By the end of this lesson, you should be able to:

Procedure

1. There is a reference manual on the FDM that must stay with the machine in Room AT 136. Please refer to it as needed.

2. Turn on the computer system. It is a Windows 2000 system, so you will be prompted for a username and password. Use "student" as both the username and no password.

3. Turn on the FDM by pressing the white Start button. This turns on the heating elements.

4. Check the three temperature indicators on the FDM. They indicate the set and actual temperatures of the build material, the support material, and the modeling area or envelope, in degrees centigrade. For modeling with ABS, the recommended settings are as follows:

Modeling Material: 270
Support Material: 265
Envelope: 70

The proper temperatures are probably already set, you just have to wait for the actual temperatures to reach the set temperatures. The machine will take a few minutes to reach operating temperatures, so you can go back to the computer to work on your model.

Notes about making and manipulating 3D files:

A. In order to keep the FDM computer available for building models, you should use a different computer for model creation and manipulation, unless there is no demand by others to use the FDM computer.

B. It is possible to use a variety of sources of 3D models, including the following: downloading 3D models from the Internet, scanning objects with a 3D scanner, or using software such as Unigraphics, Pro Engineer, Rhino, or 3D Studio to create or modify 3D models.

C. In order for a 3D model to work with the FDM, it should be based on solids or on polyhedral meshes. That is, objects that are "filled" on the inside, and those that are just complete hollow shells (like an egg) will work. However a model that is made up of two-dimensional elements (like a mobius strip) will not work. Nor will complex 3D (scanned) polyhedra or meshes if they have holes, or if there are overlapping triangles.

D. The model must be exported or saved as an stl file.

E. Some instructors require their students to use specified file-naming conventions, and have created directories on the D:\ drive for class files. If that is the case, copy your file from your Zip disk (or other source) to the appropriate directory.

5. Open the Insight program. (This software replaces the previous program, known as Quickslice.)

A note about Insight:

Insight is Stratasys' program that lets you import stl files. There are minimal file manipulation tools, but it does let you reorient the model and scale it. An inputted stl file is then used to create a series of horizontal cross sections at a set Z interval. For modeling with ABS, this interval is 0.010".

Models are built out of a "build" or "model" material, but to support higher layers of this model material, a "support" material is typically laid down first. After creating support material, there toolpaths must be generated for the support and build extruding heads to follow as they create the part. These toolpaths are also called "roads."

For beginning modelers, Insight should be used to reorient the model (to decrease build time), to scale the model, to generate the slices (slc) and toolpaths (sml) files, and to give the operator information about the build time and material requirements. Fortunately, much of this can be done automatically.

6. In Insight, click "File," "Open," and browse to find your stl file to load; it is probably not on the default C:\ drive. If a dialog box reports that the part is oversized, ignore it; you can re-scale the part within Insight.

7. On the right of the screen the "Modeler Setup" box will indicate the configuration. For typical operation with ABS plastic, this should indicate
 

FDM	1650		0.0100	slice height
Model	T12 tip		ABS	P400
Support	T12 tip		ABS	P400R
Part fill style		:	Perimeter/rasters
Part interior style		:	Solid-fine
Support style		:	Sparse

10. Reorient your model so that the support material required and the and build time are minimized. There are some applications where part finish or other factors affect orientation decisions. To reorient the model, click "STL", "Rotate."  Use the dialog boxes at the right to specify the rotation amount and direction. Repeat, as necessary. Even though your model might appear on the screen in the front, left of the build platform, you will be able to relocate it to any other suitable location after it is sent to the FDM, and the model should not be moved at this time, except to facilitate multiple model loading. (There is also an Automatic Orientation feature you may wish to use to, say, minimize supports.)

11. Scale your model, if appropriate. FDM material is very expensive, and large models take a very long time to build. Select "STL," "Units and Scale." You may use the values in the pull down window beside "STL scale," or type in your own factor. You may not notice a change in your object, but the size of the surrounding box might seem to change. The build envelope is a 10" cube, and the box on the screen around your object represents this envelope. Note the "STL size" readout in the "STL Units and Scale" dialog box.

