Troubleshooting an SDX Auger

Troubleshooting an SDX Auger with Inconsistent Filling


The SDX Auger is a volumetric filling device that accurately proportions powdered and granulated products.  It receives product in bulk from a product feeder and stores it in its hopper.  When the packaging machine signals it to fill a bag, it turns its proportioning screw and delivers the desired volume of product into the bag.

Inconsistent weights are a common problem with non-free flow products because of various settings and flow characteristics of the product. Listed below are some of the causes and remedies of inconsistent weights.


On non-free flow product (biscuit mix, cake mix ETC) the product needs to be pushed into the flights of the proportioning auger screw to create a consistent fill of the bag. This is done by the agitator blades rotating in the opposite direction of the auger screw. The Agitator blades need to make at least 1 complete revolution per cycle in order to fill the flights of the screw to maintain good weights.


If the Agitator Blades are not making a complete rotation per machine cycle then there is a speed adjustment for the agitator in the HMI for increase or decreasing speed.



This may cause swirling in the hopper. The Agitator blades need to make at least 1 complete revolution per cycle only.


Another common problem is if the agitator blades are not cutting through the product. The agitator blades consist of 2 different types of blades. A stirring blade and a scraper blade.

The stirring blade pushes through the center of the product in the hopper to push the product into the proportioning screw and the scraper blade rotates around the edge of the hopper to refill the center of the hopper.

If the non-free flow product is warm or clings to the agitator blades then it will swirl in the hopper and the product will not keep screw flights full causing inconsistent weights.



On the filling of the hopper it should be replenished quick enough to maintain a proper hopper fill height so that the agitator can refill the flights properly. This is done by a level probe in the hopper that signals the infeed system when the product in the hopper is low. Replenishing the hopper is critical for maintaining weights so the flights of the screw are filled consistently. If it takes too much time to refill than you will have light weights and the infeed needs to be sped up.


 If it fills too fast then the hopper will be too full and you will have heavy weights and possible infeed jams.


Rovema uses a horizonal infeed screw to fill the hopper. The level probe signals the infeed screw for the consistent filling and refilling of the hopper to maintain weight. A speed adjustment in the HMI is used to increase or decrease the speed for consistent repeatable filling.


In order to make bags are certain speeds a correctly sized proportioning screw needs to be determined. A few factors need to be accounted for in making proper weight consistency.

  • Bulk density of product
  • Volume per revolution on proportioning screw.
  • Bag weight

This will determine the answer to the question below.

  • Number of revolutions needed per cycle and should not be greater than 8-10 revolutions or your weights become inconsistent?


On the end of all proportion screws and tubes are restrictors. There are various types used for restricting the product from dribbling when the screw stops between fill cycles.

The three types of restrictors are:

  • Spinner (attached to end of proportioning screw)
  • Sieve (attached to end of auger tube with cap)
  • Washer (attached to proportioning screw with cap attached to tube to create lip)

 On non-free flow products, the spinner and sieve style are the choices for retaining the product dribble and product stoppage.

There are a variety of spinners and sieves with different pin configurations that are tested with the product for best performance.

The washer types are best used for free flow like coffee.


Below is a chart with some common auger issues with some remedies.


Operation Issues


Possible Cause(s)

Possible Solution(s)

Agitator Drive Fault

1)      The auger agitator controller has experienced a fault.

1)      Refer to the troubleshooting section of the frequency controller manual.

2)      Check mechanical binding

Agitator Motor Fault

1)      The auger agitator motor has over heated.

1)      Allow the motor to cool.  Check for excessive loading on the motor which could be causing the overheating.

2)      Check mechanical binding

Auger Out of Product Fault

1)      The Hopper is empty.

2)      The infeed system has no product.

3)      The infeed system is not delivering the product fast enough

4)      The agitator out of product timer is too short.

1)      Determine why and add more product.

2)      Determine why and add more product

3)      Determine why and speed up infeed

4)      Increase the time on the out of product timer.

Auger Axis Fault

1)      The auger servo motor has experienced a fault.

1)      Refer to the Servo Drive Manual for troubleshooting instructions.

Auger Cycle Too Long

1)      The auger move time setting is longer than the machine cycle time.

1)      Set the auger move time less than the machine cycle time. Use this formula to calculate machine cycle time: 60/Machine Speed * 1000.

Auger Housing Safety Switch

1)      The MACHINE READY push-button was pressed while the auger housing was open.

1)      Close the auger housing and press the MACHINE READY push-button again.

Auger Torque Limit Exceeded

1)      The torque on the auger has exceeded the acceptable limit.

1)      Determine if product in the auger has jammed or is the correct consistency.

Clamshell Failed To Open

1)      The clamshell device in the auger did not open properly.

1)      Determine if there is an obstruction not allowing the clamshell to open.

2)      No or low air to device

3)      No signal to solenoid to open. Switch turned off

4)      Cylinder open proximity switch defective or not set properly


Clamshell Stuck Open

1)      The clamshell device in the auger will not close.

1)      Determine if there is an obstruction not allowing the clamshell to close.

Inconsistent weights

1) Agitator blades too slow.

2) Infeed system too slow.

3) Inconsistent bulk density.

4) Too many revolutions in hopper to make weight

1) Agitator blades too slow.

2)Infeed system too slow.

3)Inconsistent bulk density.

Too many revolutions in hopper to make weight


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