Scientific Molding, In-Cavity Sensors, and Data Management - MAPP

Scientific Molding,
In-Cavity Sensors,
and Data Management
MAPP Webinar
August 19, 2009
Presented by:
Ken Fassett
RJG, Inc.
1

What is Scientific Molding?
You can know the name of a bird in all the
languages of the world, but when you’re
finished, you’ll know absolutely nothing whatever
about the bird… So let’s look at the bird and see
what it’s doing - - that’s what counts…
Richard Feynman
US Educator & Physicist
2

Why is
Scientific Molding
Important?
3

One Word
Competition
4

Knowledge is the Only
Sustainable Competitive Advantage
5

Patents Are NOT!
The best offence is a good defense, right
…where could gas assist technology be today?
6

Closed Borders are NOT!
Ask me about a certain injection
molding industry in Europe…
7

Technology is NOT!
Utilization of technology may be…
which is knowledge based!
8

The best technology in the world,
whether from Germany, or Japan, or the US,
is available for purchase in low-cost labor countries
AND THEY CAN AFFORD IT!
9

“Is it better for the trained people to leave
or the untrained people to stay?”
10

Therefore, their cost of quality is HUGE!
11

Knowledge is OUR only
Sustainable Competitive Advantage
12

Scientific Molding
•>2,500 people from the US IM industry have gone through
an RJG 3 day Scientific Molding seminar since 1991
•>1200 people from the US IM industry have gone through
an RJG 10 day Scientific Molding hands-on course since
1999
13

Knowledge
• A Constant Pursuit
• Buy it, or Invest in it
14

Why is
Scientific Molding
Important?
15

The Wall of Shame
‣ Short Shots
‣ Sink and voids
‣ Dimensional Variations
‣ Warp
‣ Flash
Cosmetic rejects like:
Splay
Specs
Off color
Are not generally process control related problems
16

Not So Independent Variables in Injection Molding
Screw
Run Time
Material
Properties
Backpressure
Drying
Material
Supplied
Colorant or
other additives
Shot Size
Items in rounded rectangles are
equipment setup parameters
Transfer Position or
Cavity Pr. Setpoint
Fill ->Pack Position
Pack Speed
Hold Pressure
Plastication Rate
(i.e. screw RPM)
Melt
Temperature
Viscosity
Pressure
Profile
Barrel
Temperatures
Hot Runner
Variation
Flow Rate
Coolant
Inlet
Pressure
Cooling
Channel
Condition
Coolant
Outlet
Pressure
Melt temperature affects
both cooling rate and mold
surface temperature
Coolant
Flow Rate
Coolant
Delta
Pressure
Check Ring
Performance
Cooling
Mold
Temperature
Speed
Settings
Coolant
Temperature
Cooling Time
(Mold Clamped time)
Times: Cycle,
Mold Open etc.
Cavity
Shape
(deflection)
9/5/07
Art Schubert
© 2007 RJG Inc.
17

• Material Viscosity Variation
– Velocity induced
– Inherent
• Imbalance
• Pressure Loss
• Machine (IN)Dependence
– Pressure vs. Intensification Ratios
– Linear Shot Measurement vs. cavity volume
18

Material Variation Over Time
Expect at Least a
20% viscosity Variation
This Is Normal
19

If You have:
Hold On Tight
• New Machines
• New Molds
• Virgin Plastic (with a 20% normal
viscosity variation over time)
• Automatic Cycle
• Air Conditioned Molding Rooms
The best you can expect is that
cavity pressure will vary just
under ________%???
Understanding why is key to
developing a robust Automated
process control strategy!
20

What is Scientific Molding?
You can know the name of a bird in all the
languages of the world, but when you’re
finished, you’ll know absolutely nothing whatever
about the bird… So let’s look at the bird and
see what it’s doing - - that’s what counts…
Richard Feynman
US Educator & Physicist
22

A Strategy Based on the
4 Plastics’ Variables
“Helps Injection Molders Succeed”
Temperature
Flow Rate
Pressure
Cooling
23

A Concept - Using Data to Verify
Process Parameter
Shot
Fill Time
Plastic
Pressure
1/t
Effective
Viscosity
30000
1 0.20 8720
5.0 1,744
27000
10
2 0.22 8160
4.55 1,795
24000
3 0.30 5440
4 0.62 4640
3.33 1,632
1.61 2,877
21000
9
5 1.47 2969
.68 4,364
18000
8
6 1.52 2960
7 1.92 6260
.65 4,499
.52 12,019
15000
8 2.13 8160
.47 17,381
12000
7
9 2.52 8560
10 3.31 8360
.40 21,571
.30 27,672
9000
6000
6
5
3000
4
3
2
1
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
.50
24

