What Factors to Consider for Selecting the Right Metal for CNC Machining

CNC metal machining offers a ton of benefits for the metal manufacturing industry. Time is an important consideration in metalworking projects. By using CNC machinery to machine metal, the time required to perform a single process is greatly reduced. In addition, CNC machining increases the speed of machining, and performing repetitive machining requires only a simple start-up procedure. On the other hand, machining metal without CNC technology requires a thorough adjustment of tools and machines during rework. By using CNC technology, the size of the machining floor can be reduced, and it is now possible to use a single machine to create a machining project, whereas in the past several were needed. 

Let’s start with mechanical properties, which are measured by the properties of materials when different forces are applied. The main mechanical properties of metals to consider include strength, ductility, elasticity, density, magnetism, damping.

1. Wear and fatigue strength of metals

In general, if you are machining a part in CNC to achieve prototype fit and function, you don’t need to worry about material wear. If you need to ensure that the strength or parts can withstand environmental performance tests such as extreme temperature, we should pay great attention to the selection of materials. Let’s break down the most important fatigue characteristics.

Fatigue strength and toughness are the stresses that a material can bear under a specific number of cycles. These changes have been extensively studied to help select the appropriate materials to meet your end-use requirements. In fact, it is estimated that about 90% of failures in metals are caused by fatigue. The failure occurs quickly and without any warning, so we usually measure the fatigue strength by the average ratio. When selecting materials, it is recommended to evaluate the fatigue strength level if you know that the part will withstand multiple stress cycles.

In most cases, the material is placed in a controlled environment and tested for high and low temperature, high and low humidity, thermal cycle, and thermal shock. High-temperature-resistant metals include titanium and stainless steel. Metals that can withstand extremely cold temperatures and maintain toughness at low temperatures are copper and aluminum.

2. The corrosion resistance of metal

Everything on earth, whether human or stone, is a process of oxidation resistance, and so is metal. Metal corrosion is the result of a chemical reaction between metal and the surrounding environment, degradation, or oxidation. The corrosion resistance of pure iron is different from that of other metals, but the corrosion resistance of pure iron is basically different from that of other metals. If you are worried about corrosion, stainless steel is a good metal choice.

3. Machinability of metals

When it comes to machinability, each supplier or manufacturing partner can have a different set of requirements according to their capabilities. If you find that your parts cannot be processed by CNC and your part design has little flexibility, you may need to change the manufacturing method to 3D printing, which can provide unique solutions for metals and plastics.

4. CNC metal machining cost

Finally, and most importantly, we should pay attention to the cost of the materials you choose. This may not be surprising to you, but if you have more material requirements or needs, you are likely to pay more for these materials. Aluminum is an affordable machining material, which we talked about above. Use DFM to optimize some of your designs and save you time and money, regardless of your material selection.