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en:scaleup_modul:scaleup_modul [2024/11/17 19:50] – [Theoretical principles] neelesten:scaleup_modul:scaleup_modul [2025/09/04 13:13] (aktuell) – [Theoretical principles] neelest
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 ===== Operation of the scale-up module ===== ===== Operation of the scale-up module =====
-The Scale-Up module offers the option of scaling processes to larger or smaller production plants. It enables the adjustment of critical process variables and the simulation of the effects of these changes. The module is operated via the menu item Project Scale-Up, which takes you to a detailed dialogue window in which both output variables of the current process and adjustments for the target process can be made.+The Scale-Up module offers the option of scaling processes to larger or smaller production plants. The module is operated via the Project Scale-Up menu item, which takes you to a detailed dialogue window in which both the output variables of the current process and adjustments for the target process can be made. 
 + 
 +You can choose between the target of a constant temperature difference (standard) and a constant heat flux density. A scale-up at constant temperature difference provides a very accurate scale-up. A scale-up at constant heat flux density is a theoretical scale-up operating point, which produces a higher mass throughput, but at the expense of scale-up accuracy. In particular, a later melting end is to be expected here. \\ 
 +A ‘target’ greater than 0.66 is recommended, however, the delayed melting process must always be taken into account when scaling up away from the constant temperature difference! 
 ====Output variables of the process==== ====Output variables of the process====
  
-The dialogue box that opens first displays the output variables of the process that describe the current operation of the machine. These variables include:+In the dialogue that opens, the output variables of the process that describe the current operation of the machine are displayed first. These variables include:
  
-  *     **Screw diameter:** The diameter of the screw, which influences the conveying capacity and the pressure build-up in the extruder. +  * Screw diameter 
-  *     **Screw length:** The length of the screw, which is decisive for material preparation and pressure build-up. +  * Screw length 
-  *     **Mass temperature:** The temperature of the melted plastic material, which influences the material properties and flow characteristics.+  * Mass temperature at the screw tip
  
 These parameters define the starting point for the calculation and simulation of a scaled process. These parameters define the starting point for the calculation and simulation of a scaled process.
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 You can define new variables for the target process that correspond to the requirements of the new machine or the new process. This provides flexibility to adapt the process to different machines or requirements. You can define new variables for the target process that correspond to the requirements of the new machine or the new process. This provides flexibility to adapt the process to different machines or requirements.
-If the target process contains a degassing zone, the Scale-Up module offers the option of calculating a modified length of the screw including the degassing zone. This is particularly important in order to correctly map the material flow and pressure conditions in the extruder.+If the target process contains a degassing zone, the scale-up module offers the option of calculating a modified length of the screw including the degassing zone (see [[en:scaleup_modul:scaleup_modul#Modified length of degassing zones|]]). 
 + 
 +====Creating and simulating the scaled process==== 
 + 
 +By pressing the //OK// button, the scaled process is created and calculated based on the adjustments made.
  
 {{ :scaleup_modul:rex171_scale_en_002.png?nolink |}} {{ :scaleup_modul:rex171_scale_en_002.png?nolink |}}
  
-====Creating and simulating the scaled process====+====Comparison of the processes====
  
-By pressing the //OK// button, the scaled process is created and simulated based on the adjustments made. The simulation provides a detailed calculation that allows you to understand the effects of the changes on the process. +After the calculation, a new window opens, which displays the results of both processes - both the initial process and the target process - in detail. This makes it easy to compare and check the calculations.
-====Calculation report and analysis====+
  
-After the calculation, a calculation log opens, which shows the results of both processes - the initial process and the target process - in detail. This makes it easy to compare and check the calculations.+By default, a diagram showing the model law exponents and a diagram comparing the pressure curve and the melting curve are opened. Other curves and individual values can also be selected for comparison. The ‘//Open all standard diagrams//’ button creates all common curves as separate diagrams, allowing a detailed comparison of the processes.
  
-Pressing the //OK// button again opens the analysis window, in which the diagram of the model law exponents is displayed in the first step. In this diagram, the speed exponent (Psi) is shown on the X-axis. The gear depth exponent (Chi) is shown on the Y-axis.+Below the diagrams, you can show and hide the two machines involved in the scale-up process. If the screw lengths are different, you can right-click on the screw display to set either a common x-axis or separate x-axes for each process. 
  
-This graphical representation allows you to analyse the interactions between speed and gear depth and to understand their influence on the process. +{{ :scaleup_modul:rex171_scale_en_003.png?nolink&1000 |}}
-You also have the option of analysing and comparing the results of the two processes, i.e. the initial process and the target process, in detail. Below the diagrams, you can show and hide the two machines involved in the scale-up process. This enables a direct visual comparison of the process parameters and machine configurations.+
  
 ====Creation of the scaled process==== ====Creation of the scaled process====
  
-If the scaled process meets the desired requirements, you can create it by clicking the //Create process// button. This takes the simulated process as the new starting point for the actual production.+If the scaled process meets the desired requirements, you can create it by clicking the ‘//Create process//’ button. The process can be named and saved in the project directory so that the scaled process is also listed in the project explorer.
  
-{{ :scaleup_modul:rex171_scale_en_003.png?nolink |}}+The aim of the scale-up is to generate a process with a larger or smaller diameter while maintaining or changing the screw length and maintaining or changing the final melt temperature. The screw diameter or the screw length must be changed compared to the initial process.
  
