What is CNC?

CNC (numerical control) is short for Computer numerical control, an automated machine tool controlled by a programme. The control system is capable of logically processing a programme specified by a control code or other symbolic instruction, and decoding it by a computer, so that the machine tool performs the specified action, and the blank material is processed into semi-finished or finished parts by tool cutting.

Characteristics of CNC

(Compared with ordinary machine tools)

1、High machining precision and stable machining quality.

2、Multi-coordinate linkage is possible, and it is capable of machining parts with complex shapes.

3、It is usually necessary to change only the CNC programme when the processing parts are changed, which saves the production preparation time.

4、High precision and rigidity of the machine tool itself, which enables to select favourable machining dosage and high productivity (generally 3~5 times that of ordinary machine tools).

5. High degree of automation of the machine tool reduces labour intensity.

6、Batch production, easy to control the quality of products.

7、Lower quality requirements for operators and higher technical requirements for maintenance personnel.

Selection of CNC equipment

Selection according to the products to be processed

Each kind of processing machine has its best processing of typical parts, so it should be based on the processing of different parts to choose different CNC machine tools.

Second, according to the main parameters of the machine tool selection

1, in all the parameters of the machine tool, the travel of the coordinate axis is the main parameter. The most basic is X, Y, Z three coordinate axes, these three coordinate axes of the travel reflects the machine tool's machining capacity.

2, tool magazine capacity is also the main parameters of the machine tool. When selecting a machine tool, according to the results of the process analysis of the machined parts to determine the number of tools required. (Vertical plus general 24 or so; horizontal plus can have 30 ~ 125 or so; standard machine choose 40 or so more appropriate).

Third, according to the machine tool precision selection

To determine the accuracy level of the machine tool according to the key parts of the machined parts machining accuracy requirements. Linear positioning accuracy, repeat positioning accuracy, milling accuracy is the evaluation of CNC machine tool accuracy of the three indicators. Normally, ordinary CNC milling machine, machining centre linear positioning accuracy of ± 0.01mm throughout, repeat positioning accuracy of ± 0.006mm, milling machine round accuracy of 0.03 ~ 0.04mm. precision machining centre linear positioning accuracy of ± 0.005mm, repeat positioning accuracy of ± 0.002mm, milling round accuracy of 0.02mm.

CNC machining ten steps

1, review the diagram. Understand the processing content, see clearly the template (or mould base) length, width direction, clamping mode and workpiece processing coordinates

2, check. According to the chart surface indicated template (or mould seat) specifications, respectively, the length of the template (or mould seat), width, height of the real number of measurements, there is no margin or with the chart surface dimensions do not match, the immediate response. Further, check the template (or mould seat) on the material indicated whether and the drawing on the same.

3, clamping. According to the CNC programming indicated by the coordinates of the clamping, clamping need to pay attention to the pressure code can not interfere with the knife path, clamping needs to be firm, safe and no hidden danger. Clamping larger templates (or mould base), should use a manual forklift, not brute force, the work should be a safe production concept.

4, school table. First school plane, template class flatness is generally guaranteed within the mould base flatness is generally guaranteed within the silk. After the school side, parallelism is generally guaranteed within.

5, touch number. Look at the CNC marking of the touch counting method, when the four sides are divided in the middle, do not be careless; when the one side is touched, pay attention to the radius of the middle cupping; if the programme is indicated in single, remember to enter the middle cupping on the basis of the radius of the middle cupping. Special note: When touching the number, the rotating speed should not be greater than 500; if the rotating speed is too fast, it is easy to damage the centre column.

6. Input coordinates. After touching the number of centring holders, the X and Y axes cannot be moved, the coordinates should be input before moving.

7, load the knife. According to the programme to find the corresponding tool, knife loading, pay attention to the length of the knife is in line with the requirements, it should be noted that the programme marked on the list is the deepest depth, the knife length should be in the deepest depth of the basis of more than 10MM.

8, to the knife. Move the Z-axis to the centre of the board position, slowly down the knife about 10MM height, and then use the knife to hold the knife, it should be noted that in the micro-adjustment of the height of the Z-axis, the knife can not be placed on the knife under the knife hold, so easy to bang the knife edge. After the knife should immediately copy the coordinates before moving the Z-axis. After the knife should remember to lift the knife before the subsequent action.

9、Transfer programme. Set the mode to "DNC" mode, feed adjustment key to "O", press the programme transfer key, find the corresponding programme in the computer, transfer to the machine controller. Note that the name of the programme in the computer should be the same as that in the programme list, and the tool in the programme should also be the same as that in the programme list.

10, machining. Down the knife should be slowly down the knife, down the knife one, twenty millimetres should look at the actual height and the height of the controller display is consistent, to prevent stepping on the knife. Processing should make full use of look, listen, smell and other ways to monitor the processing status. Abnormalities should be found immediately stop the machine to check.