Despite 3D printing’s improvements, CNC machining is the most cost-effective approach for on-demand metal manufacture. How much do they cost?
CNC Machining Company is a well-established digital manufacturing technology that creates high-quality parts directly from CAD files. Recent technological breakthroughs in digital supply chains have substantially decreased the cost of CNC machining, making it more accessible to more professionals.
3D printing, often known as additive manufacturing, is another digital manufacturing method. Because 3D printing requires no tooling, it is particularly cost effective for low volume or one-off specialised products.
Weakened expectations due to considerable mainstream media coverage of 3D printing, notably in the manufacturing of metal parts.
In this post, we’ll examine the expenses of CNC milling (machine, labour, and material prices) and compare them to 3D printing using some approximate calculations and real-world examples.
Costs of Machines:
The cost of overhead machines accounts for roughly two-thirds of the total cost of CNC machining and 3D printing. In most cases, the machine rate (cost per hour) is computed by dividing the purchase price by the total number of hours the machine is projected to run (typically eight years for 5,000 hours per year).
CNC machines are available in a variety of configurations. The usual machine per hour varies depending on the machine architecture and capabilities.
A 3-axis CNC milling machine typically costs $40 per hour (without the operator’s wage). To this, you should add the machine operator’s wage, which is normally around $35 per hour. CNC turning is usually less expensive, costing $35 per hour, whereas multi-axis CNC machining costs between $75 and $120 per hour or more.
Industrial 3D printers, on the other hand, range in price from $10-20 per hour for industrial SLS or FDM machines to more than $100 per hour for metal SLM and DMLS 3D printing systems. Expenditures associated with the chance of print failure should also be included in; according to one study, risk-related costs might treble the 3D printing operational cost.
This means that the overall cost of owning and operating a CNC machine is comparable to (or much lower in the case of metal) that of an industrial 3D printer.
Costs of Materials:
For a sheet with dimensions of 6″ x 6″ x 1″, the chart below summarises the price of standard metal alloys and plastic materials widely used in CNC (or approximately 150 x 150 x 25 mm).
The same volume of material would cost about $40 in Nylon 12 powder for SLS 3D printing (650 grammes at $60 per kg) or $1300 in stainless steel powder for DMLS or SLM metal 3D printing (4.3 kg at $300 per kg).
Of course, as a subtractive manufacturing method, CNC machining generates a lot of waste when material is taken from the original block. Parts created for 3D printing (particularly metal) should also have topology optimised to save weight and use as little material as possible.
3D printing can be wasteful: depending on the method, only 50-80% of the wasted powder (in the case of SLS and DMLS/SLM) can be reused. The expense of doing so quickly adds up, especially when considering the cost of 3D printing materials.
As a result, the cost of materials in 3D printing is significantly higher than it is in CNC.
Costs of Labor:
Because the process is mostly automated, the labour cost for the 3D printing machine operator is quite low. However, engineering and design costs for 3D printing are considerable since parts may need to be redesigned and optimised. In addition, post-processing and finishing a 3D printed object necessitates a significant amount of manual labour (cleaning, support removal, surface polishing).
Labor in CNC machining, on the other hand, is mostly associated with start-up costs (CAM programming, process design), but these are one-time expenditures that are eliminated as production volumes increase. Quoting used to necessitate a significant investment from machine shops, but that is no longer the case. Let’s have a look at why this is the case.
In recent years, CNC machining technology has remained relatively unchanged. Incremental advancements in machine design, tooling, consumables, and CAM software lead to production cycle optimization, boosting quality while having little impact on cost of CNC machined components.
The manufacturing supply chain networks that surround the CNC machining process have altered.
Online manufacturing networks, for example, are growing smarter and faster. The automation of the quoting process for both clients and manufacturers was a significant step forward. The cost of CNC machining a product (depending on its shape, material, and other requirements) can be forecasted using machine learning and artificial neural networks, and a buyer can receive an instant quote.
A process that used to take an engineer a few hours to perform (with a significant expenditure on the manufacturer’s part) is now practically instantaneous, automated, and free. The cost of CNC has been significantly decreased as a result of this breakthrough.
A Real-Life Example:
I did a small experiment to show how expensive CNC machining is now. I use the test bracket shown in the figure below as an example to get quotes from 3D Hubs’ network of manufacturing service providers for different manufacturing techniques, materials, and quantities. This is a good approximation of the “real-time” market price for making this shape because 3D Hubs operates on a global scale and has automated pricing.
If you want to make this part, you can use CNC machining to make aluminium and stainless steel parts. You can also use 3D printing to make SLS Nylon or PLA parts using FDM, which costs more.
There isn’t much of a difference even at low prices (around $55 for a one-off product). CNC milling the bracket out of aluminium and 3D printing it out of nylon is very similar. For more than 100 units, CNC machining is more cost-effective.
Using metal 3D printing with SLM, you’d have to pay more than $1,500 for a one-off part. This is just for the record.
So, why would you opt for 3D printing?
CNC machining and 3D printing are both outstanding instruments with distinct advantages that make them better suited to specific applications.
For example, constructing a single prototype of this bracket with FDM 3D printing cost less than $8, however CNC manufacturing it out of plastic (Delrin, ABS, or Nylon) cost around the same as aluminium (approximately $100).
When weight-saving topology optimization is important, like in aerospace applications. Other technologies don’t work, metal 3D printing with DMLS/SLM is still the best option.
CNC machining is usually the best way to make parts with simple shapes that can be made quickly through a subtractive process, especially when making metal parts.
There are a lot of different ways to use 3D printing and CNC machining right now.
Metal 3D printing and additive manufacturing have been getting a lot of attention in the last few years. Even though the benefits of this technology for high-end applications are very appealing. The costs far outweigh the benefits for most of today’s industrial needs.
CNC machining is still the best way to make on-demand custom parts. Today, and this isn’t likely to change in the near future.
New metal 3D printing systems that use Binder Jetting and Material Extrusion technologies may change this. But we’ll have to wait and see if they have a big impact on the industry. This is why we need to keep an eye on the new systems. Visit techairo
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