Kwa upande wa teknolojia ya kisasa, ulimwengu unakua kwa kasi sana, na ushawishi wake unaweza kutumika katika maisha yetu ya kila siku. The way we live has changed dramatically and this technological advance has led to many advanced devices that we didn’t even think of 10 years ago. Msingi wa vifaa hivi ni uhandisi wa umeme, na msingi ni printed mzunguko bodi (PCB).

PCB kawaida ni kijani na ni mwili mgumu na vifaa anuwai vya elektroniki juu yake. These components are welded to the PCB in a process called “PCB assembly” or PCBA. PCB ina sehemu ndogo iliyotengenezwa na glasi ya nyuzi, safu za shaba ambazo zinaunda, mashimo ambayo hufanya sehemu hiyo, na tabaka ambazo zinaweza kuwa za ndani na nje. Kwa RayPCB, tunaweza kutoa hadi tabaka 1-36 kwa PROTOTYPES za safu nyingi na safu za 1-10 kwa mafungu mengi ya PCB kwa uzalishaji wa kiasi. For single-sided and double-sided PCBS, an outer layer exists but no inner layer.

The substrate and components are insulated with solder film and held together with epoxy resin.The welding mask can be green, blue or red, as is common in PCB colors. Mask ya kulehemu itaruhusu sehemu hiyo kuzuia mzunguko mfupi kwa wimbo au vifaa vingine.

Ufuatiliaji wa shaba hutumiwa kuhamisha ishara za elektroniki kutoka hatua moja hadi nyingine kwenye PCB. These signals can be high-speed digital signals or discrete analog signals. Waya hizi zinaweza kufanywa kuwa nene ili kutoa nguvu / nguvu kwa usambazaji wa umeme wa sehemu.

Katika PCBS nyingi ambazo hutoa voltage ya juu au ya sasa, kuna ndege tofauti ya kutuliza. Components on the top layer are connected to the internal GND plane or internal signal layer via “Vias”.

Vipengele vimekusanyika kwenye PCB ili kuwezesha PCB kufanya kazi kama ilivyoundwa. The most important thing is PCB function. Hata kama vipinzani vidogo vya SMT havijawekwa kwa usahihi, au hata ikiwa nyimbo ndogo hukatwa kutoka kwa PCB, PCB haiwezi kufanya kazi. Kwa hivyo, ni muhimu kukusanya vifaa kwa njia inayofaa. PCB wakati wa kukusanya vifaa huitwa PCBA au PCB ya mkutano.

Kulingana na uainishaji ulioelezwa na mteja au mtumiaji, kazi ya PCB inaweza kuwa ngumu au rahisi. PCB size also varies according to requirements.

The PCB assembly process has both automatic and manual processes, which we will discuss.

Safu ya PCB na muundo

Kama ilivyoelezwa hapo juu, kuna tabaka nyingi za ishara kati ya tabaka za nje. Now we will discuss the types of outer layers and functions.

Understand PCB board assembly process and feel the green charm of PCBD

1 – Substrate: Hii ni sahani ngumu iliyotengenezwa na nyenzo za FR-4 ambazo vifaa “vimejazwa” au svetsade. Hii hutoa ugumu kwa PCB.

2- Copper layer: Thin copper foil is applied to the top and bottom of the PCB to make the top and bottom copper trace.

3- Mask ya kulehemu: Inatumika kwa tabaka za juu na za chini za PCB. This is used to create non-conducting areas of the PCB and insulate the copper traces from each other to protect against short circuits. Mask ya kulehemu pia huepuka kulehemu sehemu zisizohitajika na inahakikisha kwamba solder inaingia kwenye eneo la kulehemu, kama vile mashimo na pedi. These holes connect the THT component to the PCB while the PAD is used to hold the SMT component.

4- Screen: The white labels we see on PCBS for component codes, such as R1, C1 or some description on PCBS or company logos, are all made of screen layers. Safu ya skrini hutoa habari muhimu kuhusu PCB.

