A k factor is a percentage multiplier for locating the neutral axis. The main reason that i compared it ti the appearance ui is that it clearly has a standard library, you custom items, and also shows what is unique to the document. I am trying to understand how iv uses the k factor in sheet metal bending. We do not design precision sheet metal equipment if there is any such thing but we use the same kfactor for a hem versus a 9045etc. When a piece of metal is being formed, the inner portion. Sheet metal bending design tips, bend allowance, k factor, etc. The sheet metal model built with the sheet metal addon rear. The values of the setback, bend allowance, and bend deduction can be calculated from the sheet thickness, bend radius, bend angle, and kfactor. How to set up sheet metal gauge tables engineers rule. Bend the sheet to 90 degrees and measure length a and b. Now, you may be thinking, where this k factor is used. A reader wrote me asking me about the k factor and calculating bend allowances. How to use this k factor calculator in sheet metal reverse engineering approach step1.
Of all the mathematical constants used in precision sheet metal fabrication, the kfactor stands out as one of the most. Due to this tension and compression, the length of the sheet metal piece increases. Forming processes in manufacture of an access cover and control. Dec 27, 2016 save time bending sheet metal by not having to look up data in handbooks.
In sheet metal, the k factor is the ratio of the neutral axis to the material thickness. Sheet metal bending design tips, bend allowance, k. Pdf bend allowance constants for use in sheet metal forming. Since the kfactor is based on the property of the metal and its thickness there is no simple way to calculate it ahead of the first bend. In this article we will discuss sheetmetal bend deduction, bend allowance, kfactor, yfactor and sheet metal flat pattern calculations.
Sheet metal addon for freecad open source cad software. It is used to calculate sheet metal flat length flatpattern. K factor is actually the ratio of the offset t of the neutral axis from the inside bend and the thickness of the sheet t when a piece of sheet metal is bent. Relationship between bend deduction, bend allowance, and k factor. Learn what a kfactor is in sheet metal forming, learn how kfactor is used, and learn how to calculate kfactor in this video. The outer surface of the material is subjected to the. You can easily modify the material thickness, inside radius and kfactor for each thickness at the top of each column. Bending calculations using kfactor, bend deduction, and.
For all metals, however, there is a minimum bend radius at which the outer edge of the bend will crack. In sheet metal, the kfactor is the ratio of the neutral axis to the material thickness. It really all depends on what tooling is used to produce the sheet metal part and of course what material is being used. Use the known kfactor and the known inner bending radius to. Use the known k factor and the known inner bending radius to calculate the bending radius of the neutral line. Adding more in this series of the terminology used in sheet metal design, today i am going to write on the sheet metal k factor do you know when you bend a piece of sheet metal, one portion of its section undergoes compression and the other one undergoes tension. 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.
And if you know the bend allowance, you can extract the kfactor from it. Since the inside compression can not exceed the outside tension, the k factor can never exceed. Kfactors, yfactors, and press brake bending precision kfactors and yfactors. The k factor is defined as the ratio between the material thickness t and the neutral fibre axis t, i. Pdf the study of design constants in sheet metal forming. In sheet metal design, the kfactor is used to calculate how much sheet metal one needs to leave for the bend in order to achieve particular final dimensions, especially for between the straight sides next the bend. Calculate k factor, bend allowance and y factor for sheet metal.
In my previous post i talked about k factor, bend allowance and bend deduction and what they mean in sheet metal design. Minimum bend radii are typically specified in terms of sheet thickness t such as 1t, 2t. Sheet metal bend allowance explained with formula and. With this free online tool you can calculate the k factor, a fundamental parameter used to calculate sheet metal elongation according to your bending setting. How to calculated bending force in press tool design duration. 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. The online free fabrication calculator will help you calculate the kfactor, yfactor, bend allowance, bend deduction, flat size, neutral axis, arc length etc. In my previous post, i have talked about bend deduction and bend allowance. The kfactor approximations given below are more likely to be accurate for air bending. This is a simple calculator to help you calculate bend. A reader wrote me asking me about the kfactor and calculating bend allowances.
