CNC stands for Computer Numerical Control. Hence, CNC prototype machining is a process where a machine tool is operated by a computer according to numerical data that has been input into the machine. CAD/CAM software is typically used, that allows machine users to create the necessary designs, and the software then allows the computer to control the movements of the tool. The computer can also operate different machining tools like lathes and drills to help achieve the desired results.
The method is important because it helps manufacturing companies have product prototypes and other items created within certain criteria. These criteria include the speed of production, the quality of the prototype, and the cost of having the prototype made.
The speed of producing a prototype is a key factor that needs to be taken into consideration. When there is a production line, processes further down the line can be left idle if there is a hold-up elsewhere. This is wasteful and costly; every day there is a hold up in production it means a day in lost revenue because nothing is being sold.
While speed is important, however, it should not be at the cost of quality.
Quality is important even when it comes to prototypes. Prototypes tend to not be just about building something so we can see what the finished product will look like. It also tends to be an opportunity to test the design to see how it will stand up to what is expected of it. It is a great way of revealing any design flaws before the product is put into production. This has the potential to save a lot of time and money in correcting any issues.
The cost of manufacturing any item is, of course, an essential consideration. If production costs are high then this will pass onto the end consumer. In short, people will need to pay more to buy the product. If the cost is too high then the customer is likely to turn to more affordable alternatives instead.
Modern machinery like CNC prototype machinery plays an important part in helping to keep costs down. While the equipment is expensive to buy, a company that offers the service will be able to spread the cost of buying the machines among many customers, making the purchase cost-effective. Machinery is also able to operate more efficiently than people are, reducing the hour’s need, further helping to reduce the cost.
Additive Vs. Subtractive Manufacturing
One of the key considerations when comparing CNC prototype machining is the difference between additive and subtractive manufacturing.
One of the most common modern examples of additive manufacturing is 3D printing. It is considered to be additive because everything produced by a 3D printer has been created by adding material to existing material – a 3D printer works by adding a layer on top of the layer. The finished product may look like a complete solid unit, but it is actually made up of many parts.
CNC prototype machining is an example of subtractive manufacturing. This means that the finished product is made from a single, complete block of material (which is known as a blank). By removing material from the block, much like a sculptor would do with a hammer and chisel, complex forms can be created.
This is where one of the key benefits of CNC prototype machining comes into play.
Once a prototype has been approved, and a product goes into mass production, methods like injection molding will likely be used. This is relevant because it means the parts will also be made from a single piece of material rather than from different parts. This, in turn, helps to ensure that the final piece will perform in much the same way that the prototype will. As a result, there is little risk of any unwelcome surprises when the final product is made.
Injection molding is one of the most commonly used manufacturing methods in mass production. It can produce parts in high volumes, cost-efficiently. The parts it produces are also of very high quality and high standards of production can be maintained throughout all parts.
There is one drawback that means it is not ideal when it comes to CNC prototype machining, however.
Each product will involve the use of casts that are specifically made for each part. Each of these casts will themselves need to be designed and manufactured, and this will cost time and money. This is fine for large-scale production where a single cast is making many parts. It is far less cost-efficient where smaller projects like prototypes are concerned.
In many cases, 3D printing will be less costly than CNC prototype machining. This will depend on the materials being used, however.
3D printing will typically involve using polymers, although metal can be used in some cases. When it comes to using metals like aluminum and steel, which are often necessary for prototypes, then 3D printing becomes far more expensive.
As mentioned, 3D printing also has the disadvantage of being an example of additive manufacturing. What’s more, is that the finish that comes with 3D printing tends to be less refined.
Choosing the Right Shop
Although a lot of the process is automatic, it still requires an experienced user to create what is needed. Experienced users will also have learned what can go wrong with the process, helping them to avoid mistakes and helping everything go smoothly.
An experienced user will also be aware of the differences in using different materials. This will help ensure any parts create are of the required quality and dimensions regardless of which materials are needed. Somebody that understands the process well will also be able to give you guidance to help get the best possible results, potentially making them an important part of your team.