From prototype circuits on bread boards to designing our own lolomi laupapa matagaluega (PCBS), it was like getting off the training wheels. E tele mea e aʻoaʻo e uiga i lenei gaioiga, o lea ia tatou amata. PCB design is carried out in an electrical engineering (EE) process. EE fausia le “faiʻai” pe faʻafefea ona ola masini. 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). Oloa fua o loʻo faʻamatalaina i le taimi o le eletise inisinia faʻagasologa tisaini. You can watch a video about it here. 2. PCB vaega – O le tele o faʻaputuga, o le sili atu ona faigata o le MANUFACTURE o PCB. (Faʻaaliga: E oʻo ile tasi vaega ole PCB e mafai ona avea ma PCB faigata, ae o lea tatou te talanoa e uiga i le faigata o le faia o se PCB. O le tele o vaega o loʻo i ai i le PCB, o le sili atu foi ona taugata o le gaosia.)

Layer 2 is usually used for simple toy products

O oloa e fesoʻotaʻi Iot e masani ona i ai le 4 faaputuga

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.

Faʻamatalaga e te manaʻomia e tuʻuina atu i PCB gaosi oloa:

Aofai o faaputuga (eg 2, 4, 6, ma isi)

Mea (FR-2 (phenolic cotton pepa), FR-3 (cotton cotton ma epoxy), FR-4 (tioata alava ma epoxy… Etc.)

Thickness (0.5 mm, 1.0 mm… Etc.)

Color (red, black, green… Etc.)

Luga togafitiga (ENIG (vailaʻau nikelini / faʻatofuina auro), DIG (faʻatofuina auro tuusao), OSP (faasaoina solderable faatulagaina, ma isi)

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

Gerber faila

PCB design process:

Matagaluega mamanu

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

Masini masani

KiCad

Cadence allegro

fala

Computer aided design

Lolomi

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. O le faʻataʻitaʻi faila o le a fesoasoani ia te oe tusia le skema. 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. (Note: the details of the design process will depend on the software tool chosen).

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

O se lelei polokalame e taua tele, aua o le a faʻaaogaina o se faʻasino pepa i le taimi o debugging ma o se lelei fesoʻotaʻiga meafaigaluega ma isi inisinia. I se faʻaopopoga, e mafai e le gaosi oloa ona faʻataʻitaʻia le masini e ala i togi o suʻega i luga o lenei pepa.

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. E le pei o se polokalame faʻafuaseʻi, o se faʻavae PCB tuʻuina atu vaega moni i tonu nofoaga i luga o le PCB ma faʻaali auala e fesoʻotaʻi vaega taʻitasi i le va o le PCB faaputuga. 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. I lenei auala, oe mafai ona tausia le conductive ala puʻupuʻu ma faʻaititia le pisapisao ma faʻalavelave.

O le tagata faʻaoga (UI) e manaʻomia foʻi ona teu i lou mafaufau pe a fuafuaina se PCB. Vaega e pei o leo leo, fesoʻotaʻiga, leds, ma isi mea e manaʻomia e fetuʻunaʻi ina ia ausia le sili ona lelei le poto masani o tagata.

Once the layout is designed, a Gerber file is generated. O lau PCBA gaosi oloa o le a faʻaaogaina lenei faila. E tele kamupani o loʻo ofaina nei tautua, ma mai le HWTrek’s faletusi faʻapitoa matou te fautuaina ai Kingbrother, NexPCB, ma le HQPCB.

Sample Gerber files

O le faʻatulagaina o vaega ile PCB e taua tele. 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. Lenei o le a avea ma faʻavae e faʻateleina fausiaina le faʻavae mo le faʻaopopoina o vaega i le PCB ma gaosia le PCBA (lolomiina matagaluega komiti faʻapotopotoga).

Unassembled PCBS

PCBA (Assembly)

Sauniuniga mea

I lenei taimi i lau EE mamanu, oe tatau ona filifilia vaega. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Mataupu e manaʻomia le gauai:

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. Afai e te faʻatau laʻititi ifo i lo le mea laʻititi, ia mautinoa o vaega filifilia o loʻo teu. For small batches (up to 50), you can order online from DigiKey or Mouser. Mo sili atu aofaʻi, faʻamolemole saili fautuaga mai lau kamupanī.

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 (luga mauga tekonolosi) o le sili lautele lautele faʻaaogaina metotia i tele gaosiga. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Mea e manatua:

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

Reflow soldering o le gaioiga o le faia o vaega “pipii” i le 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. O le faʻatuatuaina PCBA gaosi oloa o le a nafa ma lenei gaioiga, ma na pau lava lau mea e manaʻomia e fai o le tuʻuina atu ia i latou ma vaega vaega.

Reflux process.

Other welding methods:

Wave soldering is mainly used for manually added components by the through-hole method. I lenei tulaga, o le a muamua alu lau PCBA i totonu o le ogaumu faʻavevelaina ogaumu, ona faʻaopopo faʻatasi ai lea o isi vaega pe a maeʻa ona oʻo atu i le masini soldering galu.

E mafai ona faʻaaogaina le uʻamea mo tulaga maʻoti, ae le mo le tele o gaosiga.

Suʻega ma lelei le asiasia

I lenei sitepu, ua faʻataʻitaʻia faʻataʻitaʻi PCBA ia mautinoa le lelei. O mea sese masani o: pupuʻu taʻamilosaga i mea e motusia, vaega faʻaseseina ma vaega o le matagaluega e le tatau ona fesoʻotaʻi. O faʻataʻitaʻiga sili ona taatele:

ICT (Suʻega i luga ole laiga). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. O le masini masini a le a faʻaaogaina nei suʻega togi mo matala / puʻupuʻu matagaluega suʻega ma siaki pe o le a le taua o le passive vaega (resistors, inductors, capacitors) o loʻo i totonu o le faʻamatalaga faʻapitoa.

AOI (Otometi asiasiga opitika). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Mo lenei faʻataʻitaʻiga, e manaʻomia e le kamupanī masini ona tuʻuina atu faʻamatalaga ma faʻapalepale i le kamupanī e seti ai tapulaʻa.

X ray. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Matamata le suʻega X-ray i lenei vitio.