Kia maarama ki te huringa huihuinga poari PCB ka rongo i te ataahua o te PCB

Mo te taha ki nga hangarau hou, kei te tere tere te tipu o te ao, ana ka kaha haere te awe o te ao i roto i o taatau ao. 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. Ko te matua o enei taputapu ko te hangarau hiko, ko te mea matua te papa poari panui (PCB).

I te nuinga o te wa he kaakaariki te PCB, he tinana maro hoki, he maha nga waahanga hiko kei runga. These components are welded to the PCB in a process called “PCB assembly” or PCBA. Ko te PCB kei roto ko te tihi i hangaia ki te karaahura, nga papa parahi e hanga ana i te takotoranga, nga kohao e hanga ana i te waahanga, me nga papa e taea ana i roto me waho. I te RayPCB, ka taea e taatau te toha atu ki te 1-36 paparanga mo nga tini-tini PROTOTYPES me nga paparanga 1-10 mo nga waahanga maha o PCB mo te mahi rōrahi. For single-sided and double-sided PCBS, an outer layer exists but no inner layer.

ipcb

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. Ma te kopare hono e aukati i te waahanga ki te karo i te ara-poto ki te riu, ki etahi atu waahanga ranei.

Ka whakamahia nga tohu parahi hei whakawhiti i nga tohu hiko mai i tetahi pito ki tetahi atu i runga i te PCB. These signals can be high-speed digital signals or discrete analog signals. Ka taea te hanga i enei waea kia matotoru kia taea ai te whakarato i te mana / kaha mo te waahanga hiko waahanga.

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. Ahakoa kaore i te tika te whakanoho i nga parenga SMT iti, ahakoa ka tapahia nga ara iti mai i te PCB, kaore pea e mahi te PCB. No reira, he mea nui kia whakaemi i nga waahanga kia tika. Ko te PCB ka whakaemi i nga waahanga ka kiia ko PCBA ko PCB huihuinga ranei.

Kei i nga whakaritenga kua whakaatuhia e te kaihoko, e te kaiwhakamahi ranei, he uaua he ngawari ranei te mahi a te PCB. PCB size also varies according to requirements.

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

Paparanga PCB me te hoahoa

Ka rite ki te korero i runga ake nei, he maha nga tohu tohu i waenga i nga papa o waho. Now we will discuss the types of outer layers and functions.

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

1 – Taapiri: He pereti maroke tenei i hangaia mai i nga taonga FR-4 e “kapi ana” nga waahanga ranei. 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- Masini paiherea: Ka tukuna ki nga papa o runga me raro o te 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. Ka karohia e te kopare tarai te tarai i nga waahanga kaore e hiahiatia ana, me te whakarite kia uru te solder ki te rohe hei whakapiri, penei i nga kohao me nga papa. 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. Ko te papa o te mata e whakaatu ana i nga korero nui mo te PCB.

There are 3 types of PCBS according to the substrate classification

1- Rigid PCB:

Ko nga PCB te nuinga o nga taputapu PCB e kitea ana e tatou i roto i nga momo PCB. He PCBS uaua, pakari, pakari hoki enei, he rereke te matotoru. The main material is fiberglass or simple “FR4”. Ko te FR4 te tikanga mo te “retarder mura-4”. Ko nga ahuatanga pirau o te FR-4 he mea whaihua mo te whakamahi i te nuinga o nga taputapu hiko-a-hiko. The FR-4 has thin layers of copper foil on both sides, also known as copper-clad laminates. Kei te whakamahia te nuinga o nga miihini whakakakahu parahi Fr-4 ki nga kaiwhakawhana hiko, ki nga taputapu hiko aratau whakawhiti, taraiwa motuka motuka, etc. Engari, ko tetahi atu papanga PCB maro e whakamahia ana i nga taputapu a te whare me nga hua IT e kiia ana ko te PCB phenolic pepa. He maama, he iti te kiato, he iti hoki, he ngawari hoki ki te pupuhi. Ko nga kaitaitai, papapihi me nga kiore etahi o ona whakamahinga.

