Date post: | 12-Jul-2015 |
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Introduction to VELProfile Products
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Introduction
> Polymer (Plastic) processing– Traditionally, development is a black box and like an art.
Extruder
Injection molding
MANDREL
BODY
Extrusion
Others
Blow molding
Others
Thermoforming
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Profiles, pipes
Round products
Flat products
Experiments on a physical extrusion line can help us to understand the process better
But - to see what is happening inside theequipment is very difficult or impossible
- not all variables can be measured- to study the effects of equipmentmodifications is difficult and expensive
Extrusion Equipment
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Extrusion
Profiles, pipes
Round products
Flat products
in which the material is:
- melted & pumped ( Extruder )- shaped ( Dies)- cooled ( Cooling systems )
- pulled - off
During the processing, some problems can occur such as material degradation .
a continuous process
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Virtual Extrusion Laboratory™ applications (VEL)
VEL Products V6.5
Extrusion Applications• Extruder module• Flat die module• Multi-Layer module• 2D FEM module• 3D FEM module• Profile Module• …
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Compuplast™ Virtual Extrusion Laboratory
> Benefits of virtual experiments (Simulations):– detailed information
– quantifiable effects of changes
– fast response and immediate feedback
– lower cost of experiments
– no risk of equipment damage
– significance of variables
– minimize number of physical experiments
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Profile Die Module
> The VEL™, Profile Die module features:– improved graphical design interface
– local mass throughput/area integration
– 'slip at the wall' boundary condition
– improved image/results saving capability
– improved Material Database interface
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There is an infinite number of profile shapes
Profile Dies
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The problem is unbalanced flows (material swell cannot compensate the unbalancing)
Aim Reality
Profile DiesCommon Problem in Profile Extrusion
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Velocity
Shear stress
Expected high swell
Many people believe that the swell can balancean unbalanced flow.
Extrudate swellUnbalanced Velocities
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The material will not swell, it will bend and wave becausethis needs less energy.
Extrudate swellProfiles, Unbalanced Velocities
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The desired final profile shape must be used for balancing.
Aim
The profile deformation outside the die is usually nearly isotropic in width and thickness
Profile DiesProfile DiesFlow Balancing Flow Balancing MethodMethod
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This lead to development of the COMPUPLAST ®
Cross-Flow Minimization Method (CFMM)
Die Design Approach
> Potentially infinite possible ways of designing the profile
> Must consider efficient design procedure and manufacturing method
> Undesired cross-flows should be eliminated
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Cross-Flow Minimization Method
> Based on forming logical flow patterns
> Directing the proper amount of material to each are a of the die
> Minimizing undesired cross-flows or material redistribution
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Unbalanced Design
HIGH FLOW AREA
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高流動區域高流動區域高流動區域高流動區域
HIGH FLOW AREA
Unbalance Design
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Balanced Profile
Flow restrictions
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Case Study
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Simple Part Shape
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Die Exit Shape
> Before the procedure can be applied, the basic shap e of the profile at the exit of the die must be specifie d.
> This shape is determined by considering the materia l, draw down, cooling/calibrator design and ease of operation
This is were experience can help!
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Lofted Shape
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Lofted Shape
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Add Cutting Planes for Plates
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Front and rear view of die plates
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Unbalanced Flow Sections
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Unbalanced Flow Sections
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Flow Balancing
> The next step is the balance the flow in each cross section using the VEL Profile Die Module.
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Required Part Shape
20%
20%
60%
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Unbalanced Flow Analysis
Insufficient Flow in these channels
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Original Die DesignProduction Rate Limited to 1 m/min !
Die developed using a linear transition from the circular adapterto the required final shape and cut with via wire EDM.
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Initial Plate Cross Sections Simulation indicates unbalanced flows
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Balancing of the Die Cross-Section
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Balancing of First Cross Section
Unbalanced Balanced
20%
20%
8%
8%84% 60%
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Unbalanced Balanced
20%
20%
Balancing of First Cross Section
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Unbalanced Balanced
20%
20%
Balancing of First Cross Section
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Unbalanced Balanced
40%
60%
Balancing of First Cross Section
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Balanced Cross Sections
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This is total die pressure drop generated on the die
Result – Pressure Drop
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Balanced Cross Sections
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Balanced Sections Exported/Importedto CAD & Lofted
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Balanced Flow Field
The die “land” length is sized to give the majority (50 – 75%) of the total die pressure drop
The die “land” cross-section is normally uniform
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Concluding Remarks
> Original cross section shape had poor flow balancin g and restricted line speed to about 1 m/min before p art was out of tolerance.
> Additional time required to balance the 4 cross sec tions was about 6 hours
> Balancing the cross sections allowed the line speed to increase to over 4 m/min.
400% Increase in production rate with a 6 hour time investment !
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VEL 與 Polyflow 軟體比較
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Polyflow 特色
> POLYFLOW軟體具有以下特點: – POLYFLOW主要包括幾個模組:POLYMAT; POLYDATE;
POLYSTATE,它們由一個主控程式POLYMAN來執行– POLYFLOW具有多種多樣的粘性模型、內容豐富的粘彈性材料庫– POLYFLOW所採用的變形網格、接觸演算法、以及網格重疊技術
,提高計算結果的準確性。– POLYFLOW與GAMBIT、IDEAS、PATRAN都具有資料介面,可以使用它們生成的網格,並且POLYFLOW內部嵌套GAMBIT軟體。POLYFLOW支援多種類型的網格。
– 現POLYFLOW放棄其自身後處理器即flpost, 採用FieldView, 以OEM軟體捆綁和作為協力廠商支援.
