Reinforcing workpiece handling and welding automation


”We manufacture heavy workpieces, the handling and welding of which takes a significant number of hours. We invest in welding automation so that we could further develop the quality and efficiency of our production process,” says Erkki Lehtonen, CEO of Lehtosen Konepaja. “By developing our operations and utilizing the latest technology to improve our readiness, we as a modern metal industry factory are responding to the challenges of the future.”

The latest LEKO Group investments are a heavy-weight PEMA APS 35000 handling table with 35 000 kg support capacity and a PEMA HD 7×5 welding tower for welding heavy and thick materials, to be delivered to Lehtosen Konepaja at Kokemäki. The size of the manufactured units and machine bodies is constantly increasing, and by investing in welding automation LEKO Group can answer the clients’ demands of high welding quality and production reliability.

The PEMA APS Skymaster APS handling table is an excellent solution for lifting, turning and tilting heavy and complicated workpieces. The height, angle and rotation speed of the workpiece are fully adjustable, which should be taken into account with respect to work ergonomy. This latest purchase, in addition to the two previous modern PEMA robot welding stations among others, complements LEKO Group’s capacity as a contract manufacturer of heavy and medium machine construction.




Planned and Systematic Measures in the Quality Assurance Process


LEKO Fans will supply the world’s largest black liquor evaporator in South Africa with two dual turbo blower sets, two lines in parallel, with a combined engine power of 16 MW and an evaporation capacity of 400 tonnes per hour. In addition to spare parts, this very extensive project also includes commissioning services and warranty testing.

LEKO Fans Quality Control Process Starts at the Drawing Board

Starting from the definition of customer needs, quality control includes all planned and systematic measures to ensure the product meets all its quality requirements. As the manufacturer is responsible for the conformity of the product with the EU Pressure Equipment Directive, as well as legislation and regulations, the inspections and the final evaluation shall be carried out by a knowledgeable third party to maximize reliability. DEKRA Industrial Oy is an inspectorate accredited by the Finnish Accreditation Service FINAS and acts as an inspection body approved by the Finnish Safety and Chemicals Agency Tukes as an inspector of pressure equipment under national law. The Ministry of Economic Affairs and Employment of Finland has certified with the European Parliament and the Council (EU) that DEKRA is a Notified Body 0875 in accordance with the Pressure Equipment Directive PED 2014/68/EU. In accordance with the necessary assessment procedure, DEKRA will carry out a conformity assessment for the product by approving the plan, verifying the quality material required for the preparation of the product and reviewing the product at a pressure test.

In accordance with the high requirement level of the application, the blower material is made of extremely corrosion-resistant and acid-proof duplex steel. Duplex stainless steels are suitable for many corrosive environments. Lehtosen Konepaja uses high-quality materials, and their partner in procurement is Outokumpu, which specializes in steel production.

Water Pressure Test Ensures Compliance with Design and Manufacturing Values

For each turbo blower unit, DEKRA monitors a water pressure test to verify that the manufacturing process has been carried out according to the plan. The pressure test reveals, among other things, any possible leak points. During the pressure test, the product must prove to be durable and shape-preserving. The manufacturer is also required to carry out welding quality monitoring in the manufacture of pressure equipment. In order to meet the requirements, the manufacturer must perform coordinated welding and use only certified welders. In the manufacture of the product, weldability in particular must be taken into account already at the time of designing the product and selecting the materials.

LEKO Fans turbo blowers are an exceptional target for pressure testing. Testing was carried out in accordance with PED regulations to meet the requirements of the customer and the product’s final destination. The audit was focused on the visual quality of the product and the quality of welding. The performance of the pressure test was documented in the test protocol and the certification body’s Certificate of Conformity allows the manufacturer to CE mark the product.

Lehtosen Konepaja Quality Assurance Also with PMI Measurement

The quality assurance of Lehtosen Konepaja covers the entire manufacturing process from the material selection to the welding quality requirements and assembly. Systematic quality control is essential for all metalworking, especially for checking safety-critical positive materials. The PMI measurement distinguishes pure metals from alloys quickly and accurately. All parts and materials associated with the same process must be tested to ensure the best possible quality for the customer and to prevent problematic situations caused by the wrong metal alloy.

The PMI measurement was carried out by Kiwa Inspecta, which operates as a control body under several EU directives and national legislation. The supplied PMI measurement confirmed that the turbo blower materials were duplex steel, and the measurement technology also allowed the checking of a small/narrow point, e.g. the weld seam. Inspecta also examines the technical documentation submitted by the customer. In module G, the Pressure Equipment Directive does not directly require a separate certificate of the examination of the plan, but in accordance with the generally accepted practices in the field, Inspecta provides an opinion on the acceptability of the design data and other technical documentation.


Eco-actions at LEKO Group

Lehtosen Konepaja is strongly involved in promoting energy efficiency and implementing a national energy and climate strategy. Finland aims to be a carbon neutral country by 2035. CEO Erkki Lehtonen is driving the Lehtosen Konepaja and the entire LEKO Group toward this goal, and he believes that this can be achieved. “New habits, artificial intelligence and energy-saving devices can have a significant impact on the energy consumption of both industry and households. Investment such as utilizing waste heat and developing new energy forms will save a vast amount of electricity in the future”, Erkki Lehtonen assures. One example of the company’s involvement in the joint effort to fight climate change is that the welding in the workshop is largely done by solar power and district heating.

