Week 7 Minor Project
MOLD FLOW ANALYSIS OF A HANDLE USING NYLON6 MATERIAL
1 INTRODUCTION
The handles are essential components in automotive and engineering applications. In industry, if a has to be lifted from one department to another, handles play a crucial role. In vehicles like buses, handles are used as support structures for people who are standing and helps them not to fall during the sudden brake of the vehicle.
Figure 1.1: Commonly used nylon handle.
Figure 1.2: Bus handle for standing passengers.
The material used for plastic handles is nylon 6/6. Nylon is a synthetic thermoplastic linear polyamide (a large molecule whose components are bound by a particular type of bond) that was first produced in 1935 by American chemist Wallace Carothers, who was then working at the DuPont research facility in Delaware. Wallace produced what is technically known as Nylon 66 (still one of the most common variants). Demand for synthetic materials in general, and Nylon in particular, grew during World War II when essential items like silk, rubber, and latex were in significantly shorter supply.
2 OBJECTIVE
The immediate objective is to model a handle and analysis using fill+pack+warp. Then observing the results such as fill time, velocity pressure switch over point, the pressure at injection, etc.
The parameters that have to be used for the model is
- Injection time: 1.2 seconds
- Packing pressure profile:
- 25Mpa for 0.2 seconds
- 20 Mpa for 2 seconds
- 15MPa for 2 seconds
- 10 Mpa for 1 second
The results that have to obtain are
- Identify the VP switchover point
- Attach an animation for fill time
- Present the results for:
- Fill Time
- Pressure at injection
- Warpage results
3 MOLD FLOW PROCEDURE
1.Create a handle like a mold using the geometry toolbar, as shown in Figure 3.1.
Figure 3.1: Mold model of a handle.
2.Mesh the model using the dual-domain mesh and check for free edges, non-manifold edges, the overlap of the mesh, aspect ratios. All these steps are given in the following figures.
Figure 3.2: Mesh of the part using dual-domain mesh.
Figure 3.3: Free edges and non manifold edges check.
Figure 3.4: Orientation of mesh elements check.
3.In the study panel, click on analysis and select the gate location analysis and start the analysis. The analysis shows the node which serves best as the gate. For the present model node, N3364 suits the gate.
Figure 3.5: Gate location analysis.
4.Now set the material by clicking on the material info in the study panel and search the material with trade name as nylon 6. All the manufacturers material with trade name nylon 6 pop-ups, select the Unitika nylon6 material and check the details.
Figure 3.6: Selection of material.
Figure 3.7: Material details.
Figure 3.8: processing parameters of the material.
5.Now set the analysis as fill+pack+warp.
Figure 3.9: Setting sequence analysis as fill+pack+warp.
6.Now Click on the process settings in the study panel and input the parameters as mentioned above such as filling time, pack pressure vs. time. Run an analysis using isolate the cause of warpage and another analysis with not using isolate cause of warpage.
Figure 3.10: Setting injection time as 1.2 s.
Figure 3.10: packing pressure vs time.
Figure 3.11: Isolate the cause of warpage.
7. Start the analysis by clicking the start analysis in the study panel.
4 FLOW ANALYSIS RESULTS
4.1 V/P Switch over point
In the process setting wizard, we kept the velocity/pressure sitch over point as automatic. It is observed from Figure 4.1 that the v/p switch over takes place at 99.03 % of volume filled and at time 1.94 s. It is observed that at v/p switch over point the pressure is 4.579 MPa. It is observed that the pressure is high at gate locationa and no large pressure changes in the near by regions. The part can be manufactured using the selected material.
Figure 4.1: v/p switch over point and pressure at v/p switch over.
In the process settings wizard, if the v/p switch over is given by the %volume filled option and input as 95%, the v/p switch over occurs at 95.13% and time as 1.864. The pressure at v/p switch over point also slightly decreased to 4.481 MPa.
Figure 4.2: v/p switch over point and pressure at v/p switch over.
4.2 ANIMATION OF THE FILL TIME
https://drive.google.com/file/d/1cAw0h9gobLri7n27xrscb41Er3WZPrOi/view?usp=sharing
4.3 TEMPERATURE AT FLOW FRONT
The temperature at the flow front should be in the range of the melt temperature of the material. It determines the quality of the product. From Figure 4.3, it is observed that at the gate location, the temperature is slightly higher than in other areas, which results in an unusual shape. The temperature at the flow front for the current model is 250˚c, which is in the range of the melt temperature of the material.
Figure 4.3: Temperature at flow front.
4.4 BULK TEMPERATURE
The bulk temperature shows the flow of the temperature through the part in cycle time. The temperature is highest at the starting of the cycle, and once the part is filled, the temperature gradually decreases.
Figure 4.4: Bulk temperature.
Animation file: https://drive.google.com/file/d/1KjBg60lZNIYRBwgn8VRJ_yiRdyCjaaLV/view?usp=sharing
4.5 PRESSURE AT INJECTION LOCATION: X-Y PLOT
Figure 4.5: Pressure vs time graph at injection location.
4.6 WELD LINES
When the temperatures of the two or more flow fronts meet at a point, weld lines occur due to high-temperature difference. The current model seems to be free from weld lines.
Figure 4.6:Weld lines.
4.7 WARPAGE RESULTS
The warpage results shows the deflections of the part from its original geometry. When the isolate cause of the warpage is given in the process setting wizard, it shows the deflections caused by differential cooling system, differential shrinkage and the orientation effect. The present model is shows the deflelction of 2.621 mm in the differential shrinkage. The deflections due to other parameters are with in the range. It is observed that the deflection is due to differential shrinkage and the it can be overcome by giving different packing profile or by imroved cooling circuits.
Figure 4.7: Deflections due to all effects.
Figure 4.8: Deflections due to differential cooling.
Figure 4.9: Deflections due to differential shrinkage.
Figure 4.10: Deflections due to orientation effect.
When the parameters are changed still the deflection is same as above mentioned. It is observed that the deflection can be over come by given different material or including coolant.
5 CONCLUSION
The handle with nylon6 material is analyzed using fill+pack+warp analysis, and it is concluded that the deflection in part is due to differential shrinkage. The analysis by changing the %fill vs. time and cooling analysis are also done, but it seems that the deflection is mainly because of the material. It is recommended to use a different material or other manufacturer material.
GDIVE LINK: https://drive.google.com/drive/folders/198gqK8cxExCWa9lXcpSD-CkNhchlK7Xi?usp=sharing