CNC machined hard and soft metals
Like all things, having multiple options is usually a good thing. But having too many options for an upcoming CNC machining project without a clear goal can be overwhelming and costly. So, we've broken down the top six factors you should consider before machining hard or soft metals.
1. Mechanical properties of metals
Let's start with mechanical properties, which are measured by how a material behaves when different forces are applied.
The main mechanical properties of metals that need to be considered are:
Strength (hard metal)
Ductility (soft metals)
Elasticity (hard metals tend to be more elastic than soft metals)
Hardness (hard metal)
Density (density ranges from soft to hard)
Fracture toughness (highest range of fracture toughness of all metals, but toughest from soft to hard)
Damping (hard metals tend to have less damping capacity)
2. Wear and fatigue properties of metals
Generally, if you're machining a part for prototype fit and function, you don't need to worry about material wear. Your choice of material will be important if you need to guarantee strength or allow parts to withstand environmental characteristics such as extreme temperatures. Let's break down the most important fatigue properties to consider.
Fatigue Strength and Toughness: This is the stress a material can withstand for a specific number of cycles. These variations have been extensively researched to help select the appropriate material to meet your end-use requirements. In fact, according to research on the subject, "it is estimated that about 90% of all metal failures are caused by fatigue." Failures occur quickly and without warning, so we usually measure fatigue strength by ratio averages. When selecting materials, we recommend evaluating a fatigue strength rating if you know your part will be subjected to multiple stress cycles.
Ambient Loops: There are many resources for ambient loop testing. In most cases, materials are placed in a controlled environment and tested for high and low temperatures, high and low humidity, thermal cycling and thermal shock, among others.
--High temperature resistant metals: titanium and stainless steel.
--Metals that can withstand extremely cold temperatures and remain ductile at low temperatures: copper and aluminum.
Creep resistance is defined as the ability of a material to resist "creep," which is the tendency of a solid material to deform over an extended period of time - due to exposure to high levels of stress. It is important to note that creep resistance may exceed the standard stress limit of the material because it takes longer to occur. Creep is especially important for use cases that may be exposed to high temperatures - think aerospace applications or spacecraft. The creep resistance of a metal is controlled by its alloy composition and melting temperature. Nickel, titanium and stainless steel have the highest creep resistance of metals. Aluminum tends to have a very low melting temperature and is not recommended for aerospace use cases.
3. Corrosion (oxidation) resistance of metals
Metal corrosion is deterioration or oxidation due to a chemical reaction between the metal and the surrounding environment. There are many reasons why metals corrode, and it is worth noting that all metals corrode. Pure iron generally corrodes very fast, but stainless steels that combine iron and other alloys corrode very slowly. If you are concerned about corrosion, stainless steel is an excellent choice for metal.
Another alternative to stainless steel is anodized aluminum. This method helps reduce corrosion and is a very durable finish. Since anodizing is an ancillary service, it may increase the lead time of your project, so it may not make sense for your project needs.
4. Thermal properties of metals
We've touched it a bit, but metals react very differently to hot pressing. Metals can expand, melt, and conduct electricity, just to name a few changes we'll explore. Let's break down the metals and their thermal properties in the table below.
5. Metal manufacturability
When it comes to manufacturability, each supplier or manufacturing partner may have a different set of requirements based on their capabilities. If you find that your part cannot be machined and your part design has little flexibility, you may need to change your manufacturing method to 3D printing, which offers unique metal and plastic solutions.
In Quote Analysis, you can access an interactive 3D image of the part design, which allows you to view the part geometry and evaluate any potential design issues such as wall thickness, narrow grooves, tolerances, threading and hole machining.
6. Metal cost
The last on the list of important factors to check before we choose a material is cost. This may not come as a surprise to you, but if you have more property requirements or needs then you may pay more for the material. Aluminum is an affordable machining material if you can weigh some of the other features we discussed above.
Shenzhen Xiehe Company is mainly engaged in the production and manufacture of non-standard precision hardware parts. It has been deeply involved in the industry for many years and has rich experience. If you have requirements for CNC lathe machining, five-axis machining services including aluminum, copper, stainless steel, iron, titanium alloys, plastics and other products, you can contact Xiehe, and we will provide you with a low-cost and high-quality integrated solution .
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