The idea of ​​trying to prototype on-the-fly using SMD parts sounds crazy, right? But then we saw [Leo Fernekes] calmly and carefully completing his process (video, embedded below). Suddenly, the SMD prototype design jumped onto the list of things we were about to try.

[Leo] speaks from a wealth of experience and a tight customer schedule, so this video is a 14-minute master class using copper clad laminate as a Manhattan-style scratch pad. He first made a renewable tool to scrape off copper by grinding and shaping an old X-Acto blade into a sharp Swiss Army knife corkscrew shape. This alone is exciting, but [Leo] keeps going.

In these prototypes, he used a through-hole version of any microcontroller in the design. For everything else, he uses the exact SMT parts that will eventually appear on the PCB that others are busy designing at the same time.

After laying the circuit board on the paper, [Leo] carved out conductive islands, beeped to check if they had shorts, polished the whole thing with steel wool, and went to town.

When he jumped and connected the ground plane with bare copper wires insulated with heat-resistant Teflon tubes, tips and tricks continued to appear, explained the benefits of building a large number of connectors, and paid for a good crimping tool.

Why do you need a good crimping tool? Because when they are done correctly, crimp connections are stronger and more reliable than solder. They are much more than you think.

The tool is convenient, but the cut seems quite wide, so it is not suitable for fine pitch materials, especially when it has more than 3 or 4 leads.

And his MCP9700, for example, also has SOT23, and even through holes. Why not use that one instead?

His focus is on using and verifying the parts that will be installed on the final board, not just parts that are convenient for prototyping. Obviously this does not apply to ultra-high-density components, but that is why he also recommends to have surfboards on hand to break these.

Yes, I get it, but I think there is no reason to think that the SOT23 version of the (a bad) temperature sensor will behave differently from the SC70 version. I am pretty sure that the actual silicon in the different packages is the same.

Any small differences in the thermal characteristics of the package will be completely overwhelmed by the differences between his prototype board and the final product, and even the differences between different silicon wafer production runs.

If you have to polish the tooltip width anyway, shouldn’t it be too difficult to adjust?

If the package is important enough that you want to use the actual design package for prototyping, then I worry that the PCB layout is equally important, and this method obviously uses a non-final layout.

Fast two-layer PCBs are cheap and will produce better results in most cases.

This type of prototype has a place, but I don't think it should be part of many design cycles.

Very good video with some high-value tips!

I agree with everything except the advice to get the official Molex crimping tool, this is not needed, the medium price (30 euros) is fine too! I have both and use the Aliexpress version more frequently because it is lighter and easier to handle. Just make sure to get a ratchet model with a perfect anvil/punch cut, not cheap stamped steel. (Actually I even have 2 Chinese models, one for adjusting thin lines and the other for thicker or double lines)

Yes, I have a deep understanding of this. I generally agree that it's worth spending a little more for a good tool...but the price of the "official" crimping tool is crazy. For the type of JST connector I use, I think the official hand tool is about $700, and it won't even make the work faster.

I just use the pliers type crimping device (Engineer PA-09), the advantage/disadvantage is that you can control the crimping force by sight and feel. It may not produce connectors that meet NASA standards, but I have absolutely no problem with the value of $680.

That said, you should probably check the actual cost of OEM tools for your connector type, because the price varies greatly. If it's only $50 or even $100, then you should probably listen to this person's advice instead of mine.

I curled up a lot. I think the ratchet curl is totally worth the money. Maybe not molex: there are after-sale copies. But in my experience, no matter how good I think I do with pressure on the hand crimp, the effect of the ratchet crimper is much better, the life/durability of the wire harness we make proves this . In addition, when you do double crimping, wire/insulation, they are much faster. It is more than 2 times faster, so after about 10 crimps, I feel that I have repaid the extra cost of the cheap ratchet crimper. The situation of automotive wiring harnesses is doubled. Quinn Dunki once pointed out a quick disconnect crimping tool for automobiles, and I got one, and I haven't even seen my old crimper since then.

