Reliably rejecting damaged containers is paramount to bottling operations. If a damaged container, especially a glass one, gets through the system it could become a high liability. This can be costly in both money and in brand identity.
Furthermore, partially rejected bottles can quickly bring the line to a standstill. These facts make the case for a verifiable high-speed bottling rejection system.
A major bottle inspection system provider approached SMAC for a high-speed bottling rejection system to reject bottles at speeds up to 1,200 parts-per-minute. The solution had to work with a variety of size and material bottles, and whether filled or empty. The device also had to be wash down since many of the company’s systems form part of food and beverage filling lines.
As with all projects there is a balance between productivity, cost and quality. Often bottling lines run at speeds more than 2,000 parts per minute. That means rejecting a 76 mm bottle every 30 milliseconds from a stream of closely packed bottles. This is further complicated by potentially high backpressures from the bottles behind them.
While the cycle speed of the reject mechanism is a major part of the reject operation, so is the stroke length. The stroke is important to ensure the ejected bottle is far enough out of the stream of bottles that the one behind it is not also affected. However, the longer the stroke length the slower the cycle time because the total travel of the shaft increases. Force also plays a role due to container weight, line backpressure and to prevent the reject mechanism from damaging or tipping over the container.
Lowering the mass of the moving part of the reject arm allows increasing speeds at higher stroke length. Moving coil actuators rods have lower mass because the windings, not the magnets, are on the shaft. As a result, the rod moves faster given the same amount of power as a servo motor.
High-speed bottling rejection
SMAC proposed their LAL95050 actuator for meeting the client’s needs due to its capability of 2,000 parts-per-minute. Real-time testing of the actuator was conducted at the customer’s facility at speeds of 1,200 parts per minute.
“It was one of our first opportunities to proof out a concept for doing container rejects using our Soft-Land technology” explained SMAC’s Mike Ferris. “The real bonus that we got to work with an industry leading inspection companies and with such a variety of containers in one application. Moreover, it shows why the two companies are using advanced technology to be leaders in their respective fields.”
Soft-Land is a key technology of SMAC’s moving coil actuators. It allows the actuator to control the standard force feedback capability to identify the exact location of the container before starting to exert the force necessary to reject it. Along with the programmability of the actuator, soft-land allows simply changing container profiles from an HMI. This saves the customer valuable time and money in making changeovers.
Furthermore, SMAC actuators are unique in that force, position and speed are programmable. They provide sub-micron accuracy at high and low speed operation with validated repeatability and a 1ms response time
Electric actuators also help the user lower their operating costs by not using compressed air. Finally, SMAC’s actuators reduce overall costs due to repair rather than replacement at the end of their initial life cycle.