Last update: Dec 12, 2022
CNC Milling Process
Before the large-scale manufacturing of any parts, prototyping is essential. Developing of prototype provides the idea about functionality, economic feasibility, and overall scope of the product. Prototyping proves the concept of parts of a product imagined by the designer. It removes the risk of failure and ensures that parts and products will work as intended. It’s a common assumption that a prototype is identical to production, but it’s a different process that includes testing, modification, and multiple iterations.
The ideal method for rapid prototyping is CNC machining, which can produce a few to hundreds of parts and products for testing in a few days. According to the concept, a CNC machine creates precise and intended pieces. Additionally, 3D designs can be quickly altered to change the parts to match desired functionality.
In this article, we will discuss the steps involved in rapid prototyping with CNC and the approach’s Importance, Advantages & Disadvantages.
Steps Involved in Rapid Prototyping
Chronological steps of CNC rapid prototyping
Step 1: Finalization of the design
Finalization of the design is the first step for prototyping with CNC machining. As we all know, CNC machines create the parts from the uploaded 3D model that needs to be finalized. In this step, designers and expert engineers create multiple possible designs without altering the functionality of required parts or products. The design includes complete dimensions, tolerances, features, and positioning. Once all the designs are ready, expert engineers select the few best designs for further proceeding.
Step 2: Creation of 3D files
CNC machines work on the 3D file, such as CAD design. Therefore, it is necessary to transform the chosen designs into 3D files like DWD and SLDPRT. All the dimensions, tolerances, features, and aesthetic requirements should be examined and validated according to the needs of the finished product while developing the 3D file.
Step 3: Identifying the machining processes
The machining steps are identified and finalized in this stage based on the 3D design. Identification of the manufacturing sequence is essential to optimize the time and material used for production. CNC machines can perform many tasks, including routing, turning, drilling, and milling. Therefore, it is necessary to decide which procedures were required and in what order, depending on the features included in the design.
Step 4: Production
CNC machining operation
The numerical control panel receives the uploaded CNC program when created. The machine is operated when the workpiece is mounted on the tool.
Once the machine runs, it completes all machining operations following the input settings. After multiple CNC machining operations, the desired prototype is produced. If the prototype has multiple parts, it requires a separate prototype and assembly later. This step is necessary for the prototype, which includes mechanical linkage and interconnected components.
Step 5: Testing of prototype
After production, the prototype goes into testing. It is the most crucial step of rapid prototyping with a CNC machine. The prototype’s functionality is tested, and all the possible failure situations get tested in this phase.
Along with the functionality, several other factors are analyzed in the testing phase, such as defects, durability, and overall efficiency. After conducting the testing, the production expert approved the prototype for further production. If the prototype fails to fulfill the requirements, alternative designs are analyzed and go for production by following the same sequence of rapid prototyping.
Rapid prototyping with CNC machining offers various advantages, from material selection options to flexibility in modification. Let’s overview some of them in detail.
1. Wide range of working materials
Unlike additive manufacturing approaches like 3D printing, CNC machining is compatible with a wide range of materials. It can work with difficult-to-machine materials. Rapid prototyping With CNC machining provides the flexibility to the developers to choose the materials. It is also easy to understand the performance, economic feasibility, and appearance when made with different raw materials.
Following are some common CNC Machining materials;
CNC Machined Metals
CNC Machined Plastics
2. Accuracy with prototyping
Since rapid prototyping requires accurate manufacturing, CNC machines can create parts with a high degree of accuracy. Because of the automated production, tight tolerance is easily achievable with each machining operation, such as cutting, drilling, turning, routing, and many more. CNC tolerance of ±4 μm is readily achievable, which is accurate enough for almost every type of part and product.
Digital Instruction to the CNC machine
If we compare CNC rapid prototyping with conventional approaches, it is far more accurate. It eliminates the risk of human error, and exact parts can be created as uploaded 3D designs.
3. Quick lead time
Because of the automatic production nature, CNC machines create prototypes in a few hours. However, the complete process from design to testing can take a few days.CNC machines reduced manufacturing and assembly time. All the tools and set-up work in a quick manner. Spindle speed, feed rate, and other circumstances do not restrict the production time of the prototype.
It offers a quick lead time and allows developers to test the prototype in a short time. It is highly advantageous to modify in case of any defects. Rapid prototyping is crucial, especially for developers who want to maintain their market advantage and outperform rivals.
