Coil Loading Procedures 250

This class explains how to properly handle and load coil onto the uncoiler, as well as describes how to thread the straightener and feed coil stock into the die area.

  • Difficulty Intermediate

  • Format Online

  • Number of Lessons 19

  • Language English


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Course Outline
  • Objectives
  • Handling Coil Material
  • Coil Lifting Tools
  • Coil Defects
  • Squatting
  • Clockspringing
  • Telescoping
  • Coil Material Defects
  • Preparing the Press for New Coil
  • Loading Coil on the Uncoiler
  • Loading Coil on a Reel
  • Loading Coil on a Cradle
  • Straightener Rolls
  • Threading the Straightener
  • The Slack Loop
  • Loading the Grip Feeder
  • Loading the Roll Feeder
  • Walking the Strip Through the Die
  • Summary
  • Describe how to use coil handling equipment.
  • Describe common coil lifting tools.
  • List types of coil defects.
  • Identify defective coil due to squatting.
  • Identify defective coil due to clockspringing.
  • Identify defective coil due to telescoping.
  • List common defects found in coil material.
  • Describe how to prepare the press for new coil.
  • Describe common guidelines for loading coil onto the uncoiler.
  • Describe how to load coil onto a reel.
  • Describe how to load coil onto a cradle.
  • Describe the purpose of straightener rolls.
  • Describe how to thread the straightener.
  • Explain the importance of the slack loop.
  • Describe how to load the grip feeder.
  • Describe how to load the roll feeder.
  • Describe how to align the strip with the die.
Vocabulary Term

bridge grip feeder

A type of grip feeder that clamps stock in the center or across its entire width.


Welding a joint by fastening its ends together without overlapping.


A coil material defect in which one edge of the material is longer than the other.

cascade rolls

Non-powered rolls at the end of some coil line components that form a waterfall shape and keep material from kinking as it enters and exits the equipment.


A lifting tool shaped like the letter "C", which is attached to a lifting device and grabs the coil for loading onto the uncoiler.


A type of coil defect in which the coil wraps separate from one another and spread around the diameter of the coil.

coil break

A coil material defect in which the material has a series of evenly spaced lines across its surface. Coil break may result in an unacceptable surface finish on parts.

coil grab

A lifting tool attached to a lifting device, which grabs the coil's outer diameter with tongs or other types of gripping mechanisms and loads the coil onto the uncoiler.

coil set

The natural curvature remaining in coil after it has been unwound.

coil stock

A long, thin sheet of metal that has been wound tightly. Stock first appears as coil for many press operations.

confining plates

Plates on a cradle uncoiler, which keep the coil stock centered in the cradle.


A type of uncoiler that supports coil from below on its outside diameter.


The curvature of the coil stock across its width. The center of coil stock with crossbow is higher than the edges.


Removing the retaining bands from the outside diameter of the coil stock.

die area

The area that contains the die. Press operators should enter the die area only with approved handling tools.

die starting position

A line or arrow marked on the die that indicates where the coil stock should be lined up before production begins.

edge wave

A coil material defect in which the edges appear scalloped. Edge wave is often caused by pinch roll pressure in the cradle, straightener, or feed.


Having an oval shape. Coil that has an elliptical inside diameter is known as squatting.

entrance pinch rolls

Pinch rolls located at the start of the straightener, which provide the power necessary to thread material into the straightening rolls.

exit pinch rolls

Pinch rolls located at the end of the straightener, which assist the straightening rolls during production.

feed clamping bar

A bar located on a bridge grip feeder, which holds down the coil stock as it enters the grip feeder.

feed clamping piston

A clamping device on an open-throat grip feeder, which applies air pressure to the coil stock as it enters the grip feeder.


The main device located in the crown of a mechanical press that is attached to the power source and regulates the reciprocating motion of the ram.

grip feeder

A type of feed mechanism that uses one stationary and one sliding clamping mechanism to intermittently feed stock into the press.


The ability of a material to resist scratching or penetration.

hold-down arm

A device usually found on a reel that applies pressure on the coil and keeps it from expanding.

idler rolls

An unpowered component on a straightener that bends stock as it passes through the equipment. Idler rolls are positioned above the stock.

inch mode

A mode of press operation in which the ram moves intermittently at different points in the stroke. Inch mode is most often used during die setup and before loading a new coil.

inside diameter

An interior cylindrical surface of a hole.


A component on a reel uncoiler that prevents the coil from sliding off the mandrels.

lifting device

A device that carries the coil stock to the uncoiler. The lifting device may be a crane, hoist, or forklift.

lifting tool

A device that picks up the coil and places it on the uncoiler. Common lifting tools consist of slings, c-hooks, and coil grabs.

loop control device

A device that detects when stock must be advanced to maintain the slack loop. Either a powered uncoiler or straightener will typically have a loop control device.


A component on a reel uncoiler that holds coil through its inside diameter. Mandrels expand to hold the coil in place.

open-throat grip feeder

A type of grip feeder that clamps stock on one edge. Open-throat grip feeders can accommodate wider stock.

outside diameter

An exterior cylindrical surface of a part or stock.

pallet decoiler

A type of uncoiler in which the coil stock is placed on a horizontal table and unwound horizontally.

photoelectric sensors

A type of sensor on the press that emits an electric beam. When the beam is interrupted, the sensor sends a signal to the press to stop the operation.

pilot hole

The hole in the strip that aligns with the pilot pin. As the ram nears the bottom of the stroke, the pilot pins must enter their pilot holes.

pilot pin

A long, slender punch with a rounded tip used to position the metal sheet by entering a previously formed hole.

pinch rolls

A component on a cradle uncoiler that assists uncoiling by pulling on the stock.

press operator

The person who operates and monitors the stamping press during production.


The main upper portion of the press that slides up and down within the press frame. The upper die shoe is attached to the ram.


A type of uncoiler that holds coil by its inside diameter and suspends it above the ground.

rest rolls

A component on a cradle uncoiler that supports the coil and rotates to unwind the coil.


A device that holds down coil stock in the uncoiler device to minimize clockspringing.

retaining bands

Bands wrapped around the coil stock to keep the coil tightly wound. The press operator clips the retaining bands once the coil is loaded on the uncoiler.

roll feeder

A type of feed mechanism that uses rotating rolls to intermittently feed stock into the press.

slack loop

Excess stock that hangs between coil-line equipment. The slack loop allows continuous and intermittent equipment to work together.


A loop of material, which picks up coil stock and places it on the uncoiler. Slings can be made of chain, wire, or nylon.


The discarded section of metal resulting from a punching or piercing operation.


A rotating shaft on a reel uncoiler, which turns mandrel arms.


A type of coil defect in which the coil appears egg-shaped. The inside diameter of squatting coil is elliptical instead of round.

stock guides

A device used to direct strip through the die.


A mechanism designed to repeatedly bend stock back and forth to remove any natural curvature.

straightening rolls

A powered component on a straightener that bends and passes stock through the equipment. Straightening rolls are positioned below the stock.


A type of coil defect in which the coil wraps protrude from the side of the coil.


To strengthen or harden metal by a heating it or heating then cooling it.

threading table

A flat table that bridges the gap between the straightener and the feed mechanism.

top dead center

The highest position in the ram's stroke. TDC is also referred to as stroke-up position.


A mechanism designed to hold coil and gradually unwind it during press operations.


A type of pivoting clamp attached to the c-hook's carrying arm that allows the c-hook to turn the coil from a horizontal position to a vertical position for loading onto the uncoiler.