Bend allowance can be calculated using manual experiment. Application allows to calculate the total flat length and kfactor for bending. For example, a flat sheet of aluminum is less stiff than that same sheet of aluminum bent into a v cross section. Bend radii and k factors for 304 stainless steel sheet. Press brake bend allowance chart free technical charts. When working with sheet metal, a gauge table in solidworks can be. Solidworks sheet metal gauge tables perception engineering. The k factor is fundamental to designing precise sheet metal products. Sheet metal k factor user modification i also thought about referencing the parameters ui, which would work well also. We can calculate the leg length 1 and 2 as follows. When you select kfactor as the bend allowance, you can specify a kfactor bend table. The kfactor approximations given below are more likely to be accurate for air bending. The bend deduction is the amount the sheet metal will stretch when bent as measured from.
You can use this sheet metal flat pattern calculator to calculate this increase in length. In order to find the k factor you will need to bend a sample piece and deduce the bend allowance. The value of the k factor should range between 0 0,5. Not sure where this shows up other than in this table. The k factor is used to calculate flat patterns because it is related to how much material is stretched during bending. Since the inside compression can not exceed the outside tension, the k factor can never exceed. Calculate k factor, bend allowance and y factor for sheet metal bending. Kfactor calculator easy and effective solidworks forums. It allows you to anticipate the bend deduction for a large variety of angles without having to rely on a chart. Kfactor or bend deduction is highly dependent on the type of bending air or coining, width of vblocks, and the material and its hardness. The kfactor is used to calculate flat patterns because it is related to how much material is stretched during bending. It reflects all real but unknown distortions in the bend region.
All sheet metal workers know the importance of an accurate kfactor or bend allowance when it comes to design. You can easily modify the material thickness, inside radius and kfactor for each thickness at. Solidworks tutorials sheet metal 2012 what is k factor. This is a basic guide to the main processes involved in sheet metal bending. Grain direction can play a role, but it is usually a much smaller contribution. You will need to know your material thickness mt, the bend angle b. One of the m ost important aspects o f good sheet metal formi ng manufacturing prac tice is the accurate. Then input the bend angle to get the arc length, bend allowance and bend deduction. The following equation relates the kfactor to the bend allowance. The process of cutting, shearing, rolling, bending and punching sheet metal to fabricate parts and pieces. Response to question concerning kfactors by material type and forming method.
Kfactor in sheet metal is a constant used to calculate sheet metal bend allowance, bend. Considering manual operation is replaced by power operated devices. Typically the k factor is going to be between 0 and. Kfactor is a ratio that represents the location of the neutral sheet with respect to the thickness of the sheet metal part. The software can automatically develop the bending schedule and the marker diagram for the bent component. In theory, the kfactor can be anywhere between 0 and 1, but for practical purposes, its more like 0. It also gives information about limitation of manually operated. The kfactor depends on many factors including the material, the type of bending operation coining, bottoming, airbending, etc. The trumpf bendguide app performs bending calculations more easily and clearly than.
Sheetmetal characteristics elongation the capability of the sheet metal to stretch without necking and failure. Calculating bend allowance, bend deduction, and kfactor. Analyzing the kfactor in sheet metal bending the fabricator. A drawbead model with sheet metal passing through multiple bendingunbending processes was employed in this study to understand the springback phenomenon and to develop a. In reality, how a real metal part will stretch as it bends depends on a number of physical factors tooling, material homogeneity etc.
How to create a custom solidworks sheet metal bend table. Please refer to the files for determining kfactor for your process. For example, the exact hardness and temper of the metal will change the k factor of the bend, and this will have a small influence on the amount of material needed to achieve the correct flange lengths. The solidworks application also comes with a kfactor bend table in microsoft excel format. A kfactor is a percentage multiplier for locating the neutral axis. I am assuming the k factor is used to affect this, but no matter what k factor i use, the bend line is. Figure 2 illustrates the sheet that is bent with the bend angle of 90 degrees. 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. 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.
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. You will need to know your material thickness mt, the bend angle b pdf entitled bendworks. Plus bend is useful for cabinet manufacturers, manufacturing of industrial enclosures, hvac and door manufacturers and a range of industries in sheet metal bending. You can also specify kfactor values in their own kfactor bend tables. You can learn to bend metal without doing this math but this video is about doing the math. The kfactor in sheet metal working is the ratio of the neutral axis to the material thickness. Solidworks sheet metal tools are relatively straight forward, but may not be clearly understood. In real live, we have static correction factors for situations, where the inner bending radius and the sheet metal type and thickness is defined. The kfactor is empirically determined for a given material, material thickness, bend radius, and bending method. The bendguide app is available for ios free of charge. The bend allowance formula takes into account the geometries of bending and the properties of your metal to determine the bend allowance. So i am looking for the parameters for 304 ss that will have the same outcome. Bending is a manufacturing process that produces a vshape, ushape, or channel shape. Bendomatic is a revolutionary professional software package to determine initial unfolded length 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.