With this free online tool we quickly get the sheet metal bend deduction, and therefore the sheet metal blank initial flat length, from the finished part measurements you only have to insert interior angle, flange lengths, k factor, inside radius, and material thickness. I have a few questions about the settings available. Jun 11, 2015 in real live, we have static correction factors for situations, where the inner bending radius and the sheet metal type and thickness is defined. Please note the bending of sample part is done in the same manner as we are planning for production. When a piece of sheet metal goes through the process of bending, its upper layer with inside radius is compressed and the lower layer with outside radius is stretched. Once you know the kfactor, you can use it to predict the bend allowance for various angles. When a piece of metal is being formed, the inner portion of the bend compresses while the outer portion expands see figure 1. Nov 30, 2018 learn what a kfactor is in sheet metal forming, learn how kfactor is used, and learn how to calculate kfactor in this video. As i mentioned in my last post you need to do some tests to calculate these values for a specific sheet. Sheet metal unfold rule equations ketiv technologies. Sheet metal k factor what is it and how to measure it.
Analyzing the kfactor in sheet metal bending the fabricator. Solidworks sheet metal tools are relatively straight forward, but may not be clearly understood. The program is used to calculate the k factor in sheetmetal bending. The inside radii are based off of a standard air bend force chart. As shown in the figure below, it is a simplified diagram of. It is a kfactor calculator developed by the new zealand company knac solutions. The present invention relates to plate bending machines of. It is an integral and indispensable part of sheet metal bending operations, that will not only automate and speed up the numerous repetitive calculations and drafting but also help you in achieving the same, with the maximum degree of accuracy and efficiency, thereby saving labor and time.
It ultimately allows you to estimate the amount of stretch without knowing what type of material you are bending. What is the formula for the development length on sheet metal. Additionally, sheets with bends are stiffer than their flat counterparts. Below the image shows how the top of the bend is compressed, and the bottom is stretched. This is a function of the bend angle, bend radius, thickness of the material, and a variable called the k factor. Response to question concerning k factors by material type and forming method. Then input the bend angle to get the arc length, bend allowance and bend deduction. Air bending is the most common type of 3 types of bending used in sheet metal shops today. In a sheet metal bending process, the bending load increases until the material exceeds the elastic limit and enters the. In this article we will discuss sheetmetal bend deduction, bend allowance, k factor, y factor and sheet metal flat pattern calculations.
In sheet metal, there is a powerful bend constant known as the k factor. Save time bending sheet metal by not having to look up data in handbooks. When sheet metal is bend, the inside bending surface is compressed. Kfactor calculator for sheet metal bending smlease design. Due to the existence of the sheet metal bending tolerance, in the direction of the bending of the sheet metal, a certain bending gap needs to be secured to avoid the bending failure caused by the interference during the bending. This causes alteration of the original form of the sheet as it passes through a pathway of series of rollers. Since the inside compression can not exceed the outside tension, the kfactor can never exceed. Mar, 2020 bend allowance is a measure of how much extra material is required to accommodate a bend in sheet metal.
Sheet metal is an external workbench evolved to design and unfold sheet metal parts. When working with different materials and tools, absolutely yes, kfactor needs to be adjustable. The mold line lengths are the distances measured to the outside mold line and are equal to the flange lengths plus the setback. Press brake bend allowance chart bend allowance chart pdf printable. Bending calculations using kfactor, bend deduction, and bend allowance. The art and science of bending sheet metal hackaday. Sheet metal k factor user modification i also thought about referencing the parameters ui, which would work well also. How to use this kfactor calculator in sheet metal reverse engineering approach step1. One of the m ost important aspects o f good sheet metal formi ng manufacturing prac tice is the accurate. Press brake bend allowance chart for your reference. Bending calculations using kfactor, bend deduction, and bend. As shown in the figure below, it is a simplified diagram of a complex bending sheet metal part.
Mathematically k factor value is equal to the ratio of position of neutral axis and sheet thickness. Cut a sample sheet and measure its total flat length and sheet thickness in mm. Our solidworks experts can setup your environment so that your team uses a comprehensive set of. Value of k factor can be calculated using reverse engineering approach. Fabrication calculator for kfactor, yfactor, bend allowance.
