Lati awọn iyika afọwọkọ lori awọn lọọgan akara lati ṣe apẹrẹ tiwa tejede Circuit ọkọ (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. Apẹrẹ PCB ni a ṣe ni ilana imọ -ẹrọ itanna (EE). EE ṣẹda “ọpọlọ” ti bii awọn ẹrọ ṣe n ṣiṣẹ. Without electronics, you’re left with little more than a pile of metal and plastic.

Awọn nkan lati mọ ṣaaju bẹrẹ apẹrẹ PCB: 1. Iwọn PCB – eyi da lori iwọn ọja rẹ (tabi iwọn ọran). Awọn iwọn ọja jẹ asọye lakoko ilana apẹrẹ ẹrọ itanna. You can watch a video about it here. 2. Awọn fẹlẹfẹlẹ PCB – Awọn fẹlẹfẹlẹ diẹ sii, eka sii ti iṣelọpọ PCB. (Akiyesi: Paapaa PCB kan ṣoṣo le jẹ PCB eka kan, ṣugbọn nibi a n sọrọ nipa idiju ti ṣiṣe PCB kan. Awọn fẹlẹfẹlẹ diẹ sii ti PCB ni, diẹ sii gbowolori ni lati ṣe.)

Layer 2 jẹ igbagbogbo lo fun awọn ọja isere ti o rọrun

Awọn ọja ti o ni ibatan Iot nigbagbogbo ni awọn fẹlẹfẹlẹ 4

Typically used for floors 6 to 8 of a smartphone or smartwatch.

3. Awọn ibeere olupese PCB rẹ. Be sure to read the guidelines for rhythm, trace size, power isolation, and file naming before you start designing.

Alaye ti o nilo lati pese si awọn aṣelọpọ PCB:

Nọmba awọn fẹlẹfẹlẹ (fun apẹẹrẹ 2, 4, 6, bbl)

Awọn ohun elo (FR-2 (iwe owu phenolic), FR-3 (iwe owu ati iposii), FR-4 (okun gilasi ati epoxy… Etc.)

Sisanra (0.5 mm, 1.0 mm… Etc.)

Color (red, black, green… Etc.)

Itọju oju -ilẹ (ENIG (kemikali nickel/immersion goolu), DIG (immersion goolu taara), OSP (awọn ohun idena eleto, ati bẹbẹ lọ)

Iwọn iwuwo Ejò (1 iwon (35 microns), 2 oz (70 microns), 0.5 oz (18 microns)… Etc.)

Gerber faili

Ilana apẹrẹ PCB:

Apẹrẹ Circuit

For this step, you need to create the schematic. Eyi jẹ iwe -ipamọ, bii ilana -iṣe, ti o ṣe apejuwe bi awọn paati ṣe ni ibatan si ara wọn ati ṣiṣẹ papọ. Lati ṣẹda faili sikematiki, iwọ yoo nilo irinṣẹ sọfitiwia kan. A fẹ Quadcept nitori pe o jẹ iṣapeye fun apẹrẹ PCBS fun iṣelọpọ (fun apẹẹrẹ, o le okeere Bill of Material (BoM) taara lati ọpa) ati pe o da lori awọsanma, nitorinaa o le lo ni irọrun nibikibi. (Wọn tun funni ni ẹya agbegbe ọfẹ ti ọpa fun awọn aṣelọpọ ati awọn ọmọ ile -iwe.)

Ọpọlọpọ awọn aṣayan miiran wa ti o le yan lati:

Altium

ExpressPCB

Ẹrọ igbohunsafẹfẹ

KiCad

Cadence allegro

akete

Computer aided design

DipTrace

After you install the selected tools, you need to obtain the component specifications for each selected component. Nigbagbogbo wọn le rii lori oju opo wẹẹbu olupese. Faili awoṣe yoo ran ọ lọwọ lati fa aworan naa. Paati yii yoo wa ni ibi ipamọ data nigbati o ba gbe awoṣe si ọpa sọfitiwia. Lẹhinna, gbogbo ohun ti o ni lati ṣe ni tẹle iwe afọwọkọ data ki o so okun waya pọ si PIN kọọkan ninu paati naa. (Akiyesi: awọn alaye ti ilana apẹrẹ yoo dale lori irinṣẹ sọfitiwia ti o yan).

