Minn ċirkuwiti prototipi fuq twavel tal-ħobż għad-disinn tagħna stess b’ċirkwit stampat (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. Id-disinn tal-PCB jitwettaq fi proċess ta ‘inġinerija elettrika (EE). EE toħloq il- “moħħ” ta ‘kif jaħdmu l-apparati. 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). Id-dimensjonijiet tal-prodott huma definiti matul il-proċess tad-disinn tal-inġinerija elettronika. You can watch a video about it here. 2. Saffi tal-PCB – Iktar ma jkun hemm saffi, iktar tkun kumplessa l-MANIFATTURA tal-PCB. (Nota: Anke PCB b’saff wieħed jista ‘jkun PCB kumpless, imma hawn qed nitkellmu dwar il-kumplessità li tagħmel PCB. Iktar ma jkun hemm saffi PCB, iktar jiswa l-manifattura.)

Layer 2 is usually used for simple toy products

Prodotti relatati ma ‘ħafna ġeneralment ikollhom 4 saffi

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.

Informazzjoni li għandek bżonn tipprovdi lill-manifatturi tal-PCB:

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

Materjali (FR-2 (karta tal-qoton fenoliku), FR-3 (karta tal-qoton u epossi), FR-4 (fibra tal-ħġieġ u epossi … Etc.)

Ħxuna (0.5 mm, 1.0 mm … Etc.)

Color (red, black, green… Etc.)

Trattament tal-wiċċ (ENIG (immersjoni kimika tan-nikil / deheb), DIG (immersjoni diretta tad-deheb), OSP (preservattivi organiċi li jistgħu jiġu ssaldjati, eċċ.)

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

Fajl Gerber

PCB design process:

Disinn taċ-ċirkwit

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

Apparat tal-frekwenza

KiCad

Cadence allegro

Ikel

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. Il-mudell tal-fajl jgħinek tiġbed l-iskematika. 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. (Nota: id-dettalji tal-proċess tad-disinn jiddependu fuq l-għodda tas-software magħżula).

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. Barra minn hekk, il-manifattur jista ‘jittestja l-apparat permezz tal-punti tat-test fuq dan id-dokument.

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. B’differenza minn skematiku, tqassim tal-PCB jassenja l-komponenti attwali għal postijiet eżatti fuq il-PCB u juri l-linji li jgħaqqdu kull komponent flimkien bejn is-saffi tal-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. B’dan il-mod, tista ‘żżomm it-traċċa konduttiva qasira u tnaqqas l-istorbju u l-interferenza.

L-interface tal-utent (UI) jeħtieġ ukoll li jinżamm f’moħħu meta jiġi ddisinjat PCB. Komponenti bħal ġakkijiet tal-awdjo, konnetturi, leds, eċċ għandhom jiġu aġġustati biex tinkiseb l-aħjar esperjenza tal-utent.

Once the layout is designed, a Gerber file is generated. Il-manifattur tal-PCBA tiegħek se juża dan il-fajl. There are many companies that offer these services, and from HWTrek’s expert library we recommend Kingbrother, NexPCB, and HQPCB.

Sample Gerber files

It-tqegħid tal-komponenti fuq il-PCB huwa importanti ħafna. 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. Din se tkun il-bażi biex tkompli tibni l-pedament biex iżżid komponenti mal-PCB u timmanifattura l-PCBA (assemblaġġ tal-bord taċ-ċirkwit stampat).

Unassembled PCBS

PCBA (Assembly)

Preparazzjoni tal-materjal

F’dan il-punt fid-disinn tal-EE tiegħek, suppost għażilt il-komponenti. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Kwistjonijiet li għandhom bżonn attenzjoni:

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. Jekk tixtri inqas mill-minimu, kun żgur li l-komponenti magħżula huma fl-istokk. For small batches (up to 50), you can order online from DigiKey or Mouser. Għal aktar kwantitajiet, jekk jogħġbok fittex parir mingħand il-manifattur tiegħek.

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)

SMT (teknoloġija tal-immuntar fuq il-wiċċ) huwa l-iktar metodu użat fil-produzzjoni tal-massa. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Affarijiet li niftakru:

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.

Reflow soldering

L-issaldjar mill-ġdid huwa l-proċess li tagħmel il-komponenti “jeħlu” mal-PCB. The PCBA heats the circuit board through a reflow furnace or an infrared lamp until the solder melts, thereby permanently attaching the component to the circuit board.

The trickiest part here is not to overheat or damage the components, because the thermal characteristics of each package are different. Manifattur affidabbli tal-PCBA se jkun responsabbli għal dan il-proċess, u kull ma trid tagħmel hu li tipprovdihom bi speċifikazzjonijiet tal-komponenti.

Proċess ta ‘rifluss.

Other welding methods:

L-issaldjar bil-mewġ huwa prinċipalment użat għal komponenti miżjuda manwalment bil-metodu tat-toqba li tgħaddi. F’dan il-każ, il-PCBA tiegħek l-ewwel jgħaddi mill-forn tal-iwweldjar mill-ġdid, u mbagħad iżid manwalment komponenti oħra wara li jgħaddi mill-magna tal-istann tal-mewġ.

L-iwweldjar tal-ħadid jista ‘jintuża għal sitwazzjonijiet speċifiċi, iżda mhux għall-produzzjoni tal-massa.

Ittestjar u spezzjoni tal-kwalità

F’dan il-pass, il-kampjuni tal-PCBA jiġu ttestjati biex tiġi żgurata l-kwalità. Żbalji komuni huma: short circuits f’komponenti skonnettjati, komponenti allinjati ħażin u partijiet taċ-ċirkwit li m’għandhomx ikunu konnessi. L-iktar testijiet komuni:

ICT (Ittestjar onlajn). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. Il-magna ICT tuża dawn il-punti tat-test għall-ittestjar ta ‘ċirkwit miftuħ / qasir u tivverifika li l-valuri tal-komponenti passivi (resistors, inductors, capacitors) huma fil-medda ta’ speċifikazzjoni.

AOI (Spezzjoni ottika awtomatika). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Għal dan it-test, il-kreatur tal-ħardwer ikollu bżonn jipprovdi speċifikazzjonijiet u tolleranzi lill-manifattur biex jistabbilixxi l-parametri.

X-ray. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Ara t-test tar-raġġi X f’dan il-video.