For professionals working with CNC machinery, particularly when utilizing software like Mach4, grasping the nuances of speed settings is crucial. Mach4 offers a range of customizable parameters to control the velocity of your CNC machine, ensuring precision and efficiency in various operations. This article breaks down the key speed settings within Mach4: Velocity, Feed Rate, Jog Rate, and Rapid Rate, providing a clear understanding of how each contributes to machine control.
In the motor configuration of Mach4, the Velocity setting defines the absolute maximum speed your motor can achieve. This parameter acts as a ceiling, limiting the speed during jogging, feeding, or rapid movements. It’s essential to set this value at least as high as your fastest desired motor speed.
Mach4 also provides on-screen controls to adjust rates dynamically. This real-time override capability is invaluable for fine-tuning machine behavior during operation.
The Feed Rate is dictated by the G-code program, which instructs the machine on how quickly to move during cutting operations. Mach4 allows you to override this commanded feed rate using a percentage adjustment. This override can either increase or decrease the feed rate, but it is always capped by the Velocity setting configured for the motor. This provides a safety mechanism, preventing accidental commands from exceeding the motor’s physical limits.
Rapid Rate and Jog Rate are both expressed as percentages of the Velocity setting. The Rapid Rate governs the speed of non-cutting movements between operations, while the Jog Rate controls the speed when manually moving axes using the jog controls. In the example provided, with a Velocity set to 1001 IPM (inches per minute), a Jog Rate of 20% translates to 200 IPM, and a Rapid Rate of 50% equates to 500 IPM. This percentage-based system allows for coordinated speed adjustments across different movement types relative to the maximum Velocity.
For moments when full Velocity jogging is needed, Mach4 offers a bypass: holding down the shift key while jogging will override the Jog Rate percentage, allowing movement at the full Velocity setting.
It’s important to note that Mach4 features a single DRO (Digital Readout) for displaying both Rapid and Jog Rates. This display reflects the rate percentage multiplied by the Velocity setting of MOTOR 0, which is commonly the X-axis on many setups. However, the actual Jog and Rapid speeds will be individually calculated for each motor based on its specific Velocity setting and the displayed percentage.
Finally, Mach4 resets the override percentages for Feed, Jog, and Rapid Rates to default values upon restarting the software. While the Feed Rate reverts to 100%, Jog and Rapid Rates are loaded from the machine.ini configuration file. This reset behavior is designed to prevent unintended speed settings from persisting across sessions, ensuring consistent and predictable machine behavior each time Mach4 is initiated. Users can modify the machine.ini file to customize these default startup values if needed, tailoring Mach4’s initial settings to their typical workflow.
[PersistentDROs]
drojograte = 20.000000
drorapidrate = 50.000000Understanding and correctly configuring these speed settings in Mach4 is fundamental for optimizing CNC machine performance, ensuring both efficiency and safety in your machining processes.
