1. The sheet metal wall thickness
2. The sheet metal default bend radius
3. The bend allowance/bend 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 the correct bend radius (based on available tooling).We can also automate the process of selecting the appropriate K-factor.

Sheet Metal Wall Thickness

We often see the specification for sheet metal wall thickness represented as a gauge value. Some examples are 10ga, 12ga or 16ga. But what do these gauge values translate to, in terms of sheet metal wall thickness? In order to answer this question, we often need to look up the values in a table.

Figure 1. An example of a reference table for looking up sheet metal thickness based on gauge size and material. Originally posted at www.unc.edu/~rowlett/units/scales/sheetmetal.html.

As we can see in Figure 1, the gauge value number will be translated to a specific wall thickness. This wall thickness will be different, depending on the material being used. These differences can be hard to keep track of, and mistakes can occur when looking up the value and manually typing this value into SOLIDWORKS.

Sheet Metal Bend Radius

The second important number when creating sheet metal designs is the bend radius value. The bend radius of a sheet metal design will be based on the wall thickness of the part and the tooling that is available in house.

Figure 2. A section view of a typical punch and die set used to create sheet metal bends.

Figure 2 shows us a typical punch and die set used to bend sheet metal. This punch and die set would be mounted in a press. The V-die would be mounted on the lower part of the press, and the punch would be mounted on the upper part of the press. The flat sheet metal would be positioned between the punch and the V-die, and the press would be forced closed, forming a bend in the sheet metal.

The punch and V-die will each have a radius at their peak, and these radii will cause a specific bend radius to be formed in the sheet metal. This technique (known as bottom bending) is just one of many methods available to create a bend radius in a sheet metal design.

Regardless of the bending method, a question that will often be asked by the designer is “What bend radius should I be using?” The answer to this question will be based on the thickness of the sheet metal and the available tooling being used in the bending process.

Bend Allowance/Bend Deduction

The third and final question that a SOLIDWORKS designer working with sheet metal will have is “How is the metal stretching/deforming in the bend region?” The phenomenon of sheet metal stretching in the bend region is often referred to as “bend deduction” or “bend allowance.” There are many techniques available to calculate what the “bend deduction” or “bend allowance” should be in these bend regions, but one of the most versatile is known as K-factor.

We could spend an entire blog describing the various options/techniques used in calculating the appropriate value to represent the stretching of sheet metal in bend regions. Instead, we will simplify this area of the blog by agreeing to work with a K-factor value of 0.5.

Sheet Metal Gauge Tables

A great tool available to SOLIDWORKS sheet metal users is the “Sheet Metal Gauge Table.” In this table, users can configure a Microsoft Excel spreadsheet to represent the appropriate sheet metal wall thickness, based on material and gauge values. Users can also specify the available default bend radius based on available tooling. Lastly, users can specify the appropriate K-factor to represent the stretch of the sheet metal in the bent corners.

For today's example, we will create three sheet metal gauge tables representing the following materials and gauge values:

Figure 3. A table of different materials, gauge thicknesses and default radii.

In Figure 3, we can see a table that might be present in a sheet metal shop. Without a sheet metal gauge table in SOLIDWORKS, whenever we create a sheet metal model, we would have to reference this table and manually type the values into SOLIDWORKS.

We are now going to create three different tables in Excel, each one representing a different material.

The tables will need to be formatted in the following layout:

Figure 4. An Excel spreadsheet layout of a standard steel sheet metal gauge table.

Figure 5. An Excel spreadsheet layout of a galvanized steel sheet metal gauge table.

Figure 6. An Excel spreadsheet layout of an aluminum sheet metal gauge table.

In Figures 4, 5 and 6, we can see the appropriate Excel layout for a sheet metal gauge tablet utilized by the SOLIDWORKS software. Keep in mind that once you make one Excel spreadsheet, you can “save as” and change the values for the next material.

We will save all of these Excel spreadsheets into one folder. I will use a folder in my C drive.

Location of the sheet metal gauge tables in an Excel format.

