A 5-axis machining center is a machine tool with vast applications, including cutting, milling, and drilling through an extensive array of materials. As the name indicates, this multi-axes machine operates along five coordinates, making it suitable for complex fabrications. It is particularly valuable for machining and processing smaller workpieces with tighter tolerances and strict dimensional accuracy requirements.
The five motion axes of the 5-axis CNC machining center include the typical X, Y and Z coordinates, allowing simple linear movements during machining. The other two coordinates – A and B – serve for rotational motion, which accounts for its improved precision compared to 3-axis and single-axis machining centers. Since the machine can rotate the workpiece, there is reduced human interference, as the machinist need not turn the workpiece when making complex features and contours.
The 5-axis machining possesses sophisticated tooling and an advanced control system. This allows it to achieve extreme precision and accuracy, up to 0.001 inches, making it a valuable machine tool for high-precision manufacturing and processing, especially for smaller workpieces.
Setting up a 5-axis CNC Machining Center
One primary advantage of the 5-axis machining center is the simple and minimized machine setup. It does not require complex fixtures and clamping systems for holding workpieces in place. The workpiece is to be placed on the table center of the machine, held in place by a zero clamp vice or a hydraulic clamp. This ensures that the workpiece remains in position during machining.
However, it is important that the workpiece is placed such that the cutters and spindle can easily move around it across the five different cutting axes. Also, the automatic tool changer magazine should contain the necessary cutting tools and tool holders for the seamless fabrication of the programmed design.
However, before kickstarting any machining process, the machinist must first recalibrate all the machine axes. This ensures that every axis of the machine functions optimally and prevents accumulation of tolerances which will be detrimental for high-precision parts.
However, some 5-axis CNC machining center are devoid of this functionality, as machinists see it as an uneasy way to reduce the overall cost of the device. Needless to say, the machine may initially meet tight tolerance requirements, but over time it’ll start to fail, resulting in fabrications that fail to meet up to the required accuracy.
In addition, during the machine set-up, you should check for any possible collision areas before kickstarting the device. Then you may choose to sample the whole operation, observing the stepwise function of your machine tool and paying attention to how it switches from one cutting tool to another. Running this system analysis allows you to prevent a crash, which may result in a misalignment of the tools. It is best to avoid these issues, considering repairing them is cost-intensive.
Tool Selection for 5-axis machining of Smaller Workpieces
Like in similar multi-axis machining centers – 3+2 and 4+1 machining – 5-axis CNC machining utilizes shorter cutting tools and spindles. This feature gives it an edge over 3 and 4-axis machines. It allows it to use more rigid cutters for a quicker machining process, considering the specificity of the tools is amplified, with fewer tool deflections and vibrations towards achieving a more accurate result, even for minute workpieces.
In addition, since we are working on smaller workpieces, the use of shorter cutting tools improves the cutting conditions of the machines. This enables it to achieve the required tight tolerance specifications. Also, it enhances the surface finishes of the product, even when dealing with heavier and deeper cuts.
Furthermore, 5-axis machines utilize automatic tool changers (ATC). A typical example is the AWC – automatic workpiece changer, which further reinforces process automation and allows for improved precision. Moreover, the ATC magazines are larger than the regular ones, accommodating more tools which are essential for complex fabrications containing sophisticated fixtures.
For example, the standard tool magazine has about 30 to 40 stations. However, tool magazines with this number of stations may be insufficient when manufacturing complex structures. Therefore, it is better to use a magazine with larger stations – 60 or even up to 120. The aim is to avoid switching cutting tools midway, as this may increase the chances of error, affecting the part’s precision, especially when machining smaller workpieces.
Besides accommodating as many tools as required for fabricating the part, this feature also enables easier integration of sister tools. These tools of similar sizes and specifications may be interchanged, reducing wear and tear conditions and increasing the durability of either instrument. The entire machining process is automated, such that immediately, the machine detects that the lifetime of a particular tool is running out; it just replaces it with its sister tool. This feature also positively affects the improved precision of the machine, as there is little to no weakening or breakage of the tools. Therefore, machining continues with all the necessary tools functioning optimally.
Conclusion
Generally, all CNC operations are precise; after all, the processes run on computer codes and programs with little to no human interference. However, the 5-axis CNC machines are more complex with more sophisticated functionalities, making them superior to conventional machine tools.
For example, one of the most significant advantages of the 5-axis CNC machining centers is that the machines have free access to approach the different surfaces and sides of the workpiece, even when clamped. This allows the cutters to perform multiple CNC operations without repositioning or reclamping the material. Therefore, other than the improved precision, it also hastens the manufacturing process and reduces the need for additional labor or other machines.
