Overview
TMAC offers several modes of operation. Each mode of operation changes how TMAC processes, stores and displays data. The following modes of operation are available:
- Cutting Mode: Monitor power, vibration, strain, coolant flow, coolant pressure, spindle speed, and various other important machine factors. Multiple channels can be monitored simultaneously while monitored channels are tested against user-programmed limits to alert the operator of machining anomalies.
- Bearing Health Mode: TMAC can perform a bearing analysis on machine bearings to aid in diagnosing bearing conditions.
- Millivolt Mode: TMAC allows passing limits through commands without utilizing the job structure
Cutting Mode
TMAC learns the operation and all limits are programmed as a percentage of the learned value. On subsequent runs of a learned operation, each limit is compared to the learned value. If any of the programmed limits are reached, an alarm con- dition is triggered. In addition, TMAC can trigger a machine response to the alarm.
TMAC can monitor multiple channels with various hardware, but the basic premise of monitoring is the same, no matter what is being monitored.
Note: Some aspects of Cutting Mode require more extensive documentation and are allotted individual chapters throughout the document.
Channel Classes
TMAC is capable of monitoring operations with a wide variety of sensors. These sensors are typically referred to as Channels in TMAC. The following Channel Classes are available in TMAC:
- Primary: The primary channel class includes power, strain, and vibration. Primary channels have full access to TMAC features and capabilities in the Job Editor.
- Coolant: The coolant channel class includes all coolant flow and pressure sensors.
- Spindle: The spindle channel class includes all spindle speed sensors
- Passive Channels: Passive channel classes are used to gather additional machine data while monitoring. Passive channel data is viewable on the details tab of the Data Viewer and in the Channels tab of the System Menu Diagnostics.
Power Monitoring
Measuring true motor power is one of the most accurate and cost-effective ways to determine tool wear or breakage. In addition, sensing true power can help determine the integrity of the motor. The power used by an operation is a more accurate indicator of tool condition than, for example, measuring spindle or axis motor current or voltage.
TMAC isolates the power used by the tool by measuring the motor power at idle and subtracting it from the power used during the operation. As a tool wears, it requires more power to cut a part. By measuring true motor power for a spindle or feed axis, TMAC can determine when a tool is worn or broken. TMAC compares measurements of motor power to programmed limits, commanding the control to take corrective action before tools or parts are destroyed.
Vibration Monitoring
Vibration monitoring operates on the principle that as a tool wears, vibration magnitude increases. TMAC can monitor the magnitude of vibration during a cut using vibration sensor data measured in units of g (gravitational constant).
TMAC vibration monitoring is particularly useful, but not limited to, the following:
- In an operation where a static tool is making light cuts and the power is too small to be detectable by TMAC
- A constant surface operation, such as a turning operation, where the power is constantly increasing to the maximum. This tends to mask wear or breakage of cutting tools
- Pinch Turning
Strain Monitoring
Strain monitoring is used for applications requiring force measurement. When a tool is in contact with a part, the tool may flex or bend depending on the material being cut. This flexing is measured as strain by a strain gauge sensor. Strain Gauge monitoring operates on the principle that as a tool wears, the strain on the tool increases.
Coolant Monitoring
TMAC can monitor the flow and/or pressure of coolant with a variety of sensors. While monitoring coolant pressure and/or flow, an alarm is triggered when a programmed limit is reached. Refer to the System Integrators manual for information pertaining to the hardware used in Coolant monitoring.
Spindle Speed Monitoring
TMAC measures the spindle speed and warns of deviations from a programmed set point. A system integrator can configure TMAC for up to three different gear ranges with different spindle speed parameters.
Bearing Health Mode
TMAC can utilize a vibration sensor attached to a machine bearing housing to perform an acceleration and velocity analysis on the vibration signal. The analysis diagnoses bearing health and other bearing issues.
Performing a Bearing Health Analysis
A bearing health analysis can be started from the HMI or by sending a command through the CNC. A bearing health analysis should be performed when the machine is running at max RPM and is not engaged in cutting. Bearing health analysis also requires a balanced tool in the spindle. CEI recommends using a hydraulic clamp or shrink fit tool. To start a bearing health analysis from the HMI, perform the following steps:
- Click the MODE button on the TMAC Action Bar
- Select Bearing Health from the menu
- Prepare the machine for a bearing health analysis
- Ensure that the current view displays the desired vibration channel by selecting it at the bottom of the HMI.
- Click the START button on the bottom-right of the live graph.
Once started, TMAC begins recording vibration signal data to be analyzed. A progress wheel in the center of the live graph displays the progress of the bearing health analysis.
Reviewing Bearing
A full bearing health analysis consists of acceleration analysis and velocity analysis. The acceleration analysis is displayed graphically over a range of frequencies, by default. In addition to the graphical representation, two bars for the velocity and acceleration analysis display whether the bearing is in good health or needs further diagnosis. Each bar has a range of RMS (root-mean-squared) values that aid in determining the bearing health.
Millivolt Mode
TMAC allows passing of limits through commands without utilizing the job structure. In Millivolt mode, TMAC displays analog output data in mV. Millivolt monitoring operates on the principal that as a tool deteriorates, the millivolt level increases. Certain machining specifications may require the power displays and alarm settings to be in millivolts. A millivolt scale reveals the actual analog output signal. The millivolt scale is only supported for specific operations. Certain features are unavailable for millivolt operations. In Millivolt mode, the job structure is not used. All parameters for an operation are passed in commands from the CNC.
Note: Millivolt mode utilized a fixed power scale from 0 to 10000 mV.
Limit Alarms and Delays in Millivolt Operation
Machining specifications calling for a Millivolt display format may refer to the limit alarms as a "yellow limit" and a “red limit”. The "yellow limit" and “red limit” correlate to wear and extreme limits, respectively.
There is always a one second delay in issuing a yellow or red limit alarm. The yellow limit or red limit must be exceeded for one second before an alarm is issued in all cases.