So after going though a list of higher design principles I want to impart on my design team this year with the addition of several new CAD Wizards in Training, I was curious as to what standards other may have in the respect of design optimization of material ie: your removal of unnecessary material from brackets, motor plates, etc.
I have my own method to the madness, but would love input from others in the community who may have been doing it longer than myself. Plus who doesn’t like to learn new tricks and tips when it comes to CAD design right?
I prefer using hole patterns (most obvious example of that in my work is my most recent beetleweight post). I try to keep at least 1/4” of material on all sides of holes/pockets.
We start with materials that are already close to the right shape…so we don’t need to remove any material, aside from the cuts and holes necessary to make the part, and attach it.
Hard second to the lighten featurescript in onshape. It is incredibly powerful and very simple to work with once you are familiar with the workflow. Just a few lines compared to all of the offsets, cuts, and radiuses you would normally do to accomplish the same thing in most other programs. Plus, when (not if) your design changes, it is significantly easier to fix up that single sketch than all of the other features you would have in other programs.
Thanks for sharing this I hadn’t seen the vent tool before. Is it possible to use it across already created geometry like the gearbox plate that Ty posted?
I haven’t found a way to do gearboxes yet. It’s really meant for doing things like sheet metal fan vents, so it removes everything within the outer boundary and then adds back material based on the sketch.
Really good for things like that triangular grid, but not so much if you have critical features inside of the weight reduction area.
As a bonus, it gives your percentage of the boundary region that will be removed so it’s pretty easy to tweak weight patterns to maximize material removal.
I’ve gotten a few questions about how to use Onshape’s Lighten Featurescript. So I figured I’d write it up here:
Create a new sketch.
Use the “Use” tool to transfer the outer edges of the part to the sketch.
Use sketch lines to define the center of the ribs you’d like to add.
Exit the sketch.
Select the lighten tool, choose the cut depth (or through), choose the tool radius, and choose the web thickness.
Click on the sketch regions you’d like to remove material from.
Watch the magic happen.
Tips:
When getting started, click one region at a time and wait for the preview to update. If Lighten has issues, it’s not very descriptive of the problem. Going one region at a time will help you find the region that is causing Lighten to fail.
Lighten will try to automatically split regions in two if the middle section is too narrow for the tool to fit through.
You don’t need to copy the edges of holes into the sketch for Lighten to work.
Lighten works with closed regions. If you’re having trouble getting a region to lighten successfully, try extending your web lines to the edge of the part.
