are of a superior standard. We have a large setup with mass production capacity. So, we can offer customized products as per your needs. Feel free to contact us for a quote or any further questions.