I always ask my students "Which line connection failures can we tolerate?" When they look at the wire nest they just created, it will quiet them down quickly. I have a lot of expensive crimpers-if you value your reputation, it is actually a cheap insurance in the long run.

Good crimping tools are worth it. The smaller the connector, the more important the chip size. Especially when you crimp hundreds of terminals for products that need to work.

In many cases, the hacking technique in the squeegee is fast, but at the same time, according to your personal workflow, the composite board can be used for CNC engraving almost as quickly. Not to mention, there are additional capacitors to consider, when you have a huge copper surface...definitely like it. These are still killer tips that remain in the toolbox.

However, it is very suitable for apartment buildings, because there you can't have a howling desktop CNC machine to process the sound and the fiberglass dust it emits.

You can check it out later. Remind me that I need to sharpen/file off the dots on the punch tools of those style riser factories.

It looks like an interesting watch with good details.

The precise grounding shown is very difficult to hold. In the jewelry trade, they use "carving knives". Usually used with palm handles. They are only a few dollars. Easier to hold and control than precise. I have assortments of different widths from the hairline to 100 mils or better. You can get regular HSS that requires frequent sanding (it's easy to use Dremel or stone). Or, you can get a cemented carbide that can last longer, but you need a diamond grindstone or grinding wheel to sharpen it. Use small wooden blocks with small ledges to secure your planks and avoid stabbing yourself 100 times. Use carbon paper (what's that?!!!) to transfer the lines to the board. Or, paint with Sharp.

Be careful with double-sided PCBs. For 250 million square inches of pads, there is usually 17 pF or 1.5 pF of capacitance per square inch. You need to take this into account in the circuit design and remove copper from the back side (usually ground) if necessary. You can make vias on the back to avoid jumpers. You can carefully lift a corner of the large copper area and peel off the copper to remove the larger area. It is faster and cleaner than scrubbing with a knife. I have been making breadboards this way for decades.

The heat gun makes it about 20 times easier to remove the copper on the back. I use hot air pencils. It peels off like a sticker on a banana. If you use a heavy-duty xacto to place a cutting line on the copper plate, then you can more easily use the engraving machine to cut along this line. I want something that can separate the two wires by about 0.2mm, because then I can strip the 0.2mm wires and get a nice wide spacing. At work, I use the LPKF board plotter, and set the insulation width according to the voltage, and then use a hot air pencil to peel off the copper in the middle (or all copper without mesh, if there is a problem with the capacitor). The board came out very well, which is really helpful to our designers. We can make four different board layouts/revisions every day until they get the one they like, and then we turn it into a green board, It will show up after three days. However, sometimes we make 10 or 20 revisions in the first few days.

If you want to remove some of the pads on the prototype board, the heating technique is also very effective. Just place the iron on the heating pad and peel it off with a knife.

This is a cool technique; I have used it many times to build video game prototype cassettes. And thank the author for making and sharing the video.

I personally prefer to use Chan's enameled wire method.

http://elm-chan.org/docs/wire/wiring_e.html

https://cdn.instructables.com/F5K/WU8U/H67NSJA9/F5KWU8UH67NSJA9.LARGE.jpg

...Or there is no free space.

I need some small boards, but don't waste the entire $2 blue paper on two small boards (for example, less than one square inch). So I took out the diamond file kit and drew it freehand like this. I think the best takeaway here is the tool he created, which is much cleaner than the triangular diamond file I usually use. I will make one now.

Ah yes, this is one thing I have used, the end of a needle file. I have been trying to remember my "preferred tool", but it seems that I use different things every time because I don't do it often. The other thing is that the broken hacksaw blade keeps the teeth tilted towards you, and the last tooth at the end is more or less the same shape as his edge. Then I used drywall screws, they are always harder steel and stay pointed. However, recently, I have a toothpick with a backhoe-shaped end, and I grade it with any high-definition craft knife or pocket knife I have on hand, and then rake it out. I may have abused the pointed ends of scissors and side cutters.

