Purpose: Material storage to supply the feed while the unwinder /decoiler/straightener accelerates to line speed. To absorb and store material while the unwinder decelerates after the feed stops; storage requirement is based on speed and feed length-vs.-acceleration rate of the unwinder.
The amount of material stored is equal to the total slack length minus the straight line length. Storage is increased by greater depth not length. Rule of thumb: 2 to 3 times feed length in slack for best operation. Types of Slack Loops include Horizontal, Overhead and paddle.
| Loop Size and Accumulation Chart Using The Chart: Select material thickness and passline intersect LENGTH shows desired loop length and STORED shows amount of slack |
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| Loop Depth Material Passline Height | |||||||||||||||||||||||||
| Material | Thickness | 36″ | 48″ | 60″ | 72″ | ||||||||||||||||||||
| Length | Stored | Length | Stored | Length | Stored | Length | Stored | ||||||||||||||||||
| 0.032 | 3.8′ | 56″ | 3.8′ | 87″ | 3.8′ | 120″ | 3.8′ | 155″ | |||||||||||||||||
| 0.063 | 7.3′ | 31″ | 7.6′ | 57″ | 7.6′ | 81″ | 7.6′ | 105″ | |||||||||||||||||
| 0.090 | 9.6′ | 27″ | 10.4′ | 43″ | 10.7′ | 57″ | 10.8′ | 88″ | |||||||||||||||||
| 0.125 | 12′ | 22″ | 13.2′ | 35″ | 14.1′ | 50″ | 14.6′ | 65″ | |||||||||||||||||
| 0.156 | 13.7′ | 20″ | 15.3′ | 31″ | 16.5′ | 44″ | 17.4′ | 59″ | |||||||||||||||||
| 0.187 | 15.2′ | 18″ | 17.1′ | 28″ | 18.6′ | 40″ | 19.8′ | 53″ | |||||||||||||||||
| 0.212 | 16.4′ | 17″ | 18.5′ | 26″ | 20.2′ | 37″ | 21.6′ | 50″ | |||||||||||||||||
| 0.250 | 18′ | 15″ | 20.3′ | 24″ | 22.3′ | 34″ | 24′ | 45″ | |||||||||||||||||
| 0.312 | 20.3′ | 13″ | 23′ | 21″ | 25.4′ | 30″ | 27.4′ | 40″ | |||||||||||||||||
| 0.375 | 22.4′ | 12″ | 25.6′ | 19″ | 28.2′ | 27″ | 30.5′ | 36″ | |||||||||||||||||
Some newer coil feeding design concepts challenge conventional space and slack loop/pit requirements. Space saver coil feed lines are now available that incorporate an integrated reel, and powered feeder straightener combination. This design greatly reduces floor space requirements. Servo feeds integrated with pull through straighteners also offer opportunity for space savings but require careful evaluation of application parameters.
Use this Coil Feeding Calculator to determine coil weights and production run time.
