K-Factor and Bend Allowance
- Definitions. Bend allowance, L b, is the length of the neutral axis and is used to determine the blank length of a bent part.
- Rules of Thumb
- Minimum Bend Radius for Various Materials at Room Temperature. Values in this table are based on the minimum bend radius, which is that radius which does not produce a crack ...
What is k factor in sheet metal bend allowance?
The position of the neutral axis depends on the material, grain direction, tooling, and environmental conditions. Mathematically K factor is the ratio of the position of the neutral axis and sheet thickness. There is a direct relationship between sheet metal bend allowance and the K-factor.
What is the bend allowance formula?
The Bend Allowance Formula takes into account the geometries of bending and the properties of your metal to determine the Bend Allowance. You will need to know your Material Thickness (MT), the Bend Angle (B<), the Inside Radius (IR), and the K-Factor (K).
What is the base bend allowance of sheet metal?
Bend allowance is the amount of extra material you need to add while calculating the flat pattern of any sheet metal part. What is K factor? K factor is the ratio between the distance between the inside radius of the bend and the neutral axis to the sheet thickness. A typical value of the K factor varies between.33 to.50
What is k-factor in sheet bending?
Where t is the distance from inside face to the neutral sheet and T is the sheet thickness (Figure 1). In practice, K-Factor is used when you don’t know the process or machine that is going to be used to bend the sheet.
What is the meaning of K factor?
K Factor is a metric for app developers that reveals your app's virality, by measuring how many additional users each of your existing users brings along to the app. The term K Factor actually comes from the world of medicine, where it's used as a metric to measure how quickly a virus spreads.
What is the K factor for 43 degree bend?
K-Factor ChartRadiusSoft / AluminumMedium / Steel0 - Mt..33.38Mt. - 3*Mt..40.433*Mt. - >3*Mt..50.50Bottom Bending8 more rows
What is K factor for bend radius?
The K-factor comes from the ratio of the neutral radius divided by the thickness of the material on prepared charts and has a value between 0.3 and 0.5. The Y-factor looks at a similar value, but it takes the stresses inherent in the material into consideration, making it more accurate than the K-factor.
What is the K factor formula?
Mathematically, K = (180×BA) / (π×θ×T) − (Rᵢ/T) .
What is a good K-factor?
A good K-factor is one that is higher than one, even fractionally. This indicates viral growth and that your K-factor surpasses your churn rate. A K-factor of one indicates stability as your app isn't growing or declining. Conversely, a K-factor below one reveals that your app's virality is in exponential decline.
How is bend allowance calculated?
To calculate bend allowance: Obtain the properties of the bend (bend radius, angle, and method used). Obtain the characteristics of your material (thickness and K-factor for this specific bend). Input everything into the bend allowance formula: BA = angle × (π/180) × (radius + K-factor × thickness) .
What is difference between K-factor and Y factor?
K factor is a ratio between the distance from the neutral bend line to the inside bend radius and the material thickness. K factor uses the formula K factor = δ/T. Y factor uses the formula Y factor = K factor * (Π/2). The default value for the Y-factor is 0.50.
What is K value of mild steel?
3.14. 5 Thermal conductivity coefficientMetalsNickel920.0087Silver419Steel mild50Steel: mild5048 more rows
How do you calculate airflow K-factor?
Alternatively, it may be the airflow K-Factor, which is the velocity factor times the inlet area. For an 8 inch Krueger unit, therefore, this would be 2625 * 0.349, or 916. A separate factor is required for each size. All Krueger VAV terminals have round inlets.
What is K-Factor 8?
The k-factor is dependent upon the orifice diameter of the sprinkler - a low k-factor (such as K2. 8) restricts the flow of water, while a larger k-factor (such as K22.
What is orifice k-factor?
Essentially, the k-factor is the orifice size needed for a particular flow and pressure. Low k-factors have a smaller diameter and restrict the flow while larger k-factors allow for more flow. Meyer Fire offers a tool to compare pressure requirements and flow rates for different k-factors.
What is K-factor in calibration?
K-Factors are calibration values (pulses per unit of volume) used to convert flow sensor output frequencies to flow rates. This calculation tool helps you to determine the correct K-Factor for your flow sensor.
How do you calculate airflow K-factor?
Alternatively, it may be the airflow K-Factor, which is the velocity factor times the inlet area. For an 8 inch Krueger unit, therefore, this would be 2625 * 0.349, or 916. A separate factor is required for each size. All Krueger VAV terminals have round inlets.
How do you calculate K-factor for flow?
The K-factor is the frequency divided by the flow rate => [1/s] / [g/s] = 1/g. Knowing the K-factor for each calibration point, the factory determines the best fitting K-factor for that particular flowmeter. Calibration points are determined by averaging all K-factors.
How do you calculate K-factor growth?
How to calculate the k-factor? The most common formula is k-factor = i*c, where i is an average number of invitations sent by one user, c is an average conversion from received invitation into registration.
