Pico Digital Probe User Manual

Owned by Q Rothing
Last updated: Jul 10, 2024
9 min read

The Solo milling machine utilizes a small wireless measuring tool, known as the “Pico Digital Probe”, for setting offsets, checking dimensions or adjusting tool settings within the milling machine. This document was written to help end users set up & use the various features of the Pico Digital Probe.  Throughout this document, the Pico Digital Probe may be referred to as the “probe”, “measuring tool” or “Tool 14”.

Table of Contents

Probe Components

The Penta Machine Pico Digital Probe contains three main components; the probe body, the Renishaw TP20 touch trigger (module), and the probe stylus.

Styli range in tip size (0.5mm - 6mm), shape & length (10mm - 60mm) allowing end users to measure a wide range of part features. Styli can be changed at any time, but require alignment & calibration immediately afterwards. Styli fasten to the TP20 touch trigger with an M2 thread and should be tightened with styli tools. (See Probe Assembly)

The TP20 touch trigger magnetically attaches to the probe body. It functions as a switch, sensing force applied to the stylus in the X, Y & Z direction, or any combination of the three. Three tapered groves located on one end of the TP20 module accurately maintain its position relative to the probe body, while two gold contacts electrically connect the switching mechanism to the probe’s electronics.

Probe Assembly

New probes require assembly of the four main components; probe body, TP20 touch trigger (module), stylus & silicone O-ring.  Use the following steps to complete the assembly.

  1. Using the S7 stylus tool provided, fully hand-tighten the stylus into the stylus mount on the end of the TP20 module. The recommended tightening torque is 0.05 Nm to 0.15 Nm (maximum permissible torque is 0.3 Nm). In general hand-tightening is enough to achieve a torque within the recommended range.

  2. Install the silicone o-ring around the outer edge of the TP20 module’s mounting grooves.

  3. Install TP20 touch trigger module onto the probe body making sure to position & pair electrical connections, while making sure to maintain position of the o-ring. Installed correctly, the TP20 module should sit firmly atop three ball bearings and force applied to the side of the TP20 module will displace the unit from its magnetic mount.

Probe Alignment

Styli must be concentric with the rotation of the spindle to take accurate measurements. The stylus position can be manipulated in two directions (X & Y) by adjusting the four set screws located on the end of the probe body.

To align a new stylus, begin by installing the Pico Digital Probe into the spindle by placing the whole probe assembly into position 14 of the Solo’s tool drawer and then commanding a tool change to tool 14. Tool changes can be commanded by clicking the “Tx” button in the tool table or by manually inputing a tool change command in the MDI command bar, as seen below.

With the Pico Digital Probe in the spindle, set up a dial indicator to measure the runout of the ruby at the end of the stylus. To reduce runout to an acceptable amount, tighten or loosen the set screws on the end of the probe body in pairs, using an M1.5 hex wrench.

NOTE: A dial indicator can be mounted to the machine’s spindle by threading an indicator positioner (like a Noga arm) into the threaded hole on the right side of the Y stage, near where the spindle mounts. The threads are M8 x 1.25.

 

 

Probe Calibration

The Pico Digital Probe should not need any major calibration right out of the box. However, if the stylus is changed, the probe is crashed, or anything else is done to the probe assembly that could have had an effect on its runout or length, the following steps should be taken:

  1. Align the probe’s stylus using procedure stated in the “Probe Alignment” section above

  2. Measure the tool length offset of the probe by typing o<measure-probe> call into the MDI command bar and pressing Enter

    1. If you are simply verifying the TLO already stored in the machine, take note of the TLO value for tool 14 before executing the above command. After the probe has been measured, compare the two values. If the values differ by more than .001”, consider reaching out to Penta Machine Co. to discuss the potential need for investigation into the cause of the variance.

Probe Battery

The Pico Digital Probe uses a rechargeable battery. Charging occurs while the probe is seated in position 14 of the Solo tool drawer and the optical lens faces towards the machine front. Placing the probe in position 14 will switch the probe on and out of its shipping mode. Once the probe is out of shipping mode, battery information is automatically transmitted to the machine and displayed in the user interface.

Optimal charging occurs while the optical lens is positioned within 5º of the forward facing position, beyond 5º may result in a charging error status. Note that charging can only occur while the Solo is powered on. Information regarding the state of the battery (charging, not charging, charging errors & battery level) are transmitted to the machine & displayed under the “Manual” & “Production” tabs.  While the probe is charging, a lightning bolt will be displayed inside the battery icon. The lightning bolt is replaced with an exclamation mark when a charging error has occurred, this usually indicates a misalignment between the probe & charger. 

