Views: 10020 Author: Site Editor Publish Time: 2020-01-18 Origin: Site
A CNC machine is a computer controlled carving machine. It generally speaking reads G Code that instructs the machine how to move, what feedrate and spindle speed to use, which cutting tool should be in the spindle, etc. The cutter that the machine has in the spindle will carve through the material (generally metal) and create the intended shape. The material that has been removed is called "chips" and it will usually be recycled.
CNC (Computer Numerical Control) machining is a subtractive manufacturing technology. This means that parts are created by removing material from a solid block (called the blank or the workpiece) using a variety of cutting tools.
A CNC machine removes material from a solid block using a variety of cutting tools to produce a part based on a CAD model.
To create different geometries, CNC machines use different cutting tools. Their different geometry allows the machining of features with different details.
The CNC machining process begins with the creation of a 2D vector or 3D solid part CAD design either in-house or by a CAD/CAM design service company. Computer-aided design (CAD) software allows designers and manufacturers to produce a model or rendering of their parts and products along with the necessary technical specifications, such as dimensions and geometries, for producing the part or product.
Designs for CNC machined parts are restricted by the capabilities (or inabilities) of the CNC machine and tooling. For example, most CNC machine tooling is cylindrical therefore the part geometries possible via the CNC machining process are limited as the tooling creates curved corner sections. Additionally, the properties of the material being machined, tooling design, and workholding capabilities of the machine further restrict the design possibilities, such as the minimum part thicknesses, maximum part size, and inclusion and complexity of internal cavities and features.
Once the CAD design is completed, the designer exports it to a CNC-compatible file format, such as STEP or IGES.
In most cases a CNC machine is programmed by a programmer using CAM software who uses the software to apply tool paths to a 3D or 2D model of the part they want to make. Once the programmer has finished his/her programming work, the program is fed into a post processor which will turn the CAM program into the G code the machine can read. The G code is uploaded into a the CNC machine along with all the cutting tools needed, raw material and work holding needed to hold the raw material. Then a machinist will put the machine into automatic mode and start the program to make the part.