There are 3 types of PCBS according to the substrate classification

1- Rigid PCB:

PCB ni vifaa vingi vya PCB tunavyoona katika aina anuwai za PCB. Hizi ni PCBS ngumu, ngumu na ngumu, na unene tofauti. The main material is fiberglass or simple “FR4”. FR4 inasimama kwa “moto wa moto-4”. Sifa za kujizima za FR-4 hufanya iwe muhimu kwa matumizi ya vifaa vingi vya kiufundi vya kiufundi vya msingi ngumu. The FR-4 has thin layers of copper foil on both sides, also known as copper-clad laminates. Fr-4 laminates zilizofunikwa kwa shaba hutumiwa haswa katika viboreshaji vya nguvu, vifaa vya umeme vya hali, umeme wa servo, n.k. Kwa upande mwingine, sehemu nyingine ngumu ya PCB inayotumika sana katika vifaa vya nyumbani na bidhaa za IT inaitwa PCB phenolic PCB. Ni nyepesi, msongamano wa chini, bei rahisi na rahisi kupiga. Kikokotoo, kibodi na panya ni baadhi ya matumizi yake.

2- Flexible PCB:

Made from substrate materials such as Kapton, flexible PCBS can withstand very high temperatures while being as thick as 0.005 inches. It can be easily bent and used in connectors for wearable electronics, LCD monitors or laptops, keyboards and cameras, etc.

3-metal core PCB:

In addition, another PCB substrate can be used like aluminum, which is very efficient for cooling.Aina hizi za PCBS zinaweza kutumika kwa matumizi ambayo yanahitaji vifaa vya joto kama vile elektroniki za nguvu kubwa, diode za laser, nk.

Installation technology type:

SMT: SMT inasimama kwa “teknolojia ya kupanda juu”. Vipengele vya SMT ni ndogo sana kwa saizi na huja katika vifurushi anuwai kama vile 0402,0603 1608 kwa vizuia na viboreshaji. Vivyo hivyo, kwa ics zilizojumuishwa za mzunguko, tuna SOIC, TSSOP, QFP na BGA.

Mkutano wa SMT ni ngumu sana kwa mikono ya wanadamu na inaweza kuwa mchakato wa usindikaji wa wakati, kwa hivyo hufanywa kimsingi na roboti za kubeba na uwekaji.

THT: THT inasimama kwa teknolojia ya kupitia-shimo. Components with leads and wires, such as resistors, capacitors, inductors, PDIP ics, transformers, transistors, IGBT, MOSFET, etc.

The components must be inserted on one side of the PCB on one component and pulled by the leg on the other side, cut the leg and welded. THT assembly is usually done by hand welding and is relatively easy.

Sharti la mchakato wa Mkutano:

Prior to the actual PCB fabrication and PCB assembly process, the manufacturer checks the PCB for any defects or errors in the PCB that could cause the failure. This process is called the Manufacturing design (DFM) process. Watengenezaji lazima wafanye hatua hizi za kimsingi za DFM kuhakikisha PCB isiyo na kasoro.

1- Component layout considerations: Through-holes must be checked for components with polarity. Like electrolytic capacitors must be checked polarity, diode anode and cathode polarity check, SMT tantalum capacitor polarity check. Noti ya IC / mwelekeo wa kichwa lazima ichunguzwe.

Kipengele kinachohitaji kuzama kwa joto kinapaswa kuwa na nafasi ya kutosha kubeba vitu vingine ili bomba la joto lisiguse.

2-Hole and through-hole spacing:

The spacing between holes and between holes and traces should be checked. Pad na kupitia shimo haitaingiliana.

3- Brazing pad, thickness, line width shall be taken into account.

By performing DFM inspections, manufacturers can easily reduce manufacturing costs by reducing the number of scrap panels. This will help in fast steering by avoiding DFM level failures. At RayPCB, we provide DFM and DFT inspection in circuit assembly and prototyping. Katika RayPCB, tunatumia vifaa vya kisasa vya OEM kutoa huduma za PCB za OEM, soldering ya wimbi, upimaji wa kadi ya PCB na mkutano wa SMT.

