The Knotts Company

Industrial Automation and Motion Control Blog | The Knotts Company

Reduce Cycle Time with Automatic Sorting System

Posted by Mark Howe on February 14, 2018 09:00 AM

This post is brought to you by Intelligent Actuator

System Overview of a potential automation application.

1. Explanation of Process Cardboard boxes containing CDs travel on a conveyor. There are five different types of cardboard boxes, and each type contains different CDs. Boxes are sorted by type and transferred onto five product conveyors.

2. Explanation of Operation

  • A cardboard box moves on the transfer conveyor and passes the product identification unit. The unit reads the bar code on the cardboard box and identifies the type of CDs packed in it.
  • As the cardboard box arrives in front of the applicable conveyor, it is pushed by the sorting air cylinder onto the conveyor.

Problems Experienced While Using the Air Cylinder

The company was considering ways to shorten the cycle time of their automatic sorting system. The cycle time can be shortened by increasing the speed of the sorting air cylinder. However, a higher speed may cause the sorting push-out plate to bump the cardboard box and damage the products inside. This is why the company couldn’t shorten the cycle time by increasing the air cylinder speed. When they were using an air cylinder for their system, the cycle time was 5 seconds.

Improvements Achieved by the ROBO Cylinder

Changing the speed during movement to reduce the cycle time

The ROBO Cylinder lets you set the speed, acceleration, and deceleration separately. Using the ROBO Cylinder, the company was able to shorten the cycle time by 1 second by setting a low speed in the range where the sorting push-out plate contacts a cardboard box and setting a high speed in the range where the plate subsequently performs push-out operation.

No more damaged product

The company was experiencing occasional returns of shipped products. On checking the returned boxes, the company found damaged CD cases. The investigation of the damage cause revealed that the air cylinder of the automatic sorting system was bumping the cardboard boxes upon contact. After changing the Air Cylinder to the ROBO Cylinder, bumping stopped, and there are no more reports of damaged product.

Process Improvement with the Seven Benefits of the ROBO

  • Cylinder With the ROBO Cylinder, the speed, acceleration, and deceleration can be set for each position. A stable movement is possible by setting the best speed, acceleration, and deceleration.
  • You can also change the speed during movement.

Cost Cutting Effect

1. Conditions One operator oversees three lines.

Production volume: 8,300 boxes
Labor cost: $18*/hour
Annual operating days: 250 days

2. Comparison of Air Cylinder and ROBO Cylinder

Item System using air cylinder System using ROBO Cylinder
Cycle time 5.0 seconds 4.0 seconds
Line operating hours (day) 11.5 hours/day Cycle time 5.0 seconds x 8,300 boxes = 11.5 hours 9.2 hours/day Cycle time 4.0 seconds x 8,300 boxes = 9.2 hours
Labor cost (annual) $17,250* 11.5 hours/day x $6*/hour x 250 days/year = $17,250* $13,800* 9.2 hours/day x $6*/hour x 250 days/year = $13,800*

Note: One operator oversees three lines, so the labor cost per hour is calculated as $18* / 3 lines = $6*.

3. Cost Cutting Effect

  Air cylinder ROBO Cylinder  
Labor Cost (annual) $17,250* - $13,800* = $3,450*
    Difference = $3,450*


By adopting the ROBO Cylinder, the cycle time was reduced by 20%, and annual cost savings of $3,450* was achieved.

Topics: intelligent actuator, automation