This blog post is about geometry challenges that you can experience no matter which CAD program you prefer. There are solutions for everything, and in SOLIDWORKS there is the special tool that can be helpful, and that is Check.
Check is one of several diagnostic tools found in SOLIDWORKS. This is a tool that has been in the program for many years, but which may not be something you use every day. There are a couple of different modeling situations where Check is a necessary tool - and we will take a closer look at Check her.
Check checks and measures various properties of the geometry. It is special to places where Check is useful; to look for geometry errors in a model, and to indicate how large shell thickness models allow when using Shell.
Using Check for geometry errors in part files
This first function is very useful for you who work a lot with importer geometry, and especially free form geometry. Sometimes some of the details in the importer files may have errors in them that are not so easy to detect. By using Check, you will know where on models the problematic details lie.
When importing geometry, the program will offer you to check for defects in models with Import Diagnostics features. Import Diagnostics fixes either all errors, some of them or none of them. If you are left with errors in models after this, it is often best to ask for a different file format if you can, for example Parasolid or STEP - and see if the new files behave differently.
If you choose not to use Import Diagnostics on a part file and add features to it, Import Diagnostics will not be able to be used - and then you risk being left with undetected errors in the model.
A model that has geometry errors can look absolutely fine on the screen, but can contribute to problems in downstream operations, i.e., in all models that are to be used when it has been modeled, technical drawing, strength calculation, production, etc. With some types of geometry errors will you not be notified automatically, and therefore it is a good rule to check the importer geometry for errors after import.
These errors can therefore use Check to find. Check will show you which areas of models are problematic. If you want to correct the errors after this, it is common practice to remove the problem areas and next reconstruct the area with new geometry - often with surface modeling.
Our course «Surface Modeling» among other things deals with such a scenario and teaches you how to proceed to replace bad geometry in a model.
Use of Check to find out how large a shell thickness you can have before applying a Shell feature
When working with products that are to be cast, you usually want to have an even wall thickness so that you are left with a shell of the model. The workflow is usually that you build up the outside geometry of the product and the next use Shell so that the inside is hollowed out. If you have a very detailed shape or certain types of free-form geometry on the outside of models, you can risk that Shell give an error messages - and that in the worst case you will not be able to add the wall thickness you want.
In the example above, the minimum radius of curvature is about 3.45 mm. If you make a Shell of 3.46 mm, you get an error message. If you select 3.45, Shell is created without an error message. If 3.46 mm or thicker is required, go in and correct the surface Check is points to.
The reason for error messages in the Shell feature is often that the value you have entered for the required shell thickness is not allowed by the outer surfaces of models. Here you can use Check to find out what on models that prevent the desired wall thickness.
It is the smallest radius of curvature on models that sets the limit on how thick you can have the shell. If you want a 3 mm shell thickness, none of the details on the outside should have a radius of curvature less than 3 mm. In Check, it is the value "minimum radius of curvature" that you should then check for. The areas that have less than 3mm radius will be listed, and you can then click on each one to let the program point out where in the model there is less radius than this.
An imaginary section through models shows the connection between the outer radius of curvature and which shell thicknesses Shell may have problems with. In this case, shell thicknesses above 3mm could lead to problems, while shell thicknesses below 3mm, shown by the dotted line, will work fine.
This may primarily apply to free-form geometry where surfaces with asymmetrical (elliptical) fillets and splines have been used - while on ordinary circular fillets, the program usually allows Shell with a smaller thickness than the smallest fillet radius.
Here you use Check, find out where the smallest radius of curvature is and adjust models so that you get the shell thickness you need.
These were two examples of different use of Check. If you are interested in more information about Check, can you read here.