F’termini ta ‘teknoloġija moderna, id-dinja qed tikber b’rata mgħaġġla ħafna, u l-influwenza tagħha tista’ tidħol faċilment fil-ħajja tagħna ta ‘kuljum. 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. Il-qalba ta ‘dawn l-apparati hija l-inġinerija elettrika, u l-qalba hija b’ċirkwit stampat (PCB).

PCB huwa ġeneralment aħdar u huwa korp riġidu b’diversi komponenti elettroniċi fuqu. These components are welded to the PCB in a process called “PCB assembly” or PCBA. Il-PCB jikkonsisti minn sottostrat magħmul minn fibra tal-ħġieġ, saffi tar-ram li jiffurmaw it-traċċa, toqob li jiffurmaw il-komponent, u saffi li jistgħu jkunu interni u esterni. F’RayPCB, nistgħu nipprovdu sa 1-36 saffi għal PROTOTIPI b’ħafna saffi u 1-10 saffi għal lottijiet multipli ta ‘PCB għall-produzzjoni tal-volum. 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. Il-maskra tal-iwweldjar tippermetti lill-komponent jevita short-circuiting mal-korsa jew komponenti oħra.

Traċċi tar-ram jintużaw biex jittrasferixxu sinjali elettroniċi minn punt għal ieħor fuq PCB. These signals can be high-speed digital signals or discrete analog signals. Dawn il-wajers jistgħu jsiru ħoxnin sabiex jipprovdu enerġija / enerġija għall-provvista tal-enerġija tal-komponent.

In most PCBS that provide high voltage or current, there is a separate grounding plane. Components on the top layer are connected to the internal GND plane or internal signal layer via “Vias”.

Components are assembled on the PCB to enable the PCB to operate as designed. The most important thing is PCB function. Anke jekk ir-reżisturi ċkejkna ta ‘l-SMT mhumiex imqiegħda b’mod korrett, jew anke jekk binarji żgħar jinqatgħu mill-PCB, il-PCB jista’ ma jaħdimx. Għalhekk, huwa importanti li tgħaqqad il-komponenti b’mod xieraq. Il-PCB meta tgħaqqad il-komponenti tissejjaħ PCBA jew PCB tal-assemblaġġ.

Skond l-ispeċifikazzjonijiet deskritti mill-klijent jew mill-utent, il-funzjoni tal-PCB tista ‘tkun kumplessa jew sempliċi. PCB size also varies according to requirements.

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

Saff u disinn tal-PCB

Kif imsemmi hawn fuq, hemm saffi ta ‘sinjali multipli bejn is-saffi ta’ barra. Now we will discuss the types of outer layers and functions.

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

1 – Substrat: Din hija pjanċa riġida magħmula minn materjal FR-4 li fuqu l-komponenti huma “mimlija” jew iwweldjati. This provides rigidity for the 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- Maskra tal-iwweldjar: Hija applikata għas-saffi ta ‘fuq u ta’ isfel tal-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. Il-maskra tal-iwweldjar tevita wkoll l-iwweldjar ta ’partijiet mhux mixtieqa u tiżgura li l-istann jidħol fiż-żona għall-iwweldjar, bħal toqob u pads. 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. Is-saff tal-iskrin jipprovdi informazzjoni importanti dwar il-PCB.

There are 3 types of PCBS according to the substrate classification

1- Rigid PCB:

Il-PCBs huma ħafna mill-apparati tal-PCB li naraw f’diversi tipi ta ‘PCBs. Dawn huma PCBS iebsin, riġidi u b’saħħithom, bi ħxuna differenti. The main material is fiberglass or simple “FR4”. FR4 tfisser “flame retarder-4”. Il-karatteristiċi li jitfu lilhom infushom tal-FR-4 jagħmluha utli għall-użu ta ‘ħafna apparati elettroniċi industrijali hard-core. The FR-4 has thin layers of copper foil on both sides, also known as copper-clad laminates. Laminati miksijin bir-ram Fr-4 jintużaw prinċipalment f’amplifikaturi tal-enerġija, provvisti tal-enerġija tal-modalità tal-iswiċċjar, sewwieqa tal-muturi servo, eċċ. Min-naħa l-oħra, sottostrat riġidu ieħor tal-PCB użat komunement f’apparat tad-dar u prodotti tal-IT jissejjaħ PCB fenoliku tal-karta. Huma ħfief, ta ‘densità baxxa, irħas u faċli biex tittaqqab. Kalkulaturi, tastieri u ġrieden huma wħud mill-applikazzjonijiet tagħha.

