As one of the most popular material categories in the world, ceramics are used widely across a variety of industries. Most commonly associated with pottery and household objects, ceramics can also be utilized in other products, including the ones with electrical appliances and medical equipment.
CNC machining is by far the best method for large-scale manufacturing of ceramic products. As a hands-off, computer-controlled approach, it allows you to create thousands of parts in a relatively short period of time. Not to mention the high-quality, smooth finish you receive when working with methods such as laser cutting.
In this guide, we’ll go over the various applications of ceramic materials, the different types of ceramics, as well as some guidelines you should follow when designing and machining ceramic products. After reading this complete guide, you’ll have a far better understanding of what to expect, and how to get the most out of machining ceramics.
Applications of Ceramics
CNC ceramic machining can be used in any industry, from everyday household item production all the way to massively producing decorative pieces. Out of all the possible applications, three stand out the most: electronic, industrial, and medical.
In the electronics field, ceramic parts turn out to be incredibly handy as electrical parts with high wear resistance and high precision. Ceramics have very high insulating properties, which makes them the perfect choice for manufacturers who want to avoid electrical and fire hazards. Ceramic materials such as quartz, macor, or aluminum nitride are frequently used in the manufacturing process of semi-conductors.
The variety of industrial applications of ceramics is incredibly wide. While these materials are great for large, smooth pillars or structures, they are even better for creating industrial parts that are small, complex, and require high-precision. Due to their high wear resistance, ceramics are ideal for parts that are meant to last for a long time in busy industrial environments. The types of ceramic used in industrial settings include but are not limited to mullite, quartz, or mycalex.
Finally, the medical field is another area where the use of ceramics is prevalent. They are used to create implants meant to go into the body, as they do not pose a risk of adverse or allergic reactions, as opposed to other materials. Zirconia (a type of ceramic) is also widely used by dentists to create high-quality dental implants.
Different Types of Ceramics
People tend to bundle ceramics together as a singular material, but that couldn’t be further from the truth. There are dozens of different ceramics, with each one coming with different characteristics and specifications. Knowing the most popular types of ceramics used for machining is crucial, as it will allow you to choose the one that suits your business niche the most.
Thanks to its great electrical and mechanical properties, alumina works incredibly well for manufacturing smaller parts of larger tools or appliances. It can be easily machined into specific shapes, and with the right brazing or metalizing techniques, it can be seamlessly joined with metals.
It is similar to alumina, with a key difference being its lower thermal expansion coefficient. This makes aluminum nitride great for semi-conductor manufacturing, as it matches the expansion of silicon wafers to a tee.
Also known as lava, alumina silicate is a type of ceramic that can withstand very high temperatures, making it great for electrical or thermal insulation purposes.
This ceramic material is carbon-based. Its density is dependent on the polymer state. With even better chemical, thermal, and shock resistance than alumina silicate, graphite is perfect for manufacturing items such as molds or furnace parts.
These polycrystalline ceramics that include Vycor, Pyrex, and other materials are extremely resistant to thermal shock. Due to these properties, ceramic glass parts make for great insulation parts.
More suited for laser cutting than machining, this ceramic material is perfectly suited for large, structural parts. It has great temperature stability, creep resistance, and strength. Mullite is frequently used for producing furniture, as well as large heat insulation parts and furnace centers.
One of the most unique ceramics out there. It is used in highly-specific industries with very strict quality control requirements, such as aerospace, semiconductors, and medicine. It does not get wet, insulates extremely well even at very high voltages, and does not deform even under the highest pressures.
Similarly to mullite, mycalex is a resistant ceramic, often found in structural parts. However, rather than being used for larger components, it is most commonly machined into small industrial parts that require durability and temperature resistance.
Due to its fantastic optical properties, you can find quartz in many lighting appliances, as well as in semi-conductors. Rather than by cutting, machining quartz into whatever you want it to become should be done via abrasive techniques.
As we mentioned earlier, zirconia is commonly used in the stomatological industry to produce dental implants. This is because this ceramic material is incredibly resistant to chemicals and corrosion, making it the best choice for tooth replacements.
Machining Ceramics Guidelines
We have already established that ceramics are highly malleable materials with differing properties (depending on what type of ceramic you decide to use). While that makes them great for all sorts of machining work, there are certain factors that you need to be aware of before beginning to work with ceramics.
First of all, always use the appropriate method for the ceramic you’re using. For example, you would not use the same machine for both zirconia and mullite. Mullite is better suited for laser cutting, whereas zirconia is more delicate (although resistant to corrosion and chemicals), and should be molded using cutting and abrasive methods. Similar rules apply to other kinds of ceramics.
Read up on the type of material you’re planning to use and make sure to adjust your techniques. The rundown included in this article is a good starting point, but you might also want to reach out to your suppliers, as well as get a second opinion from other business owners who also use the same ceramic.
Secondly, there are certain design requirements you need to consider. We’ll go into more detail on that in a moment, but for now, remember that a poorly designed ceramic part is at a high risk of breaking or cracking.
Finally, remember to always make prototypes! This guideline can really be applied to manufacturing any kind of a complex part, regardless of the material you’re using. Set your machinery to create just one copy of your component first, and see whether or not it meets all of your requirements. If it does, you can move on to machining a larger number of the same parts. If not, then you can always go back to your design and make the necessary changes without wasting a lot of money and energy on a flawed batch of products.
What to Keep in Mind When Designing
Designing ceramic parts for machining is similar to creating designs intended for other materials, but there are certain rules you need to follow in order to avoid faulty products or damaging your equipment. Here are some pointers to consider when drafting your first design:
- Avoid pointy edges (especially long ones)
- Oval designs don’t tend to work well with ceramics; make them round instead
- Corners and sharp edges increase the risk of breakage, and they can easily cut through skin
- Corner pockets are good alternatives to sharp corners if you don’t want to opt for rounded edges
- If your design includes holes, make sure they are not located too close to each other
The Bottom Line
Computer numerical control (CNC) machining is great for mass producing all sorts of products and parts that require high precision and thorough adherence to the design documents. Ceramic materials are some of the most frequently used by machinists. While popular and relatively inexpensive, they require a fair bit of knowledge before diving off the deep end and beginning the manufacturing process.
Most importantly, you need to be able to distinguish between different types of ceramics in order to use the one that best suits your products or specific components. You also need to be very careful when designing your parts so as not to increase the risk of breakage.
Hopefully, our extensive guide to machining ceramics made for a good starting point, allowing you to continue your entrepreneurial journey with more confidence and clarity regarding your next steps.