Ó chiorcaid fréamhshamhlacha ar chláir aráin go dearadh ár gcuid féin phriontáilte chuaird (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. Déantar dearadh PCB i bpróiseas innealtóireachta leictreachais (EE). Cruthaíonn EE an “inchinn” faoin gcaoi a n-oibríonn feistí. Without electronics, you’re left with little more than a pile of metal and plastic.

Things to know before starting PCB design: 1. PCB size – this depends on your product size (or case size). Sainmhínítear toisí táirge le linn an phróisis dearaidh innealtóireachta leictreonaigh. You can watch a video about it here. 2. Sraitheanna PCB – An níos mó sraitheanna, is casta MONARÚ PCB. (Nóta: Is féidir fiú PCB aon-chiseal a bheith ina PCB casta, ach anseo táimid ag caint faoin gcastacht a bhaineann le PCB a dhéanamh. An níos mó sraitheanna atá ag PCB, is costasaí é a mhonarú.)

Layer 2 is usually used for simple toy products

De ghnáth bíonn 4 shraith ag táirgí a bhaineann le Iot

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

3. Your PCB manufacturer’s requirements. Be sure to read the guidelines for rhythm, trace size, power isolation, and file naming before you start designing.

Faisnéis a chaithfidh tú a sholáthar do mhonaróirí PCB:

Number of layers (e.g. 2, 4, 6, etc.)

Ábhair (FR-2 (páipéar cadáis feanólach), FR-3 (páipéar cadáis agus eapocsa), FR-4 (snáithín gloine agus eapocsa… Etc.)

Tiús (0.5 mm, 1.0 mm… Etc.)

Color (red, black, green… Etc.)

Cóireáil dromchla (ENIG (tumadh nicil / ór ceimiceach), DIG (tumadh díreach óir), OSP (leasaithigh intuaslagtha orgánacha, srl.)

Copper weight (1 oz (35 microns), 2 oz (70 microns), 0.5 oz (18 microns)… Etc.)

Comhad Gerber

PCB design process:

Dearadh ciorcad

For this step, you need to create the schematic. This is a document, like a blueprint, that describes how components relate to each other and work together. To create the schematic file, you will need a software tool. We like Quadcept because it is optimized for designing PCBS for manufacturing (for example, you can export a Bill of Material (BoM) directly from the tool) and is cloud-based, so it can be easily used anywhere. (They also offer a free community version of the tool for manufacturers and students.)

There are many other options you can choose from:

Altium

ExpressPCB

Gléas minicíochta

KiCad

Cadence allegro

Bia

Computer aided design

DipTrace

After you install the selected tools, you need to obtain the component specifications for each selected component. They can often be found on the supplier’s website. Cuideoidh an comhad samhail leat an scéimre a tharraingt. This component becomes available in the database when you upload the model to the software tool. Then, all you have to do is follow the data manual and connect the wire to each pin in the component. (Nóta: beidh sonraí an phróisis dhearaidh ag brath ar an uirlis bhogearraí a roghnófar).

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).

Example diagram

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. Ina theannta sin, is féidir leis an monaróir an fheiste a thástáil trí na pointí tástála ar an doiciméad seo.

PCB layout + Gerber file

To design the PCB layout and create Gerber files, you can use the same software tools we mentioned in circuit design. Murab ionann agus scéimre, sannann leagan amach PCB na comhpháirteanna iarbhír chuig láithreacha beachta ar an PCB agus taispeánann sé na rianta a nascann gach comhpháirt le chéile idir na sraitheanna PCB. As mentioned at the beginning of this article, the more layers, the more complex the manufacturing required, and the higher the cost.

Divide the PCB into logical parts based on functions (e.g. power supply, audio output, etc.). Then, be sure to group the components of each section into the same area. Ar an mbealach seo, is féidir leat an rian seoltaí a choinneáil gearr agus torann agus cur isteach a laghdú.

Ní mór an comhéadan úsáideora (UI) a choinneáil i gcuimhne freisin agus PCB á dhearadh. Is gá comhpháirteanna cosúil le seacanna fuaime, nascóirí, giotaí, srl a choigeartú chun an taithí úsáideora is fearr a bhaint amach.

Once the layout is designed, a Gerber file is generated. Úsáidfidh do mhonaróir PCBA an comhad seo. There are many companies that offer these services, and from HWTrek’s expert library we recommend Kingbrother, NexPCB, and HQPCB.

