I am posting this basically to find out if anyone else would find this useful.
A little over a year ago I got feed up with making my own printed circuit boards. It had been about 10 years sense I last did home made boards. I still had my light table and all the equipment just had to get new chemicals.
I thought surely something more strait forward must have be available by this time, but I was wrong. This kind of got me obsessed with coming up with something (I never finished the project the boards were intended for). So I started digging into the problem. After numerous failures and a lot of exotic materials I finally got something that actually worked. After another couple of months I was able to make circuits for TSSOP packages and smaller down to .5mm pitch reliably. At this point the technology is only ready for prime time so to speak for through hole packaging due to the non solder process of connecting components to the circuit. I can do all the surface mount parts but it is still a mess to connect up so I am still fixing some assembly issues.
That said I finally filed my patent papers last week and so I am able to do something more with the process then just my own experiments.
It is a printing process and from Gerber file to board the process takes about 15 minutes. I have been using this for some of my projects and it definitely has meet my needs. So I was wondering if I should offer this as a service or should I crawl back down the rabbit hole until I have complete SMT working. At this point I print the circuits on paper, card stock or plastic. For circuits that require ridged mounting I do one or two single sided paper circuits and mount them on bare perfboard.
It looks like about $1 per sq inch to do it basically as a service and just a little setup. My largest circuit so far is 11"x17". What do people here think about this? Does this seem like it would be of any value to people?
Well I am starting to put info up on a web site. Hopefully I will have a way to enable people to use my technology…oh yes the guys with the pointed heads tell me I have to say my “patent pending technology”
I’m sure people would be interested but they (including myself) would want to know what the process is doing exactly and what kind of performance and quality would be expected. The “non solder process” needs to be explained. People are used to the properties of copper clad FR4 and would want to know how it compares to your method.
If you filed your patent papers all ready, I assume you can provide more details on your process?
Yes I am preparing a general information release which I will link here for people to read.
I have yet to run it through a complete set of environmental tests.
The conductor paths are copper or silver. I am still working on aluminium. For the moment and for what I would first be able to offer paper or plastic would be the only substrates. I will do some characterization of the impedance and publish a chart. I will be able to do other substrates including FR4 later. It is not a process issue but an equipment issue.
The component circuit attachment process uses a conductive glue. This process I have basically divided into DIY and automated capabilities.
For full up automated assembly services, silver filled epoxy is used. The dispense process is already a well developed technology. Automated assembly can already do SMT down to the smallest geometry I have.
For DIY I do not consider silver epoxy and acceptable method due to cost and shelf life of the material. For DIY assembly I use wire glue. It’s surface tension makes it difficult to use on smaller geometries for hand assembly. I am working through a process to use it. My approach is to use a plastic stencil from Pololu and an electrostatic chuck. The stencil is a generic one with most of the popular SMT packages. Admittedly this would be a rather slow going aligning for each part on prototypes, but if some one was further along they could get a custom one from Pololu to fit their design. I built the electrostatic chuck using my process and a negative ion generator supply from electronic goldmine.
nitchvideo:
I am posting this basically to find out if anyone else would find this useful.
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What do people here think about this? Does this seem like it would be of any value to people?
I think you’ll find a fair amount of interest.
{dang, I forgot how to use the understatement tags}
I recall reading [this and thinking “there’s an unused HP pen plotter over in the corner of the lab that no one will ever miss” :twisted: but I’m not sure how conductive such “glues” really are. So your technique is very interesting. I think a lot of people would like to be able to “print” their own PCBs directly using something like an inkjet or plotter or [reprap machine. I think you’d have more luck offering for sale a machine to make your own PCBs vs doing PCBs as a service (where you’ll be in competition with existing houses).](RepRap: Blog: First reprapped circuit)](http://inventorspot.com/articles/wire_glue_solder_replacement_31507)
Yes I intend to enable people to make their own boards as well as offer some services. I actually would like to find people offering PCB services and set them up also. It’s all a matter of time at this point. I do not really want to put something in peoples hands that I have done due diligence on.
One of the big things for me has been the 15 min turn around on printing the circuit. So trying to get setups for people to do their own is a priority.
One other thing I have found for circuits that I have not laminated to perfboard. If I have a populated circuit that I need to make some changes on, sense it is printed on paper I just cut out the area that needs to be changed. Then I print out the changed section and trim it to fit the cut out. Then I take a strip of the area where the two are joined and print out the strip mirrored. Then I put conductive glue on the traces where they two sections meet and put the mirrored strip down to join them. I have only done it on single sided circuits, but I do not see why it would not work on the double sided ones.
I will try and post some pictures but I am still hammering away trying to get a web site up for this.
Well after a few weeks of turmoil we have come up with a way to package all the materials needed, in a form that DIY enthusiast can use directly to produce printed circuits. We are currently trying to insure that we can produce circuits reliable without any of the equipment we had been using to help the process. Once we get past that part and get the production process rolling and under control, we will be offering the package through retailers. Target price is at this point is $20.00 for enough material to do a 6"x5" double sided circuit. This is our rapid prototype material which, we turn a circuit this size in about 15~20 min from the time the design files are complete. Without some of the equipment we use it will take some additional time and we are trying to keep it under an hour. Stay tuned for further updates!
You support double-sided circuit layouts? Is there any manual process needed to produce conductive vias, or are they automatically created by the fabrication process? The lack of plated through-holes and the requirement for manual via-wire placement and soldering to get conductive through-holes is one of the biggest annoyances for me in current DIY PCB fabrication.
Yes we do vias but a little differently. I also noted that I do not believe I have explicitly stated anywhere here that we are using conductive glue for component lead attachment. Which might be an issue for some people. What we will be offering for rapid prototype work will probably require this method. We have done some testing using hand soldering and we still need to do some reflow testing, but the temp margins are pretty small and that is for leaded solder.
We have two other process that we think are compatible with reflow if needed. But they become a little more involved. So it takes more then 5 min to build the first copy of the circuit.
But back to your main question. Yes we do double sided circuits. We do some simply like you normally do. Using a single substrate usually card stock paper if we want rigidity or plain paper or plastic if we want to build a flex circuit. We also sometimes build an assembly to create something as ridged as a regular FR4 board. In this case we us two single sided circuits and perfboard. to Most via connections with this technology are accomplished with a drop of conductive glue on each side of the VIA. With the rigid assembly there are usually some jumper wires used. We are going to test using plated through hole perfboard with just a drop on each side but have not done so yet.