In part five of this series about learning the basics of the Alibre Atom 3D digital design program, we are going to lift our skills to lofty heights by tackling ‘lofting’. This is how complex shapes are formed that would be difficult to draw manually. With CNC machining now commonplace, a digital drawing can be used directly to program the machine tools, such as lathes and milling machines, to create the shape needed.
The example is basically the same vee pulley we designed in the last issue. When we drew it up back then, we designed it as if it was going to be machined from a solid piece of steel — which might be the right thing to do for a one-off. However, if we want to make a production run of these vee pulleys, it makes more sense to cast them. This saves material and minimises the machining time. Cast iron or aluminium would be common materials used, and the choice would depend on the intended use.
Planning ahead
Some prior planning is a good idea so that we achieve a design that can be used for pattern making as well as a finished product design to be used for the machining of the castings. So, the plan is to model the casting before machining and save that as a file called ‘Vee Pulley Casting’. Then, carry on by making the bore and vee groove using the Extrude Cut tool to replicate what machining needs to be done. The work done is to be saved as ‘Vee Pulley Machined’.
Clean slate
We will start afresh rather than try to use our previous pulley design, as this time our approach is quite different. So, click on the Create New Part icon in the Alibre home page. Click on the Activate 2D Sketch tool in the toolbar ribbon across the top of the screen. You need to select a plane to draw on. In this instance, let’s pick the XY
