Technology of injection molding simulation has been advancing for decades. Nowadays, almost all of the companies in industry have applied this technology more or less, in-house or outsourcing, to reduce risk of having poor part design or mold design which makes the planned mass production get nowhere; and to save development cost and time caused by iterative process of trial and error. More and more companies have considered the work of injection molding simulation as an important DFM (Design for Manufacturing) element in their standard process chain of product and project development which involves plastic part. For more insights of this workflow, link https://www.linkedin.com/pulse/workflow-injection-molding-simulation-verification-hank-tsai/ .

1. V0: xxxx.xx.xx
Customer
1. Project registration for simulation &
analysis.
BuildMeshModel
1. 3D model file of part design (file type:
.PRT, .STL, .IGS, .STP, etc.) Recording the
date when receive the model and its version.
2. Gate design (number, location, size)
3. Runner design (length, layout, cross
section, dimension)
4. Cooling chnnel design (layout, length, size,
location vs. part & runner, inlet & outlet)
Design change in part thickness
Build 3D part model with attribution of gate
location and size assigned (single cavity)
Build complete "part + gate + sprue &
runner" mesh model (full cavities)
1. Mesh size and density:
Per part geometry:Global edge length (mm),
height (mm), IGES merge tolerance(mm).
2. Refine mesh:
Mesh Repair Wizard, Insert Node, Merge
Node, Swap Edge, Fill Hole, etc.
1. Qualified mesh model of "part + gate", single cavity.
2. Qualified mesh model of complete "parts + gates + sprue & runner + cooling
channels + mold box", full-cavity.
1. Name/Grade/Brand/Manufacturer of
plastic material.
2. Name/Grade/Brand/Manufacturer of mold
material.
Choose plastic/mold material from
database
1. Check mesh quality:
Overlapping Elements Diagnositc, Free
Edges Diagnositc, Aspect Ratio Diagnositc.
Check mesh quality of "part + gate" model
Check mesh quality of sprue & runner,
cooling channel and mold box model
Choose plastic/mold material from
database
1. Process conditions recommended by
material supplier.
2. Process condition interface of simulation
software/system:
Set process conditions for filling stage
(Test filling time for fast /medium/slow
injection speed)
Set process conditions for filling stage
(Test filling time for fast /medium/slow
injection speed)
Generate and refine mesh model of "part +
gate"
Generate complete mesh model including
full-cavity parts, gates, sprue & runner,
cooling channels and mold box. (Duplicate
mesh model of single cavity's part and
gate, and refine that of sprue & runner,
cooling channels and mold box.)
Design change in
gate (number,
location)
Design change in
gate (size and
dimension)
Design change in
sprue & runner
(dimension, length)
Build complete "cooling channel + mold
box" mesh model
Import "part + gate" model to simulation
software/system
Workflow of Injection Molding Simulation & Verification
Recommend process conditions 1. New material's property characterization file (if it's not in material database
of simultion software).
Provide new material's property
characterization data
Collect and confirm quality of basic input data
Create and provide
material file
Initiation&PlanningPhase
Initiation&Planning
Request simulation for new project
Request simulation for improving old
project
1. Basic data for simulation & analysis
- 3D file of part
- Name/Grade/Brand/Manufacturer of
plastic material
- Process conditions recommendation for
plastic material
- Mold size
- Preliminary design drawing about gate,
runner and cooling channels
- Purpose and objective of simulation &
analysis (weld line, sink, air trap, warpage,
etc.)
Provide basic input data
Project kick off
Confirm purpose and objective of simulation & analysis
Define objective of simulation
Input
Activity &
Milestone
Work Breakdown, Workflow & Cross-functional Team
Output
Part Design Mold Design CAE, Simulation & Analysis Molding Production Material Supplier
Software
Developer
Project
Phase
Start and finish of individual key work, directing (arrow)
to next key work and its responsible functional team.
Start and finish of supporting work, directing (dot) to
next work and its responsible functional team.
Flow of information share, review and feedback.
OK?
Yes
No OK?
Yes
No
Hank Tsai
https://www.linkedin.com/in/hank-tsai-effinno/
hank.tsai@effinno.com
Effinno Technologies Co., Ltd.