What is the K-factor of a sprinkler head?
K-factor of a fire sprinkler is defined as: K= Q/√p, where Q is flow rate, and p is static pressure. For instance, several automatic sprinklers with different nominal K-factor values are shown in Figure 1.
What is the K factor?
Mathematically K factor is the ratio of the position of the neutral axis and sheet thickness. K-Factor = Position of neutral axis / Material thickness.
What happens to the K factor value with hardness?
K factor value is inversely proportional to material hardness. Therefore with an Increase in hardness, the K factor value decreases .
What is Bend Deduction in Sheet Metal?
During sheet metal bending, the inside surface of the bend is compressed and the outer surface is stretched. Which increases total outer surface area. In other words, after bending, the total sheet-metal part length (A + B) will be greater than the sheet metal Flat Length.
What is K Factor in Sheet Metal?
K Factor in sheet metal bending is a constant that is used to calculate sheet metal flat length. Its value is a constant for a given material, thickness, and machine. The value of K-Factor may vary from machine to machine as well.
What is the mathematical bend deduction?
Mathematically Bend Deduction is equal to the difference between the total sheet metal length after bending and flat length.
How are sheet metal bend allowance and bend deduction related?
Sheet Metal Bend allowance and bend deduction are directly related to each other. Mathematically the sum of bend allowance and bend deduction is equal to two times of outside setback.
What is sheet metal bending?
Sheet metal bending is a forming operation where sheets are deformed plastically to change their shape. During sheetmetal bending, the material is stressed beyond its yield strength but below the ultimate tensile strength. After bending a sheet metal part, the total length of sheet metal is more than the flat length.
What is the bend allowance?
The Bend Allowance (BA) is the arc length of the bend as measured along the neutral axis of the material. Understanding the Bend Allowance and consequently the Bend Deduction of a part is a crucial first step to understanding how sheet metal parts are fabricated.
What is the K factor?
K-Factor is a ratio that represents the location of the neutral axis with respect to the thickness of the sheet metal part and depends on material, thickness and bend radius. K-Factor (K) can be defined as follows:
What is bend deduction?
The Bend Deduction is defined as the material you will have to remove from the total length of your flanges in order to arrive at the flat pattern.
What happens when you bend metal?
When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. As this happens you gain a small amount of total length in your part. The Bend Allowance is defined as the material you will have to add to the initial length of your flat sheet in order to arrive at the length of formed part.
Definitions
Bend allowance, L b, is the length of the neutral axis and is used to determine the blank length of a bent part.
Minimum Bend Radius for Various Materials at Room Temperature
Values in this table are based on the minimum bend radius, which is that radius which does not produce a crack in the outer fibers when bent. This is dependent on material properties and in particular the reduction of area.
90 Degrees Bend Angle
Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees. We will start by calculating the Bend Allowance. From there we can calculate the K-Factor and the Bend Deduction. After bending the sheet we need to do some measurements as shown in Figure 2.
Bending Angles Less Than 90 degrees
For our second scenario we are going to discuss the calculations for bending angles less than 90 degrees. As an example we are going to use 60 degrees as our bending angle. Again we have to do some measurements as shown in Figure 3. Then we have to calculate Leg Length 1 and Leg Length 2.
Bend Deduction Calculation
As explained in my first post the Bend Deduction can be calculated using the following equation:
Saeed Mojarad (CSWE)
Saeed Mojarad is an application engineer at Javelin Technologies. He received his B.S from Mazandaran University, Iran; and his M.S. from École de technologie supérieure (ETS), Canada. He has several years of experience using SOLIDWORKS in different industries such as manufacturing and aerospace.
What is bend allowance?
Bend allowance is a fundamental parameter to calculate sheet elongation. This is defined as the length of the neutral fibre from the beginning to the end of the arc generated by the bend.
What is the K factor?
The K factor is the most important and elusive variable of bending, because it varies both as a function of the material and according to parameters such as angle and tooling. The K factor is defined as the ratio between the material thickness (T) and the neutral fibre axis (t), i.e. the part of the material that bends without being compressed ...
What is bend allowance?
The Bend Allowance is defined as the material you will add to the actual leg lengths of the part in order to develop a flat pattern. The leg lengths are the part of the flange which is outside of the bend radius.
What happens when you bend metal?
When the sheet metal is put through the process of bending the metal around the bend is deformed and stretched. As this happens you gain a small amount of total length in your part. Likewise when you are trying to develop a flat pattern you will have to make a deduction from your desired part size to get the correct flat size.
Is sheet metal bending the same?
Unfortunately sheet metal bending is not always going to be the same in every shop. The largest variations come from the materials themselves. Protective coatings, variations in the alloy and thickness as well as many other small factors all add up to give you Bend Allowances unique to your operation. This chart will get you close enough for most applications and may not require fine tuning on your part, however if you are truly dedicated to precise bending, download the excel sheet and begin plugging in your own values.