The kfactor is fundamental to designing precise sheet metal. Then input leg length a and b to get the flat size of the sheet. K factor is required to calculate the flat pattern. You can easily modify the material thickness, inside radius and k factor for each thickness at the top of each column. Calculate k factor, bend allowance and y factor for sheet metal bending. Jan 11, 2018 an average and commonly used value for the kfactor is 0. Learn from thousands of free tutorials join the community. Press brake bend allowance chart free technical charts. Sheet metal bend deduction chart pdf sheet metal bend deduction chart excel. Calculate k factor, bend allowance and y factor for sheet. We multiply this factor by the material thickness to determine the distance the neutral axis shifted toward the inside radius during bending. Shape, bending, cylindrical, automatic, hoppers, frame, fabrication, production introduction sheet metal fabrication plays an important role in the metal manufacturing world. The information on the web site above helped me greatly achieve a somewhat accurate kfactor until i was finally given our companies kfactor chart that we go by.
Kfactor calculator easy and effective solidworks forums. Sheet metal bend parameters and bend allowance youtube. If i create a bent angle iron shape, the bend line does not show up where id expect it to, and there seems to be no setting i can change to move the bend line. Tight bend radius gradual bend radius k factor effectively 50%t max. Typically the kfactor is going to be between 0 and. Input material thickness and and inner radius to get the data of k factor, y factor, neutral layer. Calculating bend allowance, bend deduction, and kfactor. Online calculator of sheet metal bend deduction and flat. The values of the setback, bend allowance, and bend deduction can be calculated from the sheet thickness, bend radius, bend angle, and k factor. The program is very simple and user friendly and requires no previous knowledge. I came across a community sponsored application that will aid any sheet metal designer. In sheet metal design, the k factor is used to calculate how much sheet metal one needs to leave for the bend in order to achieve particular final dimensions, especially for between the straight sides next the bend.
Pdf on jul 5, 2006, karachalios and others published the study of design constants in sheet metal forming find, read and cite all the research you. In sheet metal, there is a powerful bend constant known as the kfactor. In my previous post i talked about kfactor, bend allowance and bend deduction and what they mean in sheet metal design. Pdf on jul 4, 2007, achilles vairis and others published bend allowance constants for use in sheet metal forming find, read. It also includes a set of default rule of thumb kfactors to use for. You just have to enter a value for the thickness of materials and bending radius, in inches or mm, and get the value of the k factor. Therefore, it is not part of the standard freecad install. Kfactors, yfactors, and press brake bending precision.
In order to find the k factor you will need to bend a sample piece and deduce the bend allowance. The bend deduction is the amount the sheet metal will stretch when bent as measured from. Now lets see how we can obtain these values for a specific sheet. Kfactor depends, amongst others, on material, bending mode, bending speed, bending tools.
Jun 06, 2017 calculating bend allowance, bend deduction, and kfactor article by saeed mojarad cswe createdupdated june 6, 2017 in my previous post i talked about kfactor, bend allowance and bend deduction and what they mean in sheet metal design. In order to find the kfactor you will need to bend a sample piece and deduce the bend allowance. May 18, 2016 49 thoughts on the art and science of bending sheet metal. The bent angle goes into free position with air bending. Put in your bend deduction value that you should already know from your. Typically the k factor is going to be between 0 and.
When metal is bent the top section is going to undergo compression and the bottom section will be stretched. The analysis is focused on sheet metal bending at high temperature that is a promising method for. Sheet metal bending is not always going to be the same with every application. Jul 30, 2017 this is a simple calculator to help you calculate bend deductions, and to help you reverse engineer the best kfactor to use when creating sheetmetal parts in you favorite cad program. Best way to calculate k factor in sheet metal is by reverse engineering.
The kfactor is something that i never have liked because it varies. This change in sheet length depends on the position of neutral axis or kfactor. The kfactor is nothing more than a multiplier that can give you an accurate value for the relocated neutral axis. All sheet metal workers know the importance of an accurate kfactor or bend allowance when it comes to design. Bending is a common sheet metal operation used to create flanges, curls, and seems. Bending is a manufacturing process that produces a vshape, ushape, or channel shape.
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