Whatever your CNC machining project, you want to produce the highest quality product for the lowest cost. You might assume that cost-effective milling means choosing the cheapest raw materials. Sometimes, that’s true. More often, though, the reality is a bit more complicated. In most cases, you should consider a number of factors when making decisions about which metals to use.
Cost Considerations
Of course, the raw material price does matter. Copper and titanium, for instance, are relatively expensive metals, and using them will drive up your overall costs.
However, you want to make sure you’ve chosen an appropriate metal for the part you’re manufacturing. If you need your part to be chemically resistant, for example, an inexpensive but highly reactive material won’t save you money if, in the end, the part can’t do what you need.
Other factors influence the final cost of a part. For instance, you can sometimes recoup the cost of a high-priced metal through the machining process itself. Some materials are simply easier to machine, so using them saves you time and energy.
In addition, some metals have a higher scrap return rate than others. At the end of the machining process, you get more money back from any excess material. You pay a higher price upfront but can save money in the long run.
Metal Options
Ultimately, then, choosing the right metal for your project means thinking carefully about exactly what you need and matching those needs with the particular qualities of the metal. When it comes to CNC machining, the most popular metals include:
- Aluminum: Aluminum is the most popular machining metal. Why? It comes with a low material cost, but at the same time, its high machinability saves money as well. In addition, it offers a good strength-to-weight ratio, corrosion resistance, and temperature resistance.
- Stainless steel: Like aluminum, stainless steel has a low raw material cost. While not quite as machinable as aluminum, it still saves money over other metals. In addition, it has a higher strength and hardness than aluminum, making it more suitable, for instance, for fittings and fasteners.
- Brass: You can also use brass for CNC machining. Brass’s machinability is actually higher than stainless steel, though as a raw material, it costs more. Brass also has a high scrap return, meaning using it saves money on the back end of a project. Finally, its high tensile strength and medium hardness make it an ideal metal for very particular applications such as electrical components.
- Copper: Copper is even more expensive as a raw material than brass, though it is equally machinable. Despite its higher price tag, copper has qualities important in several products. In particular, it offers good electrical and thermal conductivity, which makes it highly useful in the automotive, health care, and electronics industries.
- Titanium: Titanium is among the costliest metals to work with. It is expensive in its raw form, and at the same time, it is difficult to mill. However, it is also among the best metals you can purchase when it comes to temperature, chemical, and corrosion resistance. In addition, it has an excellent strength-to-weight ratio. In industries that demand reliability, such as aerospace and health care, titanium is often the best solution despite its price tag.
We’re all looking for ways to keep costs down. Sometimes that means choosing cheaper raw materials, but keep in mind that costs don’t only come from raw materials. Before you choose the metal for your next CNC machining project, consider both how you need your metal to perform and what factors will influence the bottom line.