-The aim of the scale-up is to generate a process with a larger or smaller diameter while maintaining or changing the screw length and maintaining or changing the final melt temperature. The screw diameter or the screw length must be changed in comparison to the initial process. 
  
 ===== Theoretical principles ===== ===== Theoretical principles =====
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 |kappa | $\kappa$ | viscosity shear rate exponent | $\kappa = -log\left( \frac{\eta}{\eta_0}\right) \bigg/ log\left( \frac{\dot{\gamma}}{\dot{\gamma}_0}\right)$| |kappa | $\kappa$ | viscosity shear rate exponent | $\kappa = -log\left( \frac{\eta}{\eta_0}\right) \bigg/ log\left( \frac{\dot{\gamma}}{\dot{\gamma}_0}\right)$|
 |Xi | $\xi$ | mass temperature exponent | $\xi = -log\left( \frac{\vartheta}{\vartheta_0}\right) \bigg/ log\left( \frac{\dot{\gamma}}{\dot{\gamma}_0}\right)$| |Xi | $\xi$ | mass temperature exponent | $\xi = -log\left( \frac{\vartheta}{\vartheta_0}\right) \bigg/ log\left( \frac{\dot{\gamma}}{\dot{\gamma}_0}\right)$|
-|Omega| $\omega$ | length exponent | $\omega= log\left( \frac{\frac{\frac{L}{D}}{\left( \frac{L}{D}\right)_0}\right) \bigg/ log\left( \frac{D}{D_0}\right)$|+|Omega| $\omega$ | length exponent | $\omega= log\left( \frac{\frac{L}{D}}{\left( \frac{L}{D}\right)_0}\right) \bigg/ log\left( \frac{D}{D_0}\right)$|
  
 with with
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   ***constant heat flux density**: Assumption that the area-related heat flow of the cylinder temperature control remains identical.\\   ***constant heat flux density**: Assumption that the area-related heat flow of the cylinder temperature control remains identical.\\
  
-For the scaled process, however, the second assumption means that the cylinder temperature settings must be searched for on the system for which the surface-related heat flow is identical to that of the initial process.\\ +The second assumption only describes a theoretical similarity. Under the assumption of constant heat flux density, a higher mass throughput is achieved during a scale-up compared to the assumption of constant cylinder temperature, but the higher throughput also leads to a later melting end. This reduces the accuracy of the scaling.\\ 
-However, as this is not usually the case and an identical temperature profile is used, the accuracy of the scaled process is reduced. However, higher throughputs are achieved with the assumption of constant heat flux density than with the assumption of constant cylinder temperature. A compromise can be concluded from both assumptions, so that a higher throughput is possible at the expense of scaling accuracy compared to the assumption of constant cylinder temperature. \\ +A compromise can be concluded from both assumptions, so that a higher throughput is possible at the expense of scaling accuracy compared to the assumption of a constant cylinder temperature. \\ 
-This compromise can be set in REX using the ‘Target’ slider in the input screen. By default, the standard assumption of constant cylinder temperature is used due to the better scaling accuracy. However, the slider allows a setting at any position between the described boundary conditions.+This compromise can be set in REX using the ‘Target’ slider in the input screen. By default, the standard assumption of constant cylinder temperature is used due to the better scaling accuracy. However, the slider allows a setting at any position between the described boundary conditions. A ‘target’ greater than 0.66 is recommended, which is closer to the constant cylinder temperature assumption.
  
 ^ Case 1: Diameter unequal, constant cylinder temperature^ ^ Case 1: Diameter unequal, constant cylinder temperature^
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 |$\Psi=\frac{2-\kappa}{4-3\kappa+2\xi}$|  |$\Psi=\frac{2-\kappa}{4-3\kappa+2\xi}$| 
 |$\chi=\frac{\Psi(2+\xi)-1}{1-\xi}$ (smooth tube extruder) | |$\chi=\frac{\Psi(2+\xi)-1}{1-\xi}$ (smooth tube extruder) |
-|$\chi=\frac{\Psi(1+2\xi)-\xi}{1-\xi}$ (Nutbuchsenextruder) |+|$\chi=\frac{\Psi(1+2\xi)-\xi}{1-\xi}$ (grooved barrel extruder) |
  
 ^ Case 4: Diameter equal, constant heat flux density^  ^ Case 4: Diameter equal, constant heat flux density^ 
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   * Schuler, W.: Degassing during polymer production and processing. Tagungsband: Varius Aspects of Ethylene-Porpylene Based Polymers, Academia-Erasme, Louvain-La-Neuve, 1991   * Schuler, W.: Degassing during polymer production and processing. Tagungsband: Varius Aspects of Ethylene-Porpylene Based Polymers, Academia-Erasme, Louvain-La-Neuve, 1991
 </details> </details>
- 
-===== Creating a scaled process ===== 
- 
-After entering the machine size for the scale-up / scale-down and confirming with //OK//, the scaled process is created and calculated automatically. 
-After the calculation, a new window opens in which the scale-up exponents are displayed. The Diagram tab displays the pressure and melting curve for the basic and scaled process by default. The diagram can be customised using the selection at the bottom left of the window. 
- 
-**Placeholder image Window after calculation** 
- 
-The buttons at the top left of the window can be used to create additional diagram windows, open all standard diagrams or open a tabular overview of the initial and scaled process. 
- 
-If the scaled process is to be saved, this can be done using the //Create process// button. A new window opens to specify the file name and storage location.