Machining Graphite: No walk in the park…
Machining graphite is no simple task. Although graphite’s unique structure means it can be cut easily compared to many metals, it is a far messier endeavour.
Olmec Advanced Materials have been on a journey for over 30 years, learning the ins and outs of this fascinating material. Some of the ‘do’s’ and ‘don’ts’ are more obvious than others…
We have learnt all of the invaluable lessons (some of which were ‘trial and error’) from experience in this area. A couple of really crucial tips and tricks stand out to us, so we thought we could share a few here.
1. Firstly and most importantly, graphite must be machined dry. Many machining jobs benefit from the addition of liquid coolants, so this is crucial to note. There are a few reasons why this would end badly:
The mess is reason enough, as the liquid would mix with the dust produced when graphite is cut.
Worse than the mess comes later down the line. Graphite is an extremely porous material, which gives it many benefits across a range of industries. However, this means that it acts much like a sponge, drawing the liquid into the open pores. If liquid permeates the material in the machining stage, this can cause issues later.
A lot of applications using graphite choose it for its high performance capabilities under extremely high temperatures. If liquid remains in the material at this stage, it can cause expansion and eventually crack the entire part.
2. Secondly, graphite machining requires sharper tools than other machining jobs.
Sharp tools prevent edge chipping and particle pull-out. Graphite is very strong in terms of compression, but can be fractured easily, so taking care not to use dull tools is important.
Particularly when machining parts with high tolerances, using sharp tools can improve the finish on surfaces and edges.
3. Ventilation will make a crucial difference.
Ventilation is key. When machining graphite, a lot of debris including power, dust and chips is produced. This can be a real inconvenience, especially without a good system for ventilation.
Luckily for us, CNC machines can be set up and modified in a way that prevents any damage being caused. Without modifications, the dust produced when machining graphite can be drawn into the machinery and create short circuits. Using a machine that has not been modified can lead to expensive damage.