T: (+886)435095395
https://www.linkedin.com/company/e
ffinno-technologies-co-ltd/

2. 1. Theoretical number of molding cycle to start stable injection molding (after
which cooling environment is stable)
1. Theoretical cooling time for part solidification.
1. Distribution of mold surface temperature (moving half, stationary half and
temperature difference)
Recommend process conditions
of filling stage
1. Recommended process conditions by
material supplier:
- Melt temperature
- Mold temperature
2. Capacity of injection molding machine:
- Screw size
- Maximum injection pressure
- Maximum injection speed
3. Obtained filling time by preliminary filling
analysis
4. V-P switch volume and screw stroke
5. Process conditions (injection speed,
injection pressure)
Set process conditions of filling stage as
injection molding machine interface.
- Define sensor node at each gate
Confirm machine capacity and
process conditions of filling stage
TransientCollingAnalysis
1. Cooling chnnel design (layout, length, size,
location vs. part & runner, inlet & outlet)
2. Mold size (LxWxH)
3. Process conditions:
- Coolant inlets & outlets
- Total length of cooling line from coolant
exit of mold temperature controller to its
entrance.
- Pressure drop between coolant exit and
entrance of mold temperature controller.
- Size (diameter) of cooling channel
- Flow rate calculation of coolant
- Initial mold temperature
- Melt temperature
- Cooling time
- Cycle time
4. Ejection temperature of part
Confirm pump's pressure
capacity of mold temperature
controller./ Length, diameter of
external cooling hoses./ Coolant
inlet and outlet assignment.Implement transient cooling analysis
1. Confirmation of part design feasibility
2. Confirmation of mold design feasibility
Check, under stable cooling, surface temperature distribution of part @ ejection:
- Highest temperature
- Surface temperature distribution of moving half (surface temperature vs. area)
- Surface temperature distribution of stationary half (surface temperature vs. area)
- Distribution of surface temperature difference between moving and stationary halves
1. Cycle time in project quotation (Cooling
time = cycle time - filling time - packing &
holding time - mold open & close time)
2. Confirmation of part design feasibility
Provide material's HDT data and
information about its test.
Design change in cooling channels
(layout, length, size, location vs. part
& runner, inlet & outlet)
Obtain number of molding cycle to start
stable injection molding
(related to the set ejection temperature)
1. Confirmation of part design feasibility
2. Confirmation of mold design feasibility
3. Confirmation of process conditions
feasibility
Obtain cooling time needed to make part
solidified (part temperature under the set
ejection temperature)
1. Melt front advancement during filling stage
2. Distribution of part's average volumetric temperature @ end of filling
- Short shot risk evaluation (average volumetric temperature vs. stop-flow
temperature of material)
3. Distribution of melt front temperature
4. Distribution of cavity pressure @ end of filling
5. Pressure curve @ gate (single cavity model) and machine nozzle (full cavity
model)
6. Clamping force curve
7. Locations of weld lines
8. Locations of air traps
9. Distribution of cooling time
Check melt filling pattern within part cavity:
- Balance in melt filling?
- Hesitation?
- Weld line?
- Air trap?
Check melt filling balance cavity-to-cavity
Implement single-cavity model's
preliminary filling analysis
Implement full-cavitiy model's preliminary
filling analysis
PreliminaryFillingAnalysis
- Melt temperature
- Mold temperature
- Filling time
OK?
YesNo
OK?
No
Yes
OK?
No
OK?
