FDM Tutorial 3.0
The
PRL has two Fused Deposition Modeling
(FDM) Machines for three-dimensional prototyping. These machines build up the form of a given 3D CAD file in
successive layers, extruding molten material like a CNC glue gun. They are very useful for prototyping parts
that will be CNC milled, for building plastic parts that are un-machinable, and
for creating plastic or wax part patterns to be investment cast in metal.
Because these
machines are very valuable and their controllers are intricate, we require that
students make an FDM License (shown actual size at right) before they use the
machines for their own projects. This
tutorial will guide you through the steps needed to make an FDM License or any
other simple FDM part. Refer to the FDM
System Documentation notebook at the machines and the TAs for additional help.
Here are the PRL’s two FDM machines; they are very similar in operation, but they run different materials. The FDM 2000 (the machine on the left) is usually set up to run standard ABS or Investment Casting Wax (ICW), and the FDM 3000 (the machine on the right) is almost always set up to run WaterWorks ABS, which has a water-soluble support material. The FDM 2000 can also be set up to run Elastomeric Material. Please contact a TA or Craig Milroy for details concerning this option.
WaterWorks ABS
Overview
The FDM 3000 is usually set up for WaterWorks ABS model and support material. This support material is dissolvable, which allows for much more intricate part creation without the worry of having to remove the support material by hand. The model material is still ABS-400, just like that on the FDM 2000. To remove the Support Material, drop the part into the WaterWorks ultrasonic tank in the materials room. This requires supervision of a TA, as the chemical make-up of the solution is critical to effective Support removal. Expect a minimum of 3 hours for complete removal, longer for large parts. The solvent bath must be replaced completely for every half spool of support material used.
Investment Casting Wax (ICW) Overview
The
FDM 2000 can also be set up for ICW model and support material. This capability allows the user to design a
solid model, build that model on the FDM, and then investment cast the part in
metal. Rapid Prototyping at its finest!
·
The head on the FDM will need to be changed to accommodate
this material. Talk to a TA to arrange
this – it is a rather complicated procedure that only a few people can do.
·
The ICW material is extremely delicate! You must be very careful when installing new
spools (ONLY by a TA!) and attention should be given to ensure both Model and
Support Material LOAD properly.
·
Because of the low melting temperature of the ICW, small
parts tend to lose surface finish quality due to the heat build-up from the tip
“spreading” previously deposited (yet still liquid) material. To avoid this problem, several parts should
be run at one time, or a “dummy” part should be included to help distribute heat.
·
Realize that hand finishing will likely be required for many
parts. Use a hot knife to smooth any surface irregularities.
How to Create a Part on the FDM
Make Your Solid Model (STL)
Use
Solid Edge to build a 3D model of your part and save the file as an STL. If you are doing your FDM license, you
should use the FDM_key_license.STL file in the FDM_user folder instead of
making your own STL. Create your own
sub-folder in the FDM_user folder on the Users drive, and put the STL file that
you want to build into this folder so you can access it from the FDM
computers.
Login to FDM Computer
From
the machine shop, have a TA log you on to the appropriate FDM computer as
FDM_user. The FDM computers are located
to the right of the FDM machines; each computer is labeled to show which
machine it controls.
Warm-up FDM: Set Material Temperatures
Set
the temperatures on your intended machine’s temperature controllers to the
correct values as described below. The
FDM should already be on, and its front door should be closed and latched.
The
temperature controllers are located at the top front of the machines. The green number is the current temperature
of the item (model, support, or envelope) in degrees Celsius. The red number is the temperature that the
machine is currently set to maintain.
Change the set temperature by using the increase decrease buttons on
each controller. Note that it is
important to use the correct temperatures or the material will not behave
properly.
Standard ABS on the FDM
2000:
Material Temperatures
Model: 270°
Support: 265°
Envelope:
70°
WaterWorksÒ ABS
on the FDM 3000:
Material Temperatures
Model: 270°
Support: 233°
Envelope:
70°
Note: The FDM 3000
has a “Low Temp Set” feature that reduces the support material temperature to
210° upon start-up
and after program execution. BEWARE! To
override, press the ENTER key on the keypad before and after running a
program. This will provide enough time
for the support material to come to temperature before running the part. You
should never run a part at low temp setting or before the material has gotten
up to temperature! Doing so would
destroy the FDM tip.
