Rapid Prototyping is a necessary step during a product development milestone, it helps validate a design’s appearance and functionality before tooling kicks off. CNC Prototyping makes it possible to make prototypes fast with low cost from a single prototype to low-volume parts.
In this blog, we will explore the CNC prototyping techniques, applications, and benefits of this prototyping method.
What Is CNC Prototyping?
CNC prototyping is a rapid prototyping method that creates prototypes quickly using a CNC machine. It involves using a computer-controlled machine to carve out a product model from a solid block of material, such as plastic or metal. The prototype created by CNC prototyping can determine how a part will look when finished and tested to check it will function as intended.
Type of CNC Prototyping techniques
There are mainly two prototype CNC machining operations available based on the principle of CNC machines working. The specific operation chosen for a design depends on the product’s mechanical structure and materials used.
CNC Milling
CNC milling leverages milling machines to create prototypes. It’s a subtractive process wherein the machine precisely carves materials from a workpiece to form a CNC-milled prototype of varying shapes. The milling machine uses different milling-cutting tools to execute sharp cuts of various lengths and shapes as it revolves. The depth and type of cut made on the workpiece depend on the product’s complexity.
CNC Turning
CNC turning utilizes a turning machine and a lathe tool to manufacture prototypes. It is good at producing prototypes and final products which have cylindrical attributes. Unlike milling machines, turning machines create cylindrical components using a single-point cutting tool that removes material from a bar stock.
In this process, the lathe-cutting tool remains stationary while the workpiece rotates in close proximity. CNC turning is commonly used for linear exterior features on a prototype, as well as internal elements like slots, threads, and tapers.
Benefits of Using CNC Prototyping
CNC prototyping brings a lot of benefits to the rapid prototyping process, making it a perfect choice for creating prototypes, engineering models, and top-notch end-use components.
Machining FAST
With the help of modern CAD/CAM design software, a three-dimensional design can swiftly transition into a G-code cutting program, transmitted to a multi-axis mill within a few hours. Once programmed, a proficient mill or lathe can start cutting workpieces at a set pace, and turn the raw metal from blanks into finished parts.
Cost-effective
CNC prototyping is a good option in terms of price point if you need to make just a few prototypes. CNC prototyping could start immediately once the programs and machines are set just after a few days which contributes to a low cost.
Tooling Flexibility
CNC machining doesn’t need a fixed tooling. The only tools involved are the hardened metal cutting inserts nestled within the spindles. These diverse cutting tools can execute different cutting functions on the workpiece to form different shapes. When thoughtfully arranged on an automated turntable, these tools can be swapped and replaced within seconds, making CNC machining highly adaptable.
High Accuracy and Precision
In a CNC machine shop, achieving high accuracy and precision is primarily determined by computer-controlled cutting tools. This level of precision produces small tolerances as +0.05mm or 50 microns which can achieve the needs of most commercial products. For even tighter tolerances demanded by aerospace, automotive, or scientific applications, specialized cutting tools under controlled conditions can be enlisted.
Material Versatility
Unlike there are limitations on the materials suitable for prototyping processes such as 3D printing and injection molding, CNC prototyping enables the machining of a wide array of materials, from plastics and wood to robust metal prototypes. The material options available for CNC prototype machining cover the most engineering plastic materials and metals.
Applications of CNC prototyping
CNC Prototyping is widely used in the product Research and Development phase in various industries. Some industries utilize this process more frequently due to its specific advantages.
Automotive Industry
The automotive industry demands components and prototypes with exceptionally high precision and tight tolerances Such as brakes, gears, and wheels, all these components require ultra-precise dimensions to ensure vehicle safety. CNC prototyping can fulfill this requirement, unlike other methods such as 3D printing.
Medical Industry
The medical field is undergoing rapid changes, Applications in medical equipment demand precision at the microscopic level and the use of robust materials. CNC machining stands out as the preferred manufacturing method for producing precise functional prototypes for these medical devices, given its unmatched accuracy compared to alternative techniques.
Military Industry
CNC prototyping is used a lot in the Military industry, where the demand for highly complex and precision-engineered equipment is constant. The production of ammunition and armored vehicles often involves intricate mechanical systems and technologies. Prototyping is important to test and perfect these mechanisms before mass production. CNC prototypes can accurately replicate the complex components required for military applications.
Aerospace Industry
The aerospace industry demands perfection to ensure safety and efficiency. Prototypes are critical for testing components before aircraft use, CNC prototypes guarantee precision and reliability, ensuring components like landing gear ports, bushings, manifolds, and airfoils meet stringent standards.
CNC Prototyping vs 3D prototyping
Both CNC machining and 3D printing are common prototyping processes, but they are quite different from each other both in the method and solution provided. Here is a comparison table between these two processes.
| Factor | CNC Prototyping | 3D Prototyping |
|---|---|---|
| Working Principle | Additive manufacturing builds parts layer by layer. | Additive manufacturing, builds parts layer by layer. |
| Supported Materials | Versatile, works with metals, wood, plastics, and alloys. | Limited to thermoplastic materials. |
| Possible Geometry | Limited internal complexity, focuses on external features. | Supports complex internal geometries. |
| Wastage | Significant material wastage, but recyclable. | Subtractive manufacturing removes material to shape parts. |
| Manufacturing Time | Faster, creates parts in minutes. | Slower, takes hours to create a single piece. |
| Material Consumption | The high tolerance level of ±0.01 mm. | Low material wastage, used as needed. |
| Prototyping Cost | Relatively expensive due to machine and accessories costs. | More cost-effective for prototypes. |
| Part Tolerance | High tolerance level of ±0.01 mm. | Slightly lower tolerance of ±0.1 mm. |
| Part strength | CNC parts tend to be tougher. | Higher material wastage, less efficiency. |
CNC Prototyping vs Rapid injection molding
Injection-molded prototypes have good precision but may have appearance defects and limited material options. CNC-machined prototypes offer high precision, better surface finish, and versatile materials, but they may have higher material costs. Here is a comparison table between these two processes.
| Factor | Injection-Molded Prototypes | CNC Machined Prototypes |
|---|---|---|
| Part Tolerance | ±0.1 to 0.7mm due to shrinkage | Very high tolerance of ±0.01mm |
| Prototype Material | Mostly plastics or elastomers | Wood, plastic, or metal |
| Surface Quality | May have minor defects like warping, sink marks, flow lines, etc. | Better surface finish due to extensive tooling |
Getting Started in CNC Prototyping with KUSLA
CNC prototyping is one of the best ways to make your prototypes because of its relatively faster method and quicker cycle times. KUSLA offers cost-effective CNC-machined prototypes, saving you time and expenses. Our advanced CNC technology ensures precision. Simply send us your CAD file for a quick quotation and DFM feedback. With 3, 4, and 5-axis CNC machines, we handle custom prototypes or low-volume production efficiently. Benefit from our ISO 9001:2015 certified quality standards, delivering top-quality finished parts at a lower price than the industry average.
