With the price and speed of custom PCBs becoming so cheap, it makes little sense to reproduce your own PCBs, especially when you consider messy etching steps and suboptimal results. Of course, this is not the only way to create a PCB. If you happen to be able to use a 20-watt fiber laser, you can get some beautiful homemade PCBs that are difficult to distinguish from commercial circuit boards.

Fortunately, Kurokesu's well-known [Saulius Lukse] had such a laser on hand. Through a carefully adjusted tool chain and some compromises, he was able to produce a PCB with a 0.1 mm pitch in 30 minutes. Compromises include single-sided boards and no through holes, but this should still allow many different useful designs. The process starts with Gerbers through FlatCAM, and then is imported into EZCAD for laser processing. Quite a few manual adjustments are required before the laser starts to burn off the copper between the traces. The 0.035 mm foil on FR4 requires about 20 passes. We have to admit that watching the cutting process in the video below is very cool.

After cutting the traces, apply UV-curing solder resist to the entire board. After curing, the circuit board returns to the laser for another pass to expose the pads. In the last few times, the finished board was cut by adjusting the laser to 11 times. We want to know why laser drilling is not used; we know that through-holes are difficult to connect to the other side, but it seems that through-hole components can be supported. Maybe this is where [Saulius] will eventually go, because there are traces that end in what appears to be a through-hole pad.

No matter what the goal is, these boards are very smooth. We usually see the use of laser to remove resist before traditional etching, so this is a good change.

How to be faster and/or more effective (energy, time, etc.) compared to traditional methods (mask transfer)?

Sometimes, we trade speed/efficiency for the coolness factor.

Let your CNC milling machine or laser do better in terms of working hours-you spend the same time drawing and layout, and then let the machine do most of the work for you (and the machine is easier to get excellent double-sided effect boards).

Manual mask transfer, repair of defects, and then etching all require supervision or manual participation.

Q: Light-curing resin is commonplace, why not make ionized resin suitable for electroless plating? Plated through holes are made in such a way that the chemicals injected into the through holes will cause the metal to be plated from the plating solution. If the resin can do the same thing, people can print traces and plate them in a simple bath without having to burn anything. Additive engineering is the future...

In a DIY environment? To be fair... the only chemical that needs to be stored is the solder mask, and the laser engraving machine does not have any consumables.

Since chemicals are rarely used, the workload is low... Lithography is very troublesome. This is higher than the transmission quality.

I will not give this machine in my room.

I guess it’s time to tear off the laser diode from the old CD burner?

The CD recorder diode does not help. You need pulse energy. In fact, the fiber laser machine is very cheap, the price starts from $1.5k

Oh. Mind how many links?

I hope my financial situation can say that $1500 is "very cheap!"

Well, it is not cheap. Not long ago, the price tag was about US$5,000, and local greedy dealers charged US$20,000 for machines of similar specifications. So it makes it "quite cheap" :)

If you can accept the intermediate steps involving chemical etching, then cheap laser engraving machines can be used.

If the engraving machine laser can burn the UV solder mask, you can use the solder mask as a chemical etching resist, and then burn off the resist on the pad.

You can paint on the PCB board, then use a laser to spray the paint off, and then etch as usual.

This works, although the laser spot size of my makerspace is too large (cannot leave a trace between two 0.1 inch pads).

Take a look at Sarbar's video, it will *appear* that a well-tuned CO2 laser system can etch thin enough lines for this. Obtaining any well-tuned laser is a project in itself, but if you can succeed, it will be a huge benefit for hackers.

If you want to try, you can start with regular black spray paint, and then bake the board to make sure all the paint dries well.

I will try to use my SLA printer soon because it has a higher resolution. It should be possible to lay a single (or a small amount) layer directly on the copper board and then etch from it. SLA printers are now very cheap.

It worked for me with the help of chemistry: https://hackaday.io/project/26216-pcb-exposer

Good result! thanks for sharing!

Sell ​​me a pair. One for my shop and the other for my garage.

Actually you are completely wrong, you don’t need a $1.5K fiber laser, you can use a 405nm blue laser diode and a 3-element lens to connect a good 3d/CNC printing bed frame and get excellent results, photoresist and etching The sensitization is a long process and requires some trial and error. This is the "ultraviolet laser" and photoresist used in today's most advanced factories... But I am on your boat, but get a budget-friendly 1.5K Dollar fiber laser, it saves a lot of time and trouble, and you will always use fiber laser to get reproducible results. I saw some 405nm fiber lasers, which I plan to use telecentric lenses to obtain.

Well, the whole experiment is to eliminate etching and machining. But glad you mentioned the poor man's solution :)

Unfortunately, it will not be strong enough. In addition, you do need fiber lasers to process metals.

Today's advanced factories do not use fiber lasers to burn copper, which is a stupid way of doing things, mainly because it is very expensive and inefficient. They used a UV laser with a wavelength close to 405nm or below to sensitize the photoresist film applied on the FR4 copper-clad layer and etch it away. This is more logical. Even aerospace and military grade PCBs do not even use fiber lasers. However, they may indeed use lasers to make vias. There are advantages and disadvantages to using lasers to make vias...

Of course they didn't! In fact, they use ultraviolet lamps instead of ultraviolet lasers. The process I described is very useful for rapid prototyping, with minimal PCB processing between different process stages. For single-sided, drilled and green solder mask coated boards, 30 minutes is an acceptable time, right?

