Determining the kfactor for sheet metal cr4 discussion thread. In sheet metal, there is a powerful bend constant known as the kfactor. When you bend sheet metal, the neutral axis shifts toward the inside surface of the bend. Sheet metal bending is the plastic deformation of the work over an axis, creating a change in the parts geometry.
Sheet metal bending pressbrakes can be setup to produce more than one type of part without. Since the inside compression can not exceed the outside tension, the kfactor can never exceed. Jul 04, 2011 in solidworks there are several options for sheet metal bend allowance calculations. It is one of the fundamental forms used in metalworking, and can. Sheet metal bend allowance calculations with solidworks software. Mechanics of sheet metal forming college of engineering. As i mentioned in my last post you need to do some tests to calculate these values for a specific sheet. Finite element simulation of sheet metal forming is a wellestablished tool which is. In inventor this ratio determines the final size of the unfolded sheet metal part. The line where the transition from compression to stretching occurs is called the neutral axis. It is an important factor to determine the quality of sheet metal forming. Pdf bend allowance constants for use in sheet metal forming. Pdf sheet metal bending is one of the most widely applied sheet metal operations. Up to 10 mm sheet thickness depending on the tool type.
The program is very simple and user friendly and requires no previous knowledge. Bending of sheet metal the international journal of engineering. Pdf bending force and springback in vdiebending of. In general, the tooling only touches the sheet metal along these 3 lines.
Therefore, it is not part of the standard freecad install. Oct, 2011 tanel another option that is not so close to the theory of this pdf but you will help a lot the guys on the bending machine is the following. V l2 rt bend allowances for cincinnati incorporated. However, it also applies to everyone using sheet metal in inventor. The k factor in sheet metal is the ratio of thickness to the location of the neutral line in the metal cross section. The sheet metal model built with the sheet metal addon rear. Response to question concerning kfactors by material type and forming method. Standard kfactors can be found from your sheet metal supplier, online, or through real world testing. I had a question on kfactors for our 3d modeling software. In flat metal, this boundary evenly bisects the materials thickness. May 29, 20 so for a very large radius bend where the neutral axis lies right in the center of the material, the k factor would be exactly 0. The only truly effective way of working out the correct bend allowance is to reverse engineer it by taking a. Most cad systems that have sheet metal design tools will allow you to input a k factor that the software uses to calculate the unfolding to give an accurate blank, or flat pattern.
Spring back in bending is difficult to estimate theoretically. Bending processes are commonly used in sheet metal forming production of automotive components. Mathematically k factor value is equal to the ratio of position of neutral axis and sheet thickness. Use the known k factor and the known inner bending radius to calculate the bending radius of the neutral line. I too have been upset with how complicated it is to modify k. The kfactor is something that i never have liked because it varies. The yfactor is used, as far as i know, solely by ptcs proengineer, now known as creo elementspro. 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. Sheet metal bending bending of sheet metal is a common and vital process in manufacturing industry.
The present study investigates the springback phenomenon of mild steel twb strips in u bending process. The bend allowancebend deduction of the sheet metal specified in k factor by configuring and utilizing a sheet metal gauge table, we can speed up the process of selecting the correct wall thickness based on gauge value and selecting. So for a very large radius bend where the neutral axis lies right in the center of the material, the kfactor would be exactly 0. Right now it works with inches as the unit of measure. How to set up sheet metal gauge tables engineers rule. It is used to calculate sheet metal flat length flatpattern.
Determining the k factor for sheet metal 12052008 9. Bend the sheet to 90 degrees and measure length a and b. Alton, prediction of spring back in air bending of advanced high strength steel dp780 considering youngs modulus. This guide will cover sheet metal best practices and tips to ensure your sheet metal parts are optimally designed for durability, manufacturability, and enduse applications. Ri is assumed constant and equal to 1 as all the tools used in the current. K factors express the amount of stretch when bending sheet metal. Vbending force calculator calculate the required force to bend a piece of sheet metal using vbending, a process in which a vshaped punch presses the sheet into a vdie. Jan 17, 2016 the difference in the k factor was on the order of in decimal form, but only reference the gauge in parentheses. The program is used to calculate the k factor in sheetmetal bending.
A k factor is a percentage multiplier for locating the neutral axis. It ultimately allows you to estimate the amount of stretch without knowing what type of material you are bending. In sheet metal, there is a powerful bend constant known as the k factor. A few among the most common applications of sheet metal parts are as automobile and aircraft panels, housings, cabinets. So it would seem if your bending brake or other apparatus were to produce an inside radius that is about 122% of the sheet metals thickness, then you could just lay out your inside dimensions and bend on them and all would come out ok. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Experimental and numerical investigations of sheet metal. K factor and flat pattern length solidworks forums.
Pdf on jul 4, 2007, achilles vairis and others published bend. How to use this k factor calculator in sheet metal reverse engineering approach step1. When a flat sheet is bent there is no reduction in its width or height, the only change takes place in its length. In solidworks there are several options for sheet metal bend allowance calculations. An approach to vary one factor at a time was employed. When you select kfactor as the bend allowance, you can specify a kfactor bend table. Three of the most commonly used options are using a k factor value, a bend allowance value, or a bend deduction value. The kfactor in sheet metal working is the ratio of the neutral axis to the material thickness. Pdf springback control of sheet metal air bending process. Going by that 66% figure, the magic inside radius seems to be 1. The bend allowancebend deduction of the sheet metal specified in kfactor by configuring and utilizing a sheet metal gauge table, we can speed up the process of selecting the correct wall thickness based on gauge value and selecting.