Analyzing Plastic Viscosity
Integral data can be broken down into fundamental parts such as the
integral during fill.
The area under the hydraulic pressure curve during fill represents the
sum of the resistance to flow during fill and, therefore, represents the
viscosity of the plastic.
Effective Viscosity or Fill Integral
PRESSURE (PSI)
Fill
Plastic
Injection
Pressure
Pack & Hold
0
Start Mold
Fill Time
TIME (SECONDS) 16
25

Systematic Approach
26
1.Part Design
2.Gate & Runner Balance
3.Press Selection
4.Process Development

Part Design
High Risk Part Design
Square corners equals risk of 5
Additions to walls equals risk of 5
Change in wall thickness equals risk of 5 if
gate location is on opposing end of part
Low Risk Part Design
Square corners equals risk of 2
Additions to walls equals risk of 5
Change in wall thickness equals risk of 3
27

Part of process control involves knowing if and when gate
seal occurs on all cavities for all molds.
Without Instrumentation
we use part weight study
With instrumentation we use post
gate psi curve including hold time
Gate Seal = Best Dimensional Control
Allowing discharge or backflow out of the gate after a set period of time:
‣ Can reduce compressive stresses near the gate
‣ Can affect pressure gradient caused warpage
28

Pressure Loss Study
15,256 ppsi
9,628 ppsi
8,343 ppsi
What happens if the
viscosity changes?
5,245ppsi
29

Intensification Ratio
Not Enough
Pressure
30

Mold Transfer
Machine A
Machine B
220 ton clamp force
‣ 2600 psi hydraulic pump
‣ General Purpose Screw
‣ 12 inch linear shot capability
‣ Maximum Injection Speed 10.2 in/sec
‣ Tie Bar Spacing is 17in x 17in
‣ 1.78 in diameter screw
‣ 12.2:1 Intensification Ratio
220 ton clamp force
‣ 2600 psi hydraulic pump
‣ General Purpose Screw
‣ 12 inch linear shot capability
‣ Maximum Injection Speed 10.2 in/sec
‣ Tie Bar Spacing is 17in x 17in
‣ 2.25 in diameter screw
‣ 9.85:1 Intensification Ratio
31

Machine Dependent
Machine A
750 psih
Machine B
32

Machine Dependent
9,150 ppsi
Machine A
750 psih
7,388 ppsi
Machine B
33

Machine INDEPENDENT
Hold Pressure
Machine A Plastic Machine B
750 psi h
9,150 ppsi 929 psi h
Settings
R I : 9.85:1
Screw Dia: 2.25”
R I : 12.2:1
Screw Dia: 1.78”
34

Intensification Ratio
Machine A
750 psih
9,150 ppsi
Machine B
929 psih
35

What about VOLUME of Plastic?
Machine A
R I : 12.2:1
Screw Dia: 1.78”
Plastic
Settings
Machine B
R I : 9.85:1
Screw Dia: 2.25”
Transfer Position
1.855 in.
4.617 in 3
1.161 in.
36

Plastic Temperature
Plastic Temp
Machine A
Barrel Temp
Zone 1-4
475
Plastic
Settings
Melt Temp
460
Machine B
Barrel Temp
Zone 1-4
482
37

Cooling
Mold Surface Temp
Machine A
Thermolator
Setting
148
Plastic
Settings
Steel Surface
145
Machine B
Thermolator
Setting
150
38

Matching Using Data
39

And for the Toughest Jobs...
Cavity
Pressure
Probably no more than 20% of molds
40

Monitoring and Containment
For Process Control
The Goal:
‣ No escapes of bad parts to the
downstream customer
41

Successful Molders
Now Realize That:
What Happens in the Cavity
Stays in the Part
42

The Problem
“Bad” parts get sent downstream
to the customer:
‣ Short Shots
‣ Sink and voids
‣ Dimensional Variations
‣ Warp
‣ Flash
Bad = Other than Normal
43

Critical Containment Applications
Here’s the 20%
‣ Monitor Cavity Pressure on high volume and high
problem jobs
• End of Cavity to detect and contain short shots and observe
variation
• Gate end to detect gate seal and detect variation over the
entire part
Use Alarm light tree or Alert to warn of problems
Contain abnormal parts
This is the start of Process Monitoring and
Control from the Plastics’ Point of View
44

