Most Common Causes of Machine Stops

Chips:

  • Build-up of chips on door rail, causing door faults
    • Solution: regular maintenance and review process to determine if chips can be deflected or redirected, with coolant or tool path changes.
  • Chips on the vise surface, causing robot mis-loads or bad parts
    • Solution: review table wash program.  Table wash needs to thoroughly wash vises, ideally with coolant.  It is better to take more time washing the vises, to ensure chip removal than to optimize the table wash for time.
  • Chips on the bottom of soft jaws, causing robot mis-loads or bad parts
    • Solution: review VersaBlast calibration, VersaBlast mount position, and VersaBlast optimal air flow shown in manual. 
  • Build-up of chips in the interface between the MultiGrip Jaws and MultiGrip Gripper
    • Solution: regular maintenance – use the provided pick to clean out the interface between job setups.

Something Moved – Causing Robot Mis-Loads or Mis-Picks to/from the CNC:

  • Is the CNC or VersaCart moving?  Has there been any recent robot collision/crash?  Has a person accidentally bumped into the Versacart?
    • Solution: recalibrate the vises and watch for possible position changes of the cart or CNC by drawing a mark around the footpads.  If CNC is moving, consider anchoring to the floor. 

Lack of Regular Maintenance:

  • Clean chips out of CNC daily (recommended daily)
  • Clean CNC door and door rails (recommended daily)
  • Clean out chips or any chip build-up on the Gripper to MultiGrip Jaw interface (recommended daily)
  • Clean robot and robot cover (if used) -(recommended daily)
  • Clean the VersaCart table top (recommended monthly)
  • Clean robot controller
  • Look for leaks in air tubing (monthly)
  • Look for kinks in air tubing (monthly)

*Review UR10e manual for recommended maintenance on robot and robot controller

*Review Operators manual for recommended maintenance on VersaBuilt components

System is Not in Auto-Mode:

Verify Diverter Valve (Auto/Manual) valve is in the Auto position, allowing air pressure to reach the automatic valves in the VSC

Also verify the Hand Valves in the CNC for the vises are in the “center-closed” position (blocking shop air from passing through the hand valves to the vises during automatic operation)

Bent Cross Pins:

MultiGrip Jaws have 2 cross-pins, with springs, connecting the left and right jaws.  These cross-pins hold the jaws together and hold the springs, allowing OD jaws to spring-open, and ID jaws to spring-closed.

If MultiGrip Jaws are dropped or mis-loaded in a vise, then clamped, it is possible that the cross-pins could get damaged or bent.

  • Bent cross-pins may cause the jaws to not open/close properly
  • Bent cross-pins may cause robot mis-loads
  • In order for the MultiGrip Gripper with MultiGrip Jaws to work properly, the OD Jaws must spring-open and ID jaws must spring-closed.
  • Jaws may get loaded in the vise, but not fully seat in Z, which can lead to parts getting machined out of spec, or jaws getting machined.

If you are noticing

  • Dropped jaws
  • Robot Misloads
  • Parts out of spec

Remove the cross-pins from the jaws, roll them on granite to check flatness/runout.  If they are not straight, discard and replace.

Vise hand valves not in center position:

When running in AUTO mode, verify the Hand Valves in the CNC for the vises are in the “center-closed” position (blocking shop air from passing through the hand valves to the vises during automatic operation)

Image shows valves in center position

CNC Communication Drivers (Program 9000, Generic Driver):

VersaBuilt Automation Systems communicate with CNC’s via “Drivers”, either a communication driver with CNC controls (e.g., Haas Driver, Fanuc Driver) or with a “Generic Driver”. 

Most Communication Drivers utilize VersaBuilt’s provided “9000” programs for CNC to Robot communication.  If your system includes a communication driver (e.g., Haas, Fanuc controls), the CNC Dispatcher 9000 program needs to be active in memory for the system to run.

If your operation utilizes 9000 programs and you would like to use a different number, Program 9000 can be changed in the VSC > System Settings – CNC Dispatcher Program.

Generic Drivers utilize a handshake between the CNC and the Automation System, with a Cycle Start Relay signal from the VSC to the CNC and a Cycle End Signal from the CNC to the VSC.

CNC Program Commands for Robot Hand-Shake:

  • VersaBuilt automation requires a hand-shake signal from the CNC. This signal is set by the 9004 program that was installed on the CNC.
  • All CNC programs must end with a call to the 9004 program
  • Insert an M98 P9004 just before the M30
  • The M98 9004 line is safe to use, even when the CNC program is not being executed by the system
  • Tip: place the call to the M98 P9004 in your CAM post processor

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M98 P9004

M30

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Vise Sensors:

MultiGrip Vise Sensors are intended to be calibrated with the Calibration Plate, simulating MultiGrip OD Jaws with a 0.125” left to right jaw gap.  An M8 Proximity sensor is threaded into the vise, detecting a “flag” inside the vise, stroking with the piston.

The intended logic of the vise sensors is to detect vise misloads by the robot, by alerting with the absence of a signal when the vise is open or closed.

If your system is detecting an error when parts are properly loaded, or if your system is not detecting errors when parts are not properly loaded, there could be multiple issues:

  • Proximity sensor may need to be adjusted or reinstalled (Refer to the Installation Guide for instructions for Vise installation instructions)
  • MultiGrip Jaw gap may be outside the working range of the vise sensors (0.125” ±0.03”
  • Sensor cable may need to be tested if they are connected properly
  • Sensor cable may need to be replaced
  • Proximity sensor may need to be replaced

An alternative to using vise sensors is to “Ignore vise sensors” and use a spindle probe to detect part or jaw presence in each CNC program.  This is a robust solution that can give more information per program than the simple logic of the vise sensors.

When installed with the Calibration Plate:

  • Vise closed, clamping Calibration Plate
  • Thread Proximity Sensor to stop
  • Tighten Nut with 13mm deep socket wrench
  • Loosen Nut
  • Loosen Proximity Sensor ¼ turn
  • Connect Vise Sensor cable to VSC
  • Open/Close vise to test 
    • Sensor on when clamping Calibration Plate
    • Sensor off when opening
  • Remove Calibration Plate and test
    • Sensor off when Vise Open
    • Sensor off when Vise Closed
    • Sensor on when passing through middle of stroke

MultiGrip Jaws setup – gap between left and right jaws out of spec:

OD Jaws should be machined or setup with a 0.125” gap when clamping on a part during milling *using provide ⅛” spacer when machining pocket in jaws

  • Gaps above 0.16” may cause robot load/unload errors due to minimal vise to jaw feature interference and may cause vise sensor errors (false negative – detecting part missing, when part is actually clamped).
  • Gaps under 0.09” may cause vise sensor errors (false negative – detecting part missing, when part is actually clamped).  There will not be robot picking errors, but note the material tolerance to guard against clamping the left and right jaw closed, before engaging the part

Door Sensors:

VersaDoor Sensors are intended to detect the position of the actuator at door open and door closed.

The sensors are attached with a clamp ring and secured with a set screw.

If door sensors trigger a failure, it could be due to:

  • Chips in the door preventing the door from moving to the open or closed position.  May need to include door rail wash with coolant and review machining process and where chips are going.
  • Sensor position moved (false failure)
    • Readjust sensor location and tighten in-place.  To further secure the position, consider securing it further with a hose clamp.
  • Door speed settings are set too slow.  Check to see if problem can be solved by opening up the speed control fittings (tool provided with door opener).  
  • CNC door rails need maintenance

An alternative to using vise sensors is to “Ignore door sensors”.  The risk of doing this change is that the robot could run into a door that isn’t open.

Most Common Causes of Machine Stops
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