The first step of PCB tlhahiso ke ho hlophisa le ho hlahloba Sebopeho sa PCB. Semela sa maiketsetso sa PCB se amohela lifaele tsa CAD ho tsoa k’hamphaning ea moralo oa PCB. Kaha software e ‘ngoe le e’ ngoe ea CAD e na le fomate ea eona e ikhethang, semela sa PCB se li fetolela molemong o kopaneng – Gerber RS-274X kapa Gerber X2 e atolositsoeng. 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.

Ho e ‘ngoe ea li-PCBS tse entsoeng hae, moralo oa PCB o hatisoa pampiring ho sebelisoa printa ea laser ebe o fetisetsoa leboteng le apereng koporo. Leha ho le joalo, nakong ea khatiso, hobane mohatisi o tloaetse ho haelloa ke enke, ho hlokahala hore o tlatse enke ka pene ea oli.

Tlhahiso e nyane e nepahetse, empa haeba sekoli sena se fetisetsoa tlhahisong ea liindasteri, e tla fokotsa ts’ebetso ea tlhahiso haholo. 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.

Tlhahiso ea boto ea mantlha

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. 4-layer PCB e entsoe ka mokhoa o ts’oanang, empa e na le poleiti e le ‘ngoe feela ea mantlha le lifilimi tse peli tsa koporo.

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. Filimi eo ea tiea ha e pepesetsoa khanya, ebe e etsa filimi e sireletsang holim’a sekoaelo sa koporo sa poleiti e koahetsoeng ka koporo.

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 uses UV lamp to irradiate the photosensitive film on copper foil. The photosensitive film is solidified under the transparent film, and the photosensitive film is not solidified under the opaque film. 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. Ka moralo oa pampiri ea PCB ea printa ea laser e fetileng, toner e ntšo e ne e koahetsoe ka foil ea koporo e lokelang ho bolokoa. 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.

Filimi e sa sebetsoang e hlatsuoa ka lye ‘me potoloho e hlokahalang ea koporo e koahetsoe ke filimi e phekotsoeng.

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.

Core poleiti cheka le tlhahlobo

Poleiti ea mantlha e entsoe ka katleho. Then make the opposite hole in the core plate for easy alignment with other raw materials.

Once the core board is pressed with other layers of PCB, it cannot be modified, so it is very important to check. Mochini o tla ipapisa le litšoantšo tsa moralo oa PCB ho lekola liphoso.

Likarolo tse peli tsa pele tsa liboto tsa PCB li entsoe

hlotsoe

Mona re hloka thepa e ncha e tala e bitsoang semi-cured sheet (Prepreg), e leng board ea mantlha le board ea mantlha (PCB layer number & GT; 4), le sekgomaretsi lipakeng tsa poleiti ea mantlha le foil e ka ntle ea koporo, empa hape e bapala karolo ea ho kenya letsoho.

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. Ka ho beoa ha nale ea counterpoint, likarolo tse peli tsa counterpoint ea tšepe ea tšepe li atlehile, mochini kamoo ho ka khonehang ho hatella sebaka pakeng tsa poleiti ea tšepe, ebe e ts’oaroa ka lipekere.

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. Ebe poleiti ea aluminium e nang le khatello e tlosoa. Letlapa la aluminium le lona le bapala karolo ea ho arola li-PCBS tse fapaneng le ho netefatsa hore foil ea koporo e boreleli karolong e kantle ea PCB. Mahlakore ka bobeli a PCB a koahetsoe ka mokato oa foil e boreleli ea koporo.

cheka

U hokahanya joang likarolo tse ‘ne tseo e seng tse amang maikutlo tsa foil ea koporo hammoho ka PCB? PCB e qala ho phunyeletsoa ka masoba, ebe e sebelisoa ka tšepe ho tsamaisa motlakase.

Mochini oa ho cheka oa X-ray o sebelisetsoa ho fumana boto ea mantlha ea lera le kahare. Mochini o tla ka tsela e iketsang fumana le fumana boemo lesoba ka boto konokono, ‘me joale etsa boemo masoba bakeng sa PCB ho etsa bonnete ba hore cheka latelang ke ka bohareng ba boemo ba lesoba.

