America’s Cutting Edge (ACE) offers three apps that provide virtual environments for exploring machining dynamics. These apps enable users to better understand the relationship between the parameters selected in computer aided manufacturing (CAM) software and milling vibrations (i.e., either forced vibration or chatter, a self-excited vibration, is obtained).
All three apps are packaged in a .zip compression folder and are available for free download. Each .zip file contains the app, supporting files, and a user’s guide. The user’s guide provides instructions for the app installation and use.
CAM+
CAM+ enables the user to explore machining dynamics in a virtual environment through three capabilities (executed using the corresponding three buttons on the application interface):
- Tap test – the tool-holder-spindle dynamics are determined using a virtual tap test
- Stability map – a stability map is generated using the tool-holder-spindle dynamics, cutting force model, and cut description
- Simulation – the time-dependent cutting force and displacement are simulated for the user-defined spindle speed-axial depth of cut combination.
Stability map
The stability_map_v1 app enables the user to explore machining dynamics in a virtual environment through four primary inputs:
- Tool tip dynamics – the tool-holder-spindle dynamics are described by the natural frequency (Hz), stiffness (N/m), and damping ratio (%) for one or two vibration modes (mode 1 is always included; mode 2 is only included when the mode 2 box is checked); symmetric dynamics are assumed in the x (feed) and y directions perpendicular to the tool axis
- Tool data – the number of teeth is selected from {2, 3, 4, 5, or 6}
- Material – the material is represented using the cutting force coefficient in N/mm/mm or N/mm2; this scales the cutting force based on the commanded chip area
- Milling parameters – the milling direction (up/conventional or down/climb) and percent radial immersion (%) are selected; 100% radial immersion is slotting
to identify the corresponding stability map. In the stability map, the blue line identifies the stability boundary that separates unstable (chatter) spindle speed-axial depth combinations (those above the line) from stable combinations (those below the line).
Time domain simulation (TDS)
The tds_v1 app enables the user to explore milling dynamics in a virtual environment through four primary inputs:
- Tool tip dynamics – the tool-holder-spindle dynamics are described by the natural frequency (Hz), stiffness (N/m), and damping ratio (%) for a single vibration mode; symmetric dynamics are assumed in the x (feed) and y directions perpendicular to the tool axis
- Tool data – the number of teeth is selected from {2, 3, 4, 5, or 6}
- Material – the material is represented using the cutting force coefficient in N/mm/mm or N/mm2; this scales the cutting force based on the commanded chip area
- Milling parameters – the milling direction (up/conventional or down/climb) and percent radial immersion (%) are selected, where 100% radial immersion is slotting; the spindle speed, axial depth of cut, and feed per tooth are also selected.
The stability map is plotted each time the tool tip dynamics, milling direction, number of teeth, cutting force coefficient, or radial immersion is changed. In the stability map, the blue line identifies the stability boundary that separates unstable (chatter) spindle speed-axial depth combinations (those above the line) from stable combinations (those below the line). A time domain simulation is executed and the cutting force and displacement are plotted each time the spindle speed, axial depth, or feed per tooth is changed. The x (feed) or y direction components of the cutting force and displacement are displayed depending on the selected radio button. For each time domain simulation, the chatter lamp is lit if the cut is unstable. The time-dependent displacement also includes the once-per-tooth samples to visually identify stable and unstable (chatter) conditions. The samples repeat for a stable cut and do not for chatter.
