CNC machine is widely used for its high precision, reliability, efficiency and ability to machine complex curved parts.
III. Precision selection
Generally, there are 20 to 30 precision inspection items for CNC machining centers, but the most distinct items are: single-axis positioning accuracy, single-axis repeated positioning accuracy, and roundness of the test part produced by simultaneous machining of two axes.
Positioning accuracy and repeated positioning accuracy comprehensively indicate the overall accuracy of each moving part of the shaft.
Single-axis positioning accuracy refers to the error range when positioning at any point within the axis travel, which directly reflects the machining accuracy of the machine tool.
Repeated positioning accuracy reflects the stability of the shaft positioning at any point in the stroke and is a basic indicator of the shaft's ability to work stably and reliably.
Between these two indicators, repeated positioning accuracy is particularly important.
4. More Specification Selection of CNC Machining Center
The key feature specifications of the CNC machining center should be selected based on the determined range of typical machining dimensions of the part.
The main specifications of the CNC machining center are the travel range of various CNC axis and the power of the spindle motor.
The three basic linear coordinate strokes (X, Y, Z) of the machine tool reflect the machining space available to the machine.
The two coordinates X and Z on the lathe reflect the permitted rotor size.
In general, the contour size of the machined part should be within the machining space of the machine tool.
For example, if a typical part is a box with dimensions of 450 mm × 450 mm × 450 mm, then a machining center with a work surface size of 500 mm × 500 mm should be selected.
Choosing a work surface that is slightly larger than a typical part takes into consideration the space needed to install the clamp.
The size of the machine tool table and the three linear coordinate strokes have a proportional relationship.
For example, for the above machine tool with a table size of 500mm × 500mm, the X-axis travel is generally 700 800mm, Y axis is 500 700mm and the Z axis is 500~600mm.
Therefore, the size of the work surface largely determines the size of the processing space.
In modern small and medium-sized CNC machining centers, mechanical displacement of the spindle box is used less frequently. Instead, a DC or AC adjustable speed motor with high power is often used to connect directly to the spindle or even in an electric spindle frame.
However, this structure has limitations in terms of torque during low-speed cutting. This is because the power output of the speed regulator motor decreases at low speeds. To ensure adequate torque at low speeds, a high horsepower motor must be used.
As a result, the spindle motor of CNC machining centers with the same specifications is several times larger than that of ordinary machine tools.
See too:
- Top 10 Global CNC Machine Tool Companies
It is important to check the machine's low-speed output torque when a large amount of low-speed machining is required on a typical part.