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.Dawn it-tipi ta ‘PCBS jistgħu jintużaw għal applikazzjonijiet li jeħtieġu komponenti termali bħal leds ta’ qawwa għolja, dijodi tal-lejżer, eċċ.

Installation technology type:

SMT: SMT tfisser “teknoloġija tal-immuntar fuq il-wiċċ”. Il-komponenti SMT huma żgħar ħafna fid-daqs u jiġu f’diversi pakketti bħal 0402,0603 1608 għar-resistors u l-capacitors. Bl-istess mod, għal ICS taċ-ċirkwit integrat, għandna SOIC, TSSOP, QFP u BGA.

L-assemblaġġ SMT huwa diffiċli ħafna għall-idejn tal-bniedem u jista ‘jkun proċess ta’ proċessar tal-ħin, u għalhekk isir primarjament minn robots awtomatiċi ta ‘ġbir u tqegħid.

THT: THT tirrappreżenta teknoloġija minn toqba. 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.

Il-prerekwiżiti tal-proċess tal-assemblaġġ:

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. Il-manifatturi għandhom iwettqu dawn il-passi bażiċi tad-DFM biex jiżguraw PCB bla difetti.

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. Id-direzzjoni tal-IC talja / ras għandha tiġi kkontrollata.

L-element li jeħtieġ is-sink tas-sħana għandu jkollu biżżejjed spazju biex jakkomoda elementi oħra sabiex is-heat sink ma tmissx.

2-Hole and through-hole spacing:

The spacing between holes and between holes and traces should be checked. Il-kuxxinett u t-toqba li tgħaddi m’għandhomx jikkoinċidu.

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. F’RayPCB, nużaw tagħmir OEM l-aktar avvanzat biex nipprovdu servizzi OEM tal-PCB, issaldjar tal-mewġ, ittestjar tal-kard tal-PCB u assemblaġġ SMT.

Assemblea tal-PCB (PCBA) proċess pass pass:

Pass 1: Applika pejst tal-istann billi tuża mudell

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. Il-mudell u l-PCB jinżammu flimkien minn apparat mekkaniku, u l-pejst tal-istann jiġi applikat b’mod uniformi għall-fetħiet kollha fil-bord permezz ta ‘applikatur. Apply solder paste evenly with applicator. Għalhekk, pejst tal-istann xieraq għandu jintuża fl-applikatur. Meta jitneħħa l-applikatur, il-pejst jibqa ‘fiż-żona mixtieqa tal-PCB. Pejst tal-istann griż 96.5% magħmul minn landa, li fih 3% fidda u 0.5% ram, mingħajr ċomb. After heating in Step 3, the solder paste will melt and form a strong bond.

Step 2: Automatic placement of components:

It-tieni pass tal-PCBA huwa li awtomatikament ipoġġi l-komponenti SMT fuq il-PCB. Dan isir billi tuża robot pick and place. Fil-livell tad-disinn, id-disinjatur joħloq fajl u jipprovdih lir-robot awtomatizzat. Dan il-fajl għandu l-koordinati X, Y programmati minn qabel ta ‘kull komponent użat fil-PCB u jidentifika l-post tal-komponenti kollha. 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.

Qabel il-miġja ta ‘magni tal-ġbir u tqegħid robotiċi, it-tekniċi kienu jtellgħu komponenti billi jużaw pinzetta u jpoġġuhom fuq il-PCB billi jħarsu bir-reqqa lejn il-post u jevitaw kull idejn li jċekċek. This results in high levels of fatigue and poor vision for technicians, and leads to a slow PCB assembly process for SMT parts. Allura l-potenzjal għall-iżball huwa għoli.

Hekk kif it-teknoloġija timmatura, robots awtomatizzati li jtellgħu u jpoġġu komponenti jnaqqsu l-ammont ta ‘xogħol tat-tekniċi, u jippermettu tqegħid veloċi u preċiż tal-komponenti. Dawn ir-robots jistgħu jaħdmu 24/7 mingħajr għeja.

Pass 3: Iwweldja mill-ġdid

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. It-temperatura hija biżżejjed biex idub l-istann. L-istann imdewweb imbagħad iżomm il-komponent mal-PCB u jifforma l-ġonta. After high temperature treatment, the PCB enters the cooler. These coolers then solidify the solder joints in a controlled manner. Dan jistabbilixxi konnessjoni permanenti bejn il-komponent SMT u l-PCB. Fil-każ ta ‘PCB b’żewġ naħat, kif deskritt hawn fuq, in-naħa tal-PCB b’inqas komponenti jew iżgħar tiġi ttrattata l-ewwel mill-passi 1 sa 3, u mbagħad għan-naħa l-oħra.

