vvzvlad March 25, 2014 at 05:11 AM

How do printed circuit boards: excursion to Technotech plant

• Madrobots Blog

Today we will perform in a slightly unusual role for ourselves, we will not talk about gadgets, but about the technologies behind them. A month ago we were in Kazan, where we met the guys from. At the same time, we visited a nearby (well, relatively close) PCB manufacturing plant - Technotech. This post is an attempt to understand how the same printed circuit boards are produced.


So how do we make printed circuit boards for our favorite gadgets?

The factory knows how to make boards from start to finish - designing a board according to your technical specification, manufacturing fiberglass, production of single-sided and double-sided printed circuit boards, production of multilayer printed circuit boards, marking, checking, manual and automatic assembly and soldering of boards.
First, I'll show you how double-sided boards are made. Their technical process is no different from the production of one-sided printed circuit boards, except that during the manufacture of OPPs, operations are not performed on the second side.

About PCB Manufacturing Methods

In general, all methods of manufacturing printed circuit boards can be divided into two broad categories: additive (from Latin additio-addition) and subtractive (from Latin subtratio- subtraction). An example of subtractive technology is the well-known LUT (Laser Ironing Technology) and its variations. In the process of creating a printed circuit board using this technology, we protect future tracks on the fiberglass sheet with toner from laser printer, and then bleed off all unnecessary in ferric chloride.
In additive methods, the conductive tracks, on the contrary, are applied to the surface of the dielectric in one way or another.
Semi-additive methods (sometimes they are also called combined.) Are a cross between the classical additive and subtractive. During the production of PCBs using this method, part of the conductive coating can be etched away (sometimes almost immediately after application), but as a rule this is faster / easier / cheaper than in subtractive methods. In most cases, this is due to the fact that most of the thickness of the tracks is built up by electroplating or chemical methods, and the layer that is etched is thin and serves only as a conductive coating for electroplating.
I will show exactly the combined method.

Manufacturing of two-layer printed circuit boards using the combined positive method (semi-additive method)

Manufacturing of fiberglass

The process begins with the manufacture of foil-clad fiberglass. Fiberglass is a material consisting of thin sheets of fiberglass (they look like a dense shiny fabric), impregnated with epoxy resin and pressed in a stack into a sheet.
The fiberglass canvases themselves are also not too simple - they are woven (like ordinary fabric in your shirt) thin, thin threads of ordinary glass. They are so thin that they can bend easily in any direction. It looks something like this:

You can see the orientation of the fibers in the long-suffering picture from Wikipedia:


In the center of the board, the light areas are the fibers perpendicular to the cut, the slightly darker areas are parallel.
Or, for example, in a photomicrograph, as far as I remember from the article:

So, let's begin.
The fiberglass cloth goes into production in the following bobbins:


It is already impregnated with partially cured epoxy resin - this material is called prepreg, from the English pre-im preg nated - pre-impregnated. Since the resin is already partially cured, it is no longer as sticky as in the liquid state - the sheets can be handled without fear of getting dirty in the resin. The resin will only become liquid when the foil is heated, and then only for a few minutes before completely solidifying.
The required number of layers together with copper foil is assembled on this device:


And here is the foil roll itself.


Next, the canvas is cut into pieces and enters the press with a height of two human heights:


In the photo, Vladimir Potapenko, production manager.
The technology of heating during pressing is implemented in an interesting way: it is not the parts of the press that are heated, but the foil itself. A current is supplied to both sides of the sheet, which, due to the resistance of the foil, heats the sheet of the future fiberglass. Pressing takes place at a strongly reduced pressure, to exclude the appearance of air bubbles inside the PCB


When pressed, due to heating and pressure, the resin softens, fills the voids and after polymerization, a single sheet is obtained.
Like this:


It is cut into blanks for boards with a special machine:


Technotech uses two types of blanks: 305x450 - small group blank, 457x610 - large blank
After that, a route map is printed for each set of blanks, and the journey begins ...


A route map is a piece of paper with a list of operations, information about the board and a barcode. To control the execution of operations, 1C 8 is used, which contains all the information about orders, about the technical process, and so on. After completing the next stage of production, the barcode on the route sheet is scanned and entered into the database.

Drilling workpieces

The first step in the production of single-layer and double-layer PCBs is drilling holes. With multilayer boards, things are more complicated, and I will talk about this later. Workpieces with route sheets are delivered to the drilling section:


A package for drilling is assembled from the blanks. It consists of a substrate (material such as plywood), one to three identical PCB blanks and aluminum foil. The foil is needed to determine the contact of the drill with the surface of the workpiece - this is how the machine determines the breakage of the drill. Every time he grips the drill, he controls its length and sharpening with a laser.


