Making precision PCBs with Sharpie and 3D printer

In my experience, etching is the easy bit. Getting a good mask is what gives trouble, takes time, and is generally frustrating.

Sylvia.

The entire process is messy and time consuming, and you can't reasonably do double-sided boards. If your time is worth anything, order a proper plated-through, solder-masked, 2 or 4 layer board from a quick-turn proto house, and work on something else until it arrives.

That's when I make sure my CM has everything they need to do the job and order any last minute parts that may have fallen through the cracks (sometimes literally).

I have three six layer boards (mother, daughter, and a simple oscillator test board - didn't take two decades to design) going out Monday or Tuesday. I'll probably take a trip up to see the CM Wednesday or Thursday to bring up most of the remainder of the parts.

I always pull a few extra of the smaller surface-mount parts. It's dependable that I'll lose a few before I get them soldered down.

On 10 Jul 2016, John Larkin writ:

Required SMD tool: vacuum cleaner (hoover to you Empire boys) with empty bag.

Sadly, the floor under my workbench is carpeted. That carpet must be some significant fraction-by-weight of electronic components by now.

I am glad the resistors and capacitors are only a few cents. If I need only one or several, I always get atleast 10 of them. Don't usually loose any if I do. If I don't or the part is several dollars or more and I get just the required ammount I usually drop one and spend lots of time looking for it.

Mantis.

I think he is just referring to a light that goes over your head, not a magnifying one.

I am sure the Mantis is very nice,but just for my hobby they are out of the price range. I did get an Amscope SE 400 for about 10% of the Mantis cost that works well for my hobby.

I keep spares of most of the values I use in anti-static bags. I never put fewer than a hundred in them. If one leaves the playing field, I don't spend a second on it. I don't want it back because I'll probably get the one I lost last year, instead. I don't want that one.

It's worse now that many resistors have goofy alphanumeric codes.

Or nothing.

We call that here the "umbrella effect". If you have an umbrella with you it does not rain.

I bought one of the China component checkers. Then modified some of the normally closed tweezers. I glued a small piece of printed circuit board to the inside of each 'prong' of the tweezer. Then soldered a foot or so of some small wire to them. Good for holding and checking resisors and capacitors of over a few hundred pico farads.

Those $ 15 component testers seem to work very well if the value of the device under test is high of enough value the leads don't upset the value.

I've got a pair of Smart Tweezers that pretty much fixes that problem.

$400 last time I checked, but worth it.

Cheers

Phil Hobbs

I had a contract where they insisted that I fabricate some boards using an Othermill . While it might have been possible to do a small, single-sided, board with no fine pitch components, it really did not work for what we were doing. Producing a single, small, board took many, many hours of very noisy grinding. At the time it only supported Macs, so I needed to borrow a Mac to hook up to it. The system hung somewhere during the process and I gave up on it.

You used to be able to buy rubber stamps with DIP patterns which you could use to stamp etch-resistant patterns onto copper. These worked pretty well. But still, doing two sided boards would be tough, and there were no plated through holes so even if you did do double sided, you needed to solder both sides of components, and solder thin wires into all vias.

Ugh, that looks like a makerbot cupcake 3D printer refitted as a mill. Quite a joke, I suspect.

Almost 20 years ago i built a laser photoplotter, and wrote the software to make raster files from Gerber files. I recently replaced the ancient Windows 3.1 computer with a Beagle Bone. It generates artwork that is accurate to a few thousandths of an inch per foot or better, so good I really have no tools to measure it. The plotting is at a resolution of 1000 DPI. I mostly use it to make solder stencils for commercially-fabricated PC boards, but occasionally make a one-off. It prints to red-sensitive litho film that then becomes the master for dry film PCB etch resist.

By having such accurate films, you can easily do double-sided boards, but you do have to hand-solder the vias.

Jon

We had one of those PCB milling machines. We got it free and it wasn't worth it.

I have a pair of them, too, but they don't work very well on 0402s, which account for >90% of the passives on my boards. To be a little more clear, they work to measure the widget but aren't worth a damn placing them. Too many motions to use both. The cleaning service will get the spillage. Eventually.