What is the definition of "closed hem"?
A type of hem that is bent back so that the surface of the workpiece touches down on the entire surface of the bend.

Learn more about closed hem in the class Die Bending Operations 130 below.


Press Brake Training


Class Information
Press Brake Training Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:Die Bending Operations 130
Description:This class describes the different types of bends that can be formed on the press brake.
Prerequisites: none
Difficulty:Beginner
Number of Lessons:14
Language:English, Spanish
 
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Class Outline
  • Objectives
  • Intro to Types of Bends
  • Common Bend Types
  • Angular Bends
  • Offset Bends
  • Hems
  • Seams
  • Curls
  • Ribs
  • Corrugations
  • Louvers
  • Radius Bends
  • U Bends
  • Summary
  
Class Objectives
  • Describe the importance of learning types of bends.
  • List common bend types.
  • Describe angular bends.
  • Describe offset bends.
  • Describe hemming.
  • Describe seaming.
  • Describe curling.
  • Describe ribbing.
  • Describe corrugation.
  • Describe louvers.
  • Describe radius bends.
  • Describe U bends.

Class Vocabulary

Vocabulary TermDefinition
acute bend An angular bend that is formed at an angle less than 90 degrees.
acute punch A punch at less than 90° that forms acute bends.
angular bend A common type of bend that is either a standard V, acute, or flange.
bead The circular portion of a curl bend, often used as a hinge.
bend The process by which a material, usually metal, is formed into a desired shape. The shape of a bend is dictated by the type of tooling used.
bumping a radius A method used to prevent springback when creating radius bends. Bumping a radius breaks up a radius bend to a series of segments of angled bends.
closed hem A type of hem that is bent back so that the surface of the workpiece touches down on the entire surface of the bend.
corrugation A series of identical bends on a panel used to add strength to the material and commonly seen on industrial rooftops.
curl An arc-shaped bend that is used to reduce sharp edges on workpieces.
curling A bending process that reduces sharp edges on a workpiece by creating an arc-shaped bend. Curls are often used for hinges.
flange An angular bend in which one edge of the workpiece is bent while the other portion of the workpiece lies flat.
flattening die A type of die set that is completely flat on both the punch and the die, designed to flatten down bends completely.
hat-shaped rib A type of rib that is box, or hat shaped. Hat-shaped ribs add strength to workpieces that are intended to lay flat.
hem A 180° bend that is performed to remove sharp edges from a workpiece.
hemming A bending process in which a section of a workpiece is bent back upon itself. A hem is formed by first forming an acute bend and then flattening it with a flattening die.
joggle bend An offset bend in which the two opposite bends are each greater than 90°, and are separated by a neutral web less than 5 workpiece thicknesses apart.
leg One part of a bend. A bend is comprised of two legs.
lockseam A seam created on the press brake by placing two hems into each other and forming the seam with a flattening die to join the sections.
louvers A series of identical, raised bends on a panel. Louvers differ from corrugation because louvers are separated from the workpiece using a shearing die.
mandril A device placed between the legs of a hem so that they remain parallel for an open hem.
offset bend Two opposite bends that are seperated by a neutral web. A true offset is two opposite 90° bends with approximately 5 metal thicknesses separating the bends.
open hem A type of hem that is bent back so that just the tip of the leg on the shorter end of the workpiece touches down the other side of the workpiece surface.
press brake A type of press with an open frame and very wide bed. Press brakes are often used for bending operations, and they are typically manually operated.
radius The distance between a point on a circle and its center. The larger the radius, the more rounded the section of a bend.
radius bend Arc-shaped bend that can be used for sheet metal, tubes, or chutes.
radius-shaped rib An arc-shaped rib. Radius-shaped ribs are some of the most difficult shapes to obtain.
rib A bend placed on a flat panel intended to help keep the panel flat or add strength.
ribbing A bending process in which a bend is placed on a flat panel to help keep the panel flat or add strength.
seam A method of forming on the press brake in which two separate hems are formed together to form one part.
seaming A bending process that uses two hems to secure two separate workpieces together.
shearing The cutting and separating of material without the formation of chips. Louvers are formed by shearing sheet metal and separating a section.
springback A material's tendency to return to its original state once its state of motion has been disturbed. Springback is often corrected on bending operations with overbending.
straight punch A 90° punch that creates V bends.
true offset An offset bend in which the two directly opposite bends are at exact 90° angles and are separated by a neutral web at least 5 workpiece thicknesses apart.
U bend A large arc-shaped bend that is similar to a radius bend, but with a radius that is much larger.
V bend An angular bend that is formed at a 90° angle.
V-shaped rib A type of rib that is at a 90° angle. V-shaped ribs are one of the most common types of ribs to add strength to a workpiece material.
web The neutral unformed portion of a workpiece that separates the bent sections of an offset bend.
wiping die A type of die used to create a flange. While the flat end of the workpiece is secured, the punch comes down for the bend, which forces the workpiece alongside the die.
Z bend An offset bend in which the two opposite bends are each less than 90 degrees.