Cntting Tool changes are not frequently necessary when developing the prototype with a CNC machine. This phenomenon shortens production time. With the ability to manage resources and quality, the cost of prototyping was reduced significantly. So, it is a cost-effective approach to prototype development.
5. Easy for modification
Since CNC prototyping is a speedy process, it enables engineers to modify the parts and products in a matter of hours in case of flaws or functional deficiencies. Developers can rapidly swipe the models after testing. It simplifies testing and reduces the possibility of error.
6. Easy to change
CNC machines are completely computer-controlled systems that enable quick changes to CNC programs and 3D designs. If you use the concept of continuous improvement, you may quickly adapt and modify your prototype. On the other side, it will cost more to alter and change the prototype using different techniques, such as 3D printing and injection molding. Quick design and program changes save not only money but also time.
7. Outstanding Result
CNC machine offers high-quality manufacturing for a few to hundreds of prototypes. The finished prototypes become functional and high strength. The as-machined surface finish also provides roughness in the range of Ra 3.2 micrometers, which is pretty well compared to other approaches like 3D printing (Ra 15 micrometers).
8. Complex prototypes
Complex prototype of automobile part made with CNC
Prototype with complex geometries is easily created with a range of CNC machining operations, such as milling, drilling, turning, routing, and many more. It also offers precision in complex parts because of the automated production.
There are only two major disadvantageous of CNC machining on rapid prototyping, Material wastage & restriction for some complex geometries.
1. Material wastage
As a subtractive manufacturing method, CNC machining produces parts by removing materials from the workpiece. The material gets wasted during the removal process in the form of chips. In essence, you require more material than you will ultimately use.
2. Challenging for complex geometries
With CNC machining, some hidden geometries can be challenging to produce as the tool goes from top to bottom. Compared to CNC machining, other production techniques like 3D printing may make it easier to create complicated shapes.
Is CNC machining best for Rapid Prototyping?
Prototypes show how the final product will behave and provide a visual picture. Before mass manufacturing, it is a valid scientific approach to confirm the product’s original requirements. It allows the identification of failure points and offers areas for improvement. Additionally, prototypes are utilized to direct the R&D process or show investors the results. The importance of prototyping in the product development process makes it crucial to adopt cutting-edge manufacturing technology that enables high-end precision.
If you believe that 3D printing is mainly used for rapid prototyping, your idea may not be accurate, you can check “CNC machining vs. 3D printing” for the difference. For rapid prototyping, developers prefer CNC machining over 3D printing. CNC machining provides a variety of material choices, making it simple to choose the one that best matches the desired characteristics and properties. Accuracy is another factor, CNC machining approach offers accuracy and an excellent as-machined surface finish. However, 3D printing might be more appropriate for smaller plastic products.
Upgrade your prototyping process with Prolean
The advanced and fully automated CNC machining system at Prolean provides a professional prototyping service for your parts or products faster than you thought possible. You can innovatively machine almost every material with precision in hours once you finalize your 3D design. We also run the computer simulation for the sensitive parts to visualize the prototype’s performance before it undergoes production. You will get your prototype on your desk within a matter of days. In addition, we also provide ongoing technical support after the delivery.
Before going into mass manufacturing, rapid prototyping is the best choice for product creators to test the product’s technical and financial feasibility. Rapid prototyping with CNC is the ideal option to check the visual aspect and functionality of the product. CNC machine offers a wide range of material options with a high degree of accuracy and surface finish with only a few days lead time; the process is quick. Additionally, it enables rapid testing and modification of the product if any adjustments are required.
Rapid prototyping is a strategic and complex process. It required expert engineers and experienced operators for different sensitive tasks. Sensitive tasks include selecting machining sequences, creating CNC programs, and machine handling. Pro lean offers rapid prototyping for your parts and products with high-end precision. We optimize prototypes’ functionality, material uses, features, and tolerance.
What is mean by prototyping?
Prototyping is creating parts or an entire product from a concept to see how it will look and work. Prototypes can vary from a few to a hundred, depending on their complexity and the required acceptance tests.
What are the steps involved in rapid prototyping with CNC machining?
There are five steps: design finalization, creation of 3D files, identification of machining sequence, production, and testing.
Why is CNC machining the best approach for Rapid prototyping?
Compared to other approaches like injection molding and 3D printing, it offers a wide range of material options, quick lead time, low cost, flexibility for modification, and precision.
How long did it take to produce a prototype using CNC machining?
Once your 3D design is finalized, you can have your prototype using CNC machining in a few hours to a few days. It depends on the size and complexity of the prototype.
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