Overview: Autodesk Inventor Frame Generator Trailer

A large part of our welding/fabricating career is spent working with angle, channel, pipe, tube and other pre-made structural shapes. Autodesk Inventor has a specific module in the assembly environment called Frame Generator that allows you to efficiently create structures out of these standard shapes. This tutorial will guide you through how to make a basic utility trailer frame. Once we have the basics, we can create frames quickly and easily. We will be able to create drawings for individual members as well as plan materials.

Using Autodesk Inventor will also allow us to easily leverage the following CNC technologies to increase productivity and reduce complexity of advanced projects:

- CNC Tube Profilers: This equipment allows you to create pre-profiled members to ease assembly and speed up production.

- CNC Tube Benders: This equipment can bend members to specifications, creating accurate and consistent profiles for use in weldments.

This Instructable assumes familiarity with Autodesk Inventor (Inventor) Part, Assembly and sketching environments.

Organization is key to the success of any project, and it is especially true for Inventor assemblies. Creating a new folder for each project is important.

Create a standard Assembly File. We will not deal with weldments in this tutorial, but the same module is available in weldments.

This step is important!! We must make sure to save our assembly for this to work. Make sure to select an appropriate name for your assembly. We want to avoid renaming inventor files, so choose an appropriate name the first time.

Frame generator utilizes a part file with sketches to define where the members are located and how long they are. We are going to create a part inside our assembly for that purpose. Click Create to make a new part in your assembly. After you have input an appropriate name and made sure it is saving in your folder that you created in step 1, click OK and then you have to click to place the part in the assembly.

Create the sketch shown to define the members that make up the bottom of the trailer. Use a Center Point Rectangle centered on the origin to define the perimeter. Orientation relative to the origin is important. Make sure your sketch is fully constrained.

Finish Sketch

Create a work plane offset 18in from the XZ Plane (or whatever plane sketch1 is on)

This sketch will define the upper portion of the trailer. Place points along the sides to define the vertical member positions. Use the center point rectangle oriented on the origin to ensure that the 2 rectangles line up. Fillet the left side corners to make rounded trailer corners.

Finish Sketch

Rename your sketches and work plane to indicate what they will be used for and return to the Assembly environment by using the return button on the top right side.

Make sure you save at this point!

Select the Design Tab and Insert Frame Members

The Structural Members are organized into various standards. We are going to use the ANSI Standard.

For each standard there are Families (shapes) that can be used. We are going to select U channel

For a given family, there are various sizes. We are going to pick the C3 x 3.5 channel. This is interpreted as 3" channel that is 3.5 pounds per foot.

Click the first line

Using the flip button and rotation if required, obtain the orientation as shown.

Select the various radio buttons around the member to locate it in the correct position

Click the remaining perimeter lines to form the rectangular perimeter.

Press Apply and OK

Select ANSI L Equal Angles and the 2 x 2 X1/4 member

Place as cross members on all 3 mid lines, adjusting the rotation as required and orientation

Press Apply and OK once selected

Following the same process as previous members, place the tongue tube (2 x 2 x 1/4 tubing)

Note the -3 offset to put the tube below the frame

Using the Change Tool we can change the size of the first angle cross member. This will allow it to touch the tongue member. Note you have to change families to Unequal Angles and select 3 x 2 x 1/4. You will have to adjust the orientation to get it correctly aligned.

Click Yes to create a new member and OK.

Cancel out of the change dialogue box

Go to Insert Frame and this time we are inserting ANSI ASTM - Pipe 1 x 0.133

Clear any offset or rotation in the dialogue box

Select the first line and get the orientation correct.

Select the remaining perimeter lines except the rear of the trailer

BEFORE SELECTING APPLY click the merge box in the lower left corner. This tells Inventor to make the top rail out of one piece of bent pipe instead of sections.

Click Apply

In addition to placing members on lines, we can also place members between 2 points.

Switch to point to point placement in the insert frame member dialogue box.

Select one of the end points of the lines for the cross members and select the point on the upper sketch that is above the lower point. Note we can only put one member at a time.

Click Apply

Repeat for the other verticals.

Use ANSI AISC HSS (Square) 1-1/4 x 1-1/4 x 3/16 for the rear members

Now that all of the members are placed, its time to apply some end treatments. Before we get started, lets turn the visibility of the trailer frame skeleton off as we don't need it anymore.

The Miter tool create miter joints where 2 members meet. We are going to create miter joints in the corners where the channels meet.

Select the 4 channels

Apply a gap if desired

Select OK and all 4 members will be mitered

We use the notch tool to notch out members to fit other members. In this case we are going to notch the cross members to the channel.

Select the frame members to be notched in selection 1 (Frame Members)

Select the 2 side channels in the second dialogue box (Notch Tool)

Click OK

Repeat the Notch for the uprights, using the top rail as the notch tool.

We are going to use Trim/Extend to cut the diagonals to the face of the square tube.

Select the frame member you want to cut

Click the face selection and select the side face of the square tube.

Click Apply

Repeat for the other side

You will notice the front does not have any vertical bars. Edit the sketches to add points and add your own front members. Turn the visibility of the Skeleton Part so see the sketches.

At this point you need to save.

Start a new drawing just like we have done previously.

Edit the sheet size to be C size (right click, edit sheet)

Use Base View to place an isometric view of your trailer frame.

1/8 scale worked for me, but choose something reasonable.

Turn on Shading to make the view realistic looking

Move to the annotate tab

Select Parts List

Select the view

Select the Structured BOM View

Hit OK twice and place the parts list in the top right corner

Using Balloon we can add Balloons to the parts

Click the Balloon Tool

Click the part you want to balloon

click where to place the balloon

Right click

Select continue

Repeat for all members

Make sure you save your file in the folder you created for this project!

You can add views of your frame and dimension using the skills you already have. Multiple sheets would be required or view selection would need to be different. There are may options for Assembly Drawings, but this gives you the basics. Explore and experiment to fully document this trailer frame.