Continuous Creeping Chain Reduces Non-Productive Time
Keeping non-productive time to a minimum is the key to improving towline efficiency. One way is to maximize production by using a Continuous Creeping Chain.
Towlines can move work pieces in three different ways:
- Continuous Creeping
- Indexing via PLC timer or operator release
- Non-synchronous with operator-released stops
In Continuous Creeping operation, the chain and carts never stop and the operators work on the product while the cart passes by at a very slow speed. In either index and dwell or non-synchronous operation, the chain moves at a high-speed between stations, causing operators to wait while the product is in motion between stops.
For example, assume 12 minutes of work per station with stations 12’ on center. In the Continuous Creeping mode, assume the chain would travel at 1’ per minute so the operator would complete work in 12 minutes (1 FPM x 12 feet). However, in either of the other modes, assume a chain speed of 30 FPM (too fast to work on but safe around operators) for 12 feet and then 12 minutes of work per piece. In this instance, the total cycle time per station is 24 seconds to index, plus 12 minutes of work time, equaling 12.4 minutes of total cycle time. While .4 minutes doesn’t sound like much, it adds up very quickly!
The Continuous Creeping line inherently produces higher volumes than the other operating modes as it paces the operators without losing any transit time. The volumes become higher yet when compared with indexing and non-synchronous systems where operators are allowed to pace the system via operator “complete” or “index hold” push buttons. This can result in even lower throughput.
Continuous Creep Provides Real Time Monitoring and Management
To allow “real time” interaction with the Continuous Creep towline system, an Andon system can be custom designed to monitor identified system events, thereby allowing management to spot bottlenecks and other system/station issues for subsequent corrective actions.
Through displays and reporting aids, this system notifies management, maintenance and other workers of a process problem at a specific workstation using a combination of large illuminated displays and accompanying audio/visual alerts.
Some displays simply indicate the location of problem encountered; others may specifically indicate the nature of the problem (i.e. “Operator Needs Assistance”). The alert can be activated manually by the operator using a pull cord or button, or can be activated automatically by the production equipment itself when it senses an abnormality or out-of-tolerance condition. The system can include a means to stop production so the issue can be corrected before advancing to the next workstation, thereby not passing the problem forward.
Control system upgrades that allow management to track specific towline performance parameters can also improve line productivity. Conditions such as frequency of stoppage at individual workstations can be recorded and uploaded to a factory control system for analysis. From that analysis, corrective action that might include mechanical, process fixes or operator retraining can be implemented.
SI Systems provides a wide range of Lo-Tow Towline in-floor conveyor systems that include unique Gap-Track™ jam-free operating technology, field proven extended life, remote dial in controls support, integrated NFF (No Fault Forward) assembly systems, zero-pit 6 inch trench technology, Rejuvenation & Retrofit (R&R) program and over 50 years of experience. Visit www.sihs.com or email: email@example.com for more information