No
Yes
Yes

3. 1. Melt front advancement during filling stage (indivudal cavity & full cavities)
2. Distribution of average volumetric temperature @ end of filling (individual
cavity and full cavities)
- Evaluate risk of short shot (average volumetric temperature vs. stop-flow
temperature of material)
3. Distribution of melt front temperature
4. Distribution of pressure @ end of filling (individual cavity and full cavities)
5. Maximum filling pressure @ machine nozzle
- Evaluate risk of short shot (maximum filling pressure vs. set value of
injection pressure vs. machine capacity)
6. Pressure curve @ machine nozzle
7. Curve of clamping force
8. Pressure curve @ gate
9. Locations of weld lines
10. Locations of air traps
11. Distribution of cooling time (part + sprue & runner)
1. Process conditions for packing & holding
stage (pressure and time)
1. Confirmation of mold design feasibility
2. Confirmation of process conditions
feasibility
1. Distribution of average volumetric temperature (individual cavity and full
cavities) @ end of packing @ holding stage
2. Distribution of pressure (individual cavity and full cavities) @ end of packing
@ holding stage
3. Distribution of density (individual cavity and full cavities) @ end of packing
@ holding stage
4. Distribution of volumetric shrinkage (individual cavity and full cavities) @
end of packing @ holding stage
5. Distribution of sink index (individual cavity and full cavities) @ end of
packing @ holding stage
6. Distribution of frozen layer (individual cavity and full cavities) @ end of
packing @ holding stage
7. Distribution of average volumetric temperature higher than ejection
temperature (individual cavity and full cavities) @ end of packing @ holding
stage
8. Pressure curve @ machine nozzle during packing & holding stage
9. Curve of clamping force during packing & holding stage
10. Pressure curve @ each gate
11. Pressure curve @ end-filling location of each cavity
12. Solidification time of each gate
13. Curves of shot weight & part weight
ExecutionPhase
s
1. Process conditions:
- Coolant inlets & outlets assignment on
mold
- Total length of cooling line from coolant
exit of mold temperature controller to its
entrance.
- Pressure drop between coolant exit and
entrance of mold temperature controller.
- Size (diameter) of cooling channel
- Flow rate calculation of coolant
- mold temperature
- Melt temperature
- Cooling time
- Ejection time + Mold open & close time
- Cycle time
2. Ejection temperature of part
Set process conditions of cooling stage as injection
molding machine interface.
- Define sensor node at each gate
- Define sensor node at end-filling location of each
cavity
- Define sensor node at the thickest location of each
cavity
- Define sensor node at the thickest location of full
model including sprue and runner (ex. bottom of
tapered sprue)
Confirm pump's pressure
capacity of mold temperature
controller./ Length, diameter of
external cooling hoses./ Coolant
inlet and outlet assignment.
Recommend process conditions
of cooling stage
Implement cooling analysis
Recommend process conditions
of packing & holding stage
Implement packing & holding analysis
Check quality of packing & holding effect:
- Effective pressure reaches gate and end-
filling location
- Packing time
- Holding time for gate solidification.
- Pressure distribution within cavity
Implement static filling analysis
FillingAnalysis
1. Confirmation of part design feasibility
2. Confirmation of mold design feasibility
3. Confirmation of process conditions
feasibility
Packing&HoldingAnalysis
Set process conditions of packing & holding stage as
injection molding machine interface.
- Define sensor node at each gate
- Define sensor node at end-filling location of each
cavity
Confirm machine capacity and
process conditions of packing &
holding stage
Check quality of melt filling:
- Melt filling balance intra-cavity (within cavity)
- Melt filling balance inter-cavity (cavity to cavity)
- Hesitation
- Weld lines
- Air traps
- Predicted maximum pressure vs. machine capacity
- Temperature change of melt
OK?
No
Yes
OK?
No
Yes

4. 1. Confirmation of process conditions
feasibility
1. Cooling time
2. Cycle time
3. Distribution of average volumetric temperature @ end of cooling (individual
cavity and full cavities)
4. Distribution of density @ end of cooling (individual cavity and full cavities)
5. Temperature curves @ gate, end-filling location, thickest location of part and
thickest location of full model
6. Distribution of part surface temperature @ end of cooling stage (individual
cavity and full cavities)