For people with "no shop and no worries", drywall screws may be easy to make "circuit screws"* Just get 4 to 6 inches of 3/4 to 1 1/4 round or square or any cork or dowel Or a wooden broomstick and pass the drywall screw through it at an angle, close to but not too close to the end, and lean toward the rest of the handle. (Make a number 7)

* Or give it a more beautiful name, a discontinuous furrow insertion tool.

* The following is a series of Manhattan-style architectural techniques not mentioned in the YouTube video:

* OLFA 1090486 PC-L plastic/laminate scriber Amazon "plexiglass cutter" option $13.45

https://www.amazon.com/dp/B003UHUZ5U

* OLFA 5014 PB-800 plastic/laminated blade, 3 packs $8.08

https://www.amazon.com/OLFA-5014-PB-800-Plastic-Laminate/dp/B000BNLJ38

* YouU 1 acrylic knives and 10 blade sets, multi-purpose knives with cutting blades Brand: YouU $9.69

https://www.amazon.com/dp/B07S75XBYS

https://www.vectorelect.com/pad-cutters.html

* Use a drill to cut the island into a copper clad laminate

https://www.youtube.com/watch?v=RKdsXU5iIF0

* PCB tip, used to create the tip of the pad on the continuously coated PCB

https://www.youtube.com/watch?v=uFLdDTT5-wk&feature=relmfu

What you do here is to cut a solid copper-clad PCB (can be 1 or 2 sides) into pads-square, rectangular, any size, depending on the circuit layout of any method you use (hint: bite tool may Very useful, especially for small pads), and then glue the cut out part (copper side up) on the surface of another solid copper-clad PCB (it can be 1 side or 2 sides, copper side up). This large solid copper-clad PCB is used as a ground plane. Some people prefer to use double-sided tape (not foam type) instead of glue, so that the pads can be lifted and moved, and after the prototype is completed, all (or part) of the pads may be removed, so the basic copper- Overlay PCB can be reused. Usually, the manufacturer cuts a bunch of small square pads. These are useful for small components connected to ground and jumper pads for multiple wire connections. These small pads can be pre-cut and purchased. A commercial example is called MeSquares (see below), which includes a series of adhesive SMT component adapters.

* Here are a few examples of this construction style:

https://hackaday.com/wp-content/uploads/2016/05/original.jpg

https://hackaday.com/wp-content/uploads/2016/05/0gfwt.jpg

* MeSquares pre-cut isolation pad and SMT upright adapter

http://qrpme.com/?p=product&id=SAM

* This is an example of a small tool that can be used to cut isolated pads:

* Parts Express nickel-plated nibbling tool $13.28

https://www.amazon.com/Parts-Express-Nickel-Plated-Nibbling/dp/B0002KRACO

Those Vector pads: too sexy. Also suitable for use with slats.

Thin copper tape, if it has an insulating backing. Cut out small squares and stick them on the original PCB. Welding, complete.

Or buy the scissor epoxy PCB material they use for multilayer board construction. I bought a few square meters of random sheets from Electronics Goldmine or All Electronics at a cheap price that day, but I was still running out of these stocks. To be honest, I use it instead of thick single-sided PCB for small jobs where the structure is not important, just b/c I am too lazy to go to the basement to cut thicker things. This is very useful for the rapid SMD breakthrough in Manhattan.

https://pbs.twimg.com/media/Bt5156ZCMAAPntv?format=jpg&name=large

You can also design your own circuit board patterns, such as double-sided copper-clad, with small islands with grid patterns on the top. Add some SMA/BNC edge connectors, install holes in the corners, and then spend a few dollars to buy a bunch of boards made in China. If you already know some specific components that will be used, please add these packages to the board.

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