Now that we have saved the Excel spreadsheets into one single folder, we need to point to this folder in the SOLIDWORKS software. We launch the SOLIDWORKS software, and choose OPTIONS>SYSTEM OPTIONS>FILE LOCATIONS. From the pull-down menu, we choose “Sheet Metal Gauge Tables” and then point to the appropriate folder.

Pointing SOLIDWORKS to the folder containing the sheet metal gauge tables.

Next we will utilize our sheet metal gauge tables in a new SOLIDWORKS sheet metal design.

Using Sheet Metal Gauge Tables in SOLIDWORKS

We have now created the sheet metal gauge tables in Excel in the appropriate format. We have saved the tables into a folder in Windows, and we have pointed SOLIDWORKS to this folder. We are now ready to use these sheet metal gauge tables. Our sheet metal design will use the following specifications: 10ga Aluminum U-Channel with the dimensions 1.5 x 6 x 10 inches long.

We will start by creating a simple sheet metal design with a three-line sketch.

Simple three-line sketch to test our sheet metal gauge tables.

Next we will choose the command Base Flange/Tab from the sheet metal toolbar.

Beginning the Base Flange/Tab command.

We will now input a depth of 10 inches for our sample sheet metal part.

We set direction 1 to utilize a blind depth of 10 inches.

At this point, we would have to answer our three questions from above:

1. What is the wall thickness for 10ga aluminum?
2. What should I use as a bend radius?
3. What is the K-factor?

We have agreed that we will be using a K-factor of 0.5, so let’s focus on the other two questions.

Without a SOLIDWORKS sheet metal gauge table, the answers to these questions would require research—often time-consuming research. We would have to look up the values for wall thickness and radius and would have to enter them into SOLIDWORKS manually. With a sheet metal gauge table, the process is simplified to just a few clicks.

First, we choose the option to use a gauge table.

Choose the check mark to use a gauge table.

Next we use the pull-down menu to select the appropriate table. In our case, we will use the table for ALUMINUM-INCH.

Choose the appropriate sheet metal gauge table.

Next we simply need to choose the specified gauge of 10.

Figure 7. Choose the specified gauge value.

As we can see in Figure 7, we simply need to choose “10 Gauge,” and the appropriate wall thickness (“0.102 in”) is automatically selected. Of course, if we selected a different sheet metal gauge table for a different material (for example, galvanized steel), the wall thickness for “10 Gauge” would be a different value.

Lastly, we choose our desired default bend radius.

Figure 8. Selecting a bend radius from predefined choices.

In Figure 8, we can see that we only have three available choices for a default bend radius. These choices will be defined in our sheet metal gauge table based on available tooling and material wall thickness. This is a great time-saver because it ensures that the SOLIDWORKS designer will not inadvertently create a model with a bend radius that we cannot manufacture with available tooling.

We can now hit the green checkmark and move forward with our sheet metal design, confident that we are using the correct wall thickness and an appropriate bend radius.

By utilizing a SOLIDWORKS sheet metal gauge table, we can save time by eliminating the step of looking up sheet metal gauge values based on different materials. We can also ensure that an appropriate sheet metal bend radius is utilized in the design process and that this bend radius can be achieved in the manufacturing processes. This can also be a great time-saver and can help us get our products to market faster by eliminating the common mistake of using a bend radius that is unrealistic.

Remember that we can always add information to an existing SOLIDWORKS sheet metal gauge table (by editing the Excel spreadsheet), including new gauge sizes and new bend radius values. We can also take one sheet metal gauge table and “save as” to create a new gauge table for a new material.

About the Author

Tobias Richard is a SOLIDWORKS elite applications engineer from Philadelphia. He has been working with SOLIDWORKS software since 1998 and has been providing training, technical support and tips and tricks since 2001.

Figures 1, 2 and 3 show several typical 3D views of sheet metal parts to present the key characteristics from different perspectives.

Figure 1. A 3D View from the back perspective.

Figure 2. A 3D View from the top perspective.

