Manufacturing of machine components Using CNC simulator software
Numerical Control Computer Numeric Control (CNC) is the automation of machine tools that are operated by precisely programmed commands encoded on a storage medium (computer command module, usually located on the device) as opposed to controlled manually by hand wheels or levers or mechanically automated by cams alone.
Most NC today is computer (or computerized) numerical control (CNC), in which computers play an integral part in the control. In modern CNC systems, end-to-end component design is highly automated using computer-aided design (CAD) and computer-aided manufacturing (CAM) programs.
The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine by use of a post-processor and then loaded into the CNC machines for production. Since any particular component might require the use of a number of different tools – drills, saws, etc. – modern machines often combine multiple tools into a single "cell".
In other installations, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine. In either case, the series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design.
Definition
Computer Numerical Control (CNC) is one in which the functions and motions of a machine tool are controlled by means of a prepared program containing coded alphanumeric data. CNC can control the motions of the work piece or tool, the input parameters such as feed, depth of cut, speed, and the functions such as turning spindle on/off, turning coolant on/off
Applications
The applications of CNC include both machine tools as well as non-machine tool areas. In the machine tool category, CNC is widely used for lathes, drill presses, milling machines, grinding units, lasers, sheet-metal press working machines, tube bending machines, etc. Highly automated machine tools such as the turning centers and machining centers which change the cutting tools automatically under CNC control have been developed. In the non-machine tool category, CNC applications include welding machines (arc and resistance), coordinate measuring machines, electronic assembly, tape laying, filament winding machines for composites, etc.
ELEMENTS OF A CNC
A CNC system consists of three basic components part program is a detailed set of commands to be followed by the machine tool. Each command specifies a position in the Cartesian coordinate system (x,y,z) or motion (workpiece travel or cutting tool travel), machining parameters and on/off function. Part programmers should be well versed with machine tools, machining processes, effects of process variables, and limitations of CNC controls. The part program is written manually or by using computer-assisted language such as APT (Automated Programming Tool).
Machine Control Unit
The machine control unit (MCU) is a microcomputer that stores the program and executes the commands into actions by the machine tool. The MCU consists of two main units: the data processing unit (DPU) and the control loops unit (CLU). The DPU software includes control system software, calculation algorithms, translation software that converts the part program into a usable format for the MCU, an interpolation algorithm to achieve smooth motion of the cutter, and editing of the part program (in case of errors and changes).
The DPU processes the data from the part program and provides it to the CLU which operates the drives attached to the machine leadscrews and receives feedback signals on the actual position and velocity of each one of the axes. A driver (dc motor) and a feedback device are attached to the lead screw. The CLU consists of the circuits for position and velocity control loops, deceleration and backlash takeup, and function controls such as spindle on/off.
Machine Tool
The machine tool could be one of the following: lathe, milling machine, laser, plasma, Coordinate measuring machine, etc. That a right-hand coordinate system is used to describe the motions of a machine tool. There are three linear axes (x,y,z), three rotational axes (i,j,k), and other axes such as tilt (9) are possible. For example, a 5-axis machine implies any combination of x,y,z, i,j,k, and 6.
1. What is the difference between absolute and incremental systems?
- An ABSOLUTE movement moves TO A COORDINATE based on your ZERO POINT.
- An INCREMENTAL movement moves A DISTANCE based on your CURRENT POSITION.
- An incremental movement does not take your part zero point into consideration.
2. What are the axes to be considered while writing the program for the CNC lathe?
Z-axis, which is parallel to the spindle axis, and an X-axis, which is at right angles to the spindle.
3. What is meant by G42?
Tool radius compensation right
4. What is meant by G90 & G91?
- G91 is incremental,
- G90 is absolute
5. What is meant by M08?
M08 is called Mist Coolant controller: used for coolant activation
6. What is meant by M09?
M09 is a coolant controller used to turn OFF Activated coolant
7. What is meant by M28?
M28 is Clutch neutral OFF
8. What is meant by M30?
M30 is End the program
9. What is meant by M98?
M98 command is used to call a subprogram followed by the program number and the amount of times that we wish to repeat running that subprogram.
10. What is meant by M99?
M99 is used at the end of a subprogram, local subprogram, or macro to return back to the main program.
11. What are the different types of CNC simulator software?
- CNC Machine Control Software.
- CNC Machining Software Origins.
- CAM Software.
- CAD Software.
- CAE Software
- CAD/CAE/CAM Software.
- Custom Manufacturing & Fabricating.
12. What is meant by Cutter radius compensation?
Cutter radius compensation compensates for the radius of a cutting tool by causing the controller to maintain a constant offset that is perpendicular to the programmed path in a two-dimensional plane.