By Jake Hughes
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24 Jun, 2024
CNC machining is such an important part of manufacturing, with industries as varied as the medical industry, aerospace , and electronics all utilising the performance, accuracy, and speed of CNC machining for a variety of parts, components, and applications. Cutting costs without negatively impacting the end product is something that is always discussed, and CNC machining is no different. One way in which the costs associated with CNC machining can be lowered is through the careful choice of materials being used within each project. What factors should you consider? There are a range of factors to consider when choosing the correct metal for your CNC machining needs. Even if you choose a metal that has a higher raw material price, if it is used correctly, with the right type of machining and gives you the desired end result, this will also mean it is the most cost-effective and desirable option for your project. Factors include: Availability of materials The cost of metals fluctuates depending on their availability in the market. Aluminium for example, often comes at a competitive price and is therefore a cost-effective choice, Machinability The higher the machinability of the machining material, the better the impact on the tools, with reduced tool wear and shorter machining times. This helps to lower labour and material costs. Set-up and tooling The hardness of a material, along with other characteristics, have an impact on tool wear and the requirements for specialised tooling. Always look for that balance where there are minimal set-up costs to help lower your budget. Minimise waste This is a crucial part of planning for CNC machining projects. Some materials, like certain alloys and plastics, have efficient use of raw materials, lowering the environmental and cost impact. Post-machining treatments How much surface finishing and coating will be required? This will have an impact on the overall cost of the project, with materials that require minimal post-processing leads to additional cost savings. Complexity of parts The more complex the parts required, the longer the machining time and therefore the higher the potential costs. Volume requirements What is the quantity of parts and components required? This will have an impact on costs, as the higher the volume requirements, the longer the production run. Industry standards In some cases, you’ll be required to produce components and parts to industry standards and regulations, as well as established machining parameters. Understanding this will help to create a streamlined manufacturing process. Consider the environment A suitable CNC metal for different environments is important, as you need to ensure that the CNC part can withstand the necessary pressure and temperature extremes. Weight of the part Considering the weight of the part will ease the manufacturing process, as heavier parts will drive up the material costs and require more expensive CNC machines and longer production times. Heat resistance Effective heat resistance is crucial for materials to withstand extreme temperatures without becoming damaged or disfigured during the process. Consistency is key within CNC machining. What are the most cost-effective metals for CNC machining? Some of the most cost-effective metals that are used for CNC machining include: Aluminium This is a metal that is available in a range of different alloys and is one of the most cost-effective metals that can be used for CNC machining. It is highly machinable (varying for different alloys slightly) and has a low raw material cost when compared with other metals. Aluminium has a high strength-to-weight ratio and has great resistance to both corrosion and temperature, making it useful within a range of industries, such as automotive, healthcare, aerospace and consumer goods, to name just a few. Stainless steel A popular, versatile CNC metal used within a variety of CNC machining applications. It is not as machinable as aluminium but does have good machinability to low raw material cost ratio. It is high in strength, resistant to chemicals and has good levels of hardness. Stainless steel is used commonly in the aerospace, automotive, marine, healthcare and food industries. Brass A cost-effective metal alloy that is made from a combination of zinc and copper. It has a higher machinability factor than stainless steel, but it has a higher cost of raw material. When comparing brass with other metals however, it does have a high level of scrap return, reducing the overall raw material cost. Brass is soft and easily machinable, which has a low impact on the machining tools, with a medium hardness and high tensile strength. Brass is used within the manufacture of consumer goods, architecture, electrical goods, and within the healthcare and automotive sectors. Copper A very high machinability rate in a similar way to brass, making it one of the most cost-effective of all CNC machining metals. The price of raw material can often be higher though, making it less cost-effective in other ways. It is commonly used in applications where there is a need for good thermal and electrical conductivity, and you’ll find copper used in industries such as electronics and healthcare due to good corrosion resistance levels. Titanium This has a higher raw material cost than the other metals in this list and can be challenging to work with due to the low thermal conductivity and high strength. There are a few unique properties though that make it a choice for some companies and for certain industries and applications. This is due to the excellent strength-to-weight ratio, and resistance to temperature, corrosion, and chemicals, making it useful within the medical and aerospace sectors specifically. There are different suitable metals for different CNC machines, different processes, and the many different desires and requirements for specific components and parts. Each is distinguished by different mechanical properties, such as strength, flexibility, resistance to corrosion, and other factors. Some materials, as you have seen above, are easier to machine than others, or are more suitable for specific components and parts for a variety of reasons. Understanding what materials work best for your specific CNC machining needs goes a long way to helping you manage your business, your project, and gaining a tighter control over the costs of CNC machining.