Investment
Casting Wax (ICW) on the FDM 2000:
Material Temperatures
Model: 71°
Support: 73°
Envelope: 43°
E-20 Elastomer on the FDM
2000:
Material Temperatures
Model: 160°
Support: 220°
Envelope:
55°
It will take about fifteen minutes for the
material and envelope to come up to temperature. You should use this time to process your STL file on the
appropriate FDM computer so that it will be ready to go when the machine is
warmed up.
Start Insight
Click the “Insight” link on the computer’s desktop, or click “Start”,
“Programs”, “InsightV21”, “Insight” to start the program. When Insight appears, it will look like the
image below. Check out the current “Modeler Setup” at the right of the screen. Verify that the program is configured
correctly (machine, material, etc.) but do not alter any of the settings. If you suspect that it is incorrect, talk to
a TA.
Menus and Toolbar
There
is a great deal of flexibility to what Insight
can do, but we have found that the standard settings and procedures work
best. Most of the commands we use
appear both in the top text menu and in the main toolbar.
Open Your STL File
From
the File menu, open your STL file. If
you are doing your license part, open FDM_key_license.STL in the FDM_user
folder on the Users drive.
Your
part will appear in the FDM coordinate system as a shaded model. You can look at it from different angles by
manipulating the small coordinate system at the top right of its window. You can also use the zoom and view sections
of the main toolbar to manipulate the view of your model as follows:
Orient Part
The
first thing you have to do is set the orientation in which you want your model
to be built. Models seldom come into Insight
in the correct orientation, and you have two options for how to correct the
situation.
Click the
“Orient by facet” icon 
in the top toolbar.
Select “Top”, “Bottom”, etc. and then click on the facet of your model that you want to face in this chosen direction.
2)
Use Automatic Orientation
From the STL
menu, choose “Automatic Orientation”.
This command lets you specify the method by which you want Insight to search for possible
orientations. You can then select your
favorite orientation from the options it suggests.
Select either
the “Maximum horizontal area” or “Minimize supports” method for most
parts. “Rotate to fit envelope” is
useful for particularly large parts that barely fit inside the FDM.
Click the
Search button 
and then browse through the orientation
options that Insight presents by using
the arrow buttons. When you find your
favorite orientation, just leave the model there. There is no confirmation action needed.
The
orientation that you choose will affect how your final part comes out because
the FDM builds up your model in layers along the z-axis. You will want to choose an orientation that
is stable, minimizing support material if possible. It is also a good idea to
place any intricate details facing up so that support material does not mar them. For the FDM license part, placing the “PRL”
facing upwards, as shown below, is the best choice. You can use either orientation method to achieve this result.
Create Slices
The
next step in preparing your file to be built on the FDM is to have Insight slice it into layers along the
z-axis.
Click the
“Slice” icon 
in the top toolbar.
Insight will then compute and display the slices that make up your
part.
You can
inspect the different layers by using the Z toolbar (shown below). If your Z
toolbar is not active, turn it on through the View menu.
If you are
doing the FDM license and you click the “View all slices” button in the Z
toolbar, your screen will probably look like the following image:
Create Supports
After
your model has been sliced, you need to have Insight create the supports that will allow your part to be built
in the FDM.
Click the
“Supports” icon 
in the top toolbar.
Insight will then create and display the necessary supports for
your part.
If you are
doing the license part and you click the “View all slices” button, it will look
something like this:
Create Toolpaths
After
creating slices and supports, Insight
needs to create the toolpaths needed to build your part.
Click the
“Toolpaths” icon 
in the top toolbar.
Insight will then compute the paths it
will take to build your part and supports and display them in the window. You
can view each one individually by using the commands in the Z toolbar.
One layer of
the FDM license part will probably look like this:
Save File
Now
that you’ve finished processing your STL, you’re ready to save the job and
start working with the FDM machine.
In the File
menu, click “Save as”, “Job”, and then navigate to your sub-folder of the
FDM_user folder and click “Save”.
This action
will cause Insight to create a folder
called ssys_filename (e.g. ssys_fdm_key_license) in your folder. It will save the processing that you just
finished as a batch of different files inside this new folder. The file that encapsulates this job is the
.sml.gz, which you can re-use later if you want to re-make the same part on the
same machine.
