Brass is a truly widely used metal material. Brass has a naturally beautiful appearance, and lustrous finish that makes it ideal for artwork, cookware, kitchen backsplashes, countertops, and even jewelry. It also has excellent Brass CNC machining and electrical properties, making it suitable for processing complex brass CNC machining parts.
There are many benefits to using brass for machined parts. Brass is one of the most versatile metals in the world, offering high corrosion resistance and good electrical and thermal conductivity. In this article, we will discuss processing methods, design considerations, and machining requirements for brass that offer more than just aesthetic benefits.
The Technology of Brass CNC Machining
Brass is difficult to machine due to its high ductility, plasticity, and toughness. But alloying brass improves its machinability and even makes brass alloys easier to machine than most other metallic materials. Most CNC-machined brass parts are made from brass alloyed with zinc, tin, aluminum, silicon, and/or nickel. These alloys require much less cutting force than machined steel or aluminum alloys of equal strength.
Brass CNC Milling
Brass alloys can be machined using a variety of techniques. CNC milling is an automated machining process that uses computer control to manage the movement and operation of multi-point rotary cutting tools. As the tools rotate and move over the surface of the workpiece, they slowly remove excess material to complete the desired shape and size. To get different shapes of brass CNC machining parts, using CNC milling can be used to create different design features such as recesses, notches, grooves, holes, slots, contours, and flat surfaces.
The following are some guidelines for CNC milling brass or brass alloys.
Common cutting materials are carbide application groups, such as N10 and N20, and HSS grades
You can reduce the cutting speed by up to 10%, thus extending tool life
When CNC milling brass casting alloys with cast skins, reduce the cutting speed by 15% for carbide group tools and 20% for HSS grade tools
Brass CNC Turning
Another technique for machining brass is CNC turning, where the tool remains stationary while the workpiece moves to produce the desired shape. CNC turning is a machining system suitable for manufacturing many electronic and mechanical parts.
There are many benefits to using CNC turning, including cost-effectiveness, accuracy and increased manufacturing speed. Careful consideration of speed is especially important when turning brass workpieces because brass is an excellent thermal conductor and it generates more heat than other materials, which can increase tool wear over time.
The following are some tips for CNC turning brass or brass alloys.
Set the tool edge angle in the range of 70°to 95°.
Softer brass that is susceptible to smearing requires a tool edge angle of approximately 90˚.
Constant depth of cut and reduced cutting edge angle reduce stress on the tool, increasing tool life and cutting speed.
Increasing the angle between the primary and secondary cutting edges (tool clamping angle) allows for higher mechanical loads on the tool and results in lower thermal stresses.
Design Tips for Brass CNC Machining
There are a variety of factors to consider when designing parts for brass CNC machining. In general, you should only use brass when necessary because it is expensive and it is not usually necessary to produce the entire part in copper. A good design can use a small amount of brass to maximize its unusual properties.
The following are some common reasons for choosing brass or brass alloy parts.
High corrosion resistance
High electrical and thermal conductivity, easy to solder
Highly machinable alloy
Choosing the right grade of material
During the design phase, it is important to select the correct grade of brass for your application. For example, it is difficult and uneconomical to use pure copper for completely mechanical parts. c101 (pure copper) has higher electrical conductivity due to its purity (99.99% copper), but is less machinable, while c110 is generally easier to CNC machine and therefore more cost-effective. Therefore, the selection of the correct material grade depends on the properties that are critical to the design function.
Design for manufacturability
No matter what material you use, DFM should always be a priority. At Tirapid, we recommend that you keep the features required for your application while relaxing tolerances as much as possible. It is also advisable to limit dimensional checks, avoid deep cavities with small radii, and limit the number of part setups.
In particular, here are some specific best practices when designing brass parts.
Maintain a minimum wall thickness of 0.5 mm
The maximum part size for CNC milling is 1200 * 500 * 152 mm and for CNC turning is 152 * 394 mm
For nibbling, maintain a square profile, full radius or dovetail profile.
Surface Finishing of Brass CNC Machining Parts
After brass CNC machining is completed, there are a variety of factors to consider when deciding which process is best for your needs. The first step in surface finish control is in the CNC machining process. Certain CNC machining parameters can be controlled to change the surface quality of the brass CNC machining parts, such as the tool tip radius or tool corner radius.
For soft brass alloys and pure copper, the quality of the finish is directly and heavily dependent on the nose radius. The head radius should be minimized to prevent the coating of softer metals and to reduce surface roughness. With doing this creates a higher quality cut surface, as a smaller tip radius reduces feed marks. Wiper inserts are the tool of choice over traditional tip radius tools because they can improve surface finish without changing the feed rate.
You can also achieve part finish requirements through post-processing by:
Hand polishing – although labor-intensive, polishing produces an attractive surface finish
Media blasting – this produces a uniform matte finish and hides small imperfections
Electrolytic polishing – due to its incredible electrical conductivity, it leaves the copper shiny and is the best choice for finishing brass.
One-stop Brass CNC machining In Tirapid
As a leading manufacturer in China, Tirapid can provide one-stop brass CNC machining service. We have over 10 years of experience in CNC machining and can provide high-quality custom machining services for various industries, including aerospace, automotive, medical, etc. Our team of skilled engineers and machinists can produce parts to the exact specifications. Our state-of-the-art facilities allow us to produce large quantities of custom CNC machined parts quickly and efficiently.
We are also ISO9001 certified, so you can be assured that we will consistently deliver high-quality products and excellent customer service. If you’re looking for a partner that can provide brass CNC machining, Tirapid is a perfect choice. Contact us now to learn more about the details.