Aluminum CNC Machining: 5 Advantages of CNC Machining vs. 3D Printing
I am trying to grow awareness about Rapid CNC Machining and how in some cases it is a viable option when compared to 3D Rapid Prototyping. It is not always the best solution, but for those wanting a real part we will explain how Aluminum CNC machining can compete with 3D printing. It can be just as fast, often cheaper, and results in great parts.
Additive manufacturing and is a method of starting with nothing and adding a thin layer of material on top of the last layer to build a item. There are currently numerous equipment manufacturers, methods of printing, service providers available. Using the simplest analogy I can think of: it’s like stacking layers of paper cutouts and gluing them as you go, this method is very similar to the early Layer Object Manufacturing (LOM).
In CNC Machining is considered a subtractive manufacturing process which means you start with an over-sized piece of material and cut away at the material so that you’re left with part your want. The simple analogy is sculpting a part out of marble you chip away at the marble until your masterpiece is revealed.
Advantages of CNC Machining vs. 3D Printing
The additive and subtractive methods are unique in their own right, however In my opinion there are several places where the improvements is CNC Machining technology have pushed the capabilities of CNC Machining to overlap 3D printing.
Cost: On small parts, around 30 cu-inches the print times are fixed at some vertical rate per hour. For example one of the desktop printer models can print approximately 8mm per hour. For a 2-3 inch tall part that is roughly 6-9 hours of 3D printer time. To produce a manufacturable part of similar volume using CNC Machining Technology with a moderate level of intricacy and nominal to high tolerances is achievable in that time or less. This provides the end user with a high quality part in a comparable timeline.
Material: CNC Machining has some material advantages over 3D printing. We are usually CNC Machining parts out of a single material where some 3D printers can produce parts using multiple materials at the same time. Our advantage is in the cost of raw material on larger parts; 3D printing resin is an average of $300 per Kg and works out to be more expensive than most standard materials. For example if we used 6061-T6 aluminum as the selected material for a part the cost is approximately $0.25-$0.30 per cu-inch. Some of this cost savings is offset in the manufacturing costs of the aluminum CNC machined parts; Most of the time the material savings is passed on to the customer.
Size: In some cases size does matter. Here at millitnow.com we can cut very large parts that are outside the normal desktop printer work envelope.
Accuracy: An addition advantage is the accuracy of CNC Machining can be controlled. We can dial in the tight tolerances where needed beyond the capabilities of a 3D printer. To quote Scott Cornell in his article, Disadvantages of 3D printing, “precise in order for engineers to get an accurate read on whether or not a part is feasible”
Volume Savings: one of the best advantages that CNC Machining has over 3D Printing is that as the volume goes up the price goes down. A Rapid Prototype printed item will cost you the same each and every time. An aluminum CNC Machined part price will drop as the volume goes up. In a machined component the cost of programming the CNC and the reduction of labor hours is a direct customer cost savings in orders of more than one piece.
Millitnow.com is a division of NCAD Products, Inc and is a Rapid CNC Machining Service provider. We are offering on demand CNC Machining services throughout North America. We offer quick turn CNC machining of prototypes and low volume projects as well as full production milling. Our offerings include Aluminum CNC machining as well as steel, stainless, copper, brass, delrin and others. Our team also offers the finishing touches with value added services like the insertion of pins and threaded inserts; we can also take care of getting your parts chemical coated for you.