Die eerste stap van PCB produksie is om die PCB -uitleg te organiseer en na te gaan. Die PCB -vervaardigingsaanleg ontvang die CAD -lêers van die PCB -ontwerponderneming. Aangesien elke CAD-sagteware sy eie unieke lêerformaat het, kan die PCB-aanleg dit omskakel in ‘n verenigde formaat-Uitgebreide Gerber RS-274X of Gerber X2. Then the engineer of the factory will check whether the PCB layout conforms to the production process, whether there are any defects and other problems.

In een van die tuisgemaakte PCBS word die PCB-uitleg met ‘n laserprinter op papier gedruk en dan na ‘n koperbeklede bord oorgeplaas. Omdat die drukker egter geneig is tot ‘n breekpunt vir inktekort, moet u die ink handmatig met ‘n oliepen vul.

‘N Klein hoeveelheid produksie is goed, maar as hierdie gebrek na industriële produksie oorgedra word, sal dit die produksiedoeltreffendheid aansienlik verminder. Therefore, the factory generally adopts the way of photocopying, printing the PCB layout on the film. If it is a multi-layer PCB, the layout of each layer will be arranged in order.

The film is then punched with counterpoint holes. Counterpoint holes are very important, and are then used to align materials on each layer of the PCB.

Kernbord produksie

Clean the copper clad plate, if dust may cause the final circuit short circuit or break.

The figure below is an illustration of an 8-layer PCB, which is actually made up of 3 copper-clad plates (core boards) plus 2 copper films and then glued together with semi-cured sheets. The production sequence starts from the core board (four or five layers of lines) in the middle, and is continuously stacked together before being fixed. Die 4-laags PCB word op dieselfde manier gemaak, maar met slegs een kernplaat en twee koperfilms.

Transfer of inner PCB layout

Therefore, the two-layer circuit of the most central Core plate should be made first. After the copper-clad plate is cleaned, the surface is covered with a photosensitive film. Die film stol wanneer dit aan lig blootgestel word en vorm ‘n beskermende film oor die koperfoelie van die koperbeklede plaat.

Insert two layers of PCB layout film and two layers of copper clad board, and finally insert the upper layer of PCB layout film to ensure that the upper and lower layers of PCB layout film stacking position is accurate.

Photosensitizer gebruik ‘n UV -lamp om die fotosensitiewe film op koperfoelie te bestraal. Die fotosensitiewe film word gestol onder die deursigtige film, en die fotosensitiewe film word nie gestol onder die ondeursigtige film nie. The copper foil covered by solidified photosensitive film is the PCB layout line needed, equivalent to the role of laser printer ink of manual PCB. In die papier -PCB -uitleg van die vorige laserdrukker was die swart toner bedek met koperfoelie om te behou. In this case, the copper foil covered with black film will corrode away, while the transparent film will be preserved as the photosensitive film solidifies.

Die ongeharde film word dan met loog afgespoel en die benodigde koperfoelie -kring word bedek deur die verharde film.

Inner core board etching

The unwanted copper foil is then etched away with a strong base, such as NaOH.

Tear off the cured photosensitive film to expose the copper foil needed for PCB layout circuit.

Kernplaatboor en inspeksie

Die kernplaat is suksesvol gemaak. Then make the opposite hole in the core plate for easy alignment with other raw materials.

Sodra die kernbord met ander lae PCB gedruk is, kan dit nie verander word nie, daarom is dit baie belangrik om dit na te gaan. Die masjien sal outomaties vergelyk word met PCB -uitlegtekeninge om foute na te gaan.

Die eerste twee lae PCB -borde is gemaak

gelamineerde

Hier het ons ‘n nuwe grondstof nodig, genaamd semi-cured sheet (Prepreg), wat die kernbord en kernbord is (PCB-laaggetal & GT; 4), en die kleefmiddel tussen die kernplaat en die buitenste koperfoelie, maar speel ook ‘n rol in isolasie.

The lower layer of copper foil and two layers of semi-solidified sheet have been in advance through the positioning hole and the lower iron plate fixed position, and then the good core plate is also put into the positioning hole, and finally in turn two layers of semi-solidified sheet, a layer of copper foil and a layer of pressure aluminum plate covered on the core plate.

In order to improve work efficiency, the factory will stack three different PCB boards together and then fix them. The upper iron plate is magnetically attracted to facilitate counterpoint with the lower iron plate. Through the placement of the counterpoint needle, the two layers of iron plate counterpoint successfully, the machine as far as possible to compress the space between the iron plate, and then fixed with nails.

PCB board clamped by iron plate is placed on the support, and then into the vacuum hot press for lamination. The heat in the vacuum hot press melts the epoxy resin in the semi-cured sheet, holding the core and copper foil together under pressure.

