Choices of the Needle for Machine Tool Probes

What is worth noting in the selection process of the stylus for the CNC machine tool probe?

We all know that the accuracy of machine tools has always been the unremitting pursuit of all those engaged in the machine tool industry. In addition to relying on the high-quality materials and processes of the hardware machine tools, some machine tool accessories (machine tool probes) are also needed to improve machine tool processing accuracy. In this regard, in order to make good use of the machine tool probes as an aid, in addition to selecting the probe itself, the stylus of the machine tool probes are also a major point to consider, so as to ensure that the machine tool probes can perform accurate, precise and efficient measurements function. So the selection of machine tool probes stylus is particularly important!

As an important component of the CNC machine tool measurement system used with the machine tool probes, the stylus of machine tool probes is an important execution element in the machine tool probes when it is used as a trigger sensor for measurement. It is mainly composed of three parts: measuring ball, measuring rod, and measuring handle. The stylus can generally be divided into the ruby stylus, ceramic stylus, and stainless steel stylus according to the ball. According to the material of the stylus, it can be divided into four categories: ceramic rod stylus, tungsten carbide stylus, stainless steel rod stylus, and carbon fiber stylus.

Different types of machine tool probes' styli can also affect the measurement results of machine tool probes. Therefore, it is necessary to choose the proper machine tool probes' stylus.

The machine tool probes can be installed on most CNC machine tools such as CNC lathes, machining centers, CNC grinders, etc. In the machining cycle, the size and position of the tool or workpiece can be measured directly without human intervention, and the offset of the workpiece or tool can be automatically corrected according to the measurement results so that the same machine tool can process parts with higher precision.

1. Choose the corresponding needle of machine tool probes based on processing materials

For example, when measuring hard workpieces, a stainless steel needle or a tungsten carbide needle with good hardness can be selected to ensure that the needle of machine tool probes will not have minimal bending during bending or bending detection and measurement.

Another example is when measuring workpieces of certain materials, care should always be taken to avoid adhesive wear of the machine styli to the corresponding material. When measuring aluminum or cast iron workpieces, ball-bonding wear on the machine styli can result in inaccurate measurements.

2. Choose the machine toll probes based on the manufacturer's requirements of measuring accuracy

In general, the shorter the length of the rod, the larger the diameter of the ball. Or the smaller the number of needle assemblies, the higher the measurement accuracy of the probe. This is because the longer the measuring rod of the needle of machine tool probes, the more prone it is to bend or deform, which can affect the measurement results of machine tool probes. The larger the diameter of the measuring ball, the more it can reduce the influence of the measuring rod on the measurement accuracy and the influence of the surface roughness of the corresponding measurement workpiece on the measurement accuracy.

The reason for choosing fewer stylus assemblies is that as the number of stylus assemblies increases, an additional connection point is added to the stylus stem. And the more connection points, the easier it is to bend the stylus stem. At the same time, too many parts will lead to excessive length and weight of the machine tool probes, thus affecting the measurement accuracy of the needle of machine tool probes.

3. Select the appropriate stylus based on the actual vibration of the installed machine tool probes

In many cases, many of these factors are not taken seriously, but this often leads to excessive vibration of the CNC machine tool, which causes the stylus on the machine tool probes to easily collide or break during measurement, and affects the measurement results of the machine tool probes.

Under normal circumstances, a carbon fiber stylus with excellent vibration resistance should be used instead of a ceramic rod stylus with poor vibration resistance when using machine tool probes for CNC machine tools with large vibration.