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This instructable consists of a step by step guide documenting a method of manufacturing professional quality PCBs at home through the use of a vinyl cutter, in a reliable, simple and efficient manner. This method allows for the production of consistent and high quality PCBs at home with few common materials and in a very short timespan. With all the files ready, the whole process can be accomplished in a few hours.
Subject of the guide, tinyDice:
For the purpose of this guide, the process will be illustrated with the production of a batch of 3 tinyDice, an electronic die based on the atTiny85 microcontroller with software charlieplexing, which allows the control of 9 LEDs with only 4 pins and 4 resistors. It is an improved version of my original tinyDice (2014), and all the source files required for this Instructable are available for download as a compressed package on the supplies step.
Origin of the method:
As an electronics enthusiast, I’ve had my fair share of experience with making PCBs in the past, but most home methods are either excessively unreliable, like the Toner transfer method, or excessively complex and laborious, like the CNC router method or the UV photoresist method (which I have covered in the past on the original tinyDice). Additionally, the final quality of the products tends to be rather poor, especially if you attempt tok implement UV soldermasks.
From these unsatisfying experiences, I decided to explore alternative methods for creating PCBs at home. As I have recently begun experimenting with a desktop vinyl cutter, it occurred to me that a vinyl stamp could make an excellent and reliable mask for PCB etching. On initial online research, I didn’t find any references of people using vinyl stamps to make PCBs, which surprised me as it seems very plausible. This motivated me to experiment with the process and find out if it could work reliably and efficiently to transfer PCB traces from the computer to the copper.
Development of the processes:
Making clean and consistent copper traces in a home PCB is in itself an achievement, but in order pof the PCBs to work properly and last long, they require some sort of soldermask, which prevents unwanted solder bridges and protects the copper traces from corrosion. Traditionally, the solder mask used is in the form of a UV curable resin, which in practice is quite difficult to work with.
Originally, I intended to use vinyl sickers indirectly as a mask for curing UV soldermask. However, on several attempts, I couldn’t get the UV soldermask to reliably cure on the intended places only, and I was never able to make a sufficiently thin and even layer, which ultimately resulted in a bunch of ruined boards. Thus I scrapped that idea and it occured to me that perhaps some sort of stamp could also direclty be used as a soldermask, although it certainly coudn’t be vinyl, as it wouldn’t whithstand the heat of reflow soldering.
With this in mind I looked to Kapton tape, which is self-adhesive, thin, and promises to resist high enough temperatures for soldering. Kapton tape is sold in rolls, but it occured to me that if it were applied over the backing of conventional vinyl, it could be cut directly on the vinyl cutter and used directly as a stamp. From the first trial of this, it was evident that the Kapton tape behaved quite promisingly on the vinyl cutter, though all the cuts that passed over tiny bubbles were jagged or incomplete, so the key to perfect kapton stamps was applying the tape perfectly on the vinyl backing without allowing any air to get trapped underneath. This initially proved quite tricky, as Kapton is excessively thin and sticky, but upon trying to lay it down using a standard plastic card I realised that it could be done perfecly and easily in this way.
Through these iterative trials I also observed some of the practical limitations of the process, which mailny have to do with the copper mask being originally a stamp. These limitations evolved into a set of design guidelines for making this process reliable.”

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