Actual Injection Molded Part differs from Analytical Prediction
In this discussion, we will explore a part that was injection molded and scanned for deflection Interestingly, the actual deflection did not match that of the analyzed part Unfortunately, this can sometimes happen and when it does, it is the responsibility of the software expert to investigate why the predicted analysis results are not matching the floor results This can be a challenging task
In the engineering world, it is common to hear the phrase ‘garbage in equals garbage out’ In other words that phrase means that all inputs plugged into any set of calculations will directly influence the outcome of those calculations When it comes to FEA, having correct input data is especially critical since technical software can only be as good as what is entered into each specific section But what steps should be taken if you have ensured that the analysis is set up correctly yet, the analytical results do not match the results on the floor? In the sample study below, we will take a closer look
For this study, we will look at a part that we will call the ‘console’:
We will compare the analytical inputs to the inputs used on the floor Then, we will explore how the analytical results compare to those on the floor
In preparation for any analysis, the user must take the necessary precautions to ensure that the inputs in the mold filling software are as accurate as possible
Part model
1) Is the part model prepared so that it meets or exceeds the standards that the software supplier recommends?
Yes, the part was modeled as a 3D model and exceeds the recommended criteria
Feed system design
2) Does the feed system match the final design of the finished product?
Yes, it was designed per the specifications provided by the tool shop
Material data
3) Is the material data in the analysis the same as what is being used on the floor?
Yes
Is the material card comprehensive ie, is it fully characterized?
Yes
Process inputs
4) Do the process inputs in the software match the floor inputs?
Yes, see the Table 1 Below
Once the inputs have been confirmed as optimal and correct, we inspect the results and compare them
First, we examine the filling pattern to see if it is predicted correctly
To determine the correlation of flow patterns between Moldflow and