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BENDING ALLOWANCE
To bend sheet metal accurately, you will need to consider the total length of each bend. This is
referred to as bend allowance. Subtract the bend allowance from the sum of the outside
dimensions of the workpiece to obtain the actual overall length or width of the piece. Because of
differences in sheet metal hardness, and whether the bend is made with the grain or against it,
exact allowances must sometimes be made by trial and error. However, bend allowances for
general use can be obtained from metal working books or from the Internet.
UNDERSTANDING SPRINGBACK
Springback, also known as elastic recovery, is the result of the metal wanting to return to its
original shape after undergoing compression and stretch. After the bending leaf is removed from
the metal and the load is released, the workpiece relaxes, forcing the bent portion of the metal to
return slightly to its original shape. The key to obtaining the correct bend angle is to over bend the
metal a little and allow it to spring back to the desired angle. All metals exhibit a certain amount
of spring back.
MATERIAL SELECTION
CAUTION:
processed through the machine are NOT potentially hazardous to the operator or
personnel working nearby.
When selecting materials keep these instructions in mind:
• Material must be clean and dry (without oil).
• Material should have a smooth surface, so it processes easily.
• Dimensional properties of material must be consistent and not exceed the machine capacity
values.
• Chemical structure of material must be consistent.
• Buy certificated steel from the same vendor when possible.
It must be determined by the customer that materials being
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