Mchakato wa hatua kwa hatua wa Mkutano wa PCB (PCBA):

Hatua ya 1: Tumia kuweka kwa solder ukitumia templeti

First, we apply solder paste to the area of the PCB that fits the component. This is done by applying solder paste to the stainless steel template. Kiolezo na PCB hushikiliwa pamoja na vifaa vya mitambo, na kuweka kwa solder hutumiwa sawasawa kwa fursa zote kwenye bodi kupitia kwa muombaji. Apply solder paste evenly with applicator. Kwa hivyo, kuweka sahihi ya solder lazima itumike kwa mwombaji. Wakati mwombaji atakapoondolewa, kuweka itaendelea kubaki katika eneo linalohitajika la PCB. Kuweka kijivu kwa solder 96.5% iliyotengenezwa kwa bati, iliyo na 3% ya fedha na 0.5% ya shaba, inaongoza bure. After heating in Step 3, the solder paste will melt and form a strong bond.

Step 2: Automatic placement of components:

Hatua ya pili ya PCBA ni kuweka kiatomati vifaa vya SMT kwenye PCB. Hii imefanywa kwa kutumia pick na mahali robot. Katika kiwango cha muundo, mbuni huunda faili na kuipatia roboti ya kiotomatiki. Faili hii ina X iliyoratibiwa mapema ya Y, Y ya kila sehemu inayotumiwa kwenye PCB na kubainisha eneo la vifaa vyote. Using this information, the robot only needs to place the SMD device accurately on the board. The pick and place robot will pick up components from its vacuum fixture and place them accurately on the solder paste.

Kabla ya ujio wa mashine za kubeba na kuweka roboti, mafundi wangechukua vifaa kwa kutumia kibano na kuziweka kwenye PCB kwa kuangalia kwa uangalifu eneo na kuepukana na kupeana mikono yoyote. This results in high levels of fatigue and poor vision for technicians, and leads to a slow PCB assembly process for SMT parts. Kwa hivyo uwezekano wa kosa ni mkubwa.

Teknolojia inapokomaa, roboti za kiotomatiki ambazo huchukua na kuweka vifaa hupunguza mzigo wa kazi wa mafundi, kuwezesha uwekaji wa sehemu ya haraka na sahihi. Roboti hizi zinaweza kufanya kazi 24/7 bila uchovu.

Hatua ya 3: Kulehemu Reflow

The third step after setting up the elements and applying the solder paste is reflux welding. Reflow welding is the process of placing the PCB on a conveyor belt with components. The conveyor then moves the PCB and components into a large oven, which produces a temperature of 250 o C. Joto linatosha kuyeyusha solder. Solder iliyoyeyuka kisha inashikilia sehemu hiyo kwa PCB na kuunda pamoja. After high temperature treatment, the PCB enters the cooler. These coolers then solidify the solder joints in a controlled manner. Hii itaanzisha uhusiano wa kudumu kati ya sehemu ya SMT na PCB. Katika kesi ya PCB yenye pande mbili, kama ilivyoelezewa hapo juu, upande wa PCB na vifaa vichache au vidogo vitatibiwa kwanza kutoka hatua ya 1 hadi 3, na kisha kwa upande mwingine.

Understand PCB board assembly process and feel the green charm of PCBD

Hatua ya 4: Ukaguzi wa ubora na ukaguzi

Baada ya kutengenezea tena, inawezekana kwamba vifaa vimepangwa vibaya kwa sababu ya harakati isiyo sahihi kwenye tray ya PCB, ambayo inaweza kusababisha unganisho mfupi wa mzunguko au wazi. These defects need to be identified, and this identification process is called inspection. Ukaguzi unaweza kuwa mwongozo na otomatiki.

A. Manual check:

Because the PCB has small SMT components, visual inspection of the board for any misalignment or malfunction can cause technician fatigue and eye strain. Kwa hivyo, njia hii haiwezekani kwa bodi za mapema za SMT kwa sababu ya matokeo yasiyo sahihi. Walakini, njia hii inawezekana kwa sahani zilizo na vifaa vya THT na msongamano wa sehemu ya chini.

B. Kugundua macho:

Njia hii inawezekana kwa idadi kubwa ya PCBS. Njia hiyo hutumia mashine za kiatomati zenye nguvu kubwa na kamera za azimio kubwa zilizowekwa kwa pembe anuwai ili kuona viungo vya solder kutoka pande zote. Kulingana na ubora wa pamoja ya solder, taa itaangazia pamoja ya solder kwa pembe tofauti. This automatic optical inspection (AOI) machine is very fast and can process large quantities of PCBS in a very short time.

