K factor a constant determined by dividing the thickness of the sheet by the location of the neutral axis which is the part of sheet metal that does not change length.
How to find k factor in sheet metal.
After bending the sheet insert the inner radius and flanges a and b.
K factor in sheet metal bending is a constant used to calculate sheet metal flat length or flat pattern.
In this article we will discuss sheetmetal bend deduction bend allowance k factor y factor and sheet metal flat pattern calculations.
The area within the sheet defined as the neutral axis does not get compressed on the inside of the neutral axis or expanded on the outside.
Flat blank dimension l1 l2 l3.
Because of the specific properties of any given metal there is no easy way to calculate that value perfectly hence the chart in figure 2.
This is defined as the length of the neutral fibre from the beginning to the end of the arc generated by the bend.
The k factor is a constant determined by dividing the material thickness of the sheet by the location of the neutral axis.
Finding y factor for sheet metal bending.
K factor 180 x ba π x complementary bend angle x mt ir mt 2.
In order to find the k factor you will need to bend a sample piece and deduce the bend allowance.
Bending angle is 90.
The k factor is defined mathematically as t mt where t is the neutral axis location and mt is the material thickness.
The k factor is usually somewhere between 0 3 and 0 5.
Best way to calculate k factor in sheet metal is by reverse engineering.
Typically the k factor is going to be between 0 and 5.
Calculating the k factor since the k factor is based on the property of the metal and its thickness there is no simple way to calculate it ahead of the first bend.
You can also use our flat pattern calculator for blank size calculation.
To calculate the bend allowance the k factor and the derived coefficient called the y factor insert the thickness and initial length of the sheet into the cells on the left.
You ll need the k factor to find the y factor.
K factor is a coefficient that is affected by the brake tooling as well as the material.
So if the thickness of the sheet was a distance of t 1 mm and the location of the neutral axis was a distance of t 0 5 mm measured from the inside bend then you would have a k factor of t t 0 5 1 0 5.
Now let s see how we can obtain these values for a specific sheet.
Mathematically k factor value is equal to the ratio of position of neutral axis and sheet thickness.
How k and y factors affect metal bending.
As i mentioned in my last post you need to do some tests to calculate these values for a specific sheet.
Publications such as machinery s handbook give general recommendations for k factors but the best practice is to determine them from actual tool set ups and materials.
In my previous post i talked about k factor bend allowance and bend deduction and what they mean in sheet metal design.
You can use this k factor calculator to calculate k factor using reverse engineering method.
