The SolidWorks Geek

After missing a week, we are finally back to building our stapler. The last time we were here, we made a multi-configured spring for the anvil without using a Design Table. Today we are going to make another spring but this time we are going to be creating a simple design table to configure the spring. So let’s see what we need to do…

Create a Variable Pitch Helix

Just like the first spring we created, we need to create a Variable Pitch Helix. In the Top Plane create a sketch with a circle having it’s center coincident with the origin and the diameter set to .360″. Exit the Sketch.

Select Helix/Spiral from Insert->Curve.

Make sure that Pitch and Revolution is selected in the Defined By field then enter the following records in the Region Parameters section after selecting Variable Pitch. Each record decreases the diameter gradually in order to create a tapered helix. This spring has 3 active coils which have a pitch of .15″ while in it’s free state. When the spring is compressed these values will change without effecting the coil diameters. Ensure that the Start angle is set to 0.00 deg. Click the green check mark.

Create the Wire Profile

Once the Helix is created, it is time to create the wire profile that will be swept along the path.

If the start angle of the helix was set to 0.00 deg, then you can create a sketch on the Right Plane. With the Circle tool activated, select the end point of the helix at the bottom.

Make the diameter of the circle .035″ and select the center point of the circle and the Origin while holding the CRTL key.

Add a Horizontal relation to fully define the sketch.

Sweep the Spring

Once the helix and profile are completed, click the Swept Boss/Base button in the Features toolbar.

Select the Profile and Helix as the path and click the green check mark.

Create a Design Table

Up until this point everything is almost the same as last time. Now this where we going in a completely different direction. For this spring we are going to create a Design Table. A Design Table is an embedded MS Excel worksheet that can be used to create multiple configurations of parts and assemblies. To create a Design Table, select Insert -> Design Table.

We could create a Design Table from scratch, but I find it is often easier to select Auto-create. This creates a Design Table from existing dimensions and parameters in your model.

Select Necessary Dimensions

In the Dimensions window you are presented with a list of dimensions that are available to be inserted into you Design Table on creation.

While holding the CTRL key, select all of the dimensions that begin with D4000 and are associated with Helix/Spiral1. These are the dimensions that control the pitches we created earlier. In addition to the Pitch dimensions, select D1@sketch2 since this is the dimension that controls the diameter of the circle in the wire profile. Click OK.

After clicking OK in the Dimensions window, the Design Table will generate inside a small window in the graphics area. If you have never seen one before, this is a Design Table. Each column in the design table coincides with a dimension name or parameter in your part or assembly. In the first column, starting at the first row below the dimension names, is where the configuration names are added. To create a new configuration, simply add some text in the first column. The cells that follow the configuration name are the values for each dimension.

Create Formula to Show Spring Height

One of the advantages to using a Design Table, is the ability to use formulas in the table. You are limited by your imagination and your excel abilities. I have seen some amazing Design Tables are are used to create complex part configurations with only a couple of value changes. Today we are not going to doing anything too hard. We are just going to add a simple formula that will be used to calculate the overall height of the spring at it’s different configurations. To get started, select the first blank cell for the row that makes up the Default configuration. Make sure that the selected cell does not have a dimension or parameter assigned to it.

In this field we are going to add a simple equation that will add up all the the cells in the column. In the Field selected type: =SUM(B3:F3). If your not familiar with excel, let me explain what this formula means. First, by placing an equal sign (=) in the field you are telling Excel that you are going to use a formula to calculate a value for the selected cell.  Next, SUM() is telling Excel that every cell listed inside the parenthesis will be added together to determine the value of the cell. Lastly, inside the parenthesis are the list of cells that will added together. By saying B3:F3, we are adding together a range of cells starting at B3 and ending at F3. Instead of using a range here, we could have individually listed to cells as B3,C3,D3,E3,F3 but that is just extra work. After pressing ENTER the cells will be added together to display the spring height.

Create Additional Configurations

With all the information for the first configuration completed, it is extremely simple to add new configurations. Select all the cells that make up the first configuration, including the cell we created to calculate the spring height. In the lower-right corner of selection box you will see a small dot. If you hover over this point the pointer will change to a plus (+). Click-drag the selection window down by this point until you have copied the cell information to the next two rows.

Release the mouse button and you have just created two new configurations that share the exact same information with the original one.

The two new rows must be edited before leaving the Design Table. Start off by changing the configuration names of the two new rows to As Assembled and Compressed. Then change the pitch for D40001, D40002 & D40003 for each configuration. These pitch values coincide with the active coils of the spring and are the only value that changes while the spring is compressed. Once the Design Table has been updated to the values shown below, click anywhere in the graphics area outside of the Design Table.

If all the Design Table was configured properly, you will receive a message stating that the design table generate the two new configurations.

View Newly Created Configurations

The newly created configurations and Design Table are available in the ConfigurationManager. Click the ConfigurationManager tab at the top of the FeatureManager.

Configurations controlled by Design Tables act the same in SolidWorks as normal configuration do. The only difference is you will see the icon changed to a green X to illustrate that it is being controlled by the Design Table.

Everybody’s Working For the Weekend…

That does it for today’s design tutorial. you can download the model I created for this article here: [download#9] . I hope everybody has a great weekend and do do anything I would.