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VEL特色
> VEL軟體具有以下特點:– VEL從前處理、數值計算方法、後處理,皆由CompuPlast 所獨立開發完成,整體而言使用上相當直覺與便利
– VEL使用參數化的方式進行幾何建立,前處理建立上相當快速,而後續的幾何設變也很容易。在前處理網格化程序,此部份由軟體內部自動生成,使用者不須手動建立網格
– VEL支援常見的泛牛頓與黏彈性模型,並內建多種常見塑料之資料庫,材料模型與資料庫內容每年持續進行更新
– VEL使用穩健的數值分析方法,計算速度相當快速,且能同時兼顧數值結果的合理準確性
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VEL 軟體分析流程Geometry Setting Project Setting
Material Selection
Results
參數化幾何建立專案整合 材料選擇
數值計算
結果解析
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軟體比較表
VEL Polyflow
前處理前處理前處理前處理
大部分模組已採用大部分模組已採用大部分模組已採用大部分模組已採用””””參數式參數式參數式參數式””””輸入方式進行幾何設定輸入方式進行幾何設定輸入方式進行幾何設定輸入方式進行幾何設定,,,,使用使用使用使用者不需網格化程序者不需網格化程序者不需網格化程序者不需網格化程序,,,,使用上相使用上相使用上相使用上相當便利與快速當便利與快速當便利與快速當便利與快速。。。。使用者不需太使用者不需太使用者不需太使用者不需太多電腦繪圖基礎多電腦繪圖基礎多電腦繪圖基礎多電腦繪圖基礎
使用者需經由傳統點使用者需經由傳統點使用者需經由傳統點使用者需經由傳統點、、、、線線線線、、、、面面面面、、、、體積體積體積體積、、、、網格流程進行幾何建立網格流程進行幾何建立網格流程進行幾何建立網格流程進行幾何建立,,,,前處理較費時前處理較費時前處理較費時前處理較費時。。。。使用者需具備使用者需具備使用者需具備使用者需具備CAD與網格相關基礎與網格相關基礎與網格相關基礎與網格相關基礎
材料庫材料庫材料庫材料庫支援常用泛牛頓與黏彈性支援常用泛牛頓與黏彈性支援常用泛牛頓與黏彈性支援常用泛牛頓與黏彈性
Model支援多種泛牛頓與黏彈性支援多種泛牛頓與黏彈性支援多種泛牛頓與黏彈性支援多種泛牛頓與黏彈性
Model
解算器解算器解算器解算器
使用適化的方程式進行分析使用適化的方程式進行分析使用適化的方程式進行分析使用適化的方程式進行分析,,,,數值分析過程相當穩定數值分析過程相當穩定數值分析過程相當穩定數值分析過程相當穩定,,,,且能且能且能且能於計算時間與結果準確度取得於計算時間與結果準確度取得於計算時間與結果準確度取得於計算時間與結果準確度取得平衡平衡平衡平衡。。。。使用者不需具備數值分使用者不需具備數值分使用者不需具備數值分使用者不需具備數值分析基礎析基礎析基礎析基礎
支援多種數值計算方式支援多種數值計算方式支援多種數值計算方式支援多種數值計算方式,,,,分析分析分析分析結果或許較精確結果或許較精確結果或許較精確結果或許較精確,,,,但相對而言但相對而言但相對而言但相對而言,,,,隨著使用的方法越多其計算越隨著使用的方法越多其計算越隨著使用的方法越多其計算越隨著使用的方法越多其計算越複雜與龐大複雜與龐大複雜與龐大複雜與龐大,,,,數值將越不容易數值將越不容易數值將越不容易數值將越不容易收斂收斂收斂收斂。。。。使用者需具備數值分析使用者需具備數值分析使用者需具備數值分析使用者需具備數值分析基礎基礎基礎基礎
後處理後處理後處理後處理 VEL專用後處理程式專用後處理程式專用後處理程式專用後處理程式,,,,使用上使用上使用上使用上相當直覺與便利相當直覺與便利相當直覺與便利相當直覺與便利
使用第三方軟體使用第三方軟體使用第三方軟體使用第三方軟體-FieldView ,,,,非非非非Polyflow 專用後處理程式專用後處理程式專用後處理程式專用後處理程式,,,,使用上較為複雜與不便使用上較為複雜與不便使用上較為複雜與不便使用上較為複雜與不便
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結論
> Polyflow 支援多種材料模型與數值計算方法,但相對的軟體複雜度較高,使用者需具備許多專業知識,例如電腦繪圖、塑膠材料知識、數值分析等,軟體上手較為困難
> VEL的軟體介面相當具親和力,其分析快速且數值計算相當穩定,使用者不需太多專業能力即可上手使用
> 整體而言,VEL較符合工業上的期望– 軟體分析快速,符合縮短研發週期– 軟體入門需求低,適用人員層面較廣泛
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