It is a kfactor calculator developed by the new zealand company knac solutions. You can specify the bend allowance or bend deduction values for a sheet metal part in a bend table. The bend deduction formula takes into account the geometries of bending and the properties of your metal to determine the bend deduction. The second is for varying kfactors among different gauges and bend. Bend allowances when sheet metal is bent, the inside surface of the bend is compressed and the outer surface of the bend is stretched. For good understanding, we suggest you to read this article on sheet metal kfactor and flat length calculations. Setbacks, bend allowances and k factors are somewhat.
A reader wrote me asking me about the kfactor and calculating bend allowances. Additionally, sheets with bends are stiffer than their flat counterparts. In sheet metal, there is a powerful bend constant known as the kfactor. Since gauge tables were introduced, all the parameters can be controlled base on the drop down selection which makes life much easier. Tight bend radius gradual bend radius k factor effectively 50%t max. 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. Shows up in the property manger of the sheet metal feature in the sheet metal gauges group box, under the table name. Sheet metal flat pattern calculator smlease design.
The below chart is for even numbered gauges 8 through 24 and has a default kfactor of. The material is stressed beyond its yield strength but below its ultimate tensile strength. Calculate k factor, bend allowance and y factor for sheet. Most sheet metal shops will produce their own bend tables by physically bending test pieces to specified angles and taking accurate.
Weve even developed our own inhouse tools, spreadsheets, or other cheat sheets to get close enough because no one wants to do the math each time. The art and science of bending sheet metal hackaday. Especially discussion made the productivity analysis of manually or power operated sheet bending machine. Below the image shows how the top of the bend is compressed, and the bottom is stretched. Kfactor, a principle fundamental to bending your sheet metal parts. Sheet metal bending design tips, bend allowance, k. 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. When metal is bent the top section is going to undergo compression and the bottom section will be stretched. A constant bending process in which sheet metal, coil, bar or strips of metal pass through rolls that form the metal. Some critical dimensions that need to be considered when setting up sheet metal in cad software are sheet metal thickness, the kfactor and bend radius. Input material thickness and and inner radius to get the data of k factor, y factor, neutral layer. After bending the sheet we need to do some measurements as shown in figure 2. Then input leg length a and b to get the flat size of the sheet. The paper deals with manufacturing or bending of sheet metal by using power operated sheet bending machine.
The line where the transition from compression to stretching occurs is called the neutral axis. Solidworks templates for two variations of this template can be downloaded below with added instructional content. The k factor is defined as the ratio between the material thickness t and the neutral fibre axis t, i. 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. The problem with a solidworks sheet metal bend table is that it can only control the bend allowance, bend deduction or kfactor but the thickness and radius is still free to be changed manually. The value of the kfactor should range between 0 0,5. Pdf the study of design constants in sheet metal forming. 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. While modern bend deduction charts now are reasonably accurate, historically bend calculation charts, both for bend allowances and bend deductions, were notorious. The bend table also contains values for bend radius, bend angle, and part thickness. Pdf on jul 4, 2007, achilles vairis and others published bend allowance constants for use in sheet metal forming. I am trying to understand how iv uses the k factor in sheet metal bending. The application allows to calculate the length of a work piece for bending of metal sheets or stripes, round or square bars and round tubes.
This video is an explanation of the math on the faa airframe test. Since the inside compression can not exceed the outside tension, the kfactor can never exceed. For instance right now in solidworks for say 11 ga sheet metal i use a bend radii of 0. 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.
Therefore it is important to have the value correct in cad software. A few among the most common applications of sheet metal parts are as automobile and aircraft panels, housings, cabinets. Calculate k factor, bend allowance and y factor for sheet metal. Db sheetmetals ltd k factors for solidworks bending is a manufacturing process by which metal can be deformed by plastically deforming the material and changing its shape. The material thickness will be measured in decimal form, not by the gauge number. Sheet metal parts are some of the most important semifinished products. You can see all our courses online, download them or get them on disc. Shows up in the property manger of the sheet metal feature in the bend allowance group box as bold text left of gauge table values.
Pdf bend allowance constants for use in sheet metal forming. It ultimately allows you to estimate the amount of stretch without knowing what type of material you are bending. Blank development for formed sheet metal parts there are many systems employed by a variety of industries aircraft, electronics, architectural, automotive, etc. You will need to know your material thickness mt, the bend angle b k factor k.
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