Each schematic symbol needs to have an associated PCB space area to define the physical dimensions of the component and the location of the through holes on the brazing pad or PCB. You should have selected the components (or are now selecting them), and we describe this process in the EE Design Process video (see video).

Apere apẹẹrẹ

A good schematic is really important, as it will be used as a reference document during debugging and is a good communication tool with other engineers. Ni afikun, olupese le ṣe idanwo ẹrọ nipasẹ awọn aaye idanwo lori iwe yii.

Ifilelẹ PCB + Faili Gerber

To design the PCB layout and create Gerber files, you can use the same software tools we mentioned in circuit design. Ko dabi igbero kan, ipilẹ PCB ṣe awọn paati gangan si awọn ipo deede lori PCB ati ṣafihan awọn orin ti o so paati kọọkan pọ laarin awọn fẹlẹfẹlẹ PCB. Gẹgẹbi a ti mẹnuba ni ibẹrẹ nkan yii, awọn fẹlẹfẹlẹ diẹ sii, eka sii ti iṣelọpọ nilo, ati idiyele ti o ga julọ.

Divide the PCB into logical parts based on functions (e.g. power supply, audio output, etc.). Lẹhinna, rii daju lati ṣajọ awọn paati ti apakan kọọkan sinu agbegbe kanna. Ni ọna yii, o le jẹ ki kaakiri idari kukuru ati dinku ariwo ati kikọlu.

Ni wiwo olumulo (UI) tun nilo lati wa ni lokan nigbati o ṣe apẹrẹ PCB kan. Awọn paati bii awọn ohun afikọti ohun, awọn asopọ, leds, ati bẹbẹ lọ nilo lati tunṣe lati ṣaṣeyọri iriri olumulo ti o dara julọ.

Ni kete ti a ṣe apẹrẹ akọkọ, faili Gerber ti ipilẹṣẹ. Olupese PCBA rẹ yoo lo faili yii. Ọpọlọpọ awọn ile -iṣẹ wa ti o pese awọn iṣẹ wọnyi, ati lati ile -ikawe iwé HWTrek a ṣeduro Kingbrother, NexPCB, ati HQPCB.

Awọn faili Gerber ayẹwo

Gbigbe awọn paati lori PCB jẹ pataki pupọ. Diẹ ninu awọn paati le dabaru pẹlu ara wọn ati fa ihuwasi airotẹlẹ. Fun apẹẹrẹ, ti o ba ni awọn modulu Bluetooth ati Wi-Fi mejeeji, wọn ni bandiwidi 2.4ghz kanna ati pe o le dabaru pẹlu ara wọn ti o ba gbe ni aṣiṣe.

PCB production

Nigbati o ba fi faili Gerber ranṣẹ si olupese PCB, wọn le tẹ atẹjade naa. Eyi yoo jẹ ipilẹ lati tun kọ ipilẹ fun fifi awọn paati kun si PCB ati iṣelọpọ PCBA (apejọ igbimọ igbimọ ti atẹjade).

Awọn PCBS ti a kojọpọ

PCBA (Assembly)

Ohun elo

Ni aaye yii ninu apẹrẹ EE rẹ, o yẹ ki o ti yan awọn paati. O le beere lọwọ olupese PCBA lati paṣẹ awọn paati ti o nilo fun ọ, tabi ṣe funrararẹ ti o ba yan olupese. Awọn nkan ti o nilo akiyesi:

Lead time: As these components come from different suppliers, keep the lead time in mind. Fun diẹ ninu awọn paati, o le gba to awọn ọsẹ 8-16.

Apoti: Paṣẹ awọn paati lati awọn kẹkẹ ti a mu laifọwọyi nipasẹ awọn ẹrọ SMT dipo gbigbe wọn lọkọọkan.

Opoiye aṣẹ ti o kere julọ: Ṣayẹwo opoiye aṣẹ ti o kere ju ti paati naa. Ti o ba ra kere ju ti o kere ju, rii daju pe awọn paati ti o yan wa ni iṣura. For small batches (up to 50), you can order online from DigiKey or Mouser. Fun awọn iwọn diẹ sii, jọwọ wa imọran lati ọdọ olupese rẹ.

