***warning this video is not a complete guide and for demonstration only***
There’s been a lot of hubbub on the internet about making PCBs using these new PCB printers. They sound all cool. They’re only thousands of dollars, they take less than an hour, have okay precision and seem to produce tolerably durable boards.
Making PCBs isn’t rocket science. People’ve been doing it for decades at home. Heck, my first PCBs were made using some mid-90’s radioshack kit.
In fact, they can be made cheaper, more durably, and faster using traditional methods!
(1) FR4 (or CEM) 0.060 1 Oz Copper Single Sided boards, available from ebay.
(2) DuPont Riston. Available from tech-place or ebay.
(3) UV Mercury Vapor Light, usually used in terrariums.
(4) ~42% Ferric Chloride, available from ebay and other shops.
IoT PCB considerations for Startups
Considering that IoT devices are so recent, you would believe that getting an IoT printed circuit board (PCB) project off the ground starts by reinventing the wheel and finding your way through a massive amount of technical headaches. That is most certainly a fallacy.
But it doesn’t indicate IoT startups have a straightforward path to fame. Facing them is various design and manufacturing concerns that are completely unique to these small products. These considerations need to be considered for the fresh IoT device to succeed.
On the plus side, it’s very important for IoT startups to recognise that the basic foundation for a successful new product exists. This simply means experience and knowhow involving the design, fabrication and assembly of these kinds of complex products are readily available. Additionally, the most sage advice is for smart IoT product business men and creators to take the recommendation that encountered electronics manufacturing services or EMS suppliers provide. These companies together with their engineering team members already have performed the job with pioneering IoT businesses in Silicon Valley going into the very first of this growing segment.
The PCB of an IoT device is a unique beast than the traditional one, which is notably larger and flat. IoT units, in contrast, are made up mainly of either rigid-flex or flex circuit assemblies, which include their very own categories of design layout, fabrication and assembly considerations and technicalities.
A key concern is to seek out knowledgeable designers who’ve achieved numerous rigid-flex PCB designs. PCB space for an IoT device is scarce. So you want the designer to have firsthand layout expertise to proficiently design important elements on that modest area.
At the same time, virtually all IoT gadgets aren’t fixed; they obtain significant movement and twisting. Here, the knowledgeable designer plays a major role in determining bend ratios and lifecycle iterations as a important part of a design. Various other important design layout considerations comprise signal trace thickness, number of rigid and flex circuit layers, copper weight and stiffener placement. Stiffeners are employed on flex circuits in order to guarantee elements mounted on the flex circuit stay tightly in position to stop movement.
One other concern is through-hole component placement in rigid-flex circuits. What makes that vital? The majority of IoT items are based on surface mount device(SMD) placement. But nevertheless , there could be through-hole elements, which are generally put on either the rigid part or the flex area of the board. Through-hole elements are often utilized to connect input/output or I/O signals to the exterior world. That way, those signals can be displayed utilising an LCD or LED monitor. Through-hole component placement is a crucial consideration in an IoT item given that when attached to the flex part of the board, right stiffeners ought to be designed and employed for effective assembly.
Eventually in the layout category, the high temperature that elements deliver has to be considered. IoT gadgets are becoming more complex with rigid-flex and flex circuits featuring in excess of 12 – 14 layers. A few gadgets are digital. But nevertheless , progressively analog units are being used in IoT units. Analog circuitry makes even more heat than digital ones. That means heat expansion plus contraction rate should be evaluated. In tech lingo, this is termed as the Coefficient of Thermal Expansion or CTE and the effective management of it.
Deciding on the best fabricator is really important and is linked to the EMS firm you have decided on. The fabricator you desire must have IoT PCB fabrication experience. Among important considerations here are making certain intense adhesions in between layers on both rigid and flex circuit sides, understanding all of the crucial calculations and having a robust expertise in when current moves from the rigid side to the flex side.
Such fabricators also need to possess an in-depth knowledge of amazingly small-scale parts including 0201 and 00105 device packages, package-on-package, and the utilization of fine-pitch ball-grid array or BGA packaged devices.
Furthermore, they should have experience of designing boards with pretty tight tolerances in terms of footprint for those kinds of BGA devices, in terms of up-to-date capabilities like laser direct imaging for putting the solder mask on the board. They need to have laser drills for via drilling with sizes of 5 mils or under as these IoT units could be so tiny that a common drill size of 5 to 8 mils may not be sufficient. They could need to go to a 3 mil, meaning you should get an cutting-edge laser drilling capability on-site.
In cases where you’re placing via-in-pad, it is a good way to utilize the small real estate that is available on the rigid-flex board, yet it presents trouble for assembly. If vias are not fully planar or flat in shape, it becomes challenging through the assembly of those tiny BGA packaged devices. The reason is non-planar surfaces can easily endanger the integrity of solder joints.
Sometimes via in pads leave bumps if they’re not scrubbed thoroughly after having the vias and gold finish on top. In the event there are bumps, then the solder joints in the assembly for those tiny BGA balls in those IoT devices may not be a perfect joint. It could create sporadic connections, which might be a larger issue to treat and mend. It all boils down to which EMS firm you’re choosing because they’re the ones who will select the fabrication facility to make a lucrative IoT item for you.
It’s very important to look at knowledgeable EMS companies that have properly assembled IoT and wearable PCBs since they have specialized tooling and fixtures already available, which are needed for assembly to ensure that components are placed appropriately, exactly and the printing is carried out properly.
Printing generally is a concern for IoT units. If it’s a rigid-flex board, then there’s a difference between thicknesses of the rigid and flex circuit portions, which suggests a special fixture is needed to keep the complete rigid-flex board planar or 100 % flat to enable effective printing to become executed.
Startups really should be prepared to choose the appropriate manufacturing partners and EMS businesses. This way they can be certain they’ve adequate experience early in advance to get the multitude of design, fabrication and assembly details effectively performed since they are key to a lucrative and timely IoT product launch.