After assembling the package, it is put into this machine:


It is so long that I had to stitch together this photo from several frames. This is a Swiss machine from Posalux, unfortunately I don’t know the exact model. According to its characteristics, it is close to this. It eats three times a three-phase power supply with a voltage of 400V, and consumes 20 kW during operation. The weight of the machine is about 8 tons. It can simultaneously process four batches using different programs, which gives a total of 12 boards per cycle (naturally, all workpieces in one batch will be drilled the same way). Drilling cycle - from 5 minutes to several hours, depending on the complexity and number of holes. Average time is about 20 minutes. Technotech has three such machines in total.


The program is developed separately and uploaded over the network. All the operator needs to do is scan the batch barcode and put the package of blanks inside. Tool magazine capacity: 6000 drills or cutters.


There is a large cabinet with drills nearby, but the operator does not need to control the sharpening of each drill and change it - the machine knows the degree of wear of the drills all the time - it records in its memory how many holes were drilled with each drill. When the resource is exhausted, he himself changes the drill to a new one; the old drills will have to be unloaded from the container and sent for re-sharpening.


This is how the insides of the machine look like:


After drilling, a mark is made in the route sheet and the base, and the board is sent one stage at a time to the next stage.

Cleaning, activation of blanks and chemical copper plating.

Although the machine uses its own "vacuum cleaner" during and after drilling, the surface of the board and holes still need to be cleaned of dirt and prepared for the next technological operation. To begin with, the board is simply cleaned in a cleaning solution with mechanical abrasives.


Labels, from left to right: "Brush chamber up / down", "Rinse chamber", "Neutral zone".
The board becomes clean and shiny:


After that, in a similar installation, the surface activation process is carried out. A serial number is entered for each surface. Surface activation is preparation for depositing copper on the inner surface of the holes to create vias between the board layers. Copper cannot settle on an unprepared surface, so the board is treated with special palladium-based catalysts. Palladium, unlike copper, is easily deposited on any surface, and later serves as centers of crystallization for copper. Installation activation:

After that, successively passing several baths in another similar installation, the workpiece acquires a thin (less than a micron) layer of copper in the holes.


Further, this layer is increased by electroplating to 3-5 microns - this improves the resistance of the layer to oxidation and damage.

Application and exposure of photoresist, removal of underexposed areas.

Then the board is sent to the area for applying the photoresist. We were not allowed there, because it is closed, and in general, there is a clean room, so we will limit ourselves to photographs through glass. I saw something similar in Half-Life (I'm talking about pipes descending from the ceiling):


Actually, the green film on the drum is the photoresist.


Further, from left to right (in the first photo): two installations for applying a photoresist, then an automatic and manual frames for illumination according to previously prepared photomasks. The automatic frame has a control that takes into account the alignment tolerance with fiducials and holes. In a hand-held frame, the mask and the board are aligned by hand. Silk-screen printing and a solder mask are exhibited on the same frames. Further - installation of development and cleaning of boards, but since we did not get there, I have no photos of this part. But there is nothing interesting there - about the same conveyor as in "activation", where the workpiece passes sequentially through several baths with different solutions.
And in the foreground is a huge printer that prints these very photomasks:


Here is the board with applied, exposed and developed:


Please note that the photoresist is applied to the places where in the future will not copper - the mask is negative, not positive, as in LUT or home photoresist. This is because in the future the build-up will take place in the places of future tracks.


This is also a positive mask:


All these operations take place under non-actinic lighting, the spectrum of which is selected in such a way as not to affect the photoresist at the same time and to give maximum illumination for a person to work in a given room.
I love ads, the meaning of which I do not understand:

Galvanic metallization

Now came through her majesty - galvanic plating. In fact, it was already carried out at the last stage, when a thin layer of chemical copper was built up. But now the layer will be increased even more - from 3 microns to 25. This is the layer that conducts the main current in the vias. This is done in these baths:


In which complex electrolyte compositions circulate:


And a special robot, obeying the laid down program, drags boards from one bath to another:


One copper plating cycle takes 1 hour and 40 minutes. One pallet can handle 4 workpieces, but there can be several such pallets in the tub.

Metal resist deposition

The next operation is another galvanic metallization, only now the deposited material is not copper, but POS - lead-tin solder. And the coating itself, by analogy with a photoresist, is called a metal resist. The boards are installed in the frame:


This frame goes through several galvanic baths we are already familiar with:


And covered with a white layer of POS. In the background, another board is visible, not yet processed:

Photoresist removal, copper etching, metal resist removal

Now the photoresist is washed off the boards, it has fulfilled its function. The still copper board now has metal resist-coated tracks. On this installation, etching takes place in a tricky solution, which etches copper, but does not touch the metal resist. As far as I remember, it consists of ammonium carbonate, ammonium chloride and ammonium hydroxide. After etching, the boards look like this:


The tracks on the board are a "sandwich" of the lower copper layer and the upper layer of the galvanic POS. Now, with another even more tricky solution, another operation is carried out - the POS layer is removed without affecting the copper layer.


