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Speed Limits and Homing

Advanced settings for the X-, Y-, and Z-axis motors

The Speed Limits and Homing options affect the motors that move the machining head.

Motion Settings for Each Axis

Max Allowed Speed
Set the maximum speed that the machining head will move (used during a rapid traverse). The default value is 200 inches per minute.

Max Acceleration
The maximum acceleration for the machining head. This value is given in terms of "G's," or the force of gravity at the earth's surface (32 ft/sec/sec or 9.8 m/sec/sec).

Max Acceleration should be set to 0.15g if you are using Acceleration Smoothing (see below) and there is little reason to adjust the value in this case. If you are not using Acceleration Smoothing, the range of values is 0.05g and 0.005g. The smaller the number, the slower the acceleration and deceleration. These numbers affect how hard the machining head accelerates or decelerates when:

They also affect how hard the machining head accelerates (but not decelerates) when using the Jog commands.

Deceleration for the Jog and Pause commands are handled though a different hardware mechanism on the GlobalMAX controller card itself (instead of being precomputed). When you press Pause, or stop a Jog command, you are interrupting a precomputed path, and the calculations for deceleration need to be handled by hardware.

Hardware Deceleration

The Hardware Deceleration slider affects how hard the machine decelerates when the Pause button is pressed, or when you lift your finger from the keyboard or mouse when jogging. It is typically set to decelerate a bit harder than normal, and may cause the machining head to shake since shaking is a cosmetic issue that does not affect part accuracy in this context.

If you want to adjust this, slide the bar to the right a notch or two, and then test by jogging the machine at full speed, and notice how hard it decelerates when you let your finger off the keyboard or mouse. Do this test in the X axis, since it has the most mass, and is the one where it's the most important to have setting correct.

NOTE: 

The Z-axis sliders only affect how the Z-axis will decelerate when JOGGING. The Z-axis sliders do NOT affect deceleration when a tool path is paused, even if the Z-axis is in motion as part of the tool path. The Z-axis slider also affects how the Tilt X and Tilt Y axis decelerates when jogging. To change how hard deceleration occurs when a tool path is running, even for the Z axis, it is necessary to adjust the slider for the X / Y axis.

 

Speed Cut Off for Deceleration Ramp

This slide affects how slow the machining head is moving before the computer considers it to be stopped. For example, when you stop jogging, the machine will decelerate, and move slower and slower. At some point it moves so slow that you might as well just stop sending it commands to move.

If you slide it to the right, then the machining head will decelerate to almost stopping, and then crawl along for a while at a very slow speed before finally stopping. If you slide it to the left, then the machine will decelerate to almost stopping, then stop quickly with perhaps a thunk.

NOTE: 

Acceleration and deceleration when actually cutting a part are constrained by the cutting model built into the software. For actual cutting, you will probably notice that the above has little effect. However, the acceleration and deceleration of the machining head will never exceed the limits imposed with the above settings, even if the cutting model allows it, which it might for some very thin or soft materials that cut quickly.

 

Homing

Ask to move Z up before going home

When this box is checked, the following dialog box appears:

This box allows you specify an distance to raise the Z-axis before the nozzle moves to the home position. You would use this if you had fixturing that might strike the nozzle while it moved home. You might also raise the nozzle if the material you were working with was uneven, or had raised sections.