Sample Gerber files

Tá socrúchán comhpháirteanna ar an PCB an-tábhachtach. Some components can interfere with each other and cause unexpected behavior. For example, if you have both Bluetooth and Wi-Fi modules, they have the same 2.4ghz bandwidth and can interfere with each other if incorrectly placed.

PCB production

When you send the Gerber file to the PCB manufacturer, they can print the board. Beidh sé seo mar bhunús chun an bunús a thógáil tuilleadh chun comhpháirteanna a chur leis an PCB agus chun an PCBA (tionól bord ciorcad priontáilte) a mhonarú.

Unassembled PCBS

PCBA (Assembly)

Ullmhú ábhair

Ag an bpointe seo i do dhearadh EE, ba cheart go mbeadh na comhpháirteanna roghnaithe agat. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Ábhair ar gá aird a thabhairt orthu:

Lead time: As these components come from different suppliers, keep the lead time in mind. For some components, it can take up to 8-16 weeks.

Packaging: Order components from reels that are automatically picked up by SMT machines instead of packaging them individually.

Minimum order quantity: Check the minimum order quantity of the component. Má cheannaíonn tú níos lú ná an t-íosmhéid, déan cinnte go bhfuil na comhpháirteanna roghnaithe i stoc. For small batches (up to 50), you can order online from DigiKey or Mouser. Le haghaidh tuilleadh cainníochtaí, faigh comhairle ó do mhonaróir le do thoil.

Loss: Order 10% more to cover loss (not for expensive components)

Install components on the PCB

There are two main ways to place components on a PCB surface:

Through-holes (through-holes) are manual methods of assembling assemblies with wires into holes on the surface of a PCB. It is also commonly known as DIP or dual in-line packaging process. (See SMT in progress in this video)

Is é SMT (teicneolaíocht suite dromchla) an modh is mó a úsáidtear go forleathan i olltáirgeadh. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Rudaí le cuimhneamh:

Your component type number must not exceed the number of reels that the manufacturer’s SMT machine can support.

Optimize and consolidate your components so that only one SMT runs.

Check manufacturer supported footprint pad sizes. Otherwise, the SMT machine will not install components correctly.

Some larger components cannot be installed by machine and still require manual through-hole work. Therefore, both technologies can be used on the same board.

Any components you need to manually add via the through-hole method add to the manufacturing cost.

Sádráil Reflow

Reflow soldering is the process of making components “stick” to the PCB. Déanann an PCBA an bord ciorcad a théamh trí fhoirnéis athlíonta nó lampa infridhearg go dtí go leáíonn an sádróir, agus ar an gcaoi sin an chomhpháirt a cheangal go buan leis an gclár ciorcad.

The trickiest part here is not to overheat or damage the components, because the thermal characteristics of each package are different. Beidh monaróir iontaofa PCBA freagrach as an bpróiseas seo, agus níl le déanamh agat ach sonraíochtaí comhpháirteanna a sholáthar dóibh.

Próiseas aife.

Other welding methods:

Úsáidtear sádráil tonnta go príomha le haghaidh comhpháirteanna a chuirtear de láimh leis an modh trípholl. Sa chás seo, rachaidh do PCBA tríd an bhfoirnéis táthú reflow, agus ansin cuirfidh sé comhpháirteanna eile de láimh tar éis dó dul tríd an meaisín sádrála tonnta.

Is féidir táthú iarainn a úsáid le haghaidh cásanna ar leith, ach ní le haghaidh olltáirgthe.

Tástáil agus iniúchadh cáilíochta

Sa chéim seo, déantar tástáil ar shamplaí PCBA chun cáilíocht a chinntiú. Is iad seo a leanas earráidí coitianta: ciorcaid ghearra i gcomhpháirteanna dícheangailte, comhpháirteanna mí-sínithe agus codanna den chiorcad nár cheart a nascadh. Na tástálacha is coitianta:

TFC (Tástáil ar líne). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. Úsáidfidh an meaisín TFC na pointí tástála seo le haghaidh tástála ciorcad oscailte / gearr agus seiceálfaidh sé go bhfuil luachanna na gcomhpháirteanna éighníomhacha (friotóirí, ionduchtóirí, toilleoirí) laistigh de raon na sonraíochta.

AOI (Cigireacht optúil uathoibríoch). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Maidir leis an tástáil seo, beidh ar chruthaitheoir na crua-earraí sonraíochtaí agus lamháltais a sholáthar don mhonaróir chun na paraiméadair a shocrú.

X-gha. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Féach ar an tástáil X-gha san fhíseán seo.