True, sometimes the POS is not removed, but is melted in special furnaces. Or the board is hot-tinned (HASL-process) - when it is lowered into a large bath of solder. First, it is coated with rosin flux:


And it is installed in this machine:


He lowers the board into the solder bath and immediately pulls it back out. Air currents blow off excess solder, leaving only a thin layer on the board. The board turns out like this:


But in fact, the method is a bit "barbaric" and does not really work on boards, especially multilayer ones - when immersed in the solder melt, the board suffers a temperature shock, which does not work very well on the internal elements of multilayer boards and the thin tracks of one- and two-layer boards.
It is much better to cover with immersion gold or silver. Here is some very good information on immersion coatings, if anyone is interested.
We did not visit the site of immersion coatings, for a banal reason - it was closed, and it was too lazy to go for the key. It's a pity.

Electrotest

Further, almost finished boards are sent for visual inspection and electrical test. An electrical test is when the connections of all contact pads are checked to each other, if there are any breaks. It looks very funny - the machine holds the board and quickly pokes the probes into it. You can watch a video of this process on my instagram (by the way, you can subscribe there). And in the form of a photo it looks like this:


That big car on the left is the electrical test. And here are the probes themselves closer:


In the video, however, there was a different machine - with 4 probes, and here there are 16. They say that it is much faster than all three old machines with four probes combined.

Solder mask application and pad coating

Next technological process- application of a solder mask. The same green (well, most often green. In general, it comes in very different colors) coating that we see on the surface of the boards. Prepared boards:


They are put into such a machine:


Which, through a thin mesh, smears a semi-liquid mask over the surface of the board:


By the way, you can also watch the video of the application on Instagram (and subscribe too :)
After that, the boards are dried until the mask stops sticking, and are exhibited in the same yellow room that we saw above. After that, the unexposed mask is washed off, exposing the contact patches:


Then they are covered with a top coat - hot tinning or immersion coating:


And they mark them - silk-screen printing. These are white (most often) letters that show where which connector is and which element is located here.
It can be applied using two technologies. In the first case, everything happens in the same way as with a solder mask, only the color of the composition differs. It covers the entire surface of the board, then it is exposed, and the uncured UV areas are washed off. In the second case, it is applied by a special printer that prints with a cunning epoxy composition:


It is both cheaper and much faster. The military, by the way, do not like this printer, and constantly indicate in the requirements for their boards that the marking is applied only with a photopolymer, which greatly upsets the chief technologist.

Manufacturing of multilayer printed circuit boards using the through-hole metallization method:

Everything that I described above concerns only one-sided and double-sided printed circuit boards (by the way, no one calls them that at the factory, everyone says OPP and DPP). Multilayer boards (MPP) are made using the same equipment, but using a slightly different technology.

Making cores

The core is the inner layer of a thin PCB with copper conductors on it. There can be from 1 such cores in the board (plus two sides - a three-layer board) to 20. One of the cores is called gold, which means that it is used as a reference layer, along which all the others are exposed. The kernels look like this:


They are made in the same way as ordinary boards, only the thickness of the fiberglass is very small - usually 0.5 mm. The sheet turns out to be so thin, then it can be bent like thick paper. Copper foil is applied to its surface, and then all the usual stages take place - application, exposure of the photoresist and etching. The result is the following sheets:


After manufacturing, the tracks are checked for integrity on the machine, which compares the picture of the board in the light with a photomask. In addition, there is also visual control. Moreover, it is really visual - people are sitting and looking at the blanks:


Sometimes one of the control stages makes a verdict about the poor quality of one of the blanks (black crosses):


This sheet of boards, in which a defect occurred, will still be completely manufactured, but after cutting, the defective board will go to the trash. After all the layers are made and checked, the next technological operation begins.

Assembly of kernels into a package and pressing

This takes place in a hall called "Pressing area":


The cores for the board are laid out in this stack:


And next to it is a map of the location of the layers:


Then comes into play semi-automatic machine pressing boards. Its semiautomatic nature lies in the fact that the operator must, at her command, feed her kernels in a certain order.


Repositioning them for insulation and bonding with prepreg sheets:


And then the magic begins. The machine captures and transfers sheets to the working area:


And then he aligns them along the reference holes relative to the gold layer.