The Pico Digital Probe is automatically taken out of sleep mode when commanded to the spindle, & automatically returns to sleep mode when placed back in tool changer position 14. The probe will remain on while idle in the spindle for 2 hours before returning to sleep mode. Triggering the stylus will manually wake the probe from its sleep state & the probe will remain on for 2 hours or until returned to tool changer position 14.

The Pico Digital Probe has enough battery life to remain in sleep mode (machine powered off) for about 30 days. Beyond 30 days it will require a partial charging prior to use. The Pico Digital Probe is able to charge at approximately 10% per hour.

Probe Status

The Pico Digital Probe provides a visual report of its status in the form of green and red blinking LEDs. Red blinks indicate errors while green blinks indicate normal functions. The different blink patterns and their meanings are as follows:

  • Red

    • 4 red blinks every 3 seconds = Battery low 

    • 2 red blinks every 4 seconds = No signal received from Solo machine

      • Note: This state is common and will not cause an issue with probing routines

  • Green

    • 1 green blink every 2 seconds = Sleep mode

    • 1 green blink every .5 seconds = Awake and sending a signal to the Solo machine

    • Solid green = Probe Stylus tripped (also generates an audible beep)

To significantly reduce the chances of a crash, critical errors will be reported in the user interface. For instance, if the machine does not receive the expected signal from the probe while executing a probing routine, the machine will stop probing and an error message will be populated in the user interface.

Probe Applications

The Pico Digital Probe takes measurements as its stylus comes in contact with surfaces in its probing path. Measurements can be taken in the X, Y, or Z axis, or any combination of the three, and at any B or C axis angle. The measurements that are taken can be used in a variety of ways depending on the CAM software used to generate the probe routines and its post processor. Below are the probing functions the Solo currently supports:

Setting Work Offsets

Work offsets define the origin of the g-code program relative to the default coordinate system used by the machine. The origin defined by the work offsets creates a work coordinate system (WCS), which gets saved in the machine’s control and used when the g-code program calls for it. Work coordinate systems are named and saved as g-codes, specifically G54 thru G59.3.

Using CAM software, probing routines can be programmed into a g-code program to take measurements and then update one or more work offsets before executing the rest of the program. This function is most often used at the beginning of program to adjust for stock that is slightly larger or smaller, or has been placed in a slightly different position within the machine, than the original piece of stock.

To use this functionality, use a CAM software’s probing routine that is meant for updating work offsets or work coordinate systems and ensure the post processor being used supports updating work offsets on the Solo.

Part Inspection

Since the Pico Digital Probe is capable of taking very precise measurements of a part while it is still in the machine, it can be advantageous to use the measurements to determine whether the part being machined is meeting specification requirements. Being able to do this without removing the part from the machine allows for g-code programs to be updated and the part to be improved without introducing error somewhere else on the part.

Using a CAM software’s part inspection probing routines, users can choose to have the results of the inspection “printed” out on the machine’s user interface. On the Solo, these results can be viewed by clicking on the small “i” icon in the bottom right corner of the screen, or by going to the HISTORY page.

To use this functionality, ensure the post processor being used supports part inspection on the Solo.

Tool Wear Compensation

Tool wear compensation is a term that refers to a machine’s ability to adjust a cutting tool’s programmed diameter in order to fine tune a part's finished dimensions. It functions by allowing users to adjust a tool's diameter within the control of the machine rather than making adjustments within the CAM software. Tool wear values are usually expressed as the amount to reduce or increase a cutting tool’s nominal diameter.

Probe measurements can be used to automatically adjust tool wear values based on the difference between the part’s nominal dimension and its measured dimension. The proper tool wear value can then be applied to the control and the part or feature can be run again to get the measured dimension closer to the nominal dimension by increasing or decreasing the amount of material that is removed during the cut.

When using tool wear compensation, the diameter field of the user interface’s Tool Offsets section will represent the change to a tool's nominal size. Negative values will increase the material removed from a surface while climb cutting.

To use this functionality, use a CAM software’s probing routine that is capable of updating tool wear values and ensure the post processor being used supports updating tool wear values on the Solo. It is also possible to use a basic part inspection probe routine and then utilize the G10 L10 g-code to update tool wear values using a hand written g-code program.

 

For any questions about the Pico Digital Probe, please feel free to reach out to Penta’s customer service team at service@pentamachine.com, we are happy to help!