The Lightning Uncoiler ™ - Eliminating the Coil Pit from High-Speed Purlin Production

For decades, the coil pit has been considered a necessary part of high-speed purlin rollforming. As purlin production speeds increased and servo-driven punching systems became more sophisticated, manufacturers accepted a fundamental limitation: to run a high-speed purlin line, you needed a deep pit in the factory floor.

ASC Machine Tools challenged that assumption. The result is the Lightning Uncoiler™—an electrically driven, servo-controlled uncoiler developed specifically to eliminate the need for a traditional coil pit while maintaining the speed, precision and responsiveness required for modern purlin production.

The challenge with high-speed purlin production starts at the front end of the line. Modern purlin lines can require the material to accelerate, decelerate and stop rapidly as the punching system positions the steel for each hole pattern. Traditional high-speed systems typically use a hydraulically driven drag-brake uncoiler with pneumatic brake system.

While this technology has proven reliable for decades, a large steel coil has significant rotational inertia. When the punching feed system suddenly accelerates, the feed roll tower pulling material from the drag brake uncoiler cannot accelerate at the same rate.

The traditional solution was to create a large loop of material between the uncoiler with the feed roll tower, and the punching system. That loop acted as a buffer, allowing the punching system to rapidly change speed without transferring all of those forces directly back to the coil handling front end. The easiest way to create that loop was to put it in the floor. 

The coil pit became the solution to a problem created by the limitations of conventional coil handling.

ASC engineers asked: What if we eliminated the need for the pit altogether? That question changed the approach to the front end of the purlin line.

ASC developed the electrically driven Lightning Uncoiler ™ as an active material pay-off system rather than a simple drag brake uncoiler. The Lightning Uncoiler uses an electric servo drive to actively accelerat3 and decelerate the coil. Working together with ASC's servo-driven Feed Roll Tower, the system synchronizes the movement of the coil with the material demand of the punching system.

Instead of allowing the coil to react to the feed system, the Lightning Uncoiler actively participates in controlling the material.  When the feed roll tower accelerate, the Lightning Uncoiler responds. When the punching cycle stops, the Lightning Uncoiler und Feed Roll Tower rapidly decelerate. Laser loop control, real-time coil diameter measurement and ASC's proprietary control software work together to coordinate the system and minimize the effects of coil inertia.

The result is a fundamentally different approach to high-speed purlin production: No Pit. No Compromise. 

The Lightning Uncoiler allows high-speed purlin lines to operate without the traditional 8- to 10-foot-deep coil pit.  That change offers advantages that go far beyond eliminating excavation.

1) A safer Production Environment

A deep floor pit introduces an obvious physical hazard into a manufacturing facility. Guardrails, covers and other safety measures can reduce the risk, but the pit remains a permanent opening in the factory floor. Eliminating the pit removes that hazard from the production environment and can also reduce concerns associated with confined spaces and potentially hazardous atmospheric conditions. For ASC, this was an important part of the design philosophy.

2) Simplifying Installation

A traditional purlin pit can require substantial construction work, including excavation, concrete work, reinforcement, waterproofing, drainage and sump systems. These requirements become particularly challenging in facilities with high water tables or difficult soil conditions. With a pitless system, the equipment can be installed directly on the factory floor, eliminating much of the specialized construction associated with a deep coil pit. That can mean less construction, fewer complications and greater flexibility when planning a new production facility.

3) More Freedom for the Factory Layout

A concrete pit is permanent. Once installed, the production line's location is largely determined. The Lightning Uncoiler™ changes that equation. By eliminating the pit, manufacturers have greater freedom when planning their factory layout and more flexibility when equipment needs to be relocated or the facility is modified in the future.

ASC has been designing and manufacturing rollforming and coil-handling equipment since 1949.