Lightweight but Demanding: How to Succeed in Aluminium CNC Machining
Aluminum is a material widely used in the production of mechanical components. Its light weight, corrosion resistance, and favorable strength-to-weight ratio make it ideal for precision engineering applications. But what makes aluminum such an attractive material also means that its machining requires more than just a standard approach. CNC machining is now the basis of modern production, including when working with aluminum. However, the effectiveness of the entire process depends on many factors. From the selection of tools and coatings, through cutting parameters, to the cooling method. It is these elements that determine the surface quality, repeatability, and durability of the finished part. Drawing on our many years of experience in CNC metalworking, this article describes specific solutions that have proven themselves in production and allow you to achieve stable quality of the finished part. Aluminum – material specifications and problems encountered in CNC machining Before we move on to cutting strategies, it is worth taking a look at the properties of aluminum that directly influence the choice of machining parameters. Understanding these properties is crucial for the stability and repeatability of the entire process. Materialproperties What does this mean in practice? Low density (2.6–2.8 g/cm³) Aluminum is lightweight, which allows for higher rotational speeds and feed rates, and the machine is not as heavily loaded as with steel. High thermal conductivity Heat quickly escapes from the cutting zone, but mainly to the tool. Without efficient cooling, the blades overheat and wear out faster. Low hardness (HV ≈ 25–120) Sharp tools with a large rake angle can be used. Cutting is smooth and the load on the machine tool remains low. Viscosity and adhesion Aluminum tends to stick to the blade. Friction-reducing coatings, polished chip grooves, and properly selected cooling help to prevent this. Although at first glance, turning and milling aluminum seems “easy,” in practice it requires a great deal of attention and technological precision. Aluminum alloys and their machinability with CNC technology Not all aluminum behaves the same when in contact with a tool. Depending on the chemical composition and hardness, different alloys may require completely different cutting parameters—from speed and force to optimal spindle speed, control, and cutting tool. Below are a few examples of popular alloys used in the production of aluminum components: Knowledge of the type of aluminum alloy facilitates the machining of the material. Without it, it is difficult to select the right tools, set the cutting parameters, and predict the behavior of the workpiece during production. Main processes and types of CNC aluminum machining Aluminum can be effectively machined in several different ways, depending on the needs of the project and the expected results. CNC milling It works well for both precision components and large structural blocks. Concurrent milling gives a better surface quality, while counter-rotating milling is suitable where stability is required. For larger volumes of material, full milling is used. Thin-walled parts are machined with minimal allowance and well-chosen cooling. CNC turning Used for axially symmetrical parts: shafts, sleeves, rings. In turning, it is crucial to maintain a stable feed rate and the correct cutting edge radius, especially for thin-walled parts. If the cutting parameters are too low, vibrations and an irregular surface will occur. If they are too aggressive, excessive chip accumulation and the risk of workpiece deformation will occur. Drilling and threading The most common problems are burrs and hole deformation. Drills with a larger point angle and good chip removal are used. Forming taps are suitable for threading — they do not cut, but shape the thread. This eliminates chips and strengthens the connection, especially in thin-walled components. Grinding and surface preparation Surface quality is crucial for anodizing. Any scratches will be visible after oxidation. Therefore, parts are often subjected to additional finishing operations — finishing milling or grinding with emulsions and fine-grained abrasives. CNC tools used for machining aluminum For aluminum, it is essential to use tools that enable efficient chip removal and reduce the risk of material build-up on the cutting edge. The most commonly used types of tools are: The choice of tool depends on the technological operation, workpiece geometry, and quality requirements. Each tool has its own specific characteristics and is best suited for specific applications. Cooling and lubrication of aluminum during the machining process CNC machining of aluminum requires special attention in terms of cooling, as aluminum quickly transfers heat to the tools. Lack of effective cooling quickly leads to a deterioration in the surface quality of the parts, accelerates tool wear, and can also cause thermal deformation of the workpiece. The most commonly used cooling and lubrication methods are: Modern aluminum cutting strategies One of the most popular approaches is HPC (High Performance Cutting) – a deep cutting technique with a narrow blade width. It allows for a significant increase in feed rate without the risk of tool overload or deterioration of workpiece parameters. HSC (High Speed Cutting) is ideal for thin-walled aluminum components. Thanks to very high rotational speeds and low cutting forces, this method ensures precise milling without deformation, even of delicate structures. Trochoidal milling is also becoming increasingly popular – a strategy that involves guiding the tool along a curved, dynamic path. This ensures even blade wear, better cooling, and minimizes mechanical and thermal loads. Summary – aluminum rewards precision Aluminum is a material with great potential, but also with complex technological characteristics. To achieve repeatable quality and high performance in CNC machining, a good machine is not enough. You need well-chosen tools, well-thought-out cutting strategies, effective cooling, and knowledge of the properties of the specific alloy. It is precisely this approach — based on practice and experience — that allows you to fully exploit the potential of aluminum and avoid typical production problems.