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.Ko enei momo PCBS ka taea te whakamahi mo nga tono e hiahia ana i nga waahanga wera penei i nga hiko hiko teitei, diode laser, etc.

Installation technology type:

SMT: Ko te SMT e tohu ana mo te “hangarau maunga mata”. Ko nga waahanga SMT he iti rawa te rahi ka tae mai ki nga momo kohinga penei i te 0402,0603 1608 mo nga parenga me nga kaiwhakaara. Waihoki, mo nga ics iahiko whakauru, kei a maatau SOIC, TSSOP, QFP me BGA.

He uaua rawa te huihuinga SMT mo nga ringaringa o te tangata, ka mutu he waa tukatuka waatea, na reira ka mahia e nga tangohanga aunoa me nga miihini whakanoho.

THT: Ko te THT te mea hangarau-a-roto. 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.

Nga whakaritenga o te hui Assembly:

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. Me mahi e nga kaihanga enei huarahi DFM taketake kia kore ai e whai koha PCB.

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. IC kia tirohia te ahunga / pane hoki.

Ko te waahanga e hiahia ana ki te wera wera kia nui te waahi hei whakauru i etahi atu waahanga kia kore e pa te wera wera.

2-Hole and through-hole spacing:

The spacing between holes and between holes and traces should be checked. Papa me te puta i te poka kaua e inaki.

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. I te RayPCB, ka whakamahia e maatau nga taputapu OEM tino pai hei whakarato i nga ratonga PCB OEM, whakapiri ngaru, whakamatau i te kaari PCB me te huihuinga SMT.

Huihuinga PCB (PCBA) mahinga-i-te-taahiraa:

Hipanga 1: Tukuna he whakapiri wairewa ma te whakamahi i te tauira

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. Ko te tauira me te PCB e mau ngatahi ana i nga miihini, ana ka taurite te whakapiri rewa ki nga tuwhera katoa o te papa ma te kaitono. Apply solder paste evenly with applicator. Therefore, appropriate solder paste must be used in the applicator. Ka tangohia ana te kaitono, ka noho tonu te whakapiri ki te rohe e hiahiatia ana o te PCB. Ko te whakapiri huka kirika 96.5% he mea hanga ki te tine, kei roto te 3% hiriwa me te 0.5% parahi, kaore he arataki. After heating in Step 3, the solder paste will melt and form a strong bond.

Step 2: Automatic placement of components:

Ko te taahiraa tuarua o PCBA ko te tuu aunoa i nga waahanga SMT ki te PCB. Ka mahia tenei ma te whakamahi i te karetao tango me te waahi. I te taumata hoahoa, ka hangaia e te kaihoahoa he konae ka hoatu ki te robot aunoa. Kei tenei konae nga kohinga X, Y i whakamaheretia i mua o ia waahanga e whakamahia ana i te PCB me te tautuhi i te waahi o nga waahanga katoa. 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.

I mua i te taenga mai o te miihini robotic me nga miihini whakanoho, ka tikina e nga tohunga hangarau nga waahanga e whakamahi ana i nga tiiweti ka tuu ki runga i te PCB ma te tiro maataki ki te waahi ka karo i nga ringaringa ruru. This results in high levels of fatigue and poor vision for technicians, and leads to a slow PCB assembly process for SMT parts. Na ko te kaha ki te hapa he nui.

Ka rite ki te pakeke o te hangarau, ko nga miihini miihini miihini ka tango ka tuu i nga waahanga ka whakaiti i te taumahatanga o nga kaitoi, ka taea ai te whakanoho waahanga tere me te tika. Ka taea e enei robots te mahi 24/7 me te kore e ngenge.

Hipanga 3: Whakauru ano

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. Ko te paemahana e ranea ana hei rewa i te reima. Ko te rewa rewa ka mau ki te waahanga ki te PCB ka hanga i te hononga. After high temperature treatment, the PCB enters the cooler. These coolers then solidify the solder joints in a controlled manner. Ma tenei ka pumau he hononga pumau i waenga i te waahanga SMT me te PCB. Mo te PCB taha-takirua, pera me te korero i runga ake nei, ko te taha PCB me te iti ake o te waahanga iti ake ranei, ka whakamaimoa tuatahihia mai i nga waahanga 1 ki te 3, ka mutu ki tetahi atu taha.

