https://www.avient.com/investor-center/news/avient-announces-quarterly-dividend-0
Rose, Vice President, Corporate Communications, Avient Corporation, +1 440-930-3162, kyle.rose@avient.com
https://www.avient.com/investor-center/news/polyone-hold-fourth-quarter-2016-conference-call
Rose, Vice President, Corporate Communications, PolyOne Corporation, +1 440-930-3162, kyle.rose@avient.com
https://www.avient.com/investor-center/news/polyone-present-goldman-sachs-2016-basic-materials-conference
Rose, Vice President, Corporate Communications, PolyOne Corporation, +1 440-930-3162, kyle.rose@avient.com
https://www.avient.com/investor-center/news/polyone-corporation-announces-quarterly-dividend-4
Rose, Vice President, Corporate Communications, PolyOne Corporation, +1 440-930-3162, kyle.rose@avient.com
https://www.avient.com/investor-center/news/polyone-hold-third-quarter-2016-conference-call
Rose, Vice President, Corporate Communications, PolyOne Corporation, +1 440-930-3162, kyle.rose@avient.com
https://www.avient.com/news/polyone-present-2014-keybanc-capital-markets-basic-materials-packaging-conference
Media Contact:
Kyle Rose
Director, Corporate Communications
PolyOne Corporation
+1 440-930-3162
kyle.rose@avient.com
https://www.avient.com/news/polyone-present-wells-fargo-2015-industrial-and-construction-conference
Media Contact:
Kyle Rose
Director, Corporate Communications
PolyOne Corporation
+1 440-930-3162
kyle.rose@avient.com
https://www.avient.com/news/polyone-present-baird’s-2014-industrial-conference
Media Contact:
Kyle Rose
Director, Corporate Communications
PolyOne Corporation
+1 440-930-3162
kyle.rose@avient.com
https://www.avient.com/sites/default/files/2022-04/Avient Announces Agreement to Acquire Dyneema_0.pdf
Rose
Vice President, Corporate Communications
Avient Corporation
+1 440-930-3162
kyle.rose@avient.com
mailto:giuseppe.disalvo@avient.com
mailto:kyle.rose@avient.com
NEWS RELEASE
https://www.avient.com/sites/default/files/2020-10/2020-gravi-tech-design-guide-.pdf
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Four Main Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Obtain Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Strategy Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Defects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Angel Hair. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Burns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Delamination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Dimension – Small . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Dimension – Large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Distortion / Deformation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Flash. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Jetting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Plate-Out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Short Shot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Sink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Splay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Surface Finish. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Gate Vestige. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Voids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Warpage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Weld Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
The Injection Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Non-Return Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Nozzle Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Important Advice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
The Clamping Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Mold Design Guidelines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Determining Cooling Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Cooling Line Spacing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Design Guide 5
CHAPTER 1 | PRODUCT SUMMARY
GRAVI-TECH™ DENSITY MODIFIED FORMULATIONS
High-Performance Alternative to Lead and Other Traditional Metals
PRODUCT DESCRIPTION
Gravi-Tech™ polymer-metal composites offer
a high-performance thermoplastic-based
alternative to lead and other traditional dense
metals.
Design Guide 25
CHAPTER 6 | TROUBLESHOOTING
FOUR MAIN AREAS
Check all of these areas before changing
anything in the process. 4
Mold
• Cooling channel obstructed
• Vent plugged
• Core bent
• Damaged tooling
• Runner shutoff partially closed
• Part stuck
• Gate plugged
• Tooling shifted
Machine or Equipment
• Thermolator unplugged
• Variac unplugged
• Material bridging
• Drying turned off
Material
• Contamination
• Lot change
• Poor mixing
• Material dust
• Material not dried
Process
• Changes
- Documented
- Undocumented
OBTAIN INFORMATION
Obtain as much information as possible about
the defect
• Ask operators
- When did it start occurring
- Is it on every part
• Set-Up Tech
- Is this how the process started up
- Has this happened before
STRATEGY THEORY
Part Consistency
• Does the defect happen randomly or
every part
Machine Cycle
• Is it consistent
• Injection pressure limited
• Screw hesitation
Check Settings
• What changed
• Did a heater band turn off
• Are valves sticking
Determine at which point in the process the
defect occurs
• Injection
• Hold time
• Gate frozen
• Ejection
• Part deforming due to ejection
• Do a short shot progression
Change ONE setting at a time, and allow time
for adjustment to affect the defect
• Change speeds and pressures first
- Take immediate effect and easily reversed
• Change temperatures last
- Take time to settle in
• Extreme Measures
- Put mold into different press
26 Gravi-Tech
Damages or worn
gate/sprue
Temperature settings
overriding or changed
Sprue breaks too soon
Lower viscosity lot
Nozzle too hot
Cooling time too low
Not enough
Reduce gate size
Increase cooling in
gate areas
Check gate for
blockages
Install a shorter nozzle or
specialty nozzle
Ensure nozzle is
temperature controlled
Dry material Add screw
Reduce nozzle tip
Angel Hair
• Commonly occurs on sprues and hot runner gates
• Long, thin strands of plastic material, which can tangle and cause components to stick together
• Can cause ejection problems
Root cause: Gate or sprue is not frozen and draws molten material with the sprue/part during mold
open phase.