ceramic pcb vid - Page 1
Forum section: electronics / rf-microwave

author: coppercone2
author_rank: Super Contributor
timestamp: October 01, 2021, 03:16:02 pm
content: so alot of people here might benefit from this processhappy to see a video about it

author: Marsupilami
author_rank: Frequent Contributor
timestamp: October 04, 2021, 04:11:34 am
content: I wish there was an easy way to use the laser to sinter the conductive pattern on it too. Something like Cermark but conductive.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2021, 04:36:04 am
content: Metallize the whole face of the ceramic PCB blank, spray with paint or lacquer as an etch resist, then laser off the resist where you don't want tracks, using the same thermal protection waterbath as is used for cutting the ceramic, and etch conventionally.Seehttps://hackaday.com/2017/08/22/laser-etching-pcbs/for how its done with copper clad FR4.Metalizing the PCB can be done a number of ways. If you've got a decent vacuum chamber, sputtering is one possibility, or you can chemically silver it. Once you've got a somewhat conductive film, it can be built up to the desired thickness by electroplating.Another option if the binder in your silver ink is insoluble in water would be to coat the whole ceramic blank with the ink, let it dry, then laser it off where you don't want it, as it wont sinter in the laser beam in the water bath. This could probably be done as the first stage of the cutting process. You'll still need to fire it after cutting to sinter the remaining ink.

author: Marsupilami
author_rank: Frequent Contributor
timestamp: October 04, 2021, 06:19:19 am
content: I'm wondering if there's something that's like 80% less steps. Probably not. I don't really need this, I just like the DIY aspect of the ceramic processing and it moves my imagination.I was thinking of something like coat the substrate with some sort of temporary mask. Laser the shape and the pattern as well. Then maybe do electroless copper then tin plating. (This would also coat vias cut into the ceramic base.) Finally remove the mask with IPA or something.E.g.:https://caswellplating.com/electroplating-anodizing/copper-plating-kits/electroless-copper-plating-kits.htmlIt says it can do 0.2mils which might be enough for certain uses.

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2021, 06:38:50 am
content: I think the whole process is problematic - cheap laser cutters are not designed to be condensation resistant, so if its been used for other materials which typically leave a film of pyrolyzed residue on all surfaces, you can expect a lot of corrosion problems. If you don't want it to become a maintenance nightmare, you'll probably need a dedicated machine with some sort of dry air purge system to rapidly remove condensation between runs.

author: Marsupilami
author_rank: Frequent Contributor
timestamp: October 04, 2021, 05:31:09 pm
content: Yep. Probably not worth it. There are a few proto services that can do this if one really needs it.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2021, 06:05:06 am
content: it probobly needs to be plated afterwards because after all its mixed with sand

author: David Hess
author_rank: Super Contributor
timestamp: October 20, 2021, 08:02:09 pm
content: Aren't thick film hybrids with fired silver traces mass produced? If so, the thick film printing of silver traces which are then fired is a solved problem.Tektronix was famous for firing silver onto ceramic terminals with fantastic results.

author: coppercone2
author_rank: Super Contributor
timestamp: October 20, 2021, 09:26:53 pm
content: well you would think its more complicated then mixing sand with silver to make a putty to smear into the PCB, that is all he does. the laser cutting is optionalits like the easiest way to make a single sided PCB if you have the stuff I think, since its just the stencil, there is nothing else.. no photoresist, etching, etc. All those processes are quite tricky IMO. Looks like the apparatus might be a coil taken out of a electric heater laid around some firebrickI thought you would need some 4 letter acronym organic flux magic binder chemical that costs 1000$ for 1g, is toxic, noxious, has a 3 week shelf life and is only sold to chemical companies... but its just fine sand and silver powder. The dangers of the refractory temperatures make up for all the good parts of this, but still.. that is just a question of being patient, there is no reason you can't fire it, leave it alone for 24 hrs till its room temp and never deal with anything hot at all.. so long you have discipline. more safe then chemical baths IMO. And the fiberglass dust is replaced with silica that is likely so fine it will be exhaled. I thought the sintering process required some 'insane industrial stuff'.