CNC metal working – the foundation of precision industrial manufacturing
Metals have been the basis of industrial construction for centuries. Their strength, conductivity, and workability make them indispensable in many applications. In the manufacturing industry, “good quality” is no longer enough—today, micrometric precision, repeatability in every series, and flexibility in design changes are what count. Under these conditions, traditional machining methods become a barrier to development. They are being replaced by solutions that combine automation with reliability, led by CNC machining, which we explain in detail in the article “What is CNC machining?” Process flow – what does metal machining on CNC machines look like? The process begins with the preparation of technical documentation in CAD (Computer-Aided Design) format, which is then converted into CAM (Computer-Aided Manufacturing) code. This code contains instructions for the CNC machine regarding the tool trajectory, rotational speed, feed rate, and other parameters. The accuracy of this data is crucial to achieving the desired end result. At this stage, the actual metalworking on CNC machines takes place. The selection of tools, cutting parameters, and machining strategies depends on the geometry of the part, the material, and the type of technological operation. Modern CNC centers are often equipped with automatic tool changers, cooling systems, and measuring sensors, which allow for high repeatability, shorter production times, and minimized risk of errors. After the main cutting operations, the surface finishing stage follows, which may include: Quality control at this stage is crucial to ensure compliance with technical requirements. Challenges in CNC metalworking Each material reacts differently to machining. What works for steel may be completely wrong for aluminum or brass. The right choice of tools and strategies is the key to quality, repeatability, and process durability. Structural steel (e.g., S235, S355) This is one of the simpler groups of materials in terms of machining. Both HSS (High-Speed Steel) and carbide tools can be used. Structural steel can be machined quickly and without major restrictions, but for longer operations it is advisable to check the wear of the tool edges regularly. Stainless steel (e.g. AISI 304, 316) Requires a more thoughtful approach. It is hard and at the same time “stretchy” – it tends to stick to the cutting edge. This causes problems with chip removal and accelerated tool wear. Blades with friction-reducing coatings, such as AlTiN (titanium and aluminum nitride), are usually recommended for machining this material. Hardened steel (>45 HRC) Hardened steel requires solid carbide tools (VHM – from German Vollhartmetall) and appropriate coatings, e.g. TiSiN (titanium and silicon nitride), which increase wear and temperature resistance. The process must be stable – rigid clamping, short strokes, precise path. The parameters must be selected sensibly, depending on the tool diameter, geometry, and machine capabilities. Aluminum Aluminum is a machinable material, but due to its ductility and low hardness, it requires a specific approach. During machining, it produces long chips that easily clog the cutting space, and when working with thin-walled parts, there is a risk of vibration and deformation. The best results are achieved with solid carbide (VHM) milling cutters with a large rake angle (approx. 45°) and a polished chip surface. Brass and copper These materials are very easy to machine and are often considered “easy” for CNC machining. An overly aggressive rake angle or a rough cutting surface can lead to material tearing, local overheating of the cutting edge, and accelerated wear. This is because the heat generated during machining is very quickly transferred to the workpiece, which in thin-walled components can result in deformation or dimensional changes. For CNC machining of brass or copper, solid carbide (VHM) cutters with very sharp, precisely ground edges and a maximally smooth surface are recommended. Understanding the physical and chemical properties of the material being machined and precisely adjusting the cutting strategy has a direct impact on the final quality of the component, the service life of the tools, and the efficiency of the entire cutting process. What can go wrong with CNC metal machining – and how can it be prevented? Three main problems can occur during CNC metal machining: 1. Chatter This leads to an uneven surface, poorer accuracy, and faster wear of the cutting surfaces. The most common causes are excessive tool projection, lack of rigidity in the clamping, or incorrect cutting parameters. 