What are the differences between Die Casting and Machining?

What are the differences between Die Casting and Machining?

Die casting has been one of the most important manufacturing processes. How many of us realise that almost all components, objects and tools in our day-to-day come out of one form of casting processes or the other. Name anything for that matter —door handles, taps, light fittings, car components, computer components,  furniture components or even components in cameras and sewing machines—and you find them all manufactured through die casting.

So, why is casting better than machining?
The first factor is the cost casting is economical compared to the machining process. For example, if you need to machine a complex geometry out of a solid aluminium billet, then you may have to remove a chunk of material that goes as wastage, at the same time, the process being time-consuming.

Die casting is a nearnetshape manufacturing process. This means that when you’re diecasting you use only the material that is required the process is iterative and fast, and if there is any postcasting machining that is required, it is only to achieve tightly toleranced features or for jobs requiring other finishing details. The time taken for machining from solid is almost cut to a fraction of the time in die casting, thereby lowering the unit cost.

There are other advantages too: faster cycle time lowers the lead time in the case of huge batch production.  Further, diecasting process, these days, are iterative and controlled, resulting in greater quality.  Several demanding industries including aerospace, precision instrumentation and medical devices now rely on diecasting for making critical components. It also finds extensive applications in all industries ranging from motion capture equipment, lifesupport machines, airline interiors and armoured fighting vehicles to lightweight items.

In all applications that involve lightening a machined component, there is additional cost in removing material, for instance, while forming recesses and pockets in heavy sections, exacting the design elements on a casting piece lowers cost. There is also a lesser use of the material. Further, the geometry of the lightening feature is formed during the course of a casting cycle.

The customer is the winner!
All said and done, machining is still a valuable option when it comes to low volume production, as then, diecasting tooling can turn out to be expensive. Therefore, what you can save with diecasting stands to reason as long as the production involves decent volume. However, with advancements in tooling manufacturing, there is an overall reduction in the breakeven threshold most part of the time.  Therefore, if you’re into the design of a new component, you need to weigh the benefits that both casting as well as machining offers in terms of investment, the volume of production, ROI, etc.