Z Axis¶

Mach4 has been designed to jog the machine using the arrow keys even while not selected as the primary window.

If this functionality is not desired, turn off keyboard jog prior to selecting another program.

Avid CNC Mach4 Users Guide

Keyboard Jogging is not enabled in Mach4.

Turn the "Keyboard Jog" toggle to ON.

Avid CNC Mach4 Users Guide

CRP850-00E breakout board is not firmly seated into motor drivers, leading to motion in only one direction.

Reseat CRP850-00E breakout board into motor drivers to ensure all motors are receiving step and direction signals

Motion may be briefly stalling due to the PC and Mach4 being overloaded by dense G-code.

To reduce the density of G-code without affecting real world results, increase the toolpath "tolerance" in the CAM software settings. Defaults are often 0.0004" - this should be increased to at least 0.001". In most cases the tolerance can be increased to 0.004" without visible effects.

Motor enable/disable switch is in the 'Off' position.

Check switch position and set to the 'On' position.

Intermittent ethernet connection between Mach4 and the ESS due to a faulty ethernet cable, USB ethernet adapter, or USB port.

Perform the following tests to eliminate the ethernet cable/adapter as the cause of motion loss:

1. Test with known good cable, between computer and Plug & Play Controller.

2. Bypassing the panel mount connector on the Plug & Play Controller by plugging ethernet directly into the ESS board.

3. Test with a known good USB-to-Ethernet adapter or new adapter.

4. Test ethernet adapter plugged into an alternate USB port.

Replace cable or adapter if necessary.

Loose power supply wiring in the Plug and Play controller.

Turn off and unplug power from the controller.

Check the 5V and 12V power supply input and output wiring is secure. If necessary, reseat and firmly tighten connections.

Check the 5V power wiring on the ESS (12V on WarpRunner/TMC3in1 for Plasma controllers) and secure if necessary.

Loose breakout board connection in the Plug and Play controller.

Turn off and unplug power from the controller.

Check that the CRP850-00E breakout board is firmly seated in the motor drives.

For Plasma controllers, check that the WarpRunner or TMC3in1 breakout board is firmly seated in the ESS connection.

Loose motor control wiring in the Plug and Play controller.

Turn off and unplug power from the controller.

Check that all motor drive connections are secure.

Motor Drive Connections

The soft limits are set too conservatively by default preventing the axis from reaching its true lower limit.

Note: This is most often seen on machines equipped with 12" Z Axis.

Option 1: Update Mach4 to latest version.

Option 2: Adjust the Z axis soft limit manually in Mach4 by navigating to: Configure -> Control -> Homing/Soft Limits.

Avid CNC Mach4 Download

There may be corruption of the network adapter settings that is causing connection interruptions.

Perform Windows Network Reset then rerun SCU application.

Network Reset Instructions

A proximity sensor may be triggered by debris.

Check the control PC for indications of triggered proximity sensors.

Clean any metal debris from around the proximity sensors.

Proximity limit switch input pins improperly assigned.

To see what pins are receiving signals when a sensor is triggered, open Mach4 then select Diagnostics -> ESS -> Inputs

Ensure correct Avid Mach4 configuration is selected.

If not using Avid Mach4 configurations, ensure pins are mapped correctly in the ESS configuration

Axis homing order incorrectly assigned after Mach4 configuration.

Note: Assigning homing order is only necessary on multi-process and shared sensor port machine.

1. In the Avid CNC Mach4 Configuration menu, choose the "Use custom homing settings" option.

2. Set the axis homing order as needed so that axes sharing a sensor port do not home simultaneously.

Mach4 Custom Configuration Menu

Assigning Homing Order

Oldham coupler motor half is positioned too far from the motor.

Reposition Oldham coupler half as shown in the instructions.

Section 6 of Assembly Instructions

Oldham coupler may be an unusually tight fit.

Reposition the motor half of the coupling slightly closer to the motor (0.5-1mm).

Apply a small amount of grease to the contact surfaces of the plastic middle section of the Oldham coupling.

The tool has moved up/down in the collet while cutting.

Check that the collet is correctly sized for the tool.

Check that the collet is free of debris and the nut is adequately tightened.

Inadequate workholding is allowing the material to flex upward/downward.

Addtional or alternative workholding solutions may be required to eliminate movement in material while cutting.

Thin materials often require additional attachment to spoilboard in the middle of parts. Thicker double-sided foam tape is strongly discouraged as it can allow significant vibration while cutting.

Drilling or vertical plunge moves caused a momentary loss of motion/steps due to excessive load leading to the physical tool height being above the position in the control software.

End mills are not designed to drill or plunge vertically at significant speed. It is recommended that a ramp or lead-in be used for pockets. If drilling a large number of holes is required, a cutting tool smaller than the desired hole diameter and a helical bore tool path is recommended in place of a vertical plunge.

These strategies reduce vertical loading on the tool and Z-axis while also providing an exit path for chips which reduces heat buildup, leading to increased tool life.

Toolpaths, Speeds, & Feeds Video Playlist

Unused height control setting in Mach4 can lead to incremental creep of Z Axis position.

Upgrading to the latest release of Mach4 will eliminate this issue. The latest version disables height control and includes bug fixes for improved reliability.

Avid CNC Mach4 Download

Program extents may be outside of the area defined by soft limits.

In Mach4 with work coordinates set and G-code loaded, click Regen Toolpath to the right of the toolpath preview window.

Inspect preview for cutting moves (green lines) or jog moves (white lines) that fall outside the machine work area (dashed yellow line).

Any lines outside the work area will trigger a soft limit error. If found, reprogram toolpaths to ensure the program stays within the set work area.

Mach4 has a "look ahead" feature which analyzes upcoming lines of G-code to ensure no command contains errors or exceeds the machine work area. The default setting is 20, meaning Mach4 is always reading 20 lines ahead. Because of this feature, a soft limit can be triggered well before the machine would have been commanded to move outside of the work area.

The dust collection hose may have triggered the proximity sensor. Dust hoses often contain metal coils.

Secure dust collection hose or shroud sensor such that a false limit cannot be triggered by moving hose.