SME
Manufacturing Processes · Problem type
FDM print time from the bead
Use this for “A 0.4 mm wide, 0.2 mm tall bead at 60 mm/s. How long does 12 cm³ of plastic take?”
This is an example. Type your own values to start a new problem.
Q (mm³/s)
=
w (mm)
×
t (mm)
×
v (mm/s)
T (min)
=
V (cm³)
Q (mm³/s)
Formulas
Q
=
w
×
t
×
v
4.8 = 0.4 × 0.2 × 60
T
=
V
Q
2,500
=
12,000
4.8
Formulas are worked in mm³, s. The step-by-step shows the conversions.
Assumptions
•
The bead is a flat strip, w wide and t tall, so its cross-section is w × t.
•
The nozzle prints at speed v the whole time: travel moves and slowing at corners are left out.
•
V is the plastic actually laid down, walls and infill together.
Step-by-step
WE KNOW
w = 0.4 mm, t = 0.2 mm, v = 60 mm/s, V = 12 cm³
FIND
flow rate (Q), print time (T)
Step 1 · Convert to the formula’s units
The formulas don’t work directly in the units you chose, so convert first (to mm³, s).
V = 12 cm³ = 12,000 mm³ (1 cm³ = 1000 mm³)
Step 2 · Find flow rate (Q)
Use Q = w × t × v
Each
second
the
nozzle
lays
a
strip
v
long
with
a
cross-section
w
×
t
.
Q
=
0.4
×
0.2
×
60
Q
=
0.08
×
60
Q
=
4.8
mm³/s
Step 3 · Find print time (T)
Use T = V ÷ Q
The volume to lay down over the volume laid each second.
T
=
12,000
4.8
T
=
2,500
s
Step 4 · Convert the answers
Change each answer back to the unit you chose.
T = 2,500 s = 41.6667 min (1 min = 60 s)
Check
Put the numbers back in. Both sides should match.
4.8 = 0.4 × 0.2 × 60 ✓
2,500
=
12,000
4.8
✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
Related lessons
Additive manufacturing
Main lesson
The stair-step error on a sloped face
Use this for “0.2 mm layers on a face at 30° from the build plate. How high is the cusp?”
The seven additive families
Use this for “Which additive family is SLS? Which is wire-and-arc DED?”
The steps of a metal print
Use this for “Put these in order for a metal powder-bed part: slice, stress-relieve, add supports, cut from the plate.”