Check FDM Temperatures
Go
to the FDM machine you are using and check to see if the model and support
material are up to temperature yet. If
they are not yet hot enough, you must wait until they reach the correct
temperature. Running the machine before
the material is up to temperature will destroy the FDM tips.
Also
note that the FDM 3000 has a “Low Temp Set” feature that reduces the
temperature of the support material to 210° upon start-up and after program execution. BEWARE!
Check the display screen of the FDM to confirm that this feature is not
active. If it is, you must override it
by pressing the ENTER key on the keypad.
You will then have to wait until the support material comes up to its
correct temperature. You
should never run a part at low temp setting!
Doing so would destroy the FDM tip.
Check
to make sure the envelope (ambient) temperature of the FDM is within five
degrees of its set temperature. Because
the enclosure can take a long time to warm up and its temperature is less
important to the success of your part and the health of the machine, you can
continue building your part as soon as it is within about five degrees of the
set point.
Obtain FDM Confirmation Card and Key
Ask
the TA on duty for an FDM confirmation card and the key that unlocks the front
door to the machine.
Hold
onto the confirmation card for the time being – you’ll fill it out soon.
Check FDM Material Loading
Before
can run your part, you must verify that the model and support materials are
loaded correctly by testing their flow.
The controls you will use are located on the FDM control panel:
Check Model Material
Press the
“MODEL/SUPPORT” button until the display reads “MODEL % 100”. This command will lower the model tip on the
FDM head (the tip on the left) if it wasn’t low already.
Press the
“LOAD” button and wait fifteen seconds for material to flow. Once it is flowing, allow it to continue for
about twenty seconds. Press the “LOAD”
button again to stop the flow.
If you get a
“LOAD TIME FAULT” message on the display, just hit “Enter” and continue.
If the model
material does not flow within ten seconds, re-press the “LOAD” button to stop
the attempted flow and see the TA on duty.
Unlock the
door and clean the extruded material off the tip with the small brass brush in
the red FDM toolbox.
Check Support Material
Press the
“MODEL/SUPPORT” button until the display reads “SUPPORT % 100”. This command will lower the support tip on
the FDM head (the tip on the right).
Press the
“LOAD” button and wait fifteen seconds for material to flow. Once it is flowing, allow it to continue for
about twenty seconds. Press the “LOAD”
button again to stop the flow.
If you get a
“LOAD TIME FAULT” message on the display, just hit “Enter” and continue.
If the support
material does not flow within ten seconds, re-press the “LOAD” button to stop
the attempted flow and see the TA on duty.
Clean the
extruded material off the tip with the small brass brush in the red FDM toolbox.
Prepare the Job
Now
that you have fully processed your file and verified that the machine is ready
to go, you are ready to send your part to the FDM to be built.
Go back to
your computer and click the “Build” icon
in the top toolbar.
The “Pack and
Download FDM” window and the “FDM Status – FDM” window will appear. For the moment, you should only worry about
the “Pack and Download FDM” window, as follows:
This window
shows your part and the platen of the FDM machine. Default part placement is at the origin, the bottom left-hand
corner of the diagram. You will be able
to move the origin (and thus where your part will be built) to any location on
the platen when you setup the machine, so it is best to leave your part at the
origin in this window.
This window
also allows you to add in other processed FDM files (of format .sml.gz), create
duplicate copies of the same part, and re-arrange them on the platen of the
machine.
If you are
doing the license part or any other single part job, you do not need to alter
anything in this window.
Send the Job
When you are
satisfied with the arrangement of your part(s) on the platen, take note of the
“Total time estimate”, make sure the FDM door is closed and latched, and press
the “Send” button, which will cause the “Details for FDM” window to appear.
This window
will stay open throughout the time your part is being built. It contains a bunch of useful information,
such as the name of the job, the start time, the elapsed time, and the material
usage.
An “FDM Status
- FDM” window will also stay open throughout the time your part is being
built. You won’t need this window.
Fill out Confirmation Card
Fill
out your FDM confirmation card with the information found in the “Details for
FDM” window and the estimated run time you noted from the “Pack and Download
FDM” window.
