What is Rapid machining?
Rapid machining is the machining of parts and prototypes with an explicit focus on reducing the time taken to make the parts.
It usually involves CNC machining (including milling, turning, etc.) but may also include manual machining for simple parts.
Machining can be expedited in various ways. Depending on the customer’s requirements, rapid machining may involve increased use of high-torque machines and roughing techniques in order to speed up material removal.
It may also involve easy-to-machine materials like aluminum alloys over materials that require more time to machine.
Although not mutually exclusive, rapid machining can be seen as a counterpoint to precision machining, which prioritizes accuracy and detail over speed.
Why is Rapid Machining so Important?
Rapid machining has always been the go-to manufacturing method for designers and engineers.
However, recent years have seen an expansion in the rapid machining market, leading to a wider client base for the process. Rapid machining has become an integral part of the manufacturing sector.
The importance of rapid machining can be credited to the following factors.
#1. Availability.
Rapid machining services are more easily accessible to people all over the world. With mature global shipping routes, you can get machining services from other countries with the minimum effect of lead times.
Traditionally you would have had to track down large factories or manufacturers and spend time and money negotiating with them. But now, you can contact any of the several global rapid machining service providers.
China alone has several hundred manufacturers that offer rapid machining services and are just one click away.
#2. Convenience.
Modern product design revolves around digital files made using CAD (computer-aided design) software.
CNC machines, like the ones used for rapid machining, are natively compatible with CAD files. Prototyping is as simple as sending a CAD design to the manufacturer and waiting for a day or two.
Additionally, if you need to make minor changes to the design, you can adjust it on the CAD file and resend it to the manufacturer.
The future of design revolves around 3D models that can be quickly machined using services like CNC turning and CNC milling.
#3. Customization.
Aside from ease of availability and unparalleled convenience, rapid machining is also very customizable.
Unlike traditional manufacturing, where you need to create expensive molds for products, this process is more streamlined.
Since CNC machining is a mold-less process, customizations and changes are very easy to implement. Hence, rapid machining is the most popular method for prototyping.
Rapid machining results in prototypes that are very close to the final product.
#4. Quick Lead Times.
Design and fabrication of parts have always been a long process. The production cycle typically has the following steps.
- Concept
- Designing
- Early Prototyping
- Testing and Verification
- Working Prototypes
- Final Testing and Evaluation
- Marketing
- Full-scale production
- Distribution.
Rapid machining improves several steps in the production cycle. Both prototyping and final production are very time-consuming processes.
And most people spend over a year working on these steps. Luckily rapid machining can cut your lead times in half.
#5. Cost
Part design and manufacturing can be very expensive, especially for smaller businesses. Low-volume production runs are particularly harsh on small businesses.
Traditional manufacturers are only price-competitive for mass production items.
Rapid machining is aimed at small and custom machining services. The cost per part is significantly lower for small volume and one-off custom designs.
Advantages And Disadvantages Of Rapid Machining
Rapid machining is an essential tool for rapid prototyping, product development, low-volume manufacturing and custom parts. However, it is not suitable for all manufacturing jobs.
These are some of the advantages and disadvantages of rapid machining:
Advantages of Rapid Machining
- The fastest way to produce parts with CNC machining equipment
- Iterates prototypes quickly to speed up product development
- Easy to fabricate multiple versions of a part for mechanical testing etc.
- Faster time-to-market
- Makes stronger parts compared to other high-speed processes like 3D printing
- No minimum order quantity
- No tooling or startup costs
- Compatible with a range of metals and plastics
- Range of surface finishing options
- Scalable since CNC machining is suitable for production at a later time
Disadvantages of rapid Machining
- Lower quality than precision machining
- Less geometrical freedom than 3D printing
- Slower than molding processes for high-volume orders (100+)
How rapid machining speeds up product development and reduces time-to-market?
For decades, rapid machining has been a go-to process for product designers looking to move their product from one stage of development to the next.
Rapid machined prototypes can be used for testing and evaluation, and it is easy to fabricate multiple iterations of a design for comparative analysis. Some rapid machined parts are even suitable for end-use.
It’s easy to see why designers engineers keep turning to rapid machining for instant parts. In this day and age, most parts are designed using CAD software, and the exported design files can be processed by CNC machines with minimal preparation.
This closes the time gap between finishing a prototype design and receiving the finished part.
And the process is often repeated several times. If product designers are ordering rapid machined prototypes for testing, they may need to tweak their designs and build several more iterations before the part is ready for production.
