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I draw most of my custom boxes in Autodesk Inventor 2014.  I can modify sheet wood (or acrylic) thickness and have my drawings automatically compensate for the material's actual thickness.

For example, I have used 1/4" MDF which has varied in thickness from .238" to .256".  Creating a drawing which can compensate has helped me a great deal in creating tight joints on my boxes or other creations.

So here's the process I have developed to modify thickness and quickly create a drawing file ready to export to CorelDraw for laser cutting.

In this Instructable, I will discuss making the thickness-to-laser process a bit easier, and I will leave box design for the reader's own development.   Some of these details may be different for your own Inventor and CorelDraw installations, based on the program settings.

I make my stuff over at TechShop in San Jose.

Step 1: Software and Equipment You'll Need

I am using the following PC-based software and equipment:
  1. Autodesk Inventor 2014 (earlier versions should work fine for my process)
  2. Microsoft Excel (some folks also create .xls files from open-source spreadsheet programs)
  3. CorelDraw v5
  4. Laser engraver (though I will not go through the details of cutting the box)

Step 2: Overview - Building a Box


I find it valuable to think of each creation (a box for example) as a Project. The creation may be a single assembly built from multiple parts or of a parent assembly which integrates sub-assemblies (each sub-assembly can be built from multiple parts).

These are the key elements I use in the Project -> Design -> Export -> Import -> Cut process.

  1. Create a New Project in Inventor, using the source directory containing the files for this project (assemblies, variables, parts, etc.) as the project's source directory. This creation step generates a project file (.ipj) and places it into this directory.
  2. When returning to Inventor to work on the project, be sure tomake this project the active project. This will continue to keep the project files where they belong, and make it easier to track the project.
  3. Create a spreadsheet file in Excel which contains the variables to be used in your parts and assemblies.
  4. Design the Parts and Assembly.
  5. For each Part or Assembly, use the variables.xls file as the source for the material thickness (or thicknesses).
  6. Once the Parts are designed and the Assembly is complete, create a Drawing with the faces of the individual Assembly parts.
  7. Update the variables.xls file with the in-hand material thickness.  Confirm this with calipers.
  8. Export a copy of the Drawing as a .dxf file.
  9. Import the dxf file to CorelDraw for arranging, grouping, and duplicating, in preparation for Laser Cutting.

Step 3: Create a New Project

Autodesk Inventor sometimes provides a splash screen when starting-up, based on the configuration on a given PC or workstation.  

A new project can be started from the splash screen, or from an Inventor window.  I will show how to create a new Project from the Inventor window.

In the Ribbon at the top of the window, choose the following:

Get Started  -> Launch -> Projects

  1. Once the Projects Window appears, select the following: New -> New Single User Project.  
  2. Select Next.
  3. Choose a Project Name and the Project (Workspace) Folder.  Inventor will show the Project File which will be created.
  4. Select Next.
  5. I accept the default libraries once the Select Libraries window appears.
  6. Select Finish.
  7. Inventor will ask if you would like to create a project path, if it does not exist.  Select OK to create the project path.
  8. The Projects window returns, and there will be a check mark next to your new Project.
  9. Select Done.  You are now working inside your newly-created Project.

Step 4: Create the Spreadsheet...

Create a spreadsheet file in Excel which contains the variables(Parameters/dimensions) to be used in your parts and assemblies. I then place this spreadsheet in the root directory of the Project.

In this example, I used the file name of variables.xls.

The screenshot shows the contents of this file - in my case it's pretty simple, but very powerful. The first column has the variable(thickness) name and the second column has the dimension and its units.

Step 5: Design From Within a Project

As a reminder, make sure to design and update your Part and Assembly files while in the appropriate Project.
  1. Make sure no files are open from a different project.
  2. Open -> Projects
  3. Select the Project, then Apply.  This will place a check mark next to the Project in the Project List.
  4. Select Done.

Step 6: Design the Parts and Assembly Using the Spreadsheet


I will explain the steps here for using the variables.xls file to import material thickness into a part file.
  1. Create a New Part.
  2. Save the New Part with an appropriate name. This will help avoid potential link problems in further steps.
  3. In the Ribbon, select Manage
  4. From the Manage tab, select fx Parameters
  5. In the Parameters window, select Link
  6. Select the variables.xls file. Then Open.
  7. Inventor populates the Parameters (variables) into the  Parameters table.
  8. Select the Immediate Update radio button. Then choose Done.
  9. The thickness(es) can now be used in the part file for dimensions where needed.
  10. Design, dimension, and confirm the fit of all parts into an Assembly
  11. Save all Part files and the Assembly. These will be placed in the Project directory.