2. Incorrect cutting parameters Excessive speed, feed rate, or cutting depth can lead to blade overheating, tool breakage, and poor surface quality. 3. Tool wear Every milling cutter, drill, and tap has a limited service life – if not checked regularly, it can damage the workpiece or cause errors in the entire series. When is it worth outsourcing CNC metalworking to an experienced company? For series production, complex geometries or high quality requirements, working with an experienced contractor helps to avoid errors and delays. Not only is a precise machine park crucial, but also practical knowledge of different alloys, their behavior during processing, and possible design limitations. Summary of CNC metalworking CNC metalworking is more than just removing excess material. It is a complex technological process in which precision tools work together with computer control, and each stage is based on engineering knowledge and familiarity with the properties of materials. Thanks to this technology, it is possible to manufacture components with complex geometries, high quality, and repeatability in a fast, safe, and economical manner. Behind the efficient CNC process is a team of specialists. The designer creates a model of the part, the programmer prepares the machining code, and the operator supervises the production process on the machine. It is the combination of human competence and the capabilities of modern machine tools that allows us to achieve a level of precision that cannot be guaranteed by traditional methods.
Training in Shrink Fit technology and spindle clamping force control at SIM Gdynia
At SIM Gdynia, we are constantly training, testing, and implementing solutions that have a real impact on the quality of CNC machining. In May 2025, our headquarters hosted a specialized technical training course organized by experts from Hahn+Kolb and Diebold, leaders in the field of tools and clamping systems. The meeting focused on shrink fit technology and spindle clamping force control systems – key solutions for precision, repeatability, and process safety. A practical approach to innovation The training was attended by our technologists, setters, and foremen – practitioners who are responsible for the reliability of production at SIM Gdynia on a daily basis. The meeting was practical in nature. Specific cases were discussed, the application of Shrink Fit technology was tested on real components, and the impact of spindle clamping force on the stability and durability of machining was analyzed. Shrink Fit is a tool clamping technology that utilizes the phenomenon of thermal expansion – after cooling, the holder clamps the tool tightly, ensuring extreme rigidity, minimal runout, and high process repeatability. The spindle clamping force measurement system, on the other hand, allows the clamping parameters in the CNC machine to be controlled, which has a direct impact on the machining quality and service life of both the tools and the spindle itself. Building an advantage with knowledge We would like to thank the representatives of Hahn+Kolb and Diebold for the inspiring training and for sharing their expert knowledge. Initiatives like this are extremely important to us – they help develop the competence of our team and directly translate into production efficiency. At SIM Gdynia, we build our competitive advantage not with words, but with action. This is another step towards even higher precision and reliability of our CNC services.
What is CNC machining?