Then the workpiece enters the hot press, and after heating and polymerization of the layers - into the cold one. After that, we get the same sheet of fiberglass, which is no different from blanks for two-layer printed circuit boards. But inside it has a kind heart, several cores with formed paths, which, however, are not yet connected in any way and are separated by insulating layers of polymerized prepreg. Then the process goes through the same stages that I described earlier. However, with a slight difference.

Drilling workpieces

When assembling the OPP and DPP package for drilling, it does not need to be centered, and it can be assembled with some tolerance - all the same, this is the first technological operation, and everyone else will be guided by it. But when assembling a package of multilayer printed circuit boards, it is very important to bind to the inner layers - when drilling, the hole must go through all the internal contacts of the cores, connecting them in ecstasy during metallization. Therefore, the package is assembled on this machine:


This is an X-ray drilling machine that sees through the textolite internal metal fiducial marks and, according to their location, drills base holes into which fasteners are inserted to install the package into the drilling machine.

Metallization

Then everything is simple - the workpieces are drilled, cleaned, activated and metallized. Hole plating connects all copper heels inside the PCB:


Thus, completing electronic circuit the insides of the printed circuit board.

Inspection and thin sections

Further from each board, a piece is cut, which is ground and examined through a microscope, in order to make sure that all the holes are normal.


These pieces are called thin slices - cross-cut pieces of a printed circuit board that allow you to assess the quality of the board as a whole and the thickness of the copper layer in the center layers and vias. In this case, not a separate board is allowed under the thin section, but the entire set of vias diameters specially made from the edge of the board, which are used in the order. A cut, embedded in transparent plastic, looks like this:

Milling or scribing

Further, the boards that are on the group workpiece must be divided into several parts. This is done either on a milling machine:


Which cuts the desired contour with a cutter. Another option is scribing, this is when the outline of the board is not cut, but cut with a round knife. It is faster and cheaper, but only allows you to make rectangular boards, without complex contours and internal cutouts. Here is the scribed board:

And here is milled:


If only the manufacture of boards was ordered, then it all ends there - the boards are put in a pile:


It turns into the same route sheet:


And waiting to be sent.
And if you need assembly and sealing, then there is still something interesting ahead.

Assembly

Further, the board, if necessary, goes to the assembly site, where the necessary components are soldered onto it. If we are talking about manual assembly, then everything is clear, people are sitting (by the way, most of them are women, when I went to them, my ears curled into a tube from the song from the tape recorder "God, what a man"):


And collect, collect:


But if we talk about automatic assembly, then everything is much more interesting. This happens on such a long 10-meter installation, which does everything - from applying solder paste to soldering using thermal profiles.


By the way, everything is serious. Even the rugs are grounded there:


As I said, it all starts with the fact that on an uncut sheet with printed circuit boards, together with a metal template, they are installed at the beginning of the machine. Solder paste is thickly smeared on the template, and the doctor blade passing from above leaves precisely measured amounts of paste in the recesses of the template.


The template is lifted up and the solder paste is in the right places on the board. Component cassettes are installed in compartments:


Each component is fed into the corresponding cassette:


The computer controlling the machine is told where which component is located:


And he begins to arrange the components on the board.


It looks like this (the video is not mine). You can watch forever:

The component installer is called the Yamaha YS100 and is capable of installing 25,000 components per hour (one takes 0.14 seconds).
Then the board goes through the hot and cold zones of the stove (cold means "only" 140 ° C, compared to 300 ° C in the hot part). Having been strictly certain time in each zone with a strictly defined temperature, the solder paste melts, forming one whole with the legs of the elements and the printed circuit board:


A sealed board sheet looks like this:


Everything. The board is cut, if necessary, and packaged to leave soon to the customer:

Examples of

Finally, some examples of what technotech can do. For example, design and manufacture of multilayer boards (up to 20 layers), including boards for BGA components and HDI boards:


C with all "numbered" military approvals (yes, each board is manually stamped with a number and date of manufacture - this is required by the military):


Design, manufacture and assembly of boards of almost any complexity, from our own or from the customer's components:


And RF, microwave, boards with a metallized end face and a metal base (I did not take photos of this, unfortunately).
Of course, they are not a competitor to resonate in terms of fast prototypes of boards, but if you have more than 5 pieces, I recommend asking them for the cost of manufacturing - they really want to work with civil orders.

And yet, there is still production in Russia. Whatever they say.

Finally, you can catch your breath, raise your eyes to the ceiling and try to understand the intricacies of pipes:

For manufacturers electronic devices PACIFIC microelectronics offers the most important: high quality and fast production at affordable prices of printed circuit boards, electronic modules, keyboards and LCD displays, turnkey products.

More than 27 years of experience of our company in the production of electronic products and strict control of all stages of production by Russian technicians, as well as the latest machines and lines ensure high quality products.

