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3D Printing versus CNC Machining Which is Best for Prototyping?

 |  Myrah Abrar

The Difference Between 3D printing and CNC machining

3D printing and CNC machining are both popular choices when it comes to prototyping. They both offer a wide range of advantages in this field, with very few drawbacks. Yet, despite the many benefits of 3D printing, CNC machines still enjoy some popularity.

And long before you set up a prototyping lab, you will have to decide whether to opt for 3D printing or CNC machining. And no matter which one you choose, when it comes to modern manufacturing, both options have proven to be extremely useful.

There's a lot that you have to consider before you take your pick, especially the bias towards one or the other technology. To make the best choice, you must avoid short-sightedness to correctly evaluate the merits of both options. It will allow you to make the right decision.

The following need to be taken into account when choosing between the two options:

1. The Turnaround Time

The first thing you need to consider when comparing 3D printing with CNC machines is the turnaround time. In short, the turnaround time is the total time it takes a machine to produce one copy of an object.

As 3D printing becomes more and more advanced, it offers a much faster turnaround time. Today, most prototyping services can use a simple CAD file to design and produce 3D printed parts in no time.

If you are interested in changing the product's design, you should consider choosing 3D printing, as it allows you to edit and print your designs rather quickly. On top of that, after using a 3D printer, you don't have to waste time recalibrating or changing the tools before you can move on to the next version of the product.

On the other hand, if you decide on CNC machines, you will benefit from faster production when it comes to larger projects. The best thing about them is that they can run continuously without the need for any supervision, and once you set them up, they can produce objects faster when compared to a 3D Printer.

However, the assumption here is that you'll use just a single 3D Printer. There are many prototyping companies that use large quantities of 3D Printers to simultaneously print several parts. Such a solution will allow you to mass-produce prototypes fast enough to keep up with CNC machines.

When you compare 3D printing and CNC machining in terms of turnaround time, you will come to notice that there is not much difference. It all depends on the number of machines you can use and the scale of production.

2. Complex Geometries

Another difference between 3D printing and CNC machine printing is that CNC machines use subtractive technology. They carve away material to make blocks, whereas 3D printing adds material, layer-by-layer. This process is known as additive manufacturing.

Both of the options can create complex geometries along with complex structures, but 3D printing has here an advantage over CNC machines. The reason for that is quite simple, as it allows you to create parts that have massive internal voids for minimizing weight.

Both technologies offer high precision, but 3D printing is a great choice if you intend to minimize waste. Open design is a walk in the park for 3D printing, so if you hope to achieve better freedom in terms of form, 3D printing is the right option.

It does not mean that it is better at just about everything. For instance, printing prototypes through CNC machines is a better option if you are aiming for greater dimensional accuracy.

In addition to the above, CNC machining also works with materials that one cannot print, like wood, for example. It also beats 3D printing when working with other materials such as metals and plastics.

 

Working with diverse materials is something that 3D printing is still not able to do. This is why CNC machining might be the perfect option for such materials.

3. Product Specifications

When we look at product specifications, it's CNC machining that truly shines the brightest, as it is a better option for working with parts that undergo a great deal of strain or stress. Typically, CNC machining uses materials that handle a heavier load, so you can expect more precise results when you opt for the option.

There is no doubt that CNC machines are the preferred choice if you require narrow and precise pieces. Similarly, it offers better tolerance. It's hard to compare the 0.01mm tolerance in 3D printing, which makes CNC machines a preferred choice when it comes to specific markets, like aerospace, for example.

Generally, CNC machines yield smoother final products in comparison to 3D printing, but it doesn't mean that it is incapable of doing so. There are plenty of web design applications that you can use to create a variety of items through 3D printing.

4. Price

Both 3D printing and CNC machining can be quite expensive, and you cannot say that either of them is cheap. You have to do a cost-benefit analysis based on the lot size to determine the right option.

Typically, if you want to make a single prototype, it would be much cheaper to go with 3D printing. The fact is that 3D printing is a more affordable option when working on a small scale, but the price will vary, depending on the used material.

ABS plastic filament also needs to be considered as it is very cheap. On the other hand, materials like PEEK costs a lot, which can make CNC machining seem like a good bargain. Overall, 3D printing wins if you require multiple iterations of the product for testing and design refinement. Additionally, it allows you to make dozens of prototypes with no effort.

To proceed with CNC machining, you will need to set-up the programming account. It will add the cost of each run, so when it comes to larger runs, CNC machines are a better option.

If you want to make anywhere from 50 to 100 prototypes, you will find CNC machining to provide you with better value. 

Besides, you can also purchase a used machine like Revelation Machinery. After you have made over a hundred items, investment casting or injection molding might be more economical. 

The price should be variable in the long-run. This is why you will need to consider things from a long-term perspective. Variability in cost should allow you to opt for 3D printing. 

There should not be much of a difference in terms of cost. However, it depends on what you are looking for. On the other hand, if you only need a prototyping machine for the short-run, you will need to stick to the number of units that you intend to produce.

Takeaway – 3D or CNC for Prototyping?

Once you have gone over our post, you will know the basics that should influence your choice between 3D printing and CNC machining. Keep in mind that there is no such thing as a one-size-fits-all manufacturing option.

Consider your specifications and choose the method accordingly. To make the right decision, you need to consider the turnaround time, lot size, performance requirements, and product dimensions, along with the price. 

Both 3D printing and CNC machining have something to offer. You can train your employees to use either of the methods. Hence, you have to think about the decision from the perspective of what you want to achieve.

Since 3D printing is undergoing tremendous advancements, it might be the perfect option for you if you require a prototyping method for the long-run. It will provide you with much-needed peace of mind.

However, it is advised that you consult with a professional to determine which option would suit you best. Their advice could point you in the right direction.

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