Energy efficiency – a strong competitive edge

At Lehtosen Konepaja cleanliness and organization is important. Recycling is part of every day business and new staff is guided through the waste sorting routines already in the job orientation phase. Organization extends to the use and storage of individual tools and equipment. “At the workshop, we have measured our own performance and systematically sought to address deficiencies. Energy saving and the circular economy are an integral part of the company’s environmental strategy. By working more efficiently, improving our working conditions and investing in logistics and public order, we work in an economically advantageous way”, Erkki Lehtonen says. A huge amount of electricity and heat has been saved through investments and modern technology. Energy savings have also resulted in economic savings, which is a competitive advantage in the technology industry.



The welding shop of Lehtosen Konepaja has the cleanest air in Finland

Welding produces a large quantity of impurities into the air, and therefore the ventilation in welding shops is demanding for the well-being of both the employees and the environment. In an hour, 2,5-3,5 times the room volume of air has to be circulated. When mechanical ventilation is used at the workplace, it has to be kept operational and cleaned sufficiently frequently, since the health of the employees must not be endangered due to, for instance, ventilation machinery malfunctions.

At Lehtosen Konepaja, cleaning the air of the welding shop is taken care of with automatised Mastervent Ltd KRS-THR ventilation machines which were deployed in the early fall. In staff interviews, the feedback has been positive; the effect of clean air in the working spaces has been immediately noticeable. The air temperature, moisture, and movement are also controlled through the ventilation. This happens by processing the intake and exhaust air. The premise is a displacing air distribution, where the exhaust with its impurities are sucked out from above the welding area and fresh air is brought in. The ventilation machinery, equipped with exhaust heat capturing and an automatic cleaning system, is also an environment-friendly solution that brings the company significant savings while ensuring the cleanest air in Finland at the welding shop.

The KRS-THR has been designed especially for welding and paint shop needs, and use experiences going back for years are very successful. The ventilation machines have no filters at all to change and clean periodically. The ventilation solution used at Lehtosen Konepaja has an efficient special rotor, which is kept clean using an automatic high pressure washing system. The exhaust is not filtered, but the impurities in the air get caught in the rotor’s disc, from which they are cleaned automatically. The washing water is conducted via special pools into the sewer. The revolving disc transfers the thermal energy in the exhaust directly into the intake air at up to 85% efficiency.


A new 8x8x4m preheating furnace from HeatMasters to be added to equipment stoc

Lehtosen Konepaja’s welding and machining operations are backed by the workshop’s lineup of preheating furnaces, the newest of which is a gas-operated bell furnace by HeatMasters, designed for handling large pieces. The large furnace operates on gas, which is an economical and energy-efficient solution. Collecting waste heat also affects the workshop’s energy consumption and heating.

The location near the workshop’s new extension hall, environmental conditions and the size of the heated pieces were taken into consideration when choosing the furnace. The preheating furnace is located outside, saving space inside the hall while being logistically close by. This new acquisition complements the resources of other HeatMasters electric furnaces. It was tailor-made to fit Lehtosen Konepaja’s and the entire LEKO Group’s needs. Measuring 8x8x4 meters, the furnace can heat-treat large welded objects. The preheating furnace contributes to ensuring that work and production progress smoothly.

Heat treatment of metal refers to a process in which a metal object’s temperature is increased to achieve desired properties. Metal does not melt during heat treatment, but it has an effect on an object’s hardness, durability, viscosity and wear resistance. The effects of heat treatment can be applied to an entire object, or only its surface or a specific part. Metal structures can have harmful tensions, for example as a result of welding. Stress relieving is performed at a temperature that is lower than the metal’s annealing temperature. The procedure relieves tension from the metal before it is worked on.

LEKO Group at Subcontracting Fair 2019, stand A 1002

Welcome to explore LEKO Group service offering and opportunities at the Subcontracting Fair in Tampere, 24-26 September 2019. The fair is an opportunity to forge new partnerships and strengthen existing customer relationships. You can find us at A 1002, where we represent a comprehensive engineering concept for the engineering and metal industry throughout the internationally expanding group. 


Juha Mäkelä appointed CEO for TK-Vilmet

TK-Vilmet, a member of the LEKO Group, will appoint a new CEO when Lasse Tyynysniemi retires. However, Lasse will continue his employment at TK-Vilmet as a special assistant to the new CEO, and provide background support during the transition period.

-Together with Juha Mäkelä we intend visit to our customers, so that the new CEO can begin his work in the most controlled way as customer relationships become stronger, says Lasse. He also assures that he will be at the customers and stakeholders disposal, even if the main responsibilities are transferred to Juha.

Lasse Tyynysniemi (left.) and Juha Mäkelä

TK-Vilmet, a medium-heavy mechanical engineering company based in Mänttä-Vilppula, is part of a larger group offering customized products to their clients.These include manufacturing of various components and steel structures for the technology industry. The company will furthermore strengthen its operations with additional production staff. Future plans also include investing in a new assembly hall.

Delivering screw conveyors even on holiday season

In spite of the ongoing holiday season in Finland Siirtoruuvi has the production almost in maximum capacity to meet customer’s delivery dates. Here are three truck loads of screw conveyors starting their trip to Germany.

Welcome to Subcontracting Trade Fair! Visit our stand A1354

Like before, LekoGroup and Lehtosen Konepaja can be found from our traditional department A1354 at Subcontracting Trade Fair.

Approximately 20,000 industry professionals participate in this annual event, which is Finland’s leading industry trade fair, where the common denominator for all participants is the desire to achieve more in a better, more effective and productive manner.

See you at A1354!