CNC machining (Computer Numerical Control) is a technological process involving the shaping of materials using numerically controlled machine tools, i.e. machines that perform tasks according to pre-programmed computer instructions. A technical design – usually prepared in a CAD (Computer-Aided Design) program, i.e. a tool for computer-aided engineering – is converted into code that directs the machine’s work. CNC milling machines, lathes, and grinders perform precise movements, removing material from the workpiece and creating a part with specific shapes and dimensions. This can be compared to the opposite of 3D printing – instead of adding material, CNC machining involves its controlled removal until the desired shape is achieved. Types of machining There are several main types of machining, each of which is used to achieve different effects: The variety of machining methods offers a wide range of possibilities for shaping components – from rough removal of material to precise surface finishing. The use of machining in industry This technology is used both in mass production and in the manufacture of unique, specialized components. Below are the key industries in which CNC machining is particularly important: Machining plays a key role wherever precision, repeatability, and the ability to work with a wide variety of materials are important. What materials can be machined with CNC? Thanks to its versatility, CNC machining can be used for both easily machinable materials and those requiring specialised tools. The most commonly machined materials include: The choice of material always depends on the intended use of the component, expectations regarding durability, geometry, production costs and possible finishing operations. Advantages of CNC machining The advantage of CNC machining is full control over the process, which makes it possible to achieve repeatable results even with very complex designs. Other key benefits include: CNC machining is ideal wherever quality, repeatability, and efficient production management are important. Summary – what is CNC machining? CNC machining is a modern manufacturing method that combines precise computer control with a wide range of technological possibilities. It allows for the efficient and economical production of parts of varying complexity – from metals, plastics, composites, and special materials. This technology is used in almost every branch of modern industry and allows for both serial and single-piece production. Its main advantages are repeatability, flexibility, reduced lead times, and reduced material waste. All this makes CNC an indispensable tool in the design and production of modern components.
SIM Gdynia supports local sport – partnership with Chwaszczyno Sports Club
At SIM Gdynia, we believe that the true strength of industry lies not only in technology, but also in the people and communities we support. That is why we are proud to announce that on May 13, 2025, we signed an official partnership agreement with Chwaszczyno Sports Club. This is the beginning of a collaboration that we hope will bring long-term benefits to young athletes and the local community. A shared vision for development The agreement was signed by Anna Szczypek, President of SIM Gdynia, and Janusz Płocki, President of Chwaszczyno Sports Club. The meeting not only confirmed the formal commitment, but also emphasized our shared values of development, passion, and commitment to local initiatives. SIM Gdynia has become the club’s main sponsor. We believe that thanks to this cooperation, young players will gain even better conditions for development, training, and achieving their sporting goals, both small and large. Young people are the future, not only in sports The partnership with KS Chwaszczyno is more than just sponsorship. It is a real investment in young people who, thanks to technical and organizational support, can spread their wings. As a manufacturing company, we understand the value of systematic work, discipline, and teamwork – and it is sport that teaches these attitudes from an early age. Our support is aimed at improving the training infrastructure, developing the training program, and enabling participation in more competitions. We want every child training at KS Chwaszczyno to have the opportunity to pursue their sporting dreams. We look to the future with hope We hope that this partnership will be the beginning of many joint projects – tournaments, campaigns promoting physical activity, and family events. Our support is not just a logo on jerseys – it is a real presence in the lives of young athletes and their families. We can’t wait for the first successes of the KS Chwaszczyno players, whom we already strongly support. We are with you – on and off the pitch!
Family Picnic on Children’s Day–join us for a celebration on June 15!
At SIM Gdynia, we believe that the strength of a company lies not only in technology and precision, but also in relationships – both professional and family. That is why we are delighted to invite SIM Gdynia employees and their loved ones to a Family Picnic on Children’s Day, which will take place on June 15, 2025 at the Toyota Arena Stadium in Chwaszczyno. The event is scheduled to start at 1:00 p.m. Why is it worth participating? The Family Picnic is a great opportunity to spend time together in a relaxed atmosphere – away from everyday responsibilities, surrounded by nature, with plenty of attractions for children and adults. The event combines physical activity, educational elements, and relaxation in the fresh air. All in a friendly, safe, and well-organized space. The program includes, among other things: Prize lottery A raffle will be held among the participants of the event, with prizes including: SIM Gdynia zone – for registered employees only For SIM Gdynia employees who register to participate in the event, we have prepared a separate tent area with free refreshments. Registration is internal. Only registered participants will be able to use this zone during the picnic. See you on June 15 in Chwaszczyno! We encourage you to participate in the event with your families – a day full of joy, integration, and shared moments that will remain in your memory for a long time awaits you.