Our company provides a full range of services for the production of any electronic products for our customers strictly in accordance with technical documentation: production of printed circuit boards of any accuracy class and of any complexity, purchase and completion of electronic components and materials, programming any microcircuits, if necessary, automatic installation of electronic components on printed circuit boards (SMD-assembly, DIP-assembly, installation of BGA microcircuits, molding of output components, etc.), production of cables and harnesses, plastic cases, keyboards and displays of various types, final assembly of the electronic module into the case, 100% functional testing of all products in production, production of printed circuit boards, packaging and labeling of products, customs clearance and delivery "to the door" of the customer.

In addition, we provide services for applying moisture-proof coatings to electronic modules. At present, the application of this type of coating is the most optimal technology to ensure the reliability of the operation of products in harsh climatic conditions and when exposed to other aggressive factors (chemicals, organic formations, etc.).

Our many years of experience work allows us to work together with the customer to reduce the cost of production of his products, to book and reserve component materials in order to accelerate production cycle, improving production technologies, redesigning products to improve manufacturability.

The technological capabilities of our production allow us to manufacture printed circuit boards, electronic modules or finished products in strict accordance with modern requirements for electronics, which is confirmed by certificates. Manufacturing of products and manufacturing of printed circuit boards to order is carried out only on automated lines of the latest generation, the technology is brought to perfection. Also, in the production process, careful quality control is carried out, checks are carried out for compliance with key indicators, different methods testing and control (X-ray, automatic optical inspection, adapter and electronic testing, functional testing according to the customer's method, visual inspection, etc.). Also performed incoming control materials supplied to production sites, allowing high-quality production and manufacture of printed circuit boards in Moscow.

With our own production facilities, we focus on complex solution the tasks set by our clients and the direct ability to manage the timing of the release of products in accordance with the wishes of our customers and partners. Today for us there are no restrictions either on the complexity of the projects being carried out, or on their volume.

Work of the division of laser cutting of stencils during the New Year holidays:

In 2014-2015, orders will be shipped until 12/30/2014 inclusive. During all holidays orders can be sent both to email, and through the order service around the clock. The mail will be checked by us. Orders will be processed and, as accumulated, will be produced and dispatched immediately on the first post-holiday days (starting 12/01/2015).

In 2013, orders will be shipped until 12/30/2013 inclusive. During all holidays, orders can be sent both by e-mail and through the order service around the clock. As they accumulate, they will be made and shipped on the first post-holiday days (09-10 / 01/2014).

A new steel thickness - 0.180mm became available for ordering. Recommended for adhesive stencils and various parts.

A new steel thickness of 0.250mm has become available for ordering. Recommended for adhesive stencils and various parts.
Also, earlier finished thicknesses of 0.08mm, 0.1mm, 0.2mm, 0.3mm were delivered to the warehouse. All thicknesses are currently in stock.

We inform you about the start of work of our new division PRONTO5 (www.pronto5.ru).

The division is engaged in the urgent production of single batches of parts. Manufactured by milling from metals and plastics.

PRONTO5 is equipped with a powerful 5-axis vertical milling machining center and a high-precision gantry coordinate measuring machine.

You can learn more about our capabilities on our website www.pronto5.ru

The "Laser-Stencil" division of the "Taberu" company was the first in Russia to master the production of multi-level stencils with variable material thickness!

"Laser-Stencil" produces multi-level stencils both with decreasing (Step-Down Stencil) and increasing the thickness of the material (Step-Up Stencil). Currently, the technology for the production of two, three and four-level stencils has been developed.

The multilevel stencil gives a unique opportunity to apply different amounts of paste through the same apertures in one pass of the squeegee. This is especially valuable when assembling assemblies that use components with different quantitative paste application requirements.

Benefits of tiered stencils:

The customer can provide more paste for certain areas of the stencil using a step-up stencil (thickening of certain areas of the stencil)

The customer can reduce the amount of paste for certain areas of the stencil using a stencil made according to the step-down principle (thinning of certain areas of the stencil)

If the printed circuit board has a thickened surface that interferes with the tight fit of the stencil, cavities can be made in the stencil from the side adjacent to the board to compensate for the protrusions on the printed circuit board.

All stencils at the enterprise are produced on German LPKF equipment in accordance with IPC recommendations.

Separately, full electropolishing of the stencil is offered to facilitate the passage of solder paste through the apertures.

Reinforcement of the stencil edge is carried out by means of resistance welding of additional strips of 0.2 mm material in the area of ​​the perforation apertures.
- Allows to reduce the likelihood of perforation breakthrough for stencils made of thin materials (from 0.1 mm or less).
- Increases the torsional rigidity of the stencil
- Makes the stencil safer to use by dulling the sharp edge

We are pleased to announce that despite the abnormal weather conditions, we are removing restrictions on the production of printed circuit boards with a period of 1, 2 and 3 weeks. Temporarily boards will be produced without electrical testing, but with 100% automatic optical control.

