Introduction

This troubleshooting guide aims to assist you in resolving suction failure issues on your ELVS (Case Erector) machine. If you've encountered the problem of a box dropping during forming, follow the steps below to identify and address potential causes.

Observation

The ELVS machine can drop a box for many reasons, but paying close attention to when the point of failure occurs during the process can help direct troubleshooting effort effectively. '

‘Failure-to-Open’ occurs when the box is successfully pulled away from the stack but remains closed during forming.  If the box is still closed when forming starts, the flat box will fold in half and break suction. 

Internal glue joints, suction cup placement, stack finger/supports, and hopper stack adjustment all play a role in how well the machine can pull a box open prior to forming and folding.  

Troubleshooting

Verify the following checklist

• Proper Suction
  • Cleaned the intake filter.
  • Check exhaust filter. The filter should be white, with clean oil. Change oil every 6-12 months, check monthly.
  • Adjust the depth positioning of the suction cups.
    • Suction cups must make good contact with the flat surface of the box.
    • Approximately half inch of spring deflection on all suction cups when the pickup arm stops.
  •  Verify Suction Cups Function Correctly
    • Spring action
    • Clear any blockages in the airlines and suction cups
    • Blow suction cups at the wye with compressed air.
  • Monitor vacuum pressures for proper levels
    • Full vacuum (closed valve): gauge at about 50%
    • During box Suction pickup: gauge will drop to about 15%-20%
• Hopper: Finger and Roller supports
  • Required to Retain the stack.
  • The two wheels provide the majority of retaining force at the top.
    • Should be mounted near (~1”) the outside corners of the box
    • At a depth of about ¼” below the top edge of the box
      • If they tear the flap or breaks suction, move them up.
      • If the stack falls inward, move them down.
  • The straight guide ‘fingers’ (top and bottom) are responsible for opening the box as it is removed from the stack.
    • Must be positioned in the cutout between flaps to catch and hold the rear flap panel.
    • Depth is contingent the size and thickness of the box
      • Larger boxes require more support or engagement from the finger (1-1.5” extension)
      • Smaller boxes need less ~ ¼”
  • The flat support should be moved up out of the way
    • Can be used on square boxes
    • Can be used on very large boxes
• Hopper: Stack Adjustment
  • The stack of boxes must be compact and tight in the hopper.
    • Loose boxes do not provide enough friction and retaining force for the fingers to do their job
    • The back pressure of the stack helps to hold the rear flaps against the fingers while the suction cups draw the front panel open.  
  • Carton feed Photo eyes at the front of the hopper advance the stack to keep it tight and within reach of the suction cups
    • Adjust position and angle of sensors.
      • If the stack is too far away, the suction cups may not seat properly during pickup
      • If the stack is too close, the chain advances too much, forcing boxes into the machine
    • Adjust sensors’ sensitivity to correctly detect the box corners
  • Proper Rear Stack support.
    • The adjustable stack support arm should be extended to properly hold the stack upright while the pickup arm makes contact with the first.
    • If the support arm is not used or collapsed, the stack can be pushed away from the suction cups by the motion of the pickup arm

More info about ELVS Sensor adjustments can be found here: ELVS Hopper Feeding Issue