Figure 3. A 3D view focusing on the flange.

In Figure 1, the model attached with the 3D product and manufacturing information (PMI) appears fairly tall vertically on the screen. Since most laptop or desktop computers are equipped with wide screens, you may want to reorient the model horizontally in a way that is similar to the orientation shown in Figure 4.

Figure 4.A horizontal orientation of the sheet metal part.

However, such a modification comes with a bit of inconvenience. The reading direction of the dimensions and tolerances is now from bottom to top, rather than the direction that is most comfortable to human eyes, from left to right. Can we reorient the PMI as well? Yes, we can achieve this by reorienting the annotation view. Here are the steps for this process.

First, edit the annotation view containing the PMI you want to rotate as shown in Figure 5.

Figure 5. Edit the annotation view.

Notice that a light yellow transparent plane is previewed to indicate the viewing direction and orientation as shown in Figure 6.

Figure 6. A light yellow transparent plane indicates the viewing direction and orientation.

To adjust the orientation, you can just type in the angle to rotate the preview plane as shown in Figure 7. I entered“90 degree” in this dialog. You can also slide the bar next to the angle text box to adjust it dynamically. Notice that the plane shown in Figure 7 has been rotated 90 degrees compared to the one in Figure 6.

Figure 7. Adjust the horizontal direction of the viewing plane.

Last, just accept the edit to this annotation view. Now when you orient it, it will display the model and the PMI horizontally to take advantage of the wider horizontal screen space as shown in Figure 8. You may need to drag and drop the callouts to tweak their placements a little bit since they have been rearranged. Of course, you can capture this nice display as a 3D view.

Figure 8. The model and PMI are displayed horizontally.

To review multiple perspectives at the same time, you can choose to display multiple viewports as shown in Figure 9. I personally prefer breaking the links between these viewports so that I can control each one individually with better flexibility.

Figure 9. Review multiple perspectives at the same time using multiple viewports.

You may have noticed another annoyance featured in Figure 8. The bend lines and bounding box are visible in the folded state, which crowd the view but don’t add much value because they are tied to the flat or unfolded state. You can easily hide them as shown in Figure 10 and recapture this cleaner display as an existing 3D view or a new one. It's nice that with the multiple selection supported, you can hide them both together.

Figure 10. Hide the bend lines and bounding box together.

Speaking of the flat state, it is indeed very important to facilitate the fabrication communication with the bend lines and bounding box. Again, 3D view comes in handy here. You can turn on the flat pattern, create a configuration for it, and light up the annotation views containing the PMI applicable to the flat view while hiding others. Finally, show the bend lines and bounding box. Once your sheet metal part puts on a clearun folded pose, just hit the button “Capture 3D View” in a way similar to taking a picture with your camera. Figure 11 illustrates the unfolded 3D view along with the dimensions between the bend lines and bend notes. You can define more PMI as discussed in the previous article.

Figure 11. Capture a 3D View of the flat or unfolded state of a sheet metal.

One possible issue is that when you rotate the model, the bend notes may be displayed backward, although the dimensions do flip automatically for easier reading as shown in Figure 12.

Figure 12. Bend notes are displayed backward after a 180-degree rotation.

One work-around is to turn on this option under System Options > Display > Display notes flat to screen.

Figure 13. Display notes flat to screen under System Options.

Now the bend notes along with other notes will always stay flat to screen for easier reading. They won't rotate any more as shown in Figure 14. Please notice the difference between the dimensions and the notes. The dimensions are tilted and aligned with the model rotation, but the notes are not.

Figure 14. Notes don't rotate with the model anymore.

In a similar fashion, you may use a special annotation view type, 2D notes area, to organize bend tables or other 2D entities so that they won't rotate with the model. Figure 15 shows a bend table assigned to a dedicated bend table 2D annotation view. SOLIDWORKS MBD 2017 added support of multiple 2D annotation views. Facing many types of 2D entities such as bend notes, bend tables, general notes, bill of material (BOM) tables and statements, you can now categorize them separately and control their visibilities at a more granular level.

