Engineering has continuously developed over the years, with new techniques and processes arriving and changing the way it makes parts and tools. As these techniques and processes become more commonplace, they are commercialised, and the costs associated with them reduce. Because of this, businesses can utilise these techniques to make specialist equipment they can use in their own manufacturing process.
To help you understand how three of the main precision engineering methods work and are able to produce highly accurate results, we have put together this brief guide which also highlights some of their benefits.
As you may have guessed from the name, wire EDM requires a physical wire. EDM stands for electrical discharge machining. This process works by having an electrically charged wire come into very close proximity with the piece of metal being worked on. Due to the close proximity, a spark is produced, making this type of manufacturing a form of spark erosion, which discharges a large amount of heat. When combined with the dielectric fluid, which the work piece is surrounded by, the fluid changes into an ionised gas or plasma. This then collapses at high pressure and forces the metal to break off a small amount to form a crater.
The process is rapidly repeated. However, this causes the wire to erode, meaning a continuous supply of wire is needed, especially for large projects. To ensure accuracy, the wire needs to be threaded through the machine extremely carefully, and modern wire EDM machines use automatic threading to achieve this. Wire EDM has the benefit of being able to cut extremely hard metals without damaging the structural integratory or physical appearance of the product. Furthermore, wire EDM can produce some incredibly intricate designs as the diameter of the wire can be varied depending on the design needs.
CNC Milling and Turning
CNC, or computer numerical control, is an excellent example of precision engineering. Based on instructions given to a machine by a computer pre-programmed with code to create a specific design, the machines can produce highly accurate designs. There are two main types of CNC machines, ‘additive’ where a product is added, such as 3D printing, or ‘subtractive’, where is it taken away. CNC milling and turning are both types of subtractive CNC machining.
A CNC milling machine works by cutting or drilling material away using a tool called a milling cutter. In comparison to a manually operated milling machine, a CNC version can move in any number of axes (2 to 5). CNC turning works slightly differently as the machine moves the piece of wood or metal rather than the actual tool head. Turning is also usually reserved for cylindrical workpieces.
The main benefits to using a CNC milling or tuning machine is the increased speed and volume of production. Furthermore, because the machine is working to a predetermined design, once the design has been finalised and approved, the machine can produce that design exactly and can do so multiple times without variation. Using a manual turning or milling machine is a skilled process. While there is a large amount of skill involved in setting up the CNC machine to produce a design, you don’t have to worry about human error and variation when producing a large order of multiple pieces.
The advantage of using precision engineering methods such as Wire EDM or CNC milling and turning is that when producing parts for other businesses, particularly other manufacturing companies, their needs can be very specific. It’s vital when producing a part or tool for another business that the job is completed to the exact measurements they provide. If not, this could be costly for both the production company and the customer, if the part is not fit for purpose, because the measurements have not been adhered to correctly. Computer controlled precision engineering methods allow for accuracy and consistency.