author: David Hess
author_rank: Super Contributor
timestamp: October 21, 2021, 03:38:43 am
content: Quote from: coppercone2 on October 20, 2021, 09:26:53 pmHe discussed what he could find out about the silver paste formulations, which was not much because companies treat it as a trade secret. But I doubt Tektronix was using anything exotic in the 1960s to do it, although the expert they had did a lot of experimentation to get it right.QuoteA thick film process strikes me as something which could be amendable to application with an inexpensive 3D printer, which would also open the possibility of printed resistors.

author: coppercone2
author_rank: Super Contributor
timestamp: October 21, 2021, 03:49:17 am
content: yes, its about formulating the paste. That would give a really good PCB, but I do wonder what happens if you try to do a ground plane with silver sintering, I wonder if it would need to be a 'grid' ground or something.The stencil is a problem because it either require a laser, heavy chemical etching of alot of copper, or other complex machinery. I think for the higher frequencies you would need to do electroforming of silver on the traces to smooth them out (over form and grind/polish carefully ).. perhaps even control height with a surface grinder to get real precision. I bought some proprietary electroforming additives to experiment with the processI do also wonder if you can connect all the structures on the PCB for electroforming, then use a micro chisel to break away the un necessary traces when you are done.. perhaps you can 'pop' off the sintered material, I imagined maybe its a bit like the very tough 'dross' that you can get on a plasma cutter cut that is not particularly oxidizing (pure nitrogen cutting mild steel gives it a ultra hard 'crater' around the cut part, but if you strike it hard with a chisel it will pop off clean, in small sections however, so it ends up being a ton of strikes.But that would only be necessary for very demanding PCBs.. I am not fond of dust so I would probobly leave my boards alone TBH

author: David Hess
author_rank: Super Contributor
timestamp: October 21, 2021, 03:55:56 am
content: Quote from: coppercone2 on October 21, 2021, 03:49:17 amThick film resistors use large continuous areas without a problem, but I think they are sintered later at a lower temperature.None of the examples I found online use a grid for large areas. Gold is another popular conductor. I wonder how that is done.

author: coppercone2
author_rank: Super Contributor
timestamp: October 21, 2021, 04:00:22 am
content: there is various SiO2 sintering articles out there relating to sintering results but I have a feeling I won't be able to reach that level of fidelity to make use of their precisely made experiments . In the end the likely problem will be consistency of reagents, heat uniformity, quality of paste mixture, etc. Why am I feeling its loaded with landmines in terms of particle shape and size giving baffling results...It has a range from 900-1100 degrees C apparantly.Lol, I wonder if you can put a circuit on a floor tile, stone, etc. Some startrek stuff right there making a complex PCB out of sand and silver veins. phaser compatible. Does anyone feel like it should just.. work.. with terracotta? That would open the door to some seriously high quality ceramic flower pot really high power inductors so long you have a kiln. or high temp cement maybe if there are mix that can hold shapes. ceramic silver 'air core' torroids, cones, etc.. no problem. turns antennas into pottery work.

author: coppercone2
author_rank: Super Contributor
timestamp: October 21, 2021, 05:32:54 pm
content: I bought some silver powder, perhaps I will try to see if it can be done by hand with a acetylene torch on the ultra fine tip......I have been wanting to use a cool looking torch on a PCB for the last, 15 years?I wonder if you can add another additive with a intermediate melting point, in order to keep the mixture together as it is being warmed (i.e. a pre-fire to 600C to fuse it to the board by the way of the additive then use more aggressive thermal transfer methods.I wonder if you can formulate a silica-silver welding rod so you can lay a bead on ceramics conventionally using a torch.....

author: coppercone2
author_rank: Super Contributor
timestamp: October 25, 2021, 11:05:43 pm
content: I got a sheet of aluminum nitride to try this on, I wonder how dependent it is on ceramic type

author: coppercone2
author_rank: Super Contributor
timestamp: December 10, 2021, 06:17:06 pm
content: well I got some heating wire and a fire brick to try to make a 'hot plate' for these circuit boards.I don't want to try the first experiment on my aluminum nitride sheet, so I think I will try a test run by smearing some of the paste on a few different ceramic objects to see if it attaches. I have a ceramic razor blade and pottery I will try to put a silver contact on. This should be interesting.