A new thickness has appeared in our range of materials - 0.120mm.

In addition, there are available thicknesses of 0.08mm and 0.100mm, which were temporarily absent from production.

We are pleased to offer a new service when ordering stencils for installation.

When ordering electropolishing, an ultrasonic
stencil cleaning in a special active solution that removes the smallest
defects in laser cutting.
Due to the effect of powerful ultrasound, the solution penetrates
into all holes of the stencil and cleans them from the remnants of small metal particles and
dross arising from laser cutting.
A special active solution acts on the steel of the stencil itself, forcing
smooth out all small irregularities on the surface of the stencil and, most importantly,
on the inner walls of the apertures.
The cleaning procedure used is different from conventional ultrasonic flushing
stencil cleaning solvents used when washing stencils, because
an active solution is used that acts on the stencil steel itself.
This operation is performed only once, during the final electropolishing.
stencil.

Ultrasonic cleaning combined with stencil electropolishing
allows:
- Improve the throughput of the solder paste stencil.
Paste prints are sharper. As a result, the time is shortened.
screen printing and increases the operating time of the stencil between cycles
washing.

Printed circuit boards are the electronic heart of any modern gadget. It is a dielectric plate with electrical conducting circuits deposited on the surface of this plate, or embedded inside it. All electronic components are connected with the help of printed circuit boards. To do this, the component pins are soldered to the board to the mounting pads or holes, and the components interact with each other due to the pattern of the electrical conductive circuits.

Usually, the conductive pattern on the board is made of foil, and the base itself - a dielectric plate - is made of fiberglass, getinax. Printed circuit boards are divided into one-sided OPP (foil on one side), double-sided DPP (foil on both sides), multilayer MPP (obtained by gluing several OPP or DPP together, so that several conductive layers with their own pattern are placed inside the dielectric plate) ... Highest demand use OPP due to the simplicity of manufacture and wide application possibilities. DPP is used less often, since their manufacture is several times more expensive, and the efficiency, in comparison with OPP, is not so high. MPP is used in expensive and compact devices, in everyday life and in small-scale production it is practically not used.

Printed circuit boards: core-dielectric categories

All sheet materials from which printed circuit boards are made are marked with an alphanumeric index FR(flame resistant, flame resistance). The numbers from 1 to 5, after the letters, indicate the quality of the material.

FR-1, FR-2, FR-3- paper impregnated with epoxy special compounds. FR-4, FR-5- fiberglass and epoxy composite. In practice, FR-1 is not used due to its low performance characteristics and fear of moisture. However, it is extremely cheap and is often used to make working prototypes of printed circuit boards with little life cycle... FR-2 is an inexpensive, reliable and high-quality dielectric; boards made of this material are widely used in manufacturing household appliances and large-scale production of printed circuit boards. FR-4 is used in the production industrial equipment and small-scale (piece) manufacturing of PP.

Printed circuit boards: manufacturing methods

The fundamental methods of manufacturing printed circuit boards can be divided into two large types - additive (from Latin additio-addition) and subtractive (from Latin subtratio- subtraction). In the first case, an electrically conductive pattern is formed in various ways on the basis of the future printed circuit board (usually by a chemical method) through a special mask. In the second case, a sheet foil is applied to the dielectric plate, then, a mask of the future circuit is formed on top and with the help of different ways(laser, chemical etching, mechanical removal) unnecessary foil sections are removed.

V industrial production, usually combined methods are used. Thus, minimization of the production cost of printed circuit boards is achieved. Also, with the progress in the use of laser technology, industrial laser prototyping machines are increasingly used.

But, whichever setting is chosen for the organization own business, all of them are highly automated and human participation in the process of manufacturing printed circuit boards is reduced to monitoring the parameters of the installation and their timely correction.

Post-processing is the same for boards manufactured in any way - this is an electrical test (checking all contact pads and the pattern for conductivity), applying a solder mask and marking.

To expand your business, you can master the installation supervision of components on printed circuit boards and manufacturing technical documentation, which allows customers to receive a completely finished product.

We open the production of printed circuit boards: business organization, the necessary equipment

The minimum area for opening a production or a workshop for the production of printed circuit boards is 80 m2, excluding the warehouse area. Most equipment requires a 380V three-phase power supply, and chemical equipment, where active solutions are drained, requires the use of special sewage drains. Therefore, it is more expedient to open a similar production in industrial clusters or zones.