- Surface temperature of moving half
- Surface temperature of stationary half
- Surface temperature difference between moving and stationary halves
7. Distribution of mold box temperature (cross sections) @ end of cooling
stage
8. Efficiency of cooling channels
9. Temperature rise of coolant
1. Confirmation of part design feasibility
2. Confirmation of mold design feasibility
3. Confirmation of process conditions
feasibility
1. Displacement, dimension and shrinkage rate @ X direction
2. Displacement, dimension and shrinkage rate @ Y direction
3. Displacement, dimension and shrinkage rate @ Z direction
4. Value of co-planarity and warpage/ Deformed curve illustration made by
sensor node values
5. Contributors to warpage (total displacement): thermal effect, fiber effect,
PVT effect
6. Critical part dimensions
7. Differences among cavity to cavity.
1. Project simulation analysis report & presentation
2. Approval @ part design, mold design and process condition design
1. Mold design drawing
2. Project simulation analysis report
Confirm the latest version's mold
desig and its real fabricated status
Check simulation model's compliance with the latest version's mold design
drawing
- Runner & gate design (gate lication on part/ gate number/ gate type/ gate
dimension/ runner layout/ runner cross section/ runner diameter)
- Orientation of part in cavity
- Cooling channel design (mold box size LxWxH/ location of "part + sprue &
runner" in mold box/ cooling channel layout/ distance between cooling
channel and part/ distance between heater bar and part/ diameter of cooling
channel/ inlets & outlets assignment on mold)
SimulationReporting&
DesignApproval
Confirm product design and feedback Confirm mold design and feedback
Confirm process conditions and
feedback
Generate written simulation analysis report
& reporting
ration
1. 2D part design drawing (latest version)
2. 3D part design model (latest version)
3. Project simulation analysis report
Confirm 2D drawing and 3D model of the
latest version's part design
Check simulation model's compliance with
2D drawing & 3D model of the latest
version's part design
- Length x Width x Height
- Nominal thickness
- Maximum thickness
- Minimum thickness
WarpageAnalysis
Set conditions for warpage analysis:
- Glass fiber effect (turn on)
- In-mold constraint effect (turn on)
- At each cavity, define sensor nodes on
surface where specifies co-planarity
Provide property data about
glass-fiber-enhanced material
(elastic modulus, poisson ratio,
etc.)
Create and provide
material file
Implement warpage analysis
Check quality of warpage effect
- Co-planarity (amount of warpage)
- Contributors of warpage
* Thermal effect
* Fiber effect
* PVT effect
CoolingAnalys
Check quality of cooling effect:
- Cooling time
- Distribution of surface temperature of part @ ejection (end of cooling stage)
* Highest temperature
* Surface temperature distribution of moving half (surface temperature vs. area)
* Surface temperature distribution of stationary half (surface temperature vs. area)
* Distribution of surface temperature difference between moving and stationary halve
OK?
No
Yes
OK?
No
Yes
PVTeffect
PVTeffect
Thermaleffect
Fibereffect

5. 1. Specification of part warpage
ultComparison
Compare results of packing & holding
stage (actual vs. simulation)
- Maximum packing & holding pressure @
machine nozzle
- Pressure curve @ machine nozzle
- Packing time
- Holding time
- Shot weight & individual part weights
- Clamping force
1. Final injection molding conditions record for mass production
2. Final samples (5 shots)
3. Real data of filling stage:
3-1. 20%, 40%, 60%, 80%, 90% filled samples and photos
3-2. filling time on machine
3-3. maximum injection pressure on machine @ machine nozzle
3-4. pressure curve on machine @ machine nozzle
3-5. weld line locations and photos
3-6. air trap locations and photos
4. Real data of packing & holding stage:
4-1. maximum injection pressure on machine @ machine nozzle
4-2. pressure curve on machine @ machine nozzle
4-3. packing time on machine
4-4. holding time on machine
4-5. shot weight and individual part weights
4-6. clamping force
5. Real data of cooling stage:
5-1. Coolant flow rate @ exit & entrance on mold temperature controller
5-2. cooling time (= theoretical holding time set on machine + cooling time
set on machine, not including theoretical packing time set on machine)
5-3. Cycle time on machine
5-4. Temperature measured on mold surface: moving half/ stationary half/
difference between moving and stationary halves
6. Measured value of co-planarity and warpage
7. Sink mark locations and photos
8. Measured value of part length, width and height; and shrinkage rates at the
three directions
1. Injection molding process conditions
record
2. Project simulation analysis report
Check intented process conditions
Filling stage:
- melt temperature
- injection speed
- injection pressure
- machine capacity (temperature/ injection
speed/ injection pressure)
Packing & holding stage:
- packing & holding pressure
- packing & holding time
- machine capacity (packing & holding
pressure)
Cooling stage:
- mold temperature
- cooling time
- mold open & close time
- cycle time
- inlets & outlets assignment on mold
- pump pressure capacity of mold
temperature controller
Confirm process conditions/
machine capacity/ mold
temperature controller capacity
Compare results of filling stage (actual vs. simulation)
- Short shot status
- Filling time
- Maximum injection pressure @ machine nozzle
- Pressure curve @ machine nozzle
- Clamping force
- Weld line locations
- Air trap locations
1. Material filling pattern comparison: short shot samples vs. melt front
advancement
2. Filling time comparison: value on machine vs. value in simulation
3. Maximum injection pressure @ machine nozzle comparison: value on
machine vs. value in simulation
4. Pressure curve @ machine nozzle comparison: curve on machine vs. curve
in simulation
5. Clamping force comparison: value on machine vs. value in simulation
6. Weld line location comparison: sample vs. simulation
7. Air trap location comparison: sample vs. simulation
1. Maximum packing & holding pressure @ machine nozzle comparison: value
on machine vs. value in simulation
2. Pressure curve @ machine nozzle comparison: curve on machine vs. curve
in simulation
3. Packing time comparison: value on machine vs. value in simulation
4. Holding time comparison: value on machine vs. value in simulation
5. Shot weight & individual part weights comparison: value measured vs. value
in simulation
6. Clamping force comparison: value on machine vs. value in simulation
1. Compliance check list of part design, mold design and fabricated status, and
machine capacity (with simulation model and intended process conditions).
