Selection Criteria for CNC Machining
CNC machining (Computer Numerically Controlled, sometimes as Computer Numerical Control) is a fast, efficient, precise and versatile industrial manufacturing method, which is moreover compatible with a wide range of common engineering materials and of variable hardness, including metals, plastics, semiconductors or elastomers. Used both in prototyping and for the mass production of fully functional products directly usable in their final application, the success of a CNC machining project, as well as the operational capabilities of the part produced, however, depend significantly on the material used. Hence the essential importance of the choice of material, which is still today a crucial step in CNC mass manufacturing.
A number of separate requirements and factors go into determining which material is best suited for a CNC machining project. For example: do you need a material with excellent mechanical properties? Or, conversely, do you place more importance on manufacturing speed? Very often, it is a question of balancing a whole series of criteria in order to have the fairest idea of the material necessary. The criteria presented below do not constitute an exhaustive list, but nevertheless make it possible to establish a sound basis for reflection as to the choice of the most appropriate material for CNC machining.
Material selection process
In order to correctly choose the best possible material for CNC machining, we can rely on the following steps:
Step 1: Determine material requirements. Consider its various properties, such as functionality, electrical properties, strength, and hardness, and determine which of these the material must possess in order to be the ideal candidate for your project. It will also be necessary to take into account the operational environment of the part, and the conditions to which it will be exposed.
Step 2: Identify potential material options. It involves sorting out possible candidates based on project requirements, including design specifications.
Step 3: Choose the ideal material. It will be the one capable of satisfying most of your requirements. It may happen that certain compromises are necessary: for example, a material with better machinability may be preferred, compared to a less expensive alternative, in order to ensure the quality of the work.
Material Selection Guide for CNC Machining
Here are the most important factors to consider when selecting the most suitable materials for your CNC machining projects.
The area of application of the part
This is probably the most important criterion to take into account when choosing the manufacturing material. Indeed, a particular material will not necessarily be suitable for a particular application: the aerospace industry requires light parts, which is not necessarily the case for parts intended for the construction of buildings. For example, 3.3211 aluminum is commonly used in the aerospace industry for its good strength to weight ratio.
The field of application will largely determine the necessary physical properties of the material, such as: its tensile strength and crack resistance, strength to weight ratio, stiffness and flexibility. As a general rule, the heavier a material, the more it is able to withstand high stresses. However, in applications where weight is a critical factor, it will be necessary to move towards lighter materials, with a good strength-to-weight ratio. Steels 1.0503 and 1.0038 are relatively heavy materials, compared to lighter aluminum alloys, such as aluminum 3.3206.
The choice of material has an influence on all stages of the production cycle, from prototyping to the performance of the part in operation, including of course its mass production. Choosing the right material is often the key to getting a fully optimized part.
This is the reason why the choice of the material of manufacture is a crucial step that must be considered with the utmost care before even starting any CNC machining operation. The criteria presented above will allow you to get a clearer idea of the material you need for your project, and will help you make an informed choice.