General list of requirements for industrial premises:

• Power lines (220 and 380V),
• Industrial hood,
• Compressed air supply and distribution,
• Water supply (general drainage system (city), water demineralization plant for preparation of active solutions),
• Sewer drain for industrial waste.

As a rule, a set of industrial equipment, arranged in the correct manner, with periodic Maintenance according to the regulations, it is capable of working in two shifts without interruptions for ~ 10 years.

Industrial equipment for the production of printed materials includes:

• Machining area... Plants for cutting, drilling, pinning, CNC milling machines. Dielectric sheet preparation.
• Pressing area. Production of foil-cladding, pressing of multilayer printed circuit boards.
• Site of wet processes. Manufacturing and installation of electrical conductive circuits on a dielectric sheet. Installations for chemical cleaning, oxidation, copper plating, development, galvanization, etc.
• Topcoat application... Preliminary and final cleaning of boards (mechanical and ultrasonic method), hot tinning, etc.
• Yellow room. Exposure and lamination of printed circuit boards.
• Quality control area.
• Area for marking.

The minimum cost of organizing such a turnkey production is from 350 thousand rubles (initial equipment) to 30 million rubles (multidisciplinary equipment). It is also necessary to allocate 600 thousand rubles for raw materials for initial production - board bases, chemical solutions, foil, copper, etc.

The choice of a set of equipment depends on many parameters of the production itself, as well as on the planned volume and satisfaction of demand. Small-scale production requires inexpensive equipment that can meet the demand for quick and short-term execution of simple orders. The quality and accuracy of boards made on such equipment will satisfy simple or private customers who need no more than 500 boards per year.

It is also possible to organize an enterprise that will work according to the scheme contract manufacturing(mass production of printed circuit boards for a large customer in compliance with the technological cycle and quality control by the customer). Of course, such a production requires significant capital investments, since the participation of business in this niche requires a clear competitive difference, primarily from the southeastern market sector (Taiwan, China, India, etc.), therefore, the equipment must be expensive and upscale. The professionalism of personnel in Russia, which is also a concrete advantage, is guaranteed to us by a high degree of training of specialists in local universities of radio electronics. Hence, contract manufacturing printed circuit boards, in the presence of specialists and good equipment, this is not a fantasy, but a completely ready-made business plan for such an enterprise. After all, the global volume of contract production exceeds $ 40 billion a year, and there is no clear leader region in this industry. Enterprises both in China and in Europe function equally effectively. This is due not only to the unification of production, but also to the quality of workmanship. Therefore, Russian enterprises, organized for contract manufacturing, there is every chance to successfully integrate and function in this niche.

Personnel and other aspects of this business

The main thing in organizing such a business is a clear knowledge and understanding of the processes. Without knowledge, participation in this business possible only in the form of co-investment. And no article with business ideas will change the situation. Therefore, it is assumed that the organizer knows all the features and subtleties, understands what equipment he needs, as well as what specialists are needed at the enterprise.

In a workshop specializing in small-scale production, 4 station wagon operators will be sufficient to monitor the production of printed circuit boards. A quality control specialist and a production manager are also needed. Handymen-movers, accountants, marketers, secretaries and cleaners can be contracted as needed.

Business expansion is possible through the organization of subsidiaries of electronics and electronic devices, where the need for printed circuit boards will be satisfied by the main production.

• Tutorial

Or how to get a designed board without getting up from behind a computer and without using chemicals, an iron or ultraviolet radiation.

How to get a board you designed without getting up from your computer, using only a mouse and keyboard. Getting a board without chemicals, solutions, irons, UV lamps, films, and noxious fumes - isn't that great?

Many novice radio amateurs do not order boards at the factory, but make them at home. If the task is to make one single board, then this decision is justified, but if you need to make 5, 10, 20 boards? Or you cannot start the etching process due to the fact that your significant other does not allow you to arrange a miniature laboratory at home? Or someone is interested in your board / device and you want to sell it? - after all, a board made at the factory - with a mask and silk-screen printing - looks much more beautiful and more solid.

In this post, I would like to tell you how to order a board from the factory, what to look out for and give some guidelines for designing a PCB.

Step-by-step instructions with comments

First thing

The first step is to decide on the plant that will produce your printed circuit boards, and find out the manufacturer's technological standards.

Common parameters

To properly prepare the boards, you need to know the minimum conductor / gap thickness, the minimum and maximum values ​​of the via diameter, minimum size the contact pad of the plated hole, the distance from the edge of the board to the elements. In theory, this is the minimum you need to know to properly route a PCB. This list only sounds so intimidating, in fact, you will remember more than half of this after the first wired board.

