Foil for BIZ

Domestic Russian manufacturers are impatiently waiting for the copper foil electrodeposition workshop to start operating in full force at the Kyshtym Copper Electrolytic Plant.

Copper for board

Electrodeposited copper foil is an important electronic component of modern smart devices. It is used for the production of clad dielectric material – the basis of the printed curcuit boards which have electrically conductive paths of electronic circuits on their surface or inside them.

There are several types of printed circuit boards: one-sided – the foil is applied only on one side of the dielectric, double-sided, when the copper wraps the plate from both sides, and multilayer – foil is also located inside the dielectric. Multilayer PCBs are manufactured by gluing single-sided or double-sided plates. This is how the foil enters the «body» of the board. The more complex an electronic device is, the more layers (and foil) it needs. Unsurprisingly, rapid technological advance is driving demand for multilayer PCBs. Foil dielectrics for PCB are produced at the Bobrovsky Insulating plant, located in the Sverdlovsk region — two hours’ drive from Kyshtym.

BIZ – is the abbreviated name for the plant – has been counting its history since 1932. Back then it had a different name and wood chemical specialization. It all started with the alcohol-turpentine and rosin workshops, then in February 1941 a soap-making division was opened, but during the wartime, electrical insulating production came to replace the initial specialization. The plant began production of insulating varnishes, press powders for fiberglass and was transferred to the Ministry of Electrical Industry. In 1954, the plant was officially renamed and since then has expanded the range of product line without changing its purpose. On the cusp of two centuries, BIZ mastered the production of foil-clad dielectrics, installed a line for its production, and in 2019 modernized it.

The process of foil-clad dielectrics production, for which Kyshtym foil is used, was commented by Andrey Dyudikov, director of BIZ LLC for general issues.

“First of all, we are preparing a special adhesive composition” – explained Andrey Dyudikov. “It is feeded into the impregnation machine, where the fiberglass is impregnated with the prepared solution, then dried, rolled into a roll, cut into sheets. The next, very important stage, takes place in a perfectly clean, dust-free room, where a “layered cake” is formed on an Italian machine from foil, slip sheets and packs of impregnated fiberglass. Further, the «cake» is sent first to a hot vacuum press for pressing, and then to a cold press for cooling.

Plate with good intentions

The cooled pack is taken apart. Materials are preliminarily inspected. Certain, specially selected samples are to be tested for pealing strength, corrosion resistance, they should pass visual and measuring control as well – foil-clad dielectrics should not have foreign inclusions, breakdowns, holes.

The dielectric that has passed all the tests will be cut into full-size sheets of 1220 x 1020 mm or blanks according to custom order, meticulously examined by the Quality Control Department, packed and sent to customers, including such corporations as Rosatom, Rostec, and the Almaz-Antey concern.

The Clean Room of the plant is really clean. Press operators are dressed in lint-free overalls, guests should wear shoe covers. However, guests are rarely allowed into the holy of holies. An exception was made for the team from JSC KMEZ, because the Kyshtym foil was loaded into the machine for the first time. BIZ received samples of products back in June 2021. They were examined in the laboratory of the plant, comments and suggestions were forwarded to the KMEZ. On the day of the Kyshtym team visit, Sverdlovsk specialists planned to make finished products from the foil, produced by KMEZ with the received comments taken into account, and thoroughly check it, to see how the material behaves during the production process, on the press at temperatures 135 to 185 degrees.

Until recently, the main suppliers of foil for the Bobrovsky Insulation Plant were European and Asian manufacturers. The covid intervened in seemingly smooth cooperation. In the midst of the pandemic, restrictions were imposed on the import of materials from China. Taking advantage of the situation, European partners began to delay the delivery of products. They referred to the fact that first of all they are obliged to fulfill the orders of their compatriots and only then send the goods for export. As a result, BIZ has been waiting for the promised and already prepaid foil for three to four months.

“We had to plan the purchase of foil almost six months in advance,” says Andrey Dyudikov. “Since we have started the mass production of 10-14 tons of dielectrics per month, we need 5 to 7 tons of foil per month. Can you imagine what kind of stock you had to form and keep in warehouse? And this, among other things, frozen funds! We are very pleased that KMEZ took on such a serious task, built a completely new modern copper foil electrodeposition workshop and started its production. Our first trip to KMEZ took place in 2019, even before the equipment was installed. We discussed the timing of the launch of production, which was awaited not only by us, but also by our customers.

Both sides are facet

The return visit of the Kyshtym team was not long in coming. Specialists of the future workshop came to the BIZ in the summer of 2020, got acquainted with the production of foil-clad dielectrics and its features. The result of the trip was an agreement of intent dated June 30, 2020 on joint testing of the foil at the BIZ plant. And in November 2020, KMEZ and BIZ entered into an agreement on the supply of products.

Such geographical and, to be honest, the mental proximity of the two plants promises, according to Andrey Dyudikov, many advantages. The speed of production and delivery, no need to keep a large warehouse stock, possibility to have a dialogue with the manufacturing plant when developing new materials and, of course, confidence in the origin of raw materials, in its purity and quality.

“We will not go far for an example” – the BIZ director for general issues demonstrates the strengths of cooperation with a domestic manufacturer right in the «clean» room where the process with Kyshtym foil is going on. “See, there are always two rolls involved in the process? Foreign suppliers sent us rolls weighing at least 250 kg. For such a machine, they are too heavy, inconvenient to use, and therefor lead to lots of problems. KMEZ met us halfway and produces rolls weighing 150 to 180 kg specially for us. It seems to be a trifle, but there are no trifles in a production process.

Of course, it is highly convenient when the supplier is in the immediate vicinity of the customer, as in the case of Kyshtym. But even for the sake of convenience, BIZ is not ready to make any allowance on the quality issues – simply has no right. Russian foil with a thickness of 18, 35 and 50 microns (this is the range used in the production of foil-clad dielectrics with a thickness of 0.1 to 3 millimeters) must meet the most stringent requirements for transmittivity, resistance, adhesion properties, that is the degree of adhesion to a base. Surface appearance is also very important. The idiom “ looks aren’t everything” does not work in the case of foil. There should not be the slightest defect on the foil surface along its entire length: no foreign inclusions, no damage and creases. Moreover, both sides of the foil are front ones. Customers have the right to rely on their smoothness and expect consistency of performance roll to roll, without jumps in test parameters.

“We are confident that the experience and competence of KMEZ specialists will be enough to compete with European and Asian manufacturers. The first step is the hardest!” – Andrey Dyudikov is sure

In the future, with the development of the import substitution program, BIZ intends to occupy more than 40 percent of the market for domestic foil-clad dielectrics, which will accordingly lead to increase in the demand for Russian (read – Kyshtym) copper foil. So the products of the new workshop have no other way but to gain strength, improve in appearance and quality.


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