Figure 15. A bend table is assigned to a dedicated 2D annotation view.

With this bend table inserted, let's capture it as a 3D view too as shown in Figure 16.

Figure 16. Capture a bend table as a 3D View.

You can also save this bend table as a generic table to be inserted into the 3D PDF template editor as shown in Figure 17. One enhancement in MBD 2017 is to allow columns and rows to be resized by dragging and dropping the handle on a table divide as pointed to by the green arrow. This way, longer strings can fit better in tables.

Figure 17. Insert a bend table into a 3D PDF template.

After a desirable template is laid out, you can publish the sheet metal part to a 3D PDF as shown in Figure 18. A nice addition to the MBD 2017 release is the ability to display supplemental geometries in 3D PDF as mentioned in a previous article. So now the bend lines and bounding box are showing up too.

Figure 18. A bend table and multiple viewports on a 3D PDF of a sheet metal part.

To conclude, there are plenty of free tutorials at MySolidWorks, including dedicated lessons on sheet metal models. I highly recommend these tutorials to anyone new to SOLIDWORKS MBD. To learn more about how the software can help you with your MBD implementations, please visit its product page.

About the Author

Oboe Wu is a SOLIDWORKS MBD product manager with 20 years of experience in engineering and software. He is an advocate of model-based enterprise and smart manufacturing.

To improve the communication clarity and reduce the 2D drawing maintenance overhead, many manufacturers are looking for ways to communicate sheet metal product and manufacturing information (PMI) in 3D using model-based definition (MBD) as an alternative to the traditional 2D drawings. In this article, we will walk through the key dimensions, notes and tables using the NIST example.

Figure 1. A sheet metal part example. (Image courtesy of NIST.)

First of all, it’s important to emphasize that you can define a sheet metal part or assembly in a way similar to other 3D models using PMI tools such as DimXpert and reference dimensions. Despite several specific requirements that we will address shortly, sheet metal models are only one type of 3D model. Therefore, typical PMI capabilities can support sheet metal models well. Figures 2 and 3 illustrate several examples. The geometric dimensioning and tolerancing (GD&T) definitions not only satisfy the NIST test case requirements, but also recognize manufacturing features such as the slot shown in Figure 2. This was discussed in more detail in “Design for Manufacturing: How to Define Features Directly.”

Figure 2. DimXpert GD&T definitions on the sheet metal main body.

Furthermore, the DimXpert feature control frames automatically create and visualize the coordinate systems according to the datum references to ease the design interpretation as shown in Figure 3. Please refer to the “PMI Enhancements in SOLIDWORKS MBD 2016” for more details.

Figure 3. DimXpert GD&T definitions on the sheet metal flange.

After these general 3D PMI definitions, let’s dive into the specific sheet metal requirements. Bend line locations are often needed to indicate where to fold a sheet during fabrication. Figure 4 shows the flat pattern with bend lines and their location dimensions. The key is to use the reference dimension tool to pick up the bend lines, which are sketch entities, rather than features. In this case, the reference dimension tool is more flexible for handling sketch elements than DimXpert. DimXpert can also call out these dimensions, but you’ll just need to create some reference geometries associated with the bend lines for DimXpert to pick up, as explained in “What’s New in SOLIDWORKS 2017: MBD.”

Figure 4. Use the reference dimension tool to define the bend line locations in a flat pattern.

As shown in Figure 5, the same reference dimension techniques can be applied to define the bounding box to estimate the raw sheet material sizes.

Figure 5. Use the reference dimension tool to define the bounding box in a flat pattern.

As you may have noticed, Figure 5 also shows two bend notes indicating that “90 degree up” is the appropriate bend angle and direction, which will be useful for fabricators. These can be added using the notes command as shown in Figure 6.

Figure 6. Use a leader note to specify the bend angle and direction in a flat pattern.

In 2D drawings, a bend table is often inserted to group the key bend parameters, as shown in Figure 7. However, in MBD, an automatic bend table function is not yet available, but here are some workarounds that require a bit more steps.