VerificationPhase
Pre-molding-trialPreparMoldingTrial
1. Process conditions in simulation analysis
report
2. Procedure of scientific injection molding
condition set up
Trial
(Process conditions for simulation analysis)
Trial
(Scientific injection molding condition set
up)
Check quality of molded part
- Short shot/ sink mark/ warpage
OK?
No
Yes
No
OK?
No
Yes

6. 1. Project simulation verification report & presentation
1. Simulation database
ClosingPhase
BuildDatabase
Build database of simulation
- Predict co-planarity & warpage
- Predict shrinkage rate
- Predict molded dimension
1. Relationship between actual co-planarity & warpage vs. output value in
simulation
2. Relationship between actual shrinkage rate vs. value in simulation
3. Relationship between molded dimension vs. value in simulation
(Data collected: plastic material/ part thickness (nominal, thickest, thinnest)/
material's maximum flow length/ part weight, length, width, height/ datum
length for warpage measurement/ datum area for co-planarity measurement/
perpendicular or parallel to material flow direction/ cavity number/ maximum
pressure during filling stage (actual value on machine vs. value in simulation)/
cavity pressure distribution @ end of filling stage (simulation)/ maximum
pressure during packing & holding stage (actual value on machine vs. value in
simulation)/ cavity pressure distribution @ end of packing & holding stage
(simulation)/ surface temperature difference between mold's moving and
stationary halves @ end of cooling stage (actual value vs. value in simulation)/
direction of material flow/ percentages of contributors to warpage (thermal
effect, fiber effect and PVT effect)(simulation)/ cavity pressure distribution @
end of cooling stage (simulation)/ part volumetric shrinkage distribution @ end
of cooling stage (simulation)/ part density distribution @ end of cooling stage
(simulation)/ etc.]
ClosingMoldingResultvs.SimulationRes
Compare results of cooling stage (actual
vs. simulation)
- Coolant flow rate & Reynold number
- Cooling time
- Cycle time
- Part surface temperature of moving half,
stationary half and its difference between
the two halves
Compare results of warpage stage (actual
vs. simulation)
- Sink mark location
- Co-planarity & warpage
- Shrinkage rate @ length, width and height
directions
For each cavity part:
1. Sink mark location comparison: sample vs. simulation
2. Co-planarity and warpage comparison: value measured vs. value in
simulation
3. Shrinkage rate comparison @ length, width, height directions: value
measured vs. value in simulation
4. Critical part dimension comparison: value measured vs. value in simulation
CompleteVerification&
Reporting
Generate written simulation verification
report & reporting
1. Coolant flow rate & Reynold number comparison: value measured or
claculated vs. value in simulation
2. Cooling time comparison: value on machine (= holding time set on machine
+ cooling time set on machine, not including packing time set on machine) vs.
value in simulation
3. Cycle time comparison: value on machine vs. value in simulation
4. Surface temperature comparison of mold's moving half: value measured vs.
value in simulation
5. Surface temperature comparison of mold's stationary half: value measured
vs. value in simulation
6. Comparison of surface temperature difference between mold's
moving/stationary halves: value measured and calculated vs. value in
simulation
1. Comparison list of actual molded result and simulation analysis
(Note: Judgement "Ok or not" here refers to satisfaction of the completeness
of comparison work, not about satisfaction of the accuracy of simulation result
whose related effort should be made before molding trial.)
OK?
No
Yes
Close