Abnormal Part Containment
45

You Can’t Manually Sort Your Way To
World Class
‣ 4 sigma companies can produce 6 sigma products
through enormous amounts of rework
‣ They can’t raise their prices to recapture their costs
because they must price their products
competitively
‣ Business quality is highest when cost is at its
absolute lowest for both the producer and the
consumer
46

Constant Machine Conditions:
Are the parts the same?
REMEMBER: What happens in the cavity stays in the part!
47

Which Do We Watch?
‣ Cavity Pressures:
• Integrals are usually best
‣ Mold Surface Temperatures Semi-Crystalline Aps
• Cooling temperature and time
• Effective Melt Temp
• Can be used for full cavity monitoring in
high cavitation mold
‣ Material Condition:
• Effective Viscosity
This is Process Control from the
Plastic’s Point of View using containment
It’s The Best!
48

In Mold Gate End Pressure
20,000
PRESSURE (PSI)
Peak PSI
• Fill Dynamics
• Correct Transfer
• Pack Rate/Time
• Peak PSI
• Static Pressure Gradient
• Cooling
• Gate Seal
• Best For Control
Pack Rate
Cooling Rate
Area or
Integral
Reduction due
to Discharge
0
Full
Packed
TIME (SECONDS) 15
49

In Mold End of Cavity Pressure
20,000
PRESSURE (PSI)
Peak PSI
• Full Part
• Pack Rate/Time
• Peak PSI
• Cooling
• Most Variable
• Best For Monitoring
No Dynamic PSI
Pack Rate
Cooling Rate
0
TIME (SECONDS) 15
50

The Opportunity
51

Relate Directly to Pressure Variation
in the Cavity!
‣ Short Shots
‣ Sink and voids
‣ Dimensional Variations
‣ Warp
‣ Flash
52

Correlate Your Data To Part Quality
29,341
29,723
30,642
31,325
32,445
32,889
33,021
34,555
Cavity Pressure
Cycle Integral
48.010
48.025
48.040
48.055
48.070
48.085
48.100
48.115
Dimensions
Looks
Good
53

Auto Alarm Capability
Sample groups can be collected
in the eDART TM Software.
54

Auto Alarm Capability
Automatically correlate data collected by the
eDART System TM to your critical part attributes
55

Close the Loop
56

The Value of Data
Viscosity
Cavity
pressure
Can SQC find the 4 bad parts??
57

Data Taken Over Time is effective for
Process Monitoring / Abnormal
Cycle Detection
Know
Immediately
when
something
has changed
58

Data Management
59

This?
Or this?
60

Why would we want to guess what is going
on when we can see – with data?…
61

Which Machine Process
is Set-up Correctly?
62

Which Machine Process
is Set-up Correctly?
Correct Set-Up
Incorrect Set-Up
63

The Match Meter
‣ In a glance see if the process is set up correctly
‣ See if the viscosity has changed
64

How do you determine whether
ALL OF YOUR MACHINES AND
PROCESSES
are set up correctly?
65

All the Machine Meters
on One page
66

Advanced System Overview
67

How was your plant running
LAST NIGHT?
68

ASO History
69

Check out the problem with a press
without leaving your desk!
70

ASO Process Viewer
71

But what did the data look like back
when the Machine Match went into the red?
72

Analyzer Mode
73

When problems occur,
how do you know what happened?
The data is stored on the eDART!
74

What is Your
Quality Accountability?
75

So, when you want to know how
your plant is running,
what data do you want to rely on?
76

This?
Or this?
77

Data Management: The Goal
‣ To Know What You Don’t Know
• Intermittent Process Variation
• Breakdowns
• Bad set ups
• Bad material
Dryness
Viscosity
78

Systematic Approach
79
1.Scientific Molding
2.Cavity Pressure Technology
3.Data Management

How RJG Can Help
Full Service Provider for Injection Molders
Training
‣Seminars
‣Master Molder Certification
‣Hands On Workshops
Process Monitoring/Control
‣ Machine
‣ Cavity Pressure
80

Make It Happen!
The greatest difference between those that have
done a lot and those that accomplish little:
High achievers set specific timetables to accomplish
seemingly impossible tasks and routinely meet or
exceeded them.
81
July 20, 1969

Let us help you in your
Transformation Process!
82

At RJG,
in all that we teach and
in all that we do,
our mission is..
Helping
Injection Molders
Succeed
www.rjginc.com
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