CNC machine selection guide

A. Typical workpieces processed by CNC machine tools

1、 Horizontal machining centre:

Box parts: vertical machining centre on the processing of the bottom surface → horizontal machining centre on the surrounding surface of each process surface.

2、 Vertical machining centre:

Plate parts: vertical or gantry milling machine processing plane → vertical machining centre or drilling and tapping machine on the processing of various types of holes;

cavity mould parts: ordinary machine tools processing shape and base surface → CNC milling machine processing surface → high-speed CNC milling or milling machine finishing → polishing or electro-etching type surface;

3. Turning machining centres:

Shaft parts: milling end face with centre hole → CNC lathe (rough machining) → CNC grinding machine (finishing);

Flange and disk type parts: CNC lathe (rough machining) → turning centre (finishing);

4, simple box class, shaped class, cavity mould workpiece, if the processing allowance is large (rough machining), and to type surface processing, tool replacement is less, generally choose CNC milling machine.

5, box type, shaped type, cavity mould workpiece, if the machining allowance is small (finishing), and to single-sided hole system processing, the need for frequent replacement of multiple tools, generally choose vertical machining centre.

6, box type, shaped type, cavity mould workpiece, if the machining allowance is small (finishing), and mainly multi-faceted hole system machining, need more frequent tool replacement, generally choose horizontal machining centre or vertical machining centre with rotary table.

7, complex multi-axis surface, space multi-angle surface or hole parts, the general choice of four-axis, five-axis machine or turning and milling composite machining centres.

Second, the similarities and differences between various types of CNC machine tools

1, CNC milling and machining centres

Used to complete a larger amount of milling workpiece processing equipment, CNC system requirements for speed in general, spindle speed 0 ~ 8000RPM or so, sometimes to consider low speed and high torque, the need for spindle deceleration to enhance the torque, focus on metal removal rate. The rigidity of the base part is very high and the rigidity of the moving part is very high.

Advantages: the ability to carry out heavy cutting, suitable for processing process focused parts; disadvantages: due to the high rigidity of the moving part and relatively heavy mass, the machine tool has a medium fast response capability, for small tool processing and rapid feed displacement can not help.

2, CNC carving and milling machine

Used to complete smaller milling volumes, or soft metal processing equipment. Requires high speed CNC system, spindle speed of about 3000~30000RPM, non-moving part of high rigidity requirements, moving part of the main consideration of fast response capability, as light as possible, while maintaining a certain amount of steel.

Advantages: relatively fine machining can be carried out with high machining accuracy. For soft metals can be high-speed processing; disadvantages: because of poor rigidity so it is not possible to carry out heavy cutting.

3、 High-speed cutting machine

Used to complete a medium milling volume, and to reduce the amount of post-milling grinding to a low processing equipment. Requires high speed CNC system and good servo motor characteristics, spindle speed 1500 ~ 30,000RPM or so, the base part of the rigidity requirements are very high, the moving part of the rigidity requirements are relatively high, and as far as possible to increase the response speed.

Advantages: the ability to carry out small to medium cuts, suitable for semi-finishing and finishing separate processes to process parts; with correct use can play a low cost, so that the amount of grinding becomes less. Disadvantages: the tool, the operator, the manufacturer requirements are high, easy because of misuse and other reasons caused by large losses.

Third, the choice of CNC machine specifications

1, the machine table area should be larger than the typical part size in order to facilitate the installation of fixtures or press plates, etc., generally larger than at least 100mm;

2, machine travel should be greater than the typical range of parts in order to facilitate access to the tool, generally greater than at least 150mm;

3. the machine table should have a load-bearing capacity greater than the weight of the part and fixture;