Touch probes are a common method of inspecting parts in a manufacturing setting. With the help of a touch probe, the machinist can gain precision when measuring distances or checking for the correct fit. Touch probes have become a staple in the manufacturing industry.
However, the advantages of CNC touch probes as a metrology tool are not necessarily widely known. They are, in fact, ideal for in-process inspection within these machine tools.
When employed this way, the machinist gains access to extra functions plus the ability to forego inspection steps. All of this can help the machining process proceed more quickly and cheaply.
Touch Probes and 5-Axis Machining Centers
The 5-axis machining centers are no exception to these benefits. Using tool touch probe cycles is now routine to precisely identify items on a worktable or fixture.
A CNC touch probe on the machine can align the parts with a flat surface or reference holes. The 5-axis CNC rotates the axes, so the part plane is perpendicular to the spindle and cutter.
Calibration of the 5-axis kinematics in a machining center is another typical use for in-process touch probes. It ensures accurate movement, pivoting, and placement of all axes, which is essential for complete 5-axis applications.
Touch Probes and In-Process Inspection
Since a CNC touch probe can facilitate high-precision measurements, one can use this metrology tool for in-process inspection.
There’s the belief that it’s never a good idea to check a machined part on the same machine used to make it. Doing so would replicate any machining flaws in the inspection measurements. This is usually the case.
A solid quality control system will require an inspection of the part in a temperature- and humidity-controlled metrology environment. To do this, one can use a CMM and other inspection methods linked to metrology.
To counter this, one can design each item with a tolerance band. A machinist can pre-inspect a product using a 5-axis machine tool with linear glass scales and a closed-loop measuring system.
If the machinist does this, it significantly cuts the time it takes to inspect the component or fixture. This can reduce machine downtime and save time spent setting up.
The in-process inspection also allows for the automatic correction of any cutting tool imperfections, which is a significant benefit.
Radius cutters have an inconsistent shape. Every tool’s actual radius has unique shape deviations from a perfect circle. A conventional tool can have a tolerance of up to 0.015 mm. However, high-end precision cutters can still have errors on the order of a few microns.
In-process machine tool touch probe inspection can detect product deviations with CNC 3-D tool compensation, allowing 3-D tool radius adjustment.
As a result, this increases the precision of the finished product, especially for free-form, complicated surfaces.
Best Touch Probe Qualities to Consider
Taking all these readings would be highly unreliable using a standard touch probe. The following are three qualities to look for in an in-process touch probe:
- Protection Against Physical Impacts
Since no one is ideal, slip-ups are inevitable and frequently occur unintentionally and out of the blue. Therefore, it’s helpful to have a touch probe that acts as a collision avoidance shield.
For instance, even with the most precise 5-axis machining, a mistaken tilting motion is always possible. This can damage the touch probe, and maybe the spindle can while measuring the workpieces in such circumstances.
At this point, the consequences of such misfortunes are not just disagreeable but extremely expensive. The costs associated with machine breakdowns, interruptions, and repairs can quickly mount up to a significant number.
In this context, machine operators want to use intelligent technologies to prevent mistakes.
- Insulation or Protection from Heat
The length of the touch probe shouldn’t increase due to the spindle’s heat. Hence the probe must have some thermal barrier or insulator.
Longer measuring cycles are more prone to heat fluxes, especially if the spindle is already hot from prior machining. This can result in false readings.
- Tools for Dependable Measurement
Features that aid in accurate measurement include wear-free optical sensors and a blowing device to clear the measuring spot. Moreover, it is critical to have a versatile data transfer system.
For example, smaller machines commonly use infrared transmission because it offers the highest precision and the quickest signal transmission times. In comparison, radio frequency technology is standard for larger devices. This is due to its greater range and the fact that one can use it on large, non-enclosed machines.
The operator should specify the best transmission mode in a production setting based on their unique needs.
Conclusion
Overall, CNC touch probes are becoming increasingly popular for usage in-process. They offer a more accurate, real-time measurement of surface properties than traditional methods such as force or displacement.
This makes them ideal for various applications such as quality control, monitoring, and machine guidance. Additionally, one can use touch probes with other sensors to obtain even more detailed information about the measured object.
Renishaw and Heidenhain machine tool probes are available with us. These touch probes offer unrivaled precision that can determine the dimensions of any object.
In addition, we also offer Renishaw probe repair and Renishaw probe replacement parts.
Get your CMM touch probes only from trusted providers. Contact us today for more information on Renishaw, Heidenhain, and other products and services.