Figure 7. An automatic bend table per the flat pattern on a 2D drawing.

First, you can insert an automatic bend table on a 2D drawing as shown in Figure 7. Then save this table as a Microsoft Excel table rather than a bend table template, as shown in Figure 8.

Figure 8. Save a 2D drawing’s automatic bend table as an Excel table.

Now open this Excel table and copy all the cells with the bend parameters, as shown in Figure 9.

Figure 9. Copy the bend table cells from the Excel spreadsheet.

Finally, inside SOLIDWORKS, paste these cells as shown in Figure 10. This is actually an embedded Excel table and you can double-click to edit it using the Excel commands.

Figure 10. Press the Ctrl+V key combination to paste the bend parameters.

With one more step, you can also insert the data as a general table, as shown in Figure 11. Just make sure the numbers of columns and rows are larger than the Excel table in order to carry over all the cells. Now you can edit this general table using the table commands. Another benefit is that you can save this table to be reused in the 3D PDF template editor later.

Figure 11. Copy and paste the cells into a general table.

Although these workarounds are less than ideal and don’t maintain the associations with the existing bend notes and sheet metal parameters, they can collect and present the key fabrication requirements in a well-organized table for the shop floor to execute. I hope the software can add a more automatic bend table command in the future.

Before concluding this article, I’d like to share several free resources for you to better understand the sheet metal support in the software. Here is a tutorial to walk you through defining the 3D PMI on a sheet metal part. Similarly, a sheet metal assembly tutorial is also available. They are part of an online series of 12 free learning modules including videos, click simulations, quizzes and sample data sets. I highly recommend this series to anyone new to MBD. To learn more about how the software can help you with your MBD implementation, please visit the product page.

About the Author

Oboe Wu is a SOLIDWORKS MBD product manager with 20 years of experience in engineering and software. He is an advocate of model-based enterprise and smart manufacturing.

Regardless of all of those requirements, designers and engineers have to get the job done, and we have to get the job done fast in order to help our company succeed in producing new and innovative products. SOLIDWORKS has some great tools to help with these. Let’s go over a few.

First off, let’s start with selecting material and gauge. The gauge table tool (see Figure 1) should be used as much as possible. It is located in C:\Program Files\SOLIDWORKS Corp\SOLIDWORKS\lang\english\Sheet Metal Gauge Tables. I personally use the K-factor version, but many may prefer bend allowance or go with a bend table. Both can be found in a nearby folder.

Properly formatting the list of gauges is important. It must be done from thinnest to largest, and there can’t be duplicate thickness. One may have to create a few of these files to fully utilize the entire catalog of a company. But once it is done and in place, it makes life easier for everyone in the company, especially if they all work off the same controlled file set. This setup builds consistency and accuracy out on the shop floor, which means less headaches for the designer.

Figure 1.  Filling this out with the help of your shop team really makes life easier. (All images courtesy of the author.)

Next, let’s look at the basics of creating a sheet metal design. There are many ways of doing this.

Base Flange/Tab

A common favorite is sketching out the profile and using the Base Flange/Tab tool (see Figure 2) that is usually located first on the Sheet Metal ribbon. Drawing a simple profile and using the Base Flange/Tab tool will open up the options that can be used. To use the gauge tables that were discussed earlier, one must check the “Use gauge table” box that opens up all selectable shop-approved gauges with their corresponding radii and the K-factor (or bend allowance), so that there is no worry of forgetting or mistyping anything. At any stage, these parameters can be overridden with drop downs and checkboxes that will correspond with input boxes to adjust for special cases. Not shown (scroll down in Property Manager) is an auto relief setting that controls how corners and relief cuts are handled.

Figure 2. Options in basic Sheet Metal Base Flange/Tab.

This same tool can be used to make a flat piece of sheet metal that one would use to add edge flanges and other useful sheet metal features.

