Every industry has its own unique challenges, but almost all industries share the objectives of reduced maintenance, increased machine uptime, energy savings, improved safety, and lower total cost of ownership. With expertise that spans a broad range of disciplines, years of experience as a technical partner to end users, and extensive experience as an equipment manufacturer in every major industry, SKF not only supplies products, but also total integrated solutions that help customers to realize their goals.
The SKF sensor unit includes electronics that require adequate sealing, mainly for mechanical protection and for preventing liquid ingress. This can be accomplished by potting and over molding.
The project involves analyzing the over-molding of electronics, connectors, and cable with printed circuit board (PCB) material as inserts.
- To identify any defects and correlate the simulation results with actual product failures for design optimization
- To decrease product development cycle time
- To decrease design iteration and prototyping times
Moldex3D Designer and Project helped to create a BLM mesh and run an effective simulation. The Moldex3D technical support team helped to explore the tool and quickly solve issues whenever necessary. Since SKF has inserts with small electronic components, connectors, cable, and so on, achieving good quality mesh was a considerable challenge. In order to achieve high quality results, the BLM mesh tool was used as recommended by the Moldex3D team.
- The simulation results allowed users to explore the reasons for product failure
- Identified defects and suggested improvements with respect to design modifications and process settings
- Improved the process parameters
In the first phase, the aim was to perform a low pressure over molding simulation for a single cavity molding. As with current process settings, identifying design and process defects was of great importance. It was essential, therefore, to attempt to find a correlation with the existing manufactured part. In the second phase, the objective was to perform a rheology over molding study to check the feasibility of molding two parts of the same product and delineate the best runner, gate design, injection point position¸ and cooling circuit dimensions. At the same time, the defect identified in the first phase must also be resolved.
SKF’s technical center simulated the molding scenario of the original design using Moldex3D Advanced solutions. BLM meshing solved the meshing issue of the small electronic component and cavity. Through Moldex3D simulation results, they were able to identify filling issues in some areas on the part due to the gate location. There was also flow hesitation in thin wall regions. Additionally, SKF was able to identify the internal residual stresses on the electronics during the molding process. Finally, they were able to optimize the process parameters to operate at the lowest possible pressure and get the best cycle time.
There was a design change in the gate type and location of the 2-cavity mold design. The dimension and design of the runner system were also altered, respectively, taking into account the defect observed in the first phase. This resulted in smooth material flow without hesitation effect, and filling was better than it was in the original design (Figure 1). The process was to obtain the best cycle time with reduced cost and operation at the lowest possible pressure. These were achieved by carrying out various runs and then comparing the graph to finalize the best solution. At the same time, the pressure, temperature, and thermal residual stresses around the electronic component were also controlled.
Figure 1. The flow is not uniform in the original design (left) and there is flow hesitation in some areas, for example, in the connector area. In the new design with 2 gates (right), one can observe that the flow is uniform and the flow hesitation has been almost entirely eliminated.
The simulation was created for the existing design using Moldex3D technology. All observations were noted, and an action plan was created with respect to design and process changes. The results obtained from simulations of the original design were close to the real scenario. This was validated with process data sheet from the production. As shown in Figure 2, the identified defects in the existing design also occurred in the existing product.
Following the design changes, Moldex3D was applied to simulate both the optimized design and the original design. The new design took into account all of the issues identified in the existing design. Additionally, the cycle time was optimized to reduce cost and production time. When compared with the actual mold trial results, SKF’s technical center found that Moldex3D simulation analysis results had a strong correlation with issues found in actual products.
Figure 2. High correlation between a simulated and actual manufactured part is shown. A sink mark is identified on the simulated model (left) and the same result is visible in the prototyped part (right).
Using a Moldex3D analysis, SKF was able to clearly understand the filling behavior and predict likely defects caused by process parameters and design deviations before prototyping and production. This saved a large amount of product development cycle time due to early analysis using the Moldex3D tool. The accuracy of the Moldex3D simulation analysis was compared and validated using an actual manufacturing process sheet and visual inspection. The result allowed SKF's technical center to improve its process parameters, identify and fix defects in products, and also compare the causes of product failures at end application with the identified defects.
This information has been sourced, reviewed and adapted from materials provided by Moldex3D.
For more information on this source, please visit Moldex3D.