PCB Categories

The laminated materials from which the printed circuit boards are made are designated by the FR (flame resistant) indices. FR-1 is the worst, FR-5 is the best.
FR-1, FR-2, FR-3 are paper impregnated with special solutions; Category FR-1 boards are highly hygroscopic, so never use an FR-1 category PCB.
FR-4, FR-5 - fiberglass with epoxy composition.
FR-4 is often used in the manufacture of industrial equipment, while FR-2 is used in the manufacture of household appliances. These two categories are industry standardized, FR-2 and FR-4 boards are suitable for most applications. If you are not chasing an ultra-low price, then I recommend using the FR-4.

Copper foil thickness

I would like to pay special attention to the thickness of the copper foil, all of the above parameters directly depend on this parameter. The standard thicknesses are 18 and 35 microns.
18 microns is used for digital electronics, in which there are no large currents, and there are high requirements for the minimum thickness of the tracks, and 35 microns is used in boards, along the tracks (buses) of which a large current flows, and you need to take into account the cross section, that is, the width of the track (tires ). As an example: high-power audio amplifiers, switching circuits of 220 volts with a decent current (5 or 10 A, where, due to the required gap, it is difficult to make a wide - with a large cross-section, conductive bus)
At the same time, small digital elements - microcontrollers, FPGAs, and so on - can easily be located on a board with a thickness of 35 microns.
For 35 μm the minimum clearance / track width is 0.24 mm - not very large, but for 18 μm the minimum clearance / track width is 0.1 mm.
Non-standard thickness - 70 microns and / or 105 (100) microns - is used on purely power boards. On such a board, due to a gap of 0.31 mm, you cannot place many surface microcircuits, for example, an atmega in a QFT package, but you can place output elements without problems. And with the same current on a board with 105 microns, the track width will be 3 times less than on a 35 micron board.
The basic rule that I would recommend using is the maximum allowable thickness. But don't sacrifice components, I always order 35 microns due to the use of surface chips. The layout of any board begins with determining the overall dimensions of the board - they are determined by the case, or mount, or "free space" in which your board will stand.

Use ground and power polygons, the larger the polygon, the better, separate analog and digital polygons if possible and necessary. If you plan that your board someday, under any circumstances, may not be assembled manually, but automatically, then use not solid polygons, but mesh, use solid ones only to shield certain places on the board.

For PCBs with more than four layers, there is general rule place high-speed signal wires between the ground and power polygons, and drain the outer layers of the low-frequency ones. Sometimes audio hobbyists make two polygons of ground on both sides of the board for shielding, if the price is not an issue, then this is a completely justified step.

Try to place the measuring and power elements as far as possible, try to shield the measuring elements. An example of power elements that are the main sources of electrical and magnetic noise are circuit breakers, transformers, motors, thyristors, triacs, relays, etc.

Prototype, experiment - try to simulate all difficult moments on a computer_ or assemble on breadboards, a proven solution is a reliable solution.

Make 3D versions of your boards, many modern editors allow this, this will help you imagine how your product will look like before assembling it, and so, you can check if your board with components fits into the case of your choice.

Your board is ready, it's time to ship

Any manufacturing plant has its own requirements for the data format in which you send files to them. Many factories that specialize in pilot batches (a batch before starting production is produced in small quantities to check the correct layout, tests, certification and demonstrations, in our case, just for work), began to accept boards in the development project files. But this is still a rarity, and it is risky to give your entire project to someone on the side, for this reason I recommend giving the files and the drilling file to the Gerber plant.
For the convenience of work, I recommend the CAM350 program, which combines files, and at the output you do not have a whole folder with a bunch of files, but only 1 file with all layers and drilling.

Sending the board

The next step is filling out an order form and / or writing an explanatory note for your board, where you must indicate the material, material thickness, foil thickness, number of layers, the presence of a mask, silk-screen printing, the name of the board file.
At many factories, the order form is standard, for example, "Rezonit". You also need to specify the method of receiving the payment. They can send it to you by mail, or by courier to your home. For example, at "Rezonit" boards are made within 3 days, in 1-2 days they are in St. Petersburg and on this or the next day you have them, in total 5-6 days. We ordered it over the weekend and received it the next weekend.

Payment of invoice

Most factories issue invoices that can be paid at a savings bank. Some, like the above-mentioned "Rezonit", made it possible to pay via the Internet, there are payment options via bank card or Yandex money.

Mini Bonus

When ordering urgent production, the factory makes a small number of boards. Sometimes on a sheet of PCB that the plant uses. There is still room for your board, and other boards are placed there, for example, by ordering 10 boards, you can get 12 - additional 2 for free, but I would like to clarify that this does not always happen and you do not need to count on it.

P.s.

I want to apologize in advance if the article contains errors or inaccuracies. Write to me personally, I will try to fix everything as quickly as possible.

Update: Found some useful material for novice developers -