Menu
Knowledge

The impact of choice of material

Have you ever tried building a house? Oh. Well, we don’t build many of those either, but stay with us for a second. 
Share
Del på facebook
Del på twitter
Del på linkedin
Del på email

The impact of choice of material

Have you ever tried building a house?

Oh. Well, we don’t build many of those either, but stay with us for a second.

We can quickly agree to the fact that whatever material you choose to build your house from, it’s quickly going to impact life in that very same house, right? 

And most likely, the entire structure of the house needs to change, if you’ve chosen the wrong materials. 

This concept isn’t, unfortunately, so unfamiliar in the PCB design world.

It can easily go very wrong with the entire electronic project if the wrong materials are chosen.

So we can only wonder why so many people choose materials for their PCB with such casualness…

 

Let’s look why it’s so important!

Like with construction of a house (we know, it’s an extreme example ;-)), the materials you choose depend on the design of the house. Let’s say you want to construct a greenhouse, but you chose red bricks for the walls… Dumb as a box of rocks – or bricks, in this case.

In the world of PCB, you need to start your design with determining the appropriate IPC standard for whatever it is you wish to produce. This is a part of your “blueprint” – and will help you determine the fitting materials for this kind of PCB.

If the goal is to protect yourself from the big, bad wolf, you need a sturdy design, with
strongmaterials. Wouldn’t it, then, be silly to choose hay?

 

If you’re wondering what IPC standards are, you can read more about it here.

The choice of materials is one of the most crucial decisions of the design process, as it covers everything from high frequencies to thickness and ratio of the various elements. There are countless pitfalls here that you can fall into. Choosing the wrong material enables a significant delay of the process – which is costly but luckily also avoidable.

One of the first things to consider, besides what the PCB will actually be used for, is what frequencies it will operate at. This means whether the PCB needs to operate at high-speed signals or not.

 

Frequencies and isolation materials

The frequencies and isolation materials are a sweet pair of love birds – you need to consider them as one!

You must consider the different frequencies of the final product and the speed of the board signals. The material the electrons must travel on will directly impact how fast or slow the signals will travel – and thus the efficiency of the board.

Especially concerning high-speed signals, the PCB material must be dimensioned correctly for the purpose in question. If, for example, there is a requirement for high frequency signals, you must take this as your starting point.

There’s also another thing concerning the high frequencies – you have to be aware of how much loss there is in the material you choose. Copper, for example, is very smooth. In most cases, it is better to have a rough surface on the copper and isolation layer, so they stick together more securely.

However, in terms of signal, especially if the signal has to be fast and reliable, the copper should be as smooth as possible. If the surface is too rough, it won’t lead the signal as accurately, seeing as the roughness impedes the electrons from moving effortlessly.

 

The devil (or should we say “wolf”) is in the detail

As with so many other materials, it’s most likely that the most effective material you’ll choose for PCB will expand and contract according to temperatures…

…if not, we’ll be pretty interested in hearing what kind of materials you are using – maybe there’s a Nobel prize on its way to you?  😉

In the meantime, you’ll spend your time wisely by considering the chosen material’s thermal coefficient expansion. Materials can change their size at certain temperatures, and this can have a major impact on the drilling and assembly process of the PCB.

This can be problematic for the manufacturers. You’ll want to ensure that there actually are manufacturers out there for your PCB, which is why the wrong material can have consequences for the production.

Imagine if you chose the wrong material, which moves too much with change in temperature, but you also chose too big of a thickness of the material… You’ll most likely not be able to make the via connections and once again risk that production of your PCB is not possible.

 

Be like the piggy with the brick wall!

We can help safeguard you against bad choices of materials.

We know the IPC-A-600 and IPC-A-610 like the back of our hands – and we’ll easily be able to guide you through, in a free PCB consultation.

No strings attached. Whatsoever!

Book a free consultation with me, and I’ll give you the tips you need to create safe and reliable PCB.

Share
Del på facebook
Del på twitter
Del på linkedin
Del på email
Get in touch

Get in touch with Steen Kaare Grøndahl E.E.

Having trouble figuring out where to start with your project? Want a chance to pick my brain for an idea or two? Feel free to contact me! I’ll do my best to help you, with some of the knowledge stored away in my brain 🙂

Related articles

See also these articles

Rørmosevej 2B
3450 Allerød, Denmark
CVR: 40868364

Download free e-book
Hassle-free PCB-design - download today and learn how!