CNC Manufacturing of Prototypes & Production parts using Plastic or Metal


Suppose you are developing a product. In that case, it might be invaluable to create a prototype before the product is put for high-volume production. At the same time, CNC precision machining, CNC Milling or Turning, introduces several benefits as a CNC rapid prototyping process. Remember, CNC means computer numerical control. Along these lines, here we will answer an FAQ:how to create a plastic or metal prototype with CNC machining? Besides that, we will also discuss the benefits of metal and plastic prototyping. So, let's get started.

How to create a Metal and Plastic Prototype with CNC Machining?

Given the part's geometry, CNC machining can be the most suitable and rapid method for creating metal and plastic prototypes. Usually, CNC machines produce 3D object by removing excess material from the solid block, with the aid of cutting tools. The movement of these tools is precisely controlled by the series of cutter paths, generated directly from the 3d CAD model. The software used for converting 3d CAD model to machine code, also called G-code, is known as computer-aided manufacturing software, abbreviated as CAM.
By now, CNC rapid prototyping has become a widely adopted method. It is highly feasible and versatile for a complex and extensive range of product sizes. Various industries, such as automotive, aerospace, healthcare, defence, electronics, etc., use CNC process for rapid prototyping or short-run production jobs.

Meanwhile, metal and plastic CNC rapid prototyping are fully capable of including threaded/undercut features. It is particularly suitable for prototypes that require tight tolerances, controlled sizes, and better surface finish. Machined parts are ready to use as processed or surface finish can be further enhanced by secondary processes such as, polishing, painting, bead blasting, plating.

The CNC rapid prototyping fast turnaround time helps experts to validate all the parameters and design fundamentals. For instance, CNC machining helps assess the form, fit, and function of injection moulded parts without investing in mould tooling.

Process of Metal and Plastic Prototyping with CNC Machining.

The CNC rapid prototyping process starts with the digital 3D design of the part, which is made using CAD/CAM software. Once the design is ready, the CNC machine is provided with instructions regarding the procedure. This information is in the form of G-Codes and M-Codes. After the codes are fed to the CNC, a subtractive process will start. It means that material will be removed from the metal or plastic block to bring it to the desired shape.

In additive manufacturing, 3D printers add layers of material to form an object. Conversely, CNC machining refers to the subtractive manufacturing. It comprises the cutting sections that remove or discard excessive material from the block of material. More complex CNC machines can work with multiple axes (3-5axis) and different tool-sets. Henceforth, allows to cut the workpiece in more complex ways and intricate geometries. It helps to boost the productivity and production speed.

Common Materials Used for Metal and Plastic Prototyping.

Commonly, plastic prototyping with CNC machines involves the use of the following materials: Polycarbonate. ABS, Acrylic/PMMA, PP, Nylon, Teflon, and Acetal/POM. On the other hand, metal prototyping with CNC machining might also utilise different materials. These usually include Stainless Steel, Aluminium, Zinc, Magnesium, Titanium, Brass and Copper.

There are various standard and easy-to-machine plastic grades. E.g., ABS is modest, adaptable, and genuinely machinable. But then, PP or POM is harder to cut and inclined to distort. Likewise, metallic materials also offer various scopes of machinability. Aluminium is probably soft, delicate, easy to cut, and speedy to machining. But steel is a lot tougher material.

Any of these materials can be used for CNC rapid prototyping as per requirements. Keep in mind that the surface finishing and quality of the prototype must remain uncompromised. Nevertheless, it matters a lot how the process is carried out. The quality of the CNC machine and tools used in making prototypes also define this.

Is CNC Machining Good for Prototyping?

Inarguably, 3D printing is considered the preferred option for plastic prototyping. However when functional prototypes are required then CNC machining still comes as the number one choice. The importance of CNC machining cannot be denied. Sometimes, CNC machining or milling can be an excellent option for metal and plastic prototyping. For example, it may be better to use CNC machining based on tolerance capabilities or material options available. Or it can also be decided based on required geometry, finishing, and appearance. But one thing is sure, the CNC machining method is cost-effective if we need 1 to 10 prototype pieces.

However, let us discuss some of its benefits:

Benefits of Metal and Plastic Prototyping with CNC Machining.

1. Prototype from File

The most significant advantage of CNC machining is the 'CNC' element. This digital process forms the prototype considering the computer file. Moreover, CNC prototyping offers a closely matched part as a final product to the digital 3D design. The same digital plan can also be used to create the ultimate part with identical dimensions. Furthermore, using 3D digital design, precise and quick alterations can be done. If the final prototype shows any malfunctioning, designers can return to the software. Hence, they can eliminate the flaws for the next prototype.

2. Consistency and Quality

Computer-controlled machines are perfect to replicate the repetitive jobs. While most prototypes depend upon human risks, CNC machines are exempt from human interaction. They even offer precise and desired results. If needed, a designer might only make a single prototype. What's more, the same job can be run again and again with minimal deviation. Simultaneously, new iterations can be easily added to the prototype to have the final piece's desired shape. Another point to note here is that CNC-machined prototypes give better accuracy and finishing.

3. Diverse Range of Materials

3D printing might be a suitable option if the final product has no mechanical purpose. In addition, if high-strength parts are not required, still 3D printing can be an appropriate alternative. Nonetheless, suppose the designed piece is intended to be used for a high-performance application. In that case, CNC machining comes up as the leading option. The reason is that it offers high mechanical and thermal resistance for functional prototypes. Above and beyond, a wide range of suitable materials further adds to its value. Unlike 3D printers, CNC machining for metal and plastic prototyping offers compatibility with many materials.

How may we help you?

ArpTech is an Australian-based company that deals in manufacturing metal and plastic prototypes. In short, we deal in low-volume custom CNC-machined parts without compromising the quality and strength. A broad scope of materials is utilised to make rapid prototypes of metal and plastic. We can assist you with making plastic and metal models that will enable you to analyse your product thoroughly. So, contact us now and get the solution to your problem.

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