After laminating, remove the top iron plate that presses the PCB. Daarna word die aluminiumplaat onder druk verwyder. Die aluminiumplaat speel ook ‘n rol om verskillende PCBS te isoleer en die gladde koperfoelie op die buitenste laag van DIE PCB te verseker. Both sides of the PCB are covered with a layer of smooth copper foil.

boor

Hoe koppel jy die vier nie-aanraak lae koperfoelie in ‘n PCB? Die PCB word eers deur gate geboor en dan gemetalliseer om elektrisiteit te gelei.

Die röntgenboormasjien word gebruik om die kernbord van die binneste laag op te spoor. Die masjien sal die gatposisie op die kernbord outomaties vind en opspoor en dan posisioneringsgate vir die printplaat maak om te verseker dat die volgende boorwerk deur die middel van die gatposisie is.

Place a sheet of aluminum on the punch machine and then place the PCB on top. Aangesien boorwerk ‘n relatief stadige proses is, word 1 tot 3 identiese PCB -borde, om die doeltreffendheid te verbeter, saamgestapel vir perforasie volgens die aantal PCB -lae. Laastens is die boonste PCB bedek met ‘n laag aluminium, die boonste en onderste lae aluminium, sodat die koperfoelie op die PCB nie skeur as die boor in en uitboor nie.

The operator then only needs to select the correct drilling procedure and the drilling machine does the rest automatically. Die boorpunt word aangedryf deur lugdruk, met ‘n maksimum rotasie van 150,000 XNUMX omwentelinge per minuut, wat hoog genoeg is om ‘n gladde gatwand te verseker.

Die vervanging van die boor word ook outomaties deur die masjien volgens die program gedoen. The smallest drill can be 100 microns in diameter, while a human hair is 150 microns in diameter.

In die vorige lamineringsproses is die gesmelte epoksie aan die buitekant van die PCB geëxtrudeer, sodat dit verwyder moes word. Die freesmasjien sny die omtrek van die PCB volgens die korrekte XY -koördinate.

Chemiese neerslag van koper op poriewand

Since almost all PCB designs use perforations to connect different layers of lines, a good connection requires a 25 micron copper film on the hole wall. This thickness of copper film is achieved by electroplating, but the hole wall is made of non-conductive epoxy resin and fiberglass board. Daarom is die eerste stap om ‘n laag geleidende materiaal op die gatwand op te bou en ‘n koperfilm van 1 mikron op die hele PCB-oppervlak, insluitend die gatwand, te vorm deur middel van chemiese afsetting. Die hele proses, soos chemiese behandeling en skoonmaak, word deur masjiene beheer.

Vaste PCB

Maak die PCB skoon

Delivery of PCB

Chemical precipitation of copper film

Transfer the layout of the outer PCB

Next, the layout of the outer PCB will be transferred to the copper foil. The process is similar to that of the PCB layout of the inner core board, which is transferred to the copper foil using photocopied film and photosensitive film. The only difference is that the positive plate will be used as the board.

The transfer of inner PCB layout introduced above adopts the subtraction method and adopts the negative plate as the board. PCB covered by solidified photosensitive film is circuit, clean the unsolidified photosensitive film, exposed copper foil is etched, PCB layout circuit is protected by solidified photosensitive film. The outer PCB layout is transferred by the normal method, and the positive plate is used as the board. The area covered by a cured film on a PCB is a non – line area. After cleaning the uncured film, electroplating is carried out. Daar is geen film wat galvaniseer kan word nie, en daar is geen film nie, eers koper en dan tinplaat. Nadat die film verwyder is, word alkaliese ets uitgevoer en uiteindelik word tin verwyder. The circuit pattern is left on the board because it is protected by tin.

Clean both sides of the copper foil PCB into the press, the press will be sensitive to the copper foil mold pressing.

Maak die PCB -uitlegfilm van die boonste en onderste lae fotostaat deur die posisioneringsgat vas en plaas die printplaat in die middel. The photosensitive film under the transmittance film is then solidified by UV lamp irradiation, which is the line that needs to be preserved.

After cleaning the film that is not needed and has not been cured, inspect it.

Clamp the PCB and electroplate the copper. As mentioned before, in order to ensure that the hole has good electrical conductivity, the copper film electroplated on the hole wall must have a thickness of 25 microns, so the whole system will be automatically controlled by computer to ensure its accuracy.

Vaste PCB

Computer control and electroplating copper

After the copper film is electroplated, the computer arranges for a thin layer of tin to be replated.

Nadat u die uitgedrukte PCB -bord afgelaai het, moet u seker maak dat die dikte van koper en tinplaat korrek is.

Buiten PCB ets

Vervolgens voltooi ‘n volledige outomatiese monteerlyn die etsproses. Maak eers die verharde film op die printplaat skoon.

‘N Sterk alkali word dan gebruik om ongewenste koperfoelie wat daardeur bedek is, skoon te maak.

Dan word die blikkie op die koperfoelie van die PCB -uitleg verwyder met ‘n tinstroopoplossing. After cleaning, 4 layers PCB layout is completed.