Precision parts refer to components where, as the name suggests, dimensional accuracy is of particular importance. Precision parts are often challenging to manufacture due to the tight tolerances, complex geometries, or difficult materials specified for them.
Precision components are needed in highly developed machines and devices. They are used, for example, in the security and aviation industry, semiconductor industry, as well as in quantum technology and medical technology.
The quality of precision parts often has a direct impact on the safety of the device's user, such as in X-ray machines, or their operating environments are very demanding. For example, quantum computers have precision parts that must function at nearly absolute zero, and parts used in satellites must operate in the extreme conditions of space.
Therefore, precision parts must work perfectly together, and their manufacturing requires excellent craftsmanship. Thus, careful selection of the manufacturing partner is essential.
Tolerances refer to the allowable deviations in the dimensions, shapes, or locations of a machined part. Tolerances are very important because they define how precisely a part must be manufactured. Tolerances are specified in the drawing according to which the part is machined. In precision parts, tolerances are usually tight, meaning that very little variation in dimensions is allowed.
A part's geometry refers to its shape, its dimensions, the positions of its surfaces relative to each other, and other physical characteristics that determine how the part is machined. The part's geometry defines the manufacturing method, the settings of the machining tools, and the sequence of operations. Therefore, geometry greatly affects the quality of a precision part and, ultimately, its functionality as part of the whole.
In addition to the material, tolerances and geometries affect the part's cost: the tighter the tolerances and the more complex the shapes, the more time it takes to manufacture the part, and the more it will cost.
>> Read the blog: Where do CNC machining costs come from?
Common materials for precision parts include various steels, titanium, hard metals, nickel alloys, aluminum, copper, and brass. Technical plastics can also be used in precision parts.
Several factors are considered when choosing a material. The mechanical and physical properties required of the part, such as hardness, strength, and corrosion resistance, affect the choice of material. The need for coating also affects material selection. In addition, the final product's operating environment must be considered: does it involve extreme temperatures or chemical exposure, for example?
The right material can be challenging to machine, meaning it can be very hard or tough, or alternatively very soft, or it can undergo changes during the manufacturing process. Machining such materials requires precise planning, experience with similar materials, and the right machining tools.
Precision parts can be manufactured using various methods, often combining different techniques. Used manufacturing methods include CNC and EDM machining, grinding, and welding.
CNC machining, is a manufacturing method where a machine tool is controlled by a computer program. CNC machining is a subtractive method, meaning the part is made by removing material from a blank. The work is done by milling, turning, or grinding.
Manufacturing precision parts through machining requires deep knowledge, experience, and precision from the operator or machinist. Operators create a program based on the part's drawings, according to which the CNC machine removes material from the blank.
Several factors must be considered when creating a CNC machine program, such as the part's geometry and material, machining and feed rates, coolant use, tool selection, and management of tool wear. The characteristics of the machine tool, such as the number of axes and their motion paths and forces, must also be considered when creating the program.
EDM machining, also known as electrical discharge machining, is a common method used in precision mechanics. It allows for the manufacture of even more complex parts. There are two approaches: wire cutting EDM and die sinking EDM.
In wire cutting EDM, a metal wire moving between wire guides cuts the blank by sparking. The method's accuracy is up to a few microns – a millimeter contains a thousand microns.
In die sink EDM, an electric current creates a voltage between the tool and the workpiece. The voltage generates a discharge or spark. The workpiece is machined by sparking to create the negative shape of the tool.
Various welding methods are also used in the manufacture of precision parts. For example, at Mectalent, orbital welding is used to manufacture pipelines used in ALD coating equipment. The welding head of the orbital machine rotates around a fixed workpiece, resulting in a uniformly high-quality and precise weld seam. The method is particularly suitable for demanding welding tasks where the quality of the weld seam is of great importance.
Quality assurance, which involves measuring and testing, is an essential part of manufacturing precision parts. Quality assurance is a process that ensures parts meet the dimensional tolerances and other requirements set for them. Quality assurance is conducted throughout the life cycle of a part, and the quality specifications come from both the customer's defined quality requirements and the manufacturer's own quality assurance processes.
For instance, very precise, micron-level tolerances are checked with measuring machines such as profile projectors and coordinate measuring machines. The eccentricity of a part is measured with dial indicators, and holes are measured with 2-point internal measuring devices. Surface roughness is verified with measuring instruments and comparison balls. All inspections, tests, and measurements made during the manufacturing process of a precision part are recorded in a measurement and inspection report, from which the customer can review the results of quality control.
At Mectalent, we also strictly adhere to the quality standards of our customers' industries. Different products have different requirements and standards that parts and products must meet. These various requirements, found in both national and EU-level regulation, ensure the safety of the products.
>> Read the blog about quality assurance of machined parts
In summary, it is crucial in the manufacture of precision parts to ensure the high quality and dimensional accuracy of components. This is achieved through careful method design, precisely selected materials, and the knowledge and expertise of experienced machining professionals.
Additionally, quality assurance processes, such as inspections and measurements at different stages of production, are essential in ensuring that each part meets its specified requirements.
Manufacturing precision parts requires top-class expertise and knowledge, which we at Mectalent have in abundance – having specialized in precision mechanics manufacturing for over 30 years.
>> Contact us, and let's discuss how we can assist you!