Place a sheet of aluminum on the punch machine and then place the PCB on top. Ka cheka ke tshebetso batlang e lieha, e le hore ho ntlafatsa bokgoni, 1 ho 3 tšoanang mapolanka PCB tla stacked hammoho bakeng sa perforation ho ea ka palo ea le dikarolo PCB. Qetellong, PCB e kaholimo e koahetsoe ka lera la aluminium, likarolo tse kaholimo le tse tlase tsa aluminium e le hore ha ho cheka ho cheka le ho tsoa, ​​koporo ea koporo ho PCB e ke ke ea taboha.

The operator then only needs to select the correct drilling procedure and the drilling machine does the rest automatically. Sesebelisoa sa ho cheka se tsamaisoa ke khatello ea moea, ka ho potoloha ho hoholo ha 150,000 ka motsotso, e phahameng ho lekana ho netefatsa lebota le boreleli la lesoba.

Phetolo ea bo-tirila bo boetse bo etsoa ka boiketsetso ke mochini ho latela lenaneo. The smallest drill can be 100 microns in diameter, while a human hair is 150 microns in diameter.

Ts’ebetsong e fetileng ea ho lata, epoxy e qhibilihisitsoeng e ile ea fetisetsoa kantle ho PCB, ka hona e ne e hloka ho tlosoa. Mochini o shoang o sila o potoloha PCB ho latela likhokahano tsa XY tse nepahetseng.

Pula ea lik’hemik’hale ea koporo leboteng la pore

Kaha hoo e ka bang meralo eohle ea PCB e sebelisa li-perforations ho hokela likarolo tse fapaneng tsa mela, khokahano e ntle e hloka filimi ea koporo ea micron ea 25 leboteng la lesoba. This thickness of copper film is achieved by electroplating, but the hole wall is made of non-conductive epoxy resin and fiberglass board. Ka hona, mohato oa pele ke ho bokella lera la lintho tse tsamaeang leboteng la lesoba, ebe o theha filimi ea koporo ea 1-micron holim’a PCB eohle, ho kenyeletsoa le lebota la lesoba, ka ho kenya lik’hemik’hale. Ts’ebetso eohle, joalo ka kalafo ea lik’hemik’hale le ho hloekisa, e laoloa ke mechini.

Tsepamisitsoeng PCB

Hloekisa PCB

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. Ha ho na filimi e ka khethiloeng ka motlakase, ‘me ha ho na filimi, ea pele ke koporo ebe e manehiloe ka thini. Ka mor’a hore filimi e tlosoe, ho etsoa mankhane a alkaline, ‘me qetellong ho tlosoa thini. The circuit pattern is left on the board because it is protected by tin.

Hloekisa mahlakore ka bobeli a PCB ea koporo ho tobetsa, mochini oa khatiso o tla tsotella khatello ea koporo ea koporo.

Lokisa filimi ea sebopeho sa PCB ea likhahla tse holimo le tse tlase tsa fotokopi ka lesoba la ho beha, ebe o beha boto ea PCB bohareng. 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.

Tsepamisitsoeng PCB

Taolo ea likhomphutha le koporo ea motlakase

Ka mor’a hore filimi ea koporo e khethoe ka motlakase, k’homphieutha e hlophisa hore ho be le sebaka se tšesaane sa thini.

Kamora ho laolla thini e tlotsitsoeng ka PCB, hlahloba ho netefatsa hore botenya ba koporo le thini bo nepahetse.

Outer PCB mananose

E latelang, mohala o felletseng oa kopano o phethela tšebetso ea mananose. Taba ea mantlha, hloekisa filimi e folisitsoeng ka board ea PCB.

Joale alkali e matla e sebelisoa ho hloekisa foil ea koporo e sa batleheng e koahetsoeng ke eona.

Ebe seaparo sa thini se sethaleng sa koporo sa sebopeho sa PCB se tlosoa ka tharollo ea thini. After cleaning, 4 layers PCB layout is completed.