CNC milling machine occupies an important position in CNC machining. CNC milling is suitable for machining high precision, small and medium batch, complex shape parts, is one of the most commonly used machining methods in machining, mainly including plane milling, contour milling and surface milling, but also the parts can be drilled, reamed, countersunk, bored and tapped threads. There are 5 types of parts that can be made on a CNC machine.
1. Flat parts
Flat parts are characterized by individual machined surfaces that are flat or can be expanded to be flat. The vast majority of parts currently machined on CNC milling machines belong to the flat class of parts. Flat parts are the simplest class of CNC milling objects, generally with 2.5 axis CNC milling machine can be processed.
2. Angled parts
The angle between the machined surface and the horizontal surface of the variable bevel class of parts is continuously changing, mostly for aircraft parts, such as integral beams, frames, rim strips and ribs, etc. The beveled surface of a beveled part cannot be expanded to a flat surface, but in machining, the surface is a straight line at the moment of contact with the circumference of the milling cutter. These parts are best machined with a 4-axis or 5 axis CNC milling machine swing angle machining, if 2.5 axis approximate machining on 3 axis CNC milling machine, the accuracy will be slightly worse.
3. Curved face parts
Face parts processing surface for the space curved surface, processing surface and milling tool is always point contact. Generally used 3-axis CNC milling machine processing, commonly used processing methods are mainly the following two.
- Machining by 2.5 axes line cutting method. The line cutting method is that only two coordinates are linked during processing, and the other coordinate is periodically fed according to a certain line spacing. This method is often used in the processing of less complex spatial surface parts.
- 3-Axis Linkage Machining. This method requires the CNC milling machine to have 3-axis linkage, which allows for milling machine. The method is a linear interpolation in space. This method is commonly used for machining more complex spatially curved parts
4. Enclosure/Box type parts
Box-type parts have more than one hole system, a certain internal cavity or cavity, in the direction of the length, height and width of a certain proportion. The main processing methods are.
- When there is both a face and a hole, the face should be milled first and the hole machined later.
- When all holes in all hole systems have been machined, finish machining is performed.
- In general, holes larger than 30 mm in diameter should be cast out of the blank; holes smaller than 30 mm in diameter of the hole can be cast without the blank hole.
- In hole system machining, large holes are machined first, followed by small holes.
- For boxes with large span coaxial holes, try to use the method of turning head machining. In short, curved contours on the workpiece, especially non-circular curves and list curve contours, complex shapes, a wide range of sizes, difficult to scribe and detect parts, difficult to observe and measure the internal and external recesses, and high-precision holes and faces, etc., are often machined by CNC milling.
With the rapid development of CNC technology, CNC milling machines are becoming more and more powerful, and different CNC milling machines, their functions are different, but, in general, CNC milling machines should have the following main functions.
- Linear interpolation: linear trajectory interpolation method, is one of the most basic functions of CNC machining should have.
- Circular interpolation: circular arc trajectory interpolation method, is one of the most basic functions of CNC machining should have.
- Fixed loop: a fixed subroutine for a specific machining process, which is simply changed during the specific machining process Variable parameters can be adapted to different machining requirements to achieve cycle machining. The use of fixed cycles can effectively simplify the program. Fixed cycles are mainly used to achieve some machining actions that need to be repeated several times, such as drilling, boring, etc.
- Tool compensation: Offset the tool path from the workpiece machining boundary by a certain distance in the specified direction. After specifying the tool compensation number, the system will automatically calculate the tool path. Tool compensation generally includes tool radius compensation, tool length compensation, etc.
- Mirroring, rotating, scaling, panning: processing and control of machining programs through the machine’s CNC system The process is made so as to simplify programming.
- Automatic acceleration and deceleration control: When the CNC machine starts, stops, and changes the feed during the machining process. When speed, in order to have smooth movement and smooth transition, automatic acceleration and deceleration control is required to automatically adjust the feed rate and maintain a stable machining state in order to try to avoid situations such as tool deformation, workpiece surface damage, and unstable machining process speed.
- Data input/output and DNC function: CNC machines generally input/output data via RS232C interface, Ethernet port, or memory card. When the executed machining program exceeds the memory space, DNC machining is used, i.e. the external computer directly controls the machine tool for machining.
- Subroutine function: To simplify programming, for machining actions or machining areas that require multiple repetitions It can be programmed as a subroutine to be called when needed by the main program. Subroutines can be nested at multiple levels.
- Self-diagnosis function: the self-diagnosis of the CNC system starts at the time of power on, only when all items All are confirmed to be error-free before entering normal operation.
About DFM Rapid
We are a CNC machining China shop in Dongguan. We have 20 CNC milling and turning machines in our shop. We can offer you CNC rapid prototyping and low-volume CNC machining services for plastic and metal parts. Also, surface finish like anodized, powder coating is available. If you need Metal & Plastic parts machined for prototypes or production, please feel free to get a quote online.
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