Edge Flanges

Edge Flange (see Figure 3) can be used to add an attached wall to any sheet metal body. This flange will inherit the radius and thickness parameters of the base flange. Of course, these can be overwritten if required. Designers can even select multiple edges that can be adjacent (by creating a mitered edge between the two) or located anywhere else on the same sheet metal body during this one operation. Designers can select flange positions that can move the flange location to the inside, outside, offset or to other less commonly used options that should be explored at your leisure.

One thing that often gets missed in the Edge Flange option is the ability to edit the flange profile. It doesn’t necessarily have to be a rectangle. It can be any shape that is required as long as it is a closed profile that connects to the original edge. Some small rules apply here that most designers will figure out quickly.

Figure 3. Edge Flange with profile adjusted.

Another thing that I would like to point out on the Edge Flange is the ability to change the angle to match another surface. This comes in handy when trying to match up awkward angles. There are some rules to this as well but, once learned, it does become invaluable in tricky spots. The result is usually very appealing and is difficult for many other CAD programs to execute. SOLIDWORKS users are lucky to have this feature. Designers should get to know it before they have to try too many workarounds.

The last thing I will touch on for the Edge Flange function is that designers should be encouraged to use a relatively new tool called the “Up to Edge and Merge” option that is located in the Flange Length dropdown. The main purpose of this is that if there are two (3D) parallel flanges that are not part of the same body (it can be the same body, but this process is rarely practical), you can use this tool to create a connecting flange between the two and create one sheet metal body. This is a good trick to keep in your back pocket.

Convert to Sheet Metal

This is a very helpful tool, especially for concept and prototype work. Basically, designers can build a bunch of flat-sided boxes with flat or curved sections. The designer can then select one face and add adjacent edges (within reason) to create a quick parametric sheet metal part. All the previously mentioned controls are available to the designer. The Split Line command (in the Surfaces ribbon), or inserting holes and cuts, can be used to control profiles of each side prior to the Convert to Sheet Metal function (see Figure 4).

Figure 4. Convert to sheet metal, with split line to control one flange.

As shown in Figure 4, the checkbox for “Keep body” has been enabled in order to reuse the same body in case the bottom and back side need to be utilized for a multibody sheet metal design.

Multi-body Sheet Metal

Designers are not limited to only one sheet metal part per file. One part can be used for a combination of mutliple sheet metal bodies, CNC parts and weldment parts. This is very smilar to how an assembly would be constructed. This is a huge timesaver in prototype design and can be used for production if configurations and design tables are used with careful strategy. The possibilities are nearly limitless but could require some well thought out and disciplined processes for this workflow to work.

Unfold and Fold

The Unfold and Fold comands are very powerful tools. One often needs to add fillets to miter corners in order to gain extra clearance during the manufacturing process—or to accomplish something that can’t be more easily done in the folded view. All the designer has to do is to select the Unfold option from the sheet metal ribbon, select a face that will be stationary and click the “Collect All Bends” option.

The part should unfold if it is made of sheet metal features and has a uniform thickness. After this operation, the designer should realize that this part is not manufacturable because of the two flanges that are highlighted (see Figure 5). In this case, a correction would need to be made. This correction can be achieved by first using the Convert to Sheet Metal function and then by adding a replacement flange to a new body (see Figure 6).

Figure 5. Unfolded sheet metal, before correction.

Figure 6. Folded sheet metal, with bottom added, after correction.

There are many other tools that can be used with this software. Miter Flange, Lofted-Bend, corner controls, Sheet Metal Gusset and Rip are all very common tools that can make life easier for the designer.

These tools are valuable for different aspects of design, and all of them are very user-friendly once the designer is aquainted with them.

About the Author

Ryan Reid is a CAD administrator, PLM enthusiast, designer, GD&T specialist, lead, lean philosophy supporter, Microsoft Office expert, 3D printing hobbyist and manufacturing-focused professional with 17 years of combined experience in those areas. Reid has accomplishments in all aspects of manufacturing engineering, from cradle to grave plastics/mold to structural, systems, process and change management design.