Workflow & Basics
Additive manufacturing builds parts layer-by-layer. What is the traditional method called where you carve or drill material away from a solid block?
Subtractive Manufacturing
What type of printer melts a plastic filament string through a heated nozzle?
FDM (Fused Deposition Modeling)
Which plastic is the cheapest and easiest to print, but melts inside hot tactical vehicles?
PLA.
What part of the printer literally melts the plastic?
The Hot End.
Why do UAS operators care about the weight of a 3D printed part going on the aircraft?
Extra weight reduces battery life and flight time.
What does "BDRF" stand for in Army logistics?
Battle Damage Repair and Fabrication.
Which type of FDM printer looks like a tall triangle and uses three vertical arms?
A Delta printer.
Which filament should you use for parts that will be mounted in direct sunlight because of its high UV resistance?
ASA / PETG
What part uses geared teeth to push and pull the filament?
The Extruder.
You print a bracket, but it snaps cleanly in half horizontally along a layer line. How do you orient it on the next print to stop this?
Rotate the part 90 degrees so the layer lines run along the length of the part, not across it.
Name one the two most common 3D file formats exported from CAD
STL or 3MF
What pulls the rubber belts to move the print head on an FDM printer?
Stepper motors
If you need a drone bracket that can take a heavy impact without shattering, would you choose PLA or TPU?
TPU (it absorbs shock)
What is the standard hole diameter for most 3D printer nozzles?
0.4 mm
What is the "Golden Rule" or "Rule of Thumb" for supports? At what angle does a 3D printer typically require support material underneath it so it doesn't print into thin air?
45 Degrees. (Often called the "45-Degree Rule").
If your slicing software says a print will take 250 layers, and each layer is 0.2mm, how tall is the object
25 millimeters (2.5 cm).
What limits the maximum size of a part you can print?
The printer's Build Volume (or Build Envelope)
What makes Carbon Fiber filament difficult to print with standard hardware?
It is highly abrasive and destroys brass nozzles.
Name the three methods to fix a clogged nozzle.
Pin needle, hot hex wrench, and Cold pull,
You are in the dirt at a COP and a bracket snaps. To recreate it in CAD, you need to know its exact X, Y, and Z dimensions. What hand-tool must you use to get those precise millimeter measurements?
Calipers
What happens if you try to print an object with a massive overhang without turning on "Supports" in the slicer?
It will print plastic into thin air (spaghetti/failure)
Which printer technology is generally safer to operate in an enclosed tent: FDM or SLA?
FDM (SLA has toxic fumes and liquid chemicals).
What happens to a print if you use wet (moisture-soaked) filament?
Stringing, popping/hissing, and weak parts.
What happens if the nozzle is too far away from the bed on the very first layer?
The plastic won't stick (spaghetti)
ou are deployed in a humid, tropical environment. You printed a replacement camera gear for your UAS last week using Nylon, and it worked perfectly.
Today, you need to print an identical replacement gear using the exact same spool of Nylon and the exact same printer settings. This time, the gear's outer dimensions are slightly warped, it has tiny air pockets on the teeth, and it strips its teeth the very first time the camera rotates.
Without touching the printer or changing the settings, what chemically happened to your raw material over the last week to cause this failure, and how do you fix it?
The Problem: The Nylon filament is hygroscopic and absorbed moisture/water from the humid tropical air over the last week. When printed, that trapped water boiled inside the hot end, creating steam pockets (bubbles) that ruined the gear's dimensions and left the plastic structurally weak and brittle.
The Fix: Put the Nylon spool in a filament dryer (or dehydrator) for several hours to bake out the trapped moisture before printing.