Olmet Technology, Rumen Olimpiev: Engineering excellence in turbine blasting and surface preparation means uninterrupted production for our clients

Rumen Olimpiev, Owner and Manager of Olmet Technology, for South-East European Industrial Market Magazine

Olmet Technology is the official representative for Bulgaria of the Slovenian manufacturer of turbine shot blasting machines, STEM. Could you tell us more about the company’s product portfolio and the application areas of the equipment you offer? Which products are most in demand on the Bulgarian market?

I have been working with STEM for more than 25 years. The company itself was established during a period of major changes affecting the entire Balkan Peninsula. STEM was founded by engineers who believed that turbine blasting machines and surface preparation systems should not be treated as standard equipment, but rather as engineered technological solutions.

Their goal was to focus on technological development, flexibility toward the end customer, and a creative approach to solving various technological challenges. We listen carefully to our customers in order to provide them with the most efficient and economically viable solutions.

Today, our portfolio includes automatic turbine blasting machines, customized shot blasting systems, integrated blasting and painting lines, heavy-duty solutions for foundry blasting, and specialized equipment for complex industrial blasting applications.

We supply equipment to foundries, steel structure manufacturers, shipbuilding and ship repair companies, railway wagon producers, automotive manufacturers, energy facilities, defense industry enterprises, and even nuclear energy plants.

In foundry environments especially, the blasting process operates under extreme conditions, where durability, turbine efficiency, abrasive control, and wear protection are critical. That is why our turbine blasting solutions are often preferred in heavy industrial applications. Beyond standard machines, STEM is well known for engineering customized turbine blasting systems tailored to specific production processes and surface preparation requirements.

You have more than 25 years of experience in shot blasting technology. How have customer requirements changed over this period?

In the early years, this part of the technology was often neglected. Few companies wanted to invest in such machines because the operation itself was seriously underestimated. Later, however, it became clear how critical proper blasting is for overall product quality.

Good corrosion protection requires proper surface preparation, including optimal roughness and high cleanliness standards. Manufacturers began insisting on sustainable quality and extended warranties, and they also started recognizing the additional costs resulting from skipping this technological step.

The next major change came with industry demand for reliable technical service and experts who truly understand the process — specialists capable of monitoring and controlling both equipment performance and final results.

I believe the added value we provide precisely in this area has made us a preferred partner. Our goal is to build long-term partnerships. We do not see ourselves merely as sellers of machines and abrasives, but as specialists who understand the process and its nuances and who can offer complete solutions, including both machinery and the correct consumables.

Which achievements and successes make you most proud?

I generally try to avoid pride because it can cloud judgment and disconnect one from reality. However, looking back, over the years we have built a foundation of trust and success with leading Bulgarian foundries such as Progress in Stara Zagora, Ossam in Lovech, Badestnost in Chirpan, Cast Iron Armature in Popovo, Villeroy & Boch in Sevlievo, and many others.

Our machines operate at every railway wagon manufacturer in Bulgaria. Our equipment is also used by all major defense industry companies, including Arsenal in Kazanlak, Dunarit in Ruse, and VMZ in Sopot. A complete blasting and painting line operates in Bulgaria’s largest ship repair yard, Odessos Shiprepair Yard in Varna. We even have machines operating at the Kozloduy Nuclear Power Plant, which means we meet the highest standards and requirements.

But what makes me the happiest, and proud in the positive sense, is being welcomed with a smile by maintenance teams and technologists — the people on the production frontline. When I hear, “Hi, we work well with you; we have no problems with the machine,” I know we have done our job properly.

Of course, problems do occur; no equipment is immune to failure. What matters is solving them in a way that leaves people feeling supported. When we become one team, that gives me real satisfaction.

What trends will shape the shot blasting and surface preparation market over the next 5 – 10 years?

Pressure from Asia on European and Bulgarian industry is significant, and manufacturers are striving to reduce costs and remain competitive. I have seen clients invest in cheaper equipment because of attractive initial prices, only to later discover hidden costs and the lack of reliable service and support, especially after the warranty period ends.