Isonu: Bere fun 10% diẹ sii lati bo pipadanu (kii ṣe fun awọn paati gbowolori)

Fi awọn paati sori PCB

Awọn ọna akọkọ meji lo wa lati gbe awọn paati sori dada PCB kan:

Through-holes (through-holes) are manual methods of assembling assemblies with wires into holes on the surface of a PCB. O tun jẹ igbagbogbo mọ bi DIP tabi ilana iṣakojọpọ laini meji. (Wo SMT ti nlọ lọwọ ninu fidio yii)

SMT (imọ -ẹrọ oke -ilẹ) jẹ ọna ti a lo julọ ni iṣelọpọ ibi -pupọ. O ṣe nipasẹ iyara, awọn ẹrọ SMT deede ti o fi akoko pamọ, owo ati yago fun aṣiṣe eniyan.

Awọn nkan lati ranti:

Nọmba iru paati rẹ ko gbọdọ kọja nọmba awọn kẹkẹ ti ẹrọ SMT ti olupese le ṣe atilẹyin.

Ṣe igbesoke ati isọdọkan awọn paati rẹ ki SMT kan ṣoṣo ṣiṣẹ.

Ṣayẹwo awọn titobi paadi ifẹsẹtẹ atilẹyin. Bibẹẹkọ, ẹrọ SMT kii yoo fi awọn paati sori ẹrọ ni deede.

Diẹ ninu awọn paati ti o tobi ko le fi sii nipasẹ ẹrọ ati pe o tun nilo iṣẹ ọwọ nipasẹ iho. Nitorinaa, awọn imọ -ẹrọ mejeeji le ṣee lo lori igbimọ kanna.

Eyikeyi awọn paati ti o nilo lati ṣafikun pẹlu ọwọ nipasẹ ọna iho-iho fi kun si idiyele iṣelọpọ.

Reflow soldering

Reflow soldering jẹ ilana ti ṣiṣe awọn paati “duro” si PCB. PCBA ṣe igbona igbimọ Circuit nipasẹ ileru atẹgun tabi fitila infurarẹẹdi titi ti alataja yoo yo, nitorinaa o so paati naa si igbimọ Circuit titilai.

Apakan ti o nira julọ nibi kii ṣe lati gbona tabi ba awọn paati jẹ, nitori awọn abuda igbona ti package kọọkan yatọ. Olupese PCBA ti o gbẹkẹle yoo jẹ iduro fun ilana yii, ati gbogbo ohun ti o nilo lati ṣe ni pese wọn pẹlu awọn pato paati.

Ilana reflux.

Awọn ọna alurinmorin miiran:

Alurinmorin igbi jẹ lilo nipataki fun awọn paati ti a fikun pẹlu ọwọ nipasẹ ọna iho-nipasẹ. Ni ọran yii, PCBA rẹ yoo kọkọ lọ nipasẹ ileru alurinmorin reflow, ati lẹhinna ṣafikun awọn paati miiran pẹlu ọwọ lẹhin ti yoo lọ nipasẹ ẹrọ ṣiṣan igbi.

Alurinmorin irin le ṣee lo fun awọn ipo kan pato, ṣugbọn kii ṣe fun iṣelọpọ ibi.

Idanwo ati ayewo didara

Ni igbesẹ yii, awọn ayẹwo PCBA ni idanwo lati rii daju didara. Awọn aṣiṣe ti o wọpọ jẹ: awọn iyika kukuru ni awọn paati ti a ti ge asopọ, awọn paati ti ko tọ ati awọn apakan ti Circuit ti ko yẹ ki o sopọ. Awọn idanwo ti o wọpọ julọ:

ICT (Idanwo ori ayelujara). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. Ẹrọ ICT yoo lo awọn aaye idanwo wọnyi fun ṣiṣi/idanwo Circuit kukuru ati ṣayẹwo pe awọn iye ti awọn paati palolo (awọn alatako, awọn inductor, awọn kapasito) wa laarin sakani asọye.

AOI (Ayẹwo opopona alaifọwọyi). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Fun idanwo yii, Eleda ohun elo yoo nilo lati pese awọn pato ati awọn ifarada si olupese lati ṣeto awọn eto.

X -ray. Olupese PCBA yoo lo awọn eegun X lati ṣayẹwo awọn ipo alurinmorin ti awọn paati BGA (ball Grid Array). Wo idanwo X-ray ninu fidio yii.