Pay For Your
Part
Pay
the TA on duty for the model and support material your part will use. The TA will know the current rate per cubic
inch. If you are doing the FDM license
part, you do not have to pay for the material you use.
Run FDM Calibration Sequence
Now
that you’ve processed your file, verified that the machine is ready, and paid
for your part, your next step in setting up the machine is to let the FDM run a
calibration sequence to find its default origin.
Press
the “Pause” button, which will turn off
the flashing pause light.
The
FDM will then perform a brief calibration sequence that ends by placing the
head at its default origin, the front left corner of the platen.
When
this process is complete, the pause light will begin flashing again.
Note: While you are working on the FDM machine, you should never use
the “Stop”, “Reset”, or “Go” buttons.
Pressing them can cause the machine to behave in a bizarre manner. If you
accidentally miss a step in this process or want to start over, just press
“Pause” and re-send your file to the FDM, which will reset it internally.
Set Part XY Origin
Next,
you have to set the origin of the coordinate system where you want your part to
be built. This point corresponds to the
bottom left-hand corner of the diagram in the “Pack and Download FDM” window in
Insight.
Locate
an area of the foam bed that is unused and that will accommodate the size of
your part. If no such area exists on
the current foam bed, ask the TA on duty to turn it over or get you a new one.
Locate the manual move keypad on the front of the FDM and make sure the green lights in the top and bottom directional move buttons are off. If they are on, press the Z-axis button to toggle them off.
Move the head of the FDM so that the Model tip (left-hand tip) is above your intended origin. Use the directional move buttons to move the FDM head initially in the positive X and Y directions (to the right and away from you.) Hold down the rapid move button in the center while pressing any of the directional keys to move the FDM head quickly.
NOTE:
Never move the FDM head in the negative direction beyond the default
origin. Moving the head to the negative
will cause inaccurate model/support offsets.
Set Z Location of Platen
The
last step of preparation is to set up the FDM machine so that it will build the
base of model on the top surface of the foam bed on the platen.
Press the
“MODEL/SUPPORT” button until the display reads “MODEL 100%”. Notice that this command lowers the model
tip on the FDM head (the tip on the left), which is the tip we want to use to
set the zero.
Press the
Z-axis button on the movement keypad to activate the Z move lights. Use the top move button to raise the foam
until it barely contacts the Model tip.
The tip should be touching the foam, or the material will not adhere to
it, but do not bury the tip inside the foam because this damages the tip.
Build Your
Model
All
that’s left to do is to build your model.
Press the “Pause”
button. The flashing green light will
turn off and the machine will begin running your part!
Watch it for a
couple of minutes to make sure it starts correctly.
Post your FDM confirmation card on the front of the machine with a magnet (NEVER with masking tape).
Put the “FDM Part is Running” sign over your FDM computer monitor to keep people from interfering with your part.
Lock the FDM door and return the key to the TA.
Return to the shop shortly after your part is due to finish. You will know it is finished when the head stops moving and the pause light comes back on.
Completed Part Removal
Ask the TA on
duty for the FDM key to unlock the door
Put on gloves
and pull the platen out of the FDM by rotating the lock holding it in place and
sliding it straight out of the machine.
Remove your
part from the foam, using a scraping tool from the red FDM toolbox if
necessary.
If you used WaterWorks ABS on the FDM 300, you may be able to remove the support material by putting your part in the WaterWorks removal tank located in the Materials Room. Talk to a TA to arrange this operation.
You can remove all other support
material with various hand tools.
Clean Up and Shut Down
If no one is
going to be using the machine immediately, lower the FDM temperatures to the
following:
For ABS: For
ICW:
Model: 50° Model: 40°
Support: 50° Support: 40°
Envelope: 35° Envelope: 35°
Sweep
out the inside of FDM machine with the paintbrush located in the FDM toolbox.
Clean up the surrounding area, put away all tools, and sweep the floor.
Ask
the TA on duty to check out your machine and give you a 5-minute shop job!
Once
you have completed your license part, you are free to use the machine for your
own projects.
Revision History
Ver 1 Dec 1999 Denise Chan
Ver 1.1 Sep 2000 Anon P. Whodunnit
Ver 1.2 Oct 2000 David and Adrian
Ver 2 Nov 2000 Ryan Connolly
Ver 3 Nov 2001 Katherine Kuchenbecker