What is CNC programming

What is CNC programming?

CNC programming is one of the main contents of the preparation stage of CNC machining, which usually includes analyzing the part drawing and determining the machining process; calculating the tool path and deriving the tool position data; writing the CNC machining program; making the control media; proofreading the program and the first test cut. There are two methods of manual programming and automatic programming. In short, it is the whole process from the part drawing to get the CNC machining program.
CNC machine tools are in accordance with the pre-prepared processing program automatically on the workpiece processing of efficient automated equipment. In the CNC machine tool processing parts, according to the requirements of the parts processing drawings in advance to determine the parts processing process, process parameters and tool movement data, and then the preparation of processing procedures, transmitted to the CNC system, in advance of the internal control software stored in the CNC device support, after processing and calculation, issued the corresponding feed motion command signal, through the servo system to make the machine according to the predetermined trajectory movement, for parts of processing.
General CNC machine tool programming in strict accordance with the following steps: analysis of the part drawing, determine the process, mathematical processing, preparation of processing procedures, program verification and the first test cut.

Step 1

Analyze the part drawing first of all to analyze the part drawing. To analyze the material of the part, shape, size, accuracy, batch, blank shape and heat treatment requirements, in order to determine whether the part is suitable for processing on CNC machine tools, or suitable for processing on which CNC machine tools, and at the same time to clarify the processing content and requirements.

Step 2

Determine the process on the basis of the analysis of the part diagram, process analysis, determine the processing method of the part (such as the use of fixtures, clamping and positioning methods, etc.), processing routes (such as tooling points, tool change points, feed routes) and cutting dosage plus V core: UG5209 lead free CNC courses (such as spindle speed, feed rate and back eat tooling amount, etc.) and other process parameters. CNC machining process analysis and processing is the premise and basis of CNC programming, and CNC programming is the CNC machining process content programmed. The development of CNC machining process, to reasonably select the processing program, to determine the processing order, processing route, clamping methods, tools and cutting parameters, etc.; at the same time also consider the CNC machine tool command function, give full play to the effectiveness of the machine tool; as short as possible to shorten the processing route, the correct choice of tooling points, tool change points, reduce the number of tool changes, and make the value of the calculation is convenient; reasonable selection of the starting point, cutting point and cutting mode, to ensure that the cutting process is smooth; to avoid the tool to avoid the smooth process. ensure that the cutting process is smooth; avoid interference between the tool and the non-machining surface to ensure safe and reliable machining process, etc.

Step 3

Mathematical processing according to the geometry of the part diagram, determine the process route and set the coordinate system, calculate the trajectory of the rough and finish machining movement of the part, and get the tool position data. For the contour processing of parts with a relatively simple shape (such as parts composed of straight lines and circular arcs), the coordinate values of the starting point, ending point of the geometric elements, the center of the circle of the arc, the intersection or tangent point of the two geometric elements should be calculated, and if the CNC device has no tool compensation function, the coordinate value of the trajectory of the tool center should also be calculated.
For the shape of the more complex parts Public: UG Programming Domain (such as parts composed of non-circular curves, surfaces), you need to use straight-line segments or circular arc segments approximation, according to the requirements of processing accuracy to calculate the node coordinate value, this numerical calculation is generally to be completed with a computer.

Step 4: prepare the program sheet

After completing the process processing and numerical calculation work, the part processing program sheet can be prepared. Programmer according to the calculated operation track coordinate value and has developed the processing route, tool number, tool compensation, cutting parameters and auxiliary action, in accordance with the use of CNC device provides the use of functional instruction code and program segment format, paragraph by paragraph to write the processing program list.
Before the program segment plus the sequence number of the program, followed by the end of the program segment sign symbol. Programmers should be familiar with the performance of CNC machine tools, plus V core: UG5209 lead free CNC course program instruction codes and CNC machine tools to process parts, in order to write the correct processing program.
The fifth step, the program verification and the first piece of test cutting
The preparation of the program list, must be verified and test cut before the official use. The method of verification is to directly input the contents of the program sheet into the CNC system, so that the machine tool air rotation, in order to check whether the machine’s movement trajectory is correct. In the CRT graphics display on the CNC machine tool, with a simulated tool and workpiece cutting process is more convenient to test the method, but these methods can only test the movement is correct, can not check the size of the workpiece error caused by improper tool adjustment or inaccurate programming calculations and processing out of the specific circumstances of the workpiece.

Therefore, the first test cut of the part should be cut to check, not only to find out the error of the program sheet, but also to know whether the machining accuracy meets the requirements. When machining errors are found, analyze the causes of errors, find out where the problem lies, or modify the program sheet, or take measures such as dimensional compensation, until the requirements of the part drawing are met.

Source: China machining solutions provider – Yaang Pipe Industry (www.machinedsgn.com)