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

Step 4: Quality inspection and inspection

Wara l-issaldjar tar-reflow, huwa possibbli li l-komponenti jiġu allinjati ħażin minħabba xi moviment mhux korrett fit-trej tal-PCB, li jista ‘jirriżulta f’konnessjonijiet ta’ ċirkwit qasir jew miftuħ. These defects need to be identified, and this identification process is called inspection. L-ispezzjonijiet jistgħu jkunu manwali u awtomatizzati.

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. Għalhekk, dan il-metodu mhuwiex fattibbli għal bordijiet SMT bil-quddiem minħabba riżultati mhux eżatti. Madankollu, dan il-metodu huwa fattibbli għal pjanċi b’komponenti THT u densitajiet ta ‘komponenti aktar baxxi.

B. Sejbien ottiku:

Dan il-metodu huwa fattibbli għal kwantitajiet kbar ta ‘PCBS. Il-metodu juża magni awtomatiċi b’kameras ta ‘qawwa għolja u riżoluzzjoni għolja mmuntati f’diversi angoli biex jaraw il-ġonot tal-istann mid-direzzjonijiet kollha. Skond il-kwalità tal-ġonta tal-istann, id-dawl jirrifletti l-ġonta tal-istann f’angoli differenti. 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. Jeħtieġ li jsiru spezzjonijiet regolarment biex jiġi evitat dewmien, xogħol u spejjeż materjali.

Pass 5: L-iffissar u l-iwweldjar tal-komponent THT

Il-komponenti tat-toqob li jgħaddu huma komuni fuq bosta bordijiet tal-PCB. These components are also called plated through holes (PTH). Iċ-ċomb ta ‘dawn il-komponenti jgħaddu minn toqob fil-PCB. Dawn it-toqob huma konnessi ma ‘toqob oħra u minn toqob permezz ta’ traċċi tar-ram. Meta dawn l-elementi THT jiddaħħlu u jiġu wweldjati f’dawn it-toqob, huma konnessi elettrikament ma ‘toqob oħra fuq l-istess PCB bħaċ-ċirkwit iddisinjat. 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. So the two main types of THT components that are welded or assembled are

A. Manual welding:

Manual welding methods are common and often require more time than an automated setup for SMT. Tekniku huwa tipikament assenjat biex idaħħal komponent wieħed kull darba u jgħaddi l-bord lil tekniċi oħra li jdaħħlu komponent ieħor fuq l-istess bord. Therefore, the circuit board will be moved around the assembly line to get the PTH component to fill on it. This makes the process lengthy, and many PCB design and manufacturing companies avoid using PTH components in their circuit designs. But the PTH component remains the favorite and most commonly used component by most circuit designers.

B. Saldjar bil-mewġ:

Il-verżjoni awtomatizzata tal-iwweldjar manwali hija l-iwweldjar bil-mewġ. F’dan il-metodu, ladarba l-element PTH jitqiegħed fuq il-PCB, il-PCB jitqiegħed fuq conveyor belt u jitmexxa għal forn apposta. Hawnhekk, mewġiet ta ‘stann imdewweb jixbħu fis-sottostrat tal-PCB fejn il-komponenti ewlenin huma preżenti. Dan iwweldja l-labar kollha immedjatament. 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. Wara dan, iċċaqlaq il-PCB għall-ispezzjoni finali.

Pass 6: Spezzjoni finali u ttestjar funzjonali

Il-PCB issa huwa lest għall-ittestjar u l-ispezzjoni. 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

Dan it-test jintuża biex jiċċekkja l-karatteristiċi funzjonali u elettriċi tal-PCB u jivvalida d-disinji tal-kurrent, tal-vultaġġ, tas-sinjal analogu u diġitali u taċ-ċirkwit deskritti fir-rekwiżiti tal-PCB.

Jekk xi wieħed mill-parametri tal-PCB juru riżultati inaċċettabbli, il-PCB jintrema jew jiġi skrappjat skond il-proċeduri standard tal-kumpanija. Il-fażi tal-ittestjar hija importanti għaliex tiddetermina s-suċċess jew il-falliment tal-proċess PCBA kollu.

Pass 7: Tindif finali, irfinar u tbaħħir:

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. Għodda għat-tindif bi pressjoni għolja bbażata fuq l-istainless steel li jużaw ilma dejonizzat huma biżżejjed biex jitnaddfu kull tip ta ‘ħmieġ. L-ilma dejonizzat ma jagħmilx ħsara liċ-ċirkwit tal-PCB. Wara l-ħasil, nixxef il-PCB bl-arja kkompressata. Il-PCB finali issa huwa lest biex jiġi ppakkjat u mibgħut bil-baħar.