You need an object made, but which is the right tool for the job?
3D printers create objects by extruding and layering up materials in fine increments until the desired shape is complete. CNC machining acts in an opposite process, precisely carving away at raw materials until the desired shape is left. Both processes offer fine control and can be applied depending on your specific needs and materials. So let’s take a look at 3D printing vs CNC machining, and some aspects that should affect your choices:
1 | MATERIALS
Most 3D printers available on the market work with a small amount of materials. The most common materials are ABS or nylon. Some high-end 3D printers can process metals or clay (we’ve all seen that truck-sized machine printing a clay house, right?) but these are typically highly specialized machines and expensive to operate. The success of a 3D print depends on having materials that extrude well and can be layered in fine increments; this process is ultimately dependent on how well your materials can be partially melted for extrusion, then solidified to hold shape, and if your machines are designed to process them properly.
For more demanding processes, and for materials like wood and minerals, CNC machines are currently the only alternative. They work on almost any material you can imagine: plastics, metals, woods, wax, stone, etc. And because they carve away at material instead of altering its physical state, the success of this process depends mostly on using correct tools and bits for the material.
2 | SPEED
3D printing is all about creating elements from scratch by applying layer by layer of thermoplastic material until the full print is obtained. The speed which the material can be applied with depends on the device, but ultimately faster speeds mean less precision and rougher layers. 3D printers are just not that fast yet, and prints on most standard machines take hours or days depending on scale.
CNC machines process material much faster than 3D printers, and with little impact on quality. Faster speeds may mean more visible tool marks, but even if you opt for slower machining and finer passes, you may see a difference of minutes, not days.
3 | PRECISION
The quality of 3D prints depends on the thickness of the applied layer. The thinner the layer, the better the quality. But how accurate are they? If you’re designing gears or mechanical parts that require precise tolerances, 3D printing may not be your best bet. While extruded prints can get very close to your original computer models, current technology just can’t control the thickness and applications of layers to that degree.
CNC machines on the other hand are made for precision. They can produce parts from watches to spacecrafts, and everything in between. You’ll get accurate sizing and smoother finishes from CNC machining every time.
4 | COMPLEXITY
The main area that 3D Printing wins out over CNC is in complexity. Not only are 3D printers typically more intuitive for hobbyists, they really shine when it comes to making complex shapes. Because they create from the ground up, 3D printers can do things like construct a round sphere in a square cage all in the same print.
CNC machines shine when it comes to precision, but they do best when machining solid shapes. Additionally most CNC machines require specialized skills and training to operate efficiently, and they can be an investment upfront.
So which do you need, 3D Printer or CNC?
Both are great technologies, well-suited to different tasks and materials. If you’re a hobbyist looking to make objects from common materials like plastics, and precision isn’t a major factor in your work, 3D printers can be an intuitive and effective solution for prototyping and crafting. However, if you need precision tooling and the ability to shape a wider range of materials at finer quality, CNC machines have been and will continue to be your go-to tool. We know CNC machines inside and out, so if you have any questions about choosing the right machine or locating tools for specific materials, give us a call and we’ll find what you need!