Step 7: Create a Drawing File to Easily Export the Part Faces

Once the Assembly is ready, and all parts fit well, it's time to prepare a drawing which will automatically be updated with changes in the parts.  

While in Inventor, select New -> Drawing from one of these locations:
  1. The Quick Access Toolbar icons above the menu
  2. From the Application Menu (this can be reached by selecting the Inventor (only click it one time) I at the top left corner of the Inventor window.  
  3. A drawing sheet is generated.
  4. Because I only want the vectors for laser cutting, I remove unnecessary sheet components.
  5. From the Browser, Right-Click and Delete the ANSI-Large Title Bar.
  6. From the Browser, Right-Click and Delete the Default Border.
  7. From the Browser, Right-Click the Sheet and select Edit Sheet.
  8. I find it handy to select Paper Size D and Landscape mode to hold my part drawings.

Step 8: Add Parts to the Drawing

In the past, I've been able to export my part faces from Inventor to .dxf files.one-at-a-time.  This is time-consuming and can be avoided by using a single Drawing with the faces from all the parts that will be cut.

When adding the Part faces, remember the following:
  1. Make sure the Scale is 1:1 as each Part is placed.
  2. Choose the Orientation that shows the face vectors to send to CorelDraw.
  3. If dimensions are shown in the view, they can be removed (without modifying the part vectors) by right-clicking and deleting dimensions as needed.
With the Drawing open, to add a Part face:
  1. Select Place Views from the Ribbon.
  2. Select Base.
  3. The Drawing View window appears.
  4. In the Component tab, locate the Part file using the File Search icon.
  5. Select the Part file, then select Open.
  6. Choose the Orientation that is the face of your Part.
  7. Use one mouse-click to place the part on the drawing sheet, then use the ESC key.
  8. The part can be moved around the drawing sheet as needed.
Once all the parts are placed, save the Drawing file.

Step 9: Export the Drawing

Once the Drawing is ready, perform the following to export:
  1. From the Application Menu (select the Inventor I icon at the top-left corner of the Inventor window) select Save As.
  2. Select Save Copy As.
  3. In the Save Copy As dialog, choose .dxf in the Save as Type pull-down menu.
  4. While still in the Save Copy As dialog, choose Options.
  5. In the DXF File Export Options window, choose File Version AutoCAD 2007 DXF.
  6. Select Finish, then give the export a File Name.
  7. Select Save.

Step 10: Import the DXF File to CorelDraw


With a CorelDraw drawing open, do the following:
  1. Right-click on the canvas and select Import.
  2. In the Import AutoCAD File box, de-select Auto-Reduce nodes.
  3. In the Import AutoCAD File box, select English Units.
  4. In the Import AutoCAD File box, select Scaling as 1:1.
  5. Select OK.
  6. Click the left mouse button once to place the drawing on your CorelDraw canvas.
  7. Group each part's vectors together.
  8. Move and duplicate the parts as needed to prepare them for Laser Cutting.

Step 11: And Cut the Vectors As Needed

Once you've confirmed the vectors are Hairline, you should now be able to send the parts to the laser for cutting.

Best of Luck!
<br>In my steps, I mention using an Excel spreadsheet to change thicknesses and other parameters in Inventor. This is invaluable- when I pick up the material and use calipers to confirm its thickness, I can modify the spreadsheet and my drawings automagically compensate - AS LONG AS MY DESIGN IS ROBUST ENOUGH TO ACCEPT THESE CHANGES.
Please perform web searches for &quot;Rahul boxmaker &quot; and &quot;maker case&quot;. The folks at these websites have provided a generous public service by allowing anyone to enter material and box parameters to generate files/drawings to import into other drawing programs. I import these often into Corel and Autodesk Inventor.
<p>Hello, thanks for the detailed instructable. Would you have any suggestions on how to make the finger joints around the edge of your box faces? I can draw them direct and extrude them but this is tedious I have tried using linear pattern but this gets destroyed when I alter the box size in excel. I would have thought doing an assembly and telling inventor you wanted a finger joint it would be able to do it it's self. I can't find a way. </p><p>Thanks...</p>

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