CX – ray inspection:

The X-ray machine allows technicians to scan the PCB to see internal defects. This is not a common inspection method and is only used for complex and advanced PCBS. If not used properly, these inspection methods may result in rework or PCB obsoletion. Ukaguzi unahitaji kufanywa mara kwa mara ili kuzuia ucheleweshaji, gharama za wafanyikazi na vifaa.

Hatua ya 5: urekebishaji wa sehemu ya THT na kulehemu

Vipengele vya kupitia-shimo ni kawaida kwenye bodi nyingi za PCB. These components are also called plated through holes (PTH). Miongozo ya vifaa hivi itapita kwenye mashimo kwenye PCB. Mashimo haya yameunganishwa na mashimo mengine na kupitia mashimo na athari za shaba. Wakati vitu hivi vya THT vikiingizwa na kuunganishwa kwenye mashimo haya, zinaunganishwa kwa umeme na mashimo mengine kwenye PCB sawa na mzunguko iliyoundwa. These PCBS may contain some THT components and many SMD components, so the welding method described above is not suitable for THT components in the case of SMT components such as reflow welding. Kwa hivyo aina kuu mbili za vipengee vya THT ambavyo vimeunganishwa au kukusanyika ni

A. Ulehemu wa mwongozo:

Manual welding methods are common and often require more time than an automated setup for SMT. Fundi kawaida hupewa kuingiza sehemu moja kwa wakati na kupitisha bodi kwa mafundi wengine wanaoingiza sehemu nyingine kwenye bodi hiyo hiyo. Kwa hivyo, bodi ya mzunguko itahamishwa karibu na laini ya kusanyiko ili kupata sehemu ya PTH ili kuijaza. Hii inafanya mchakato kuwa mrefu, na kampuni nyingi za kubuni na PCB huepuka kutumia vifaa vya PTH katika miundo yao ya mzunguko. Lakini sehemu ya PTH inabaki kuwa sehemu inayopendwa na inayotumiwa zaidi na wabunifu wengi wa mzunguko.

B. Kuunganisha wimbi:

Toleo la kiotomatiki la kulehemu mwongozo ni kulehemu kwa wimbi. Kwa njia hii, mara tu kipengele cha PTH kinapowekwa kwenye PCB, PCB imewekwa kwenye ukanda wa kusafirisha na kuhamishiwa kwenye oveni iliyowekwa wakfu. Hapa, mawimbi ya solder iliyoyeyuka hunyunyiza ndani ya substrate ya PCB ambapo sehemu inayoongoza iko. Hii itaunganisha pini zote mara moja. However, this method only works with single-sided PCBS and not double-sided PCBS, as melted solder on one side of the PCB can damage components on the other. Baada ya hii, songa PCB kwa ukaguzi wa mwisho.

Hatua ya 6: Ukaguzi wa mwisho na upimaji wa kazi

PCB sasa iko tayari kwa majaribio na ukaguzi. This is a functional test in which electrical signals and power are given to the PCB at the specified pins and the output is checked at the specified test point or output connector. This test requires common laboratory instruments such as oscilloscopes, digital multimeters, and function generators

Jaribio hili hutumiwa kuangalia sifa za utendaji na umeme wa PCB na kuhalalisha ishara ya sasa, voltage, analog na dijiti na miundo ya mzunguko iliyoelezewa katika mahitaji ya PCB

Ikiwa vigezo vyovyote vya PCB vinaonyesha matokeo yasiyokubalika, PCB hiyo itatupwa au kufutwa kulingana na taratibu za kawaida za kampuni. Awamu ya upimaji ni muhimu kwa sababu huamua kufanikiwa au kutofaulu kwa mchakato mzima wa PCBA.

Hatua ya 7: Kusafisha mwisho, kumaliza na kusafirisha:

Now that the PCB has been tested in all aspects and declared normal, it is time to clean up unwanted residual flux, finger grime and oil. Chuma cha pua kulingana na vifaa vya kusafisha shinikizo kwa kutumia maji yaliyotengwa hutosha kusafisha kila aina ya uchafu. Maji yaliyotengwa hayaharibu mzunguko wa PCB. Baada ya kuosha, kavu PCB na hewa iliyoshinikwa. PCB ya mwisho iko tayari kusafirishwa na kusafirishwa.