CNC machining is computer-driven and is reliant on uploaded instructions and translated by a Computer Aided Manufacturing Software (CAM) for the precision of the tools. It is a subtractive manufacturing method wherein the outputs produced by the machines are from a larger block and are shaped to the desired design. It utilizes sharp tools for shaping, carving, and finishing of the products. It is the most commonly used machine in the manufacturing industry due to its precision, timeliness, and ability to accommodate various materials. Similar to CNC machining, 3D printing is likewise a manufacturing innovation; this is also referred to as, Additive Manufacturing. In contrast to the CNC machining method, 3D printing resorts to layering the materials to produce a 3-dimensional part.
Although both methods are designed through CAD, are translated through a CAM software, computer driven, and are reliant on the G-code instructions encoded — each has its own characteristics and functions. Depending on the purpose – both has its advantage and disadvantages which are expounded on the following sections:
Accuracy, Precision, and Tolerance: CNC Machining vs. 3D Printing
CNC machines are reputed for their accuracy, precision and tight tolerance range. It has the ability to produce accurate outputs – either very small or large parts. In contrast to 3D printed parts/objects, CNC machines are able to produce objects with sharp edges and can be thinned as desired without affecting its accuracy.
For parts that are geometrically complex, 3D printing is recommended. It can intricately create outputs that are incomparable to traditional manufacturing. Although it can precisely duplicate the design, since 3D printing is done by layering –it creates room for inaccuracy. There may be chances that the output would be inaccurate due to shrinkage or collapse. It is important to keep in mind the design tolerances when crafting your designs:
- layer & wall thickness
- minimum detail and clearance
- maximum raw size
- possible shrinkage and accuracy – to ensure accuracy and precision from your outputs
Range of Materials
The range of materials that each method can accommodate varies. The CNC machines are capable of working with steel, brass, aluminum, super alloys, softwoods, hardwoods, thermoplastic, acrylics, modelling foams, and machining wax. Due to its diversity, this gives the operator the flexibility and creative freedom in selecting the materials used for that production. However, despite its diversity, CNC machines are not advisable for working with metals that have high melting points.
In contrast, the 3D printers are only capable of working on one material and are highly compatible with materials that are softer in nature. Plastics are more commonly used but it can also work with resins and thermoplastics.
Manufacturing Process, Speed, & Production: CNC Machining vs. 3D Printing
CNC machines require collaborative work from the operators – it requires selection of tools, speed, cutting path, and reposition materials (if needed). But once a program is selected, the CNC machines are capable of working non-stop and produce outputs aligned within the time table.
Unlike CNC machines, 3D printing is simpler. Once you have selected a file, you only need to identify the part orientation and fill of your desired parts. After which, you can start printing. Once it starts, no operator is needed to supervise the printing and can be left alone until the part is finished. However, it is not ideal for mass reproduction since it takes a single printer to create an entire product from beginning to its completion. It does have the ability to produce parts at a much faster rate and can deliver it within the span of 24 hours. It is, however, plausible if you just want to create 10 pieces utmost.
In a modern manufacturing industry, CNC automated machines are conventionally used for mass manufacturing due to its accuracy and precision. As for 3D printing, it complements the CNC automated machines as it is great for geometrically complex and small batch parts. Both methods have their own advantages and disadvantages. It really depends on your manufacturing needs as to which of the two is desirable. For more information on CNC machinery, contact the knowledgeable team at Tramar Industries today. Browse our extensive inventory of used CNC machines and we’ll help you find the right machine for the job.