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

Step 4: Quality inspection and inspection

Whai muri i te whakapiri miramira, akene ka kore e haangai nga waahanga na te mea he nekehanga he i roto i te paepae PCB, maana pea ka poto, ka tuwhera ranei nga hononga ara iahiko. These defects need to be identified, and this identification process is called inspection. Ka taea te tirotiro a-ringa me te mahi aunoa.

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. Na reira, kaore tenei tikanga e taea mo nga papa SMT o mua atu na te mea he he nga hua. Heoi, ka taea tenei tikanga mo nga pereti me nga waahanga THT me nga waahanga iti o raro.

B. Hiko tirohanga:

This method is feasible for large quantities of PCBS. Ka whakamahia e te tikanga nga miihini miihini me te kaha nui me nga kaamera taumira teitei e whakairihia ana i nga momo koki hei tiro i nga hononga whakapiri mai i nga taha katoa. Ma te kounga o te hononga whakarewa, ka marama te rama mai i te hononga whakarewa i nga waahanga rereke. 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. Me whakahaere nga tirotiro i nga wa katoa kia kore ai e roa, nga mahi me nga utu o te rawa.

Hipanga 5: THT waahanga whakatika me te maitai

Ko nga waahanga puta-poka he noa i runga i nga papa PCB maha. These components are also called plated through holes (PTH). Ko nga waahanga o enei waahanga ka haere ki roto i nga kohao o te PCB. Ko enei kohao e hono ana ki etahi atu koha, ka puta i nga kohao nga tohu parahi. Ka whakauruhia ana nga waahanga THT nei ka werohia ki roto i enei kohao, ka hono hiko ki etahi atu kohao kei runga i te PCB rite ki te ara iahiko i hangaia. 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. Ka tohua tetahi kaihangarau ki te whakauru i tetahi waahanga i ia wa ka tuku i te poari ki etahi atu tohunga whakauru i tetahi atu waahanga ki te papa kotahi. 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. Ngaru rewa:

Ko te waahanga aunoa mo te miihini a-ringa ko te ngaru ngaru. I roto i tenei tikanga, ka whakatakotoria te waahanga PTH ki runga i te PCB, ka whakanohoia te PCB ki runga i te whitiki kawe ka neke ki te oumu kua whakatapua. I konei, ka pakaru nga ngaru rewa rewa ki te tuapapa o te PCB kei reira nga waahanga o te waahanga. Ma tenei ka whitikia nga titi katoa i tenei wa tonu. 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. Whai muri i tenei, nekehia te PCB mo te tirohanga whakamutunga.

Hipanga 6: Tirohanga whakamutunga me te whakamatautau mahi

Kua rite inaianei a PCB mo te whakamatautau me te tirotiro. 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

Ka whakamahia tenei whakamatautau hei tirotiro i nga ahuatanga mahi me te hiko o te PCB me te whakamana i te waa, hiko, analog me te tohu matihiko me nga hoahoa ara iahiko kua whakaahuatia i roto i nga whakaritenga PCB

Mena ka whakaatuhia e nga waahanga o te PCB nga hua kaore e manakohia, ka panga te PCB ka whakakorehia ranei kia rite ki nga tikanga a te kamupene paerewa. He mea nui te waahanga whakamatautau na te mea ka whakatau te angitu, te ngoikore ranei o te mahinga PCBA katoa.

Hipanga 7: Te horoi whakamutunga, te whakaoti me te tuku:

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. Ko te maitai o te pungarehu ma te taputapu horoi horoi teitei ma te whakamahi i te wai taatai ​​kua ranea hei horoi i nga momo paru katoa. Ko te wai kua whakahekehia e kore e kino te ara iahiko PCB. I muri i te horoinga, whakamarokehia te PCB me te hau kapi. Ko te PCB whakamutunga kua rite inaianei ki te kiki me te tuku.