12. Slice your virtual model by selecting the "Slice" icon.
13. Generate supports by selecting the "Support" icon
14. Create toolpaths by selecting the "Toolpaths" icon.
15. It's a good idea to then click "File, Save" to save your toolpaths file

16. Back at the FDM, check to see if there is enough space on the foam build platform for your model. If there is not enough room, replace the foam.

If it is necessary to replace the foam:

A. Open the FDM front door. Watch where you put your hands; avoid getting burnt.

B. Flip the locking lever on the front, left of the build platform.

C. Pull the build platform forward, removing it from the FDM.

D. Close the FDM door.

E. Place the build platform on a table, and remove all 10 pins and the foam insert.

F. Remove any foreign materials from the build platform.

G. Flip the foam over, or if the underneath face was already used, select a new piece of foam. Note that the brown urethane foam is designed for ABS and the blue polystyrene foam is designed for investment casting wax (ICW).

H. Place the foam into the platform so it is seated firmly. This might require shearing part of the edge of the foam.

I. Invert the build platform so the foam is against a table.

J. Pressing down firmly on the platform, replace all 10 pins.

K. Blow off any debris, and replace the build platform in the FDM, securing the locking lever and closing the door.

17. Check to see of the three temperature readings are sufficient.

18. Check the Auto Shut Off status, and change it appropriately by depressing the Auto SO key on the FDM. If you will be the last to build a model for the day, turn Auto SO on; if another model will be built right after yours, leave it off.

19. Notice the button on near the top, center of the FDM that says "Prgm 0" above it and "Pause" below it. Let's call this the Pause Button. If this button has a flashing amber light, press that button now to turn off the light. If the light is on, the FDM cannot receive information from the computer.

20. Back in Insight, click the "Build" icon. In the "Pack and Download" dialog box, copy the following information to your notes:

• Estimated Model Material to be used:
• Estimated Support Material to be used
• Total time estimate:

Also, make a note of the present date and time and of the date and time when the job should finish. Click the icon to send the job to the modeler. (If you had wanted to send multiple copies to the FDM to be built simultaneously, you would have indicated so in this dialog box.)

21. The Pause Button light should be flashing; press it to turn it off. This will cause the FDM to run through initialization routines, extruding support material and wiping the tips. When it is done, the light will come on again.

22. Use the directional keys on the FDM to move the head in the XY plane, or the platform in the Z axis. Pressing the center key along with another key invokes a faster mode. There is also a toggle button so that the up/down keys can be control both the Y and Z axes. If necessary, lower the platform, open the door, and use the brass brush to gently clean the extruding tips. Be sure to also remove excess material from the inverted brush in the machine and from other areas in the machine and close the door. Reposition the left "build material" tip so that it is at the front, left of the rectangle where you wish the build to occur. Embed the tip 1 mm into the foam.

23. Press the Pause Button light.

24. Note the time, and estimate the approximate time of completion.

25. Turn off the monitor.

26. Return when the model is almost finished, or if its an overnight build, then return as soon as the lab opens in the morning.

27. Make sure your files are stored in the appropriate place for your class.

28. When the model is done building, the head will go to the home position, the Pause Button light will flash, and the FDM display will show "100%". Open the door and gently remove your model. You might wish to remove the build platform to make this easier (especially for large models), but replace the platform when you are done. A fingernail may be used to remove the model from the foam. Close the door.

29. Move any files created to the appropriate directory; do not merely copy them.

30. If no other user is about to build a model, log off of the computer, and turn off the computer, the monitor, and the FDM. The fan in the FDM will probably still operate for a while.

31. Carefully remove the support material from your model so you do not injure yourself or the model. Recommended tools for this are needle nose pliers, tweezers, and maybe a small screwdriver, and an X-Acto knife. If necessary, sand the model very lightly. Clean the FDM and, if necessary, finish your model.