Tips for Stainless Steel in CNC Machining
Stainless steel is one of the most popular materials for cnc manufacturing with many advantages to present high performance industrial parts. Since steel is available in various grades and offers several advantages and characteristics that make it suited for a range of applications, stainless steel is often machined. A minimum of 10% chromium is required for steel to be categorized as stainless steel, which gives the material its many distinctive qualities, including resistance to corrosion and the capacity to self-heal in oxygen.
Material properties of stainless steel
The corrosion resistance of stainless steels, which are high-alloy steels, is superior to that of carbon and low-alloy steels. Most stainless steel alloys grade includes at least 10% of the element, primarily responsible for their high chromium content.
Austenitic, Martensitic, Ferritic, Precipitation Hardened (PH), and Duplex are the five types of stainless steel that can be divided into them. There is a fundamental, all-purpose alloy for each group. The basic is modified slightly in composition to provide specialized features for different applications.
The crystalline structure of stainless steel allows for classification. ferritic, Austenitic, martensitic, and duplex metals are included in this:
- Stainless steel made of austenitic elements, such as the 300- and 200-series stainless steel, is very formable and does not work to harden. Furthermore, when annealed, they are non-magnetic.
- Ferritic stainless steels are more thermally conductive and magnetic than austenitic stainless steel. By applying heat, they cannot be made harder.
- Various aging or heat treatment techniques can harden martensitic stainless steel, such as grades 416 and 420.
- Austenitic-ferritic stainless steel, usually duplex stainless steel, is a highly specialized kind of stainless that offers excellent corrosion resistance. Construction in the industrial and architectural sectors often uses duplex steels.
Tips for stainless steel machining
1. RIGID MACHINES AND TOOLING
It is crucial that no dwell or rubbing occurs as a result of vibration or tool chatter while machining stainless steels. To machine austenitic stainless steel at the required feed and surface speeds, machines must be "substantial" and capable of creating deep cuts. It is pretty unlikely that stainless steel can be machined successfully on a small training or "hobbies" lathe or milling machine designed for machining mild steel, brasses, etc.
The machine bed, drives, gear boxes, and the cutting tool and mountings should not vibrate excessively. Avoid leaving long protrusions of tool shank outside the toolbox. The cross-section of the shank should be as large as feasible, and the space between the cutting tip and the toolbox support should be as little as possible. Dissipating heat away from the cutting surfaces is another benefit. Barrel milling cutter arbors should be as compact and robust as possible. The arbor should be positioned near the cutter's ends as appropriate.
2. CHOOSE THE RIGHT TOOL MATERIAL
Stainless steel CNC machining is available from a select few reliable sources—tungsten or molybdenum high-speed steel (HSS). The hardness, abrasion resistance, and strength of HSS tools determine when they are utilized. The procedure can be improved with the use of several grades. In cases when edge chipping is a problem, more robust end mills can be employed.
There's also the excellent option of cemented carbines. When larger feeds and speeds are necessary, Cemented Carbides are a viable alternative to HSS. By switching to a coated cemented carbide tool, you can decrease wear and increase durability.
3. COOLANT CHOICE
When machining stainless steel, it is essential to employ cutting fluids. This is because the poor thermal conductivity of austenitic stainless steels limits the passage of heat away from the machined faces, compounding the effects of the deep cuts and high feed rates required to counter the effects of work hardening. When machining stainless steel, it is essential to prevent overheating the surface by creating heat tinting colors that reduce corrosion resistance. Once the component has been manufactured, its corrosion resistance can be restored by pickling the surface. The distortion caused by overheating is not only annoying but also hard to fix.
Stainless steel machining by Exzellenc
Exzellenc offers multiple approaches to manufacture stainless steel. For simples stainless steel parts the recommendation is traditional cnc machinig with multi-axis cnc. The other one is metal additive manufacturing to print stainless steel parts with complex shapes design, which can greatly cut down the material cost and enhance the productivity. Metal 3D printing is our main focusing technology with know-how, empower our customers to create the high performance parts in wide rang industry.