SIM Gdynia received the OTIF95 award from the KION Group
In February, we announced that SIM Gdynia had won the OTIF95 Supplier Performance Award presented by the KION Group. Today, we are pleased to announce that we officially received this award on 03.04.2025. The award confirms our reliability in delivery and the efficiency of our operational processes. You can read more about the OTIF95 program and our cooperation with the KION Group in our previous article: SIM Gdynia wins OTIF95 Supplier Performance Award from the KION Group We would like to thank the KION Group for their trust and recognition – it is a strong motivation for us to continue improving.
What is the difference between turning and milling? – Key differences in CNC machining
In industries where every micrometer and every second of production counts, CNC machining (Computerized Numerical Control) has become the foundation of modern manufacturing. The two most important cutting methods are turning and CNC milling. Although both techniques are used to precisely shape metal and plastic parts, they differ in their range of applications, tool movement, and geometric capabilities. In this article, we explain how CNC turning differs from milling, when to use each method, and how to choose the right technology. What is CNC turning? In CNC turning, the workpiece is clamped in a chuck and rotates around its own axis, while the cutting tool moves along the X and Z axes. This principle allows for the efficient removal of material from cylindrical and conical surfaces. This technology is used, among other things, for the production of shafts, pins, bushings, rings, and threads. It is ideal for mass production, where dimensional repeatability and process stability are key. What is CNC metal milling? CNC milling is a process in which a tool (milling cutter) rotates while the workpiece remains stationary or moves along the X, Y, and Z axes – and in the case of 4- and 5-axis machines – also around the rotary axes. Milling allows the machining of flat surfaces, holes, pockets, bevels, and 3D structures. It is indispensable in projects where parts require multiple operations in different planes, from injection molds and machine bodies to medical and aerospace components. CNC milling and turning – a comparison of technologies To understand CNC milling and turning, it is worth comparing these processes in terms of key aspects: Movement of elements Workpiece geometry Machining range Milling is a highly versatile process that allows for the creation of very complex shapes. CNC turning, on the other hand, allows for the efficient creation of symmetrical elements while maintaining perfect axial alignment. How to choose the right CNC machining method? The choice between CNC milling and turning depends primarily on the geometry of the detail, the type of material and the production requirements. Geometry Turning is chosen for axially symmetrical components – shafts, sleeves, pins. Milling is used for parts with complex surfaces, spatial openings, and irregular shapes. Material Most metals can be machined using both methods. With plastics, milling provides greater dimensional stability and better process control. Accuracy Turning guarantees high coaxiality precision. Milling allows positioning relative to multiple planes. Production scale In the mass production of simple parts, turning is more effective. Milling is better suited to small-batch production of complex components. At SIM Gdynia, we combine both technologies to tailor the machining process to the customer’s requirements. We analyze each project individually in terms of functional and economic requirements. Summary CNC turning and milling are two different approaches to machining that complement each other in modern production. The choice of technology should be based on a design, tolerance and material analysis. Turning dominates in simple, axial parts where efficiency and repeatability are important. Milling allows for complete freedom in the design of spatial details and precise multi-axis machining. Understanding these differences is the foundation of effective technological cooperation – from design to the finished product.
Iscar technical training at SIM Gdynia – new Quicklogic tool line supports the development of precision CNC machining
At SIM Gdynia, we prioritize the development of our team’s technical skills and the continuous improvement of our production processes. As part of these activities, in April we had the opportunity to participate in training conducted by Iscar, a global leader in cutting tools, at their mobile training center, which was hosted at our plant. Presentation of Quicklogic tools – innovations in machining During the meeting, we were presented with a new line of Quicklogic tools, designed to increase efficiency and precision in turning, boring, milling, and drilling. These tools are a response to the modern challenges in the production of mechanical components, carried out in short series and to individual customer orders. Iscar engineers presented both the design aspects of the tools and specific examples of their practical application. Particular emphasis was placed on the possibility of shortening the machining cycle time, improving tool life and increasing process repeatability – key parameters in professional CNC machining to order. Benefits for SIM Gdynia and our customers Participation in the training allowed us to become more familiar with modern technological solutions that we plan to implement in our machine park in the near future. Thanks to them, we will be able to even more effectively carry out orders in the field of turning, milling and comprehensive CNC machining, offering our customers even higher quality of workmanship while shortening delivery times. At SIM Gdynia, we constantly invest in development, both through the modernization of our technical infrastructure and specialized training for our team. Such meetings are an important part of building our technological advantage and maintaining the highest production standards. Thanks to the Iscar team We would like to thank Iscar for organizing a professional training course and for the opportunity to learn about the latest solutions in the field of machining tools. The meeting was a valuable source of knowledge and inspiration that we will use to further improve our technological processes.