I believe the most important factor when choosing a machine supplier will remain finding a reliable partner — not merely a trader, but a technical expert who understands both equipment and process and can provide support at every stage.

Despite the development of AI, clients still want to talk to people they can reach when needed, who understand their situation and defend their interests. I often tell my clients, “Once I commission your machine, I no longer remain STEM’s representative to you; I become your representative to STEM. I protect your interests and stand on your side.”

Over 100 clients in Bulgaria operating more than 130 machines can confirm that I have kept my word. That has been our success factor.

What are the approaches for successfully optimizing blasting processes and reducing costs?

Very often, the first question a client asks is how much the blasting abrasive costs. However, turbine shot blasting machines are essentially self-destructive systems, and their largest cost components are electricity consumption and spare parts. Electricity is not cheap in our region, which makes optimization crucial.

Our added value lies in technical service and consultation on the blasting process itself. With optimal settings, we achieve optimal costs and maximum productivity. We have long collaborated with a leading premium abrasive manufacturer that operates four European testing centers and one R&D center, allowing us to deeply understand blasting process details and equipment operating modes.

Every system in the machine influences the entire process, and everything must be correctly balanced to achieve both technological and economic goals. At Olmet Technology, we invested in a mobile laboratory equipped with instruments that monitor all key blasting parameters. We use simulation software and patented devices capable of converting visual cleanliness standards into measurable and comparable values through colorimetric analysis.

Our technical visits conclude with expert reports showing clients their current situation, where costs can be saved, what can be improved, and what steps should be taken.

For example, at Vidima Ideal Standard, now Villeroy & Boch in Sevlievo, annual production was five million units. Before our intervention, 4560 castings were blasted per eight-hour shift, corresponding to eleven cycles of forty minutes each. After optimization, output increased to 8226 castings in the same time frame through fifteen cycles of eighteen minutes each. Electricity cost per unit also decreased, generating annual savings of nearly EUR 26 000 per machine, and the plant operates two machines. In the end, everything comes down to economics. (Table 1.)

Table 1. Cost optimisation and productivity increase in Villeroy & Boch, Bulgaria

What does your after-sales service program include?

After selling equipment, we become our clients’ representatives before the manufacturer, and STEM has always supported this philosophy. In case of technical issues, they respond immediately with service or parts, while investigation comes afterwards. Our priority is uninterrupted production.

Good service, process monitoring, and timely response define our identity. Our goal is to act rather than react, anticipating problems and providing preventive support. Out-of-warranty service is handled in the same way as during the warranty period, which is why we are comfortable offering extended warranties. It is simply our way of working.

You also supply abrasives for blasting. How is this market developing?

Yes, we do. Unlike many trading companies, blasting is our specialization. Our business history began with my father, Olimpi, one of the pioneers in Bulgaria in developing liquid metal granulation systems for producing shot. What began as research at the Bulgarian Institute of Metal Casting evolved into real production and business activity.

In his honor, I named the company Olimpiev Metal Technology, which later evolved into Olmet Technology. Today, the third generation continues to work in this direction, so our company is strongly connected to tradition and in-depth specialization. Producing quality abrasive involves many subtleties, and quality requires proper investment. Impressive results cannot be expected from cheap consumables.

Today, we know every abrasive producer, their strengths and weaknesses, and how each material affects both machines and processes.

What guidance do you give clients when selecting the most suitable abrasive?

Selecting an abrasive is not about price alone. It must match the material being blasted, the required surface roughness, turbine energy, the desired cleanliness class, and productivity targets.

We follow three principles: fast, cheap, and high quality, knowing that all three cannot exist simultaneously. If the process is fast and high quality, it will not be cheap. If it is cheap and high quality, it will not be fast. If it is fast and cheap, it will not deliver high quality, and this is the option we avoid. In industrial turbine blasting and surface preparation, mediocrity is expensive.

What does your development strategy for the next decade include?

Technology will continue evolving, AI will support diagnostics, and smart turbine blasting systems will become more common. STEM is already working and investing in that direction.

However, I believe something else will become even more valuable – human trust. As long as we work with people, we will remain people. And in the world of industrial blasting and surface preparation, trust is just as important as technology.

www.stem.si