Use the known kfactor and the known inner bending radius to. You just have to enter a value for the thickness of materials and bending radius, in. The present study investigates the springback phenomenon of mild steel twb strips in. Dec 27, 2016 when working in solidworks to create sheet metal designs, we will often need to know three important values. K factor is required to calculate the flat pattern. The thinning sheet forces the neutral axis to shift inward toward the inside bend radius. The program is used to calculate the kfactor in sheetmetal bending. Therefore if you have to make a bent component, plus bend can tell you what blank size you should start from, so that you get the desired dimensions of the finished component. K factor and y factor in sheet metal both look at how bending affects the material and how much bending the metal will allow. Ri is ass umed constant and equal to 1 as all the tools used in the current. Sheet metal forming involves bending, punching, drawing, stretching. Design considerations in bending sheet metal minimum bend radius, bending with respect to the direction of rolling, minimum flange widths, hole spacings etc. Relationship between bend deduction, bend allowance, and k factor. Kfactors, yfactors, and press brake bending precision.
The difference in the kfactor was on the order of solidworks application also comes with a kfactor bend table in microsoft excel format. Now lets see how we can obtain these values for a specific sheet. Often bend allowances are calculated for a sheet metal part and used to make costly. Countless everyday objects are constructed of the material. Bending sheet metal by hand is a manageable task if the piece of. Most cad systems that have sheet metal design tools will allow you to input a kfactor that the software uses to calculate the unfolding to give an accurate blank, or flat pattern. Springback university of twente research information. Nc state university sheet metalworking terminology punch. I have idea to use sheet metal to avoid bend part option in standard modeling please imagine that i have curve which consists of 10 arcs, then i need to make 10 bending operations to get the wished shapethat is the reason why i am trying with sheet metals, but k factor makes a problems with material extension. Rptnt for different thicknesses where n is variable value dimensionless 0,0. Nov 25, 2009 k factor is used in defining the bend allowance, thus by using bend allowance tables it is possible to automatically set the kfactor for defined materials see gauge tables.
When metal is bent the top section is going to undergo compression and the bottom section will be stretched. Analyzing the kfactor in sheet metal bending the fabricator. Ive created an excel spreadsheet to figure out kfactors and bend allowances. I have idea to use sheet metal to avoid bend part option in standard modeling please imagine that i have curve which consists of 10 arcs, then i need to make 10 bending operations to get the wished shapethat is the reason why i am trying with sheet metals, but kfactor makes a. Autodesk inventor kfactor sheet metal cadline community. Unfold your sheet metal part and by adjusting the kfactor try to bring your bending line in a desirable distance. Sheet metal is an external workbench evolved to design and unfold sheet metal parts. Analysis of sheet metal bending by using finite element.
Cut a sample sheet and measure its total flat length and sheet thickness in mm. The boundary inside the metal between these two is the neutral radius. Kfactor is a ratio that represents the location of the neutral sheet with respect to the thickness of the sheet metal part. In my previous post i talked about k factor, bend allowance and bend deduction and what they mean in sheet metal design. Similar to other metal forming processes, bending changes the shape of the work piece, while the volume of material will remain the. In this paper, the factors which affects the springback is determined and. The solidworks application also comes with a kfactor bend table in microsoft excel format. Kfactor calculator for sheet metal bending smlease design. Even the sheet metal bending is one of the most common metal working operations, the springback phenomenon that. Most frequently, expensive sheet metal bending tools, called brakes, are used to bend sheet metal, but you can also complete this task without one.
In this article we will discuss sheetmetal bend deduction, bend allowance, k factor, y factor and sheet metal flat pattern calculations. Pdf version a printable pdf version of this information is available here. Solidworks sheet metal tools are relatively straight forward, but may not be clearly understood. The k factor is the ratio of the neutral axis location t to the material thickness mt. When sheets of metal bend, the top surface compresses and the bottom expands. The art and science of bending sheet metal hackaday. Learn how to bend sheet metal so you can complete home and hobby projects easily without using a sheet metal brake. It is only one of the ways bend values can be determined. May 18, 2016 49 thoughts on the art and science of bending sheet metal. These calculations will determine the length of the flattened pattern shape. Improvement of springback prediction in sheet metal forming. Mar 28, 2019 bending sheet metal by hand is a manageable task if the piece of sheet metal is small and thin enough to handle. Alton, prediction of spring back in airbending of advanced high strength steel dp780 considering youngs modulus.
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. Please note the bending of sample part is done in the same manner as we are planning for production. What are bend allowance, bend deduction and kfactor. Sheet metal parts are some of the most important semifinished products. Sheet metal bend allowance calculations with solidworks.
Three of the most commonly used options are using a kfactor value, a bend allowance value, or a bend deduction value. Experimental and numerical investigations of sheet metal circular bending viorel paunoiua. Tanel another option that is not so close to the theory of this pdf but you will help a lot the guys on the bending machine is the following. Press brake bending is a commonly used process for sheet metal part fabrication. Metamodel based approach to minimize the springback in sheet. Nandedkar3 1,2department of mechanical engineering 3department of production engineering 1,2government college of engineering, aurangabad m. 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. Determining springback amount of steel sheet metal has 0. Introduction sheet metal is simply metal formed into thin and flat pieces. When working in solidworks to create sheet metal designs, we will often need to know three important values. Calculating bend allowance, bend deduction, and kfactor. Sheet metal bending design tips, bend allowance, k. It has been observed that the final bend angle, which is the angle achieved upon removal of the punch, is smaller.
In sheet metal bending process when metal is bent the material along the. Our sheet metal designs in swx got pretty involved, with some parts having as many as ten bends. So it would seem if your bending brake or other apparatus were to produce an inside radius that is about 122% of the sheet metal s thickness, then you could just lay out your inside dimensions and bend on them and all would come out ok. Sheet metal working virtual labdayalbagh educational institute. Sheet metal bending terpconnect university of maryland.
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