What materials are CNC machined? An overview of the most commonly used raw materials in the production of mechanical components at SIM Gdynia
In the precision production of mechanical components, the selection of the right material is a key stage of the process. CNC machining – whether turning, milling or 5-axis machining – requires materials that not only meet strength requirements, but also work well with tools and cutting technology. At SIM Gdynia, we have specialized in CNC services for over 45 years and know how important the quality and type of raw material is. In this article, we present an overview of the materials we use most often in our production. Materials most commonly used in CNC machining Three main material groups dominate our machinery: carbon steel, stainless steel and aluminum. These raw materials form the basis for the production of precision components for industries such as the automotive, energy and mechanical engineering sectors. Carbon steel – versatile and robust Structural steel (e.g. S235JR, S355J2) and quenched and tempered steels such as C45, 42CrMo4, 16MnCr5 are the basic materials from which we produce a wide range of parts. Their availability, the possibility of precise CNC machining and excellent mechanical properties make them a reliable choice for many projects. Stainless steel – corrosion resistance Stainless steel is a material that is used in environments requiring increased chemical resistance. At SIM Gdynia, we often machine austenitic and ferritic steels, which require the appropriate selection of cutting parameters due to their hardness and tendency to harden during machining. Aluminum – lightness and versatility Thanks to its low weight and good conductive properties, aluminum is often used in industries such as aviation, automotive and electronics. In the CNC milling process, it allows for very high accuracy and short cycle times. Less typical, but equally important materials Although the vast majority of parts produced in our hall are made of metals, there is no shortage of projects using plastics and non-ferrous metals. Plastics At SIM Gdynia, we process engineering plastics such as POM, PA and PTFE. These materials are characterized by a low coefficient of friction, good chemical resistance and ease of processing, although they require precise tool alignment and thermal deformation control. Non-ferrous metals: copper, brass, bronze These materials are used less frequently but are still important, especially for the production of electrically conductive or wear-resistant components. They require special tool geometries because they are relatively soft and can stick to the cutting edge. How do the physical properties of materials affect CNC machining? Each material reacts differently to the cutting process. Hardness affects tool wear, ductility determines the type of chip, and thermal conductivity affects dimensional stability during machining. Machinability of materials – a key technological parameter Machinability is a collective term for how easily a material can be processed. Grades such as 11SMn30 (free-cutting steel) have very good machinability and are ideal for mass-produced parts. Stainless steel or copper, on the other hand, require sharper tools, lower feed rates and more efficient cooling. Quality control and material conformity Every material used in our production undergoes a quality control process. The certification of the material and the possibility of verifying its chemical composition are crucial. Thanks to the SPECTROMAXx spectrometer, we are able to quickly and precisely confirm the material’s conformity with the specification – before it even reaches the CNC machine. We work with renowned suppliers who offer a wide range of steel bars (drawn and rolled) in grades such as 11SMn30, C35, ETG88 and 20MnCr5. These grades provide different mechanical properties, such as hardness, machinability or fatigue strength, depending on the final application of the workpiece. Summary Choosing the right material for CNC machining is not just a question of availability – it is a decision that affects the entire production cycle, the service life of the tools, the quality of the finished component and its compliance with technical requirements. At SIM Gdynia, we attach great importance to the quality of raw materials, precise control and matching of machining technology to a specific material.If you are looking for a partner who not only produces custom-made mechanical components but also advises you on the best raw material, please contact us. Our services CNC guarantee quality, experience and technological know-how.