Good ventilation and eye protection are a must

> Maybe this is where [Saulius] will eventually go, because there are traces that end in what appears to be a through-hole pad.

That, and it is still possible to use CNC drilling is still faster and easier.

In fact, the 0.2mm vias and holes are well designed: https://kurokesu.com/uploads/0.2mm_vias_drilled_with_laser.jpg The workflow will be updated in a few days.

@sauliuslukse Please also post some pictures of your laser machine. What model is it?

My laser is an old model with countless manufacturers: https://www.google.com/search?q=20w fiber laser marking machine&source=lnms&tbm=isch&sa=X

Oh cool, can you share your settings? I would love to try my raycus 30w

@steph (HaD will not let you reply to your comments) Please check the original blog post. It has all the details. Feel free to share your results!

This is how they "drill" micro-holes on the PCB. The trick part of DIY is to put the plating in the small holes to connect the top and bottom layers.

A small number of circuit boards can be processed faster and easier by just using a drill press.

Some people would think that someone would create a DIY multi-layer PCB creation machine.

If you disagree, please check how the laser drills a 0.2mm hole. It took about 5 minutes: https://kurokesu.com/uploads/0.2mm_vias_drilled_with_laser.jpg

I can almost smell the burning glass fiber in the video.

I think burning FR4 will run the risk of carbon conduction between the traces, but it is still very cool.

For vias: the ink from the CurcuitScribe pen ($6.99) will connect the traces from one side to the other through a sub-ohm resistor. In addition to our prototype silver ink printer (no drilling), we have traditionally used LPKF (Printed Circuit Board Grinding Machine) for prototyping. Capillary action pulls the ink through, so hole diameter and hole roughness are important. We do not have a fiber laser available for testing.

I work for the parent company of CircuitScribe: Electroninks.

Neat, I think copper is difficult to process with laser because it absorbs heat too fast.

Me too, I assume this is because it is a crazy high-power laser, used for short pulses with multiple passes; there is no time for heat to conduct and dissipate

When I read "Single Panel, No Through Hole", this is where I lost interest.

The technology is impressive, but who wants a single panel?

I checked the Arduino Nano clone, which is a very simple circuit board. It is a 2-sided circuit board with 92 vias.

If you read this article (or his update to your other previous comments), you will find that he did take advantage of the loopholes. My friend, read more than just the headlines.

Double-sided should be a trivial fixture. Working on my 405nm "exposer" (when I have time) I just turn the board over and align it on the other side of the fixture, which is the known distance from the other aligned edge.

Then my software simply flipped the calculation, and I got a good alignment.

I can make double panels by aligning the toner on the paper-this should be a breeze for CNC lasers. Homing the axis, place the board in the registration fixture, and it's done.

I bet Saulius just hasn't tried it yet. But now he has been playing the hole, I guess it won't be long.

I also like the method of covering all the solder masks and etching away the parts you want to remove. I would have used a UV laser and cured the parts to keep it, but just because of the relative surface area, it will take longer.

Elliot, thank you for your interest in the dual panel. Of course, these can be unfolded by vertical symmetrical flipping. It requires very little preparation.

Of course, we can consider using a DIY double-sided board with plated vias. My ultimate goal is to have a simple high-pitch PCB for rapid prototyping.

The company I worked for had a complete LPKF tool set for milling, plating, and laminating multilayer PCBs. I can say that the multi-layer printing machine has only been turned on once-try to see if it works... The electroplating bath is used more, but even commercial-grade equipment can sometimes be troublesome. PCB Milling CNC is a lifesaver in rapid prototyping and test design.

Does anyone know if there is any open source (Linux friendly) alternative to EZCAD that can be used with one of the fiber laser machines?

This seems to be the real weakness in this workflow.

This type of laser uses a galvanometer to scan the beam from a fixed position through a lens. For most boards, the beam is not perpendicular to the board, so the use of laser drilling will cause the hole to be drilled at an angle. Similarly, when the board is cut freely, there will be a chamfer on the edge, the larger the board, the more obvious the chamfer.

You need a flying head machine (just like most CO2 or diode lasers work), this is our exquisite optics, which ensures that the through holes are perpendicular to the circuit board.

Note: These machines also use f-theta lenses, which can flatten the focal plane and keep the spot size fairly round in the cutting area. There will be some deviations, but it is already pretty good. The bigger problem is that as the focal plane changes, the cutting area will increase/shrink, and _that_ will definitely introduce some taper.

A simple solution is to use a "telecentric scanning lens", which provides true 2D vector scanning, while keeping the scanning surface always in focus, no more curved vias, etc. But I have to say that what you mentioned is a valid question, and most people are not aware of galvanometer scanners that use non-telecentric f-theta lenses.

Why is it so hard to find people who sell fiber lasers? I think half of the lists on eBay are baits and switches. Amazon seems to be overpriced. Ali seems to exclude all costs related to imports from any description.

Technically speaking, import duties and fees are the buyer's responsibility. In addition, the gross weight of the transportation is usually more than 25 kg, which belongs to the category of "heavy package" and is not suitable for transportation without a trolley or forklift.

You will not buy them from eBay or Amazon, but buy them on AliExpress for $1.3K (excluding shipping)... You can thank me later. I would rather use a telecentric lens to get a true 2D etching scan.

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