Rapid machining also provides prototypes that are similar to end-use parts in terms of quality, mechanical performance, and appearance.
Other prototyping processes like 3D printing and manual assembly have their own unique advantages, but if a part will eventually be manufactured with a CNC machine, a machined prototype will obviously be more representative of the machined final part.
Committing to a consistent manufacturing process provides obvious time advantages.
If a 3D printed prototype has to be redesigned into a machinable end-use part, a whole new stage of design is added to the overall process. No such stage is required for rapid machined prototypes.
A product development workflow using rapid machining may therefore go something along these lines:
- Concept
- CAD part design
- Early-stage conceptual prototype(s) via rapid machining
- Testing and evaluation
- Working prototype(s) via rapid machining
- Mechanical testing and evaluation
- Pre-production prototype(s) via precision machining
- Presentation, marketing, etc.
- Production
- Distribution
Ultimately, faster product development and shorter time-to-market give companies a competitive edge and leads to a greater chance of market success.
What level of quality should you expect from rapid machining?
Rapid machining is most frequently used as a prototyping process.
As such, customers should remember that there are other options (precision machining, for example) that may be better suited to high-detail parts that demand tight tolerances.
As its name suggests, rapid machining prioritizes speed over other factors.
That being said, rapid machining can produce professional-grade parts and prototypes to a very high standard.
Ordering parts from a rapid machining specialist ultimately allows the customer to stipulate the level of quality of required, by specifying tolerances and choosing a material of suitable quality and price.
Loose tolerances, simple designs and the use of high-machinability materials allow machinists to make the parts faster, giving a lower priority to part quality.
During prototyping and product development, this is usually a sensible route to take, as professional machinists are still able to make good quality parts while working quickly.
Rapid machining or 3D printing: what is Better for Manufacturing?
3D printing has changed the prototyping landscape by allowing users to fabricate one-off parts in a matter of hours.
3D printers can even be operated in offices, reducing the need for traditional factories and machine shops.
Because of the speed and simplicity of 3D printing, some product developers will automatically turn to additive manufacturing over subtractive processes like rapid CNC machining when time is of the essence.
But is 3D printing always the best option for fast-turnaround parts?
For in-house prototyping, there is probably no better rapid solution than 3D printing, since 3D printers require minimal expertise to operate and can print parts in hours.
However, a professional rapid machining service may be faster and deliver better results than a comparable 3D printing service.
There are some obvious parallels between rapid machining and 3D printing. Both use digital designs that are turned into G-code, and both are all-in-one solutions that require no tooling or separate machinery.
When choosing between rapid machining and 3D printing, bear the following factors in mind:
Some parts are faster to print; others are faster to machine
- Even if 3D printing is faster, it may take a long time to rework a 3D printed prototype into a machined final part
- Both metals and plastic can be machined with the same machining equipment; 3D printers only print one or the other
- Machined prototypes are usually closer to the final part than printed prototypes
Rapid Machining vs. Rapid Prototyping (RP)
Prototyping is the process of creating models of designs and improving them with further iterations. Most products go through multiple prototype iterations before landing on a final design that enters mass production.
Rapid prototyping utilizes various manufacturing techniques to improve production cycle times. The goal is to shorten production times between each prototype iteration.
Eventually, the time savings will stack, leading to a significant decrease in time costs.
This method utilizes both CNC machining and 3D printing techniques, meaning rapid machining is essentially a type of rapid prototyping.
As a matter of fact, before additive manufacturing and 3D printing became popular, CNC machining was the preferred method of rapid prototyping.
RP is a necessity for most upstarts and newcomers. Though you might be tempted to use additive manufacturing options, in most cases, rapid machining is the best choice.
Here is a brief comparison of CNC machining against the most popular 3D printing option, FDM (fused deposition modeling) and SLA (Stereolithography).
Rapid Machining vs. Traditional Manufacturing (TM)
Just like additive manufacturing, traditional manufacturing is composed of several processes. The biggest drawback of TM is time, and prototype development can often take years to finish.
The traditional manufacturing industry is aimed at mass production. Thus, it is not suited for customizations and changes, leading to a stagnancy in innovation.
Some common traditional manufacturing processes include the following.
- Die-Casting
- Injection Molding
- Machining (CNC and Non-CNC)
- Plastic Forming
- Etc.
As you can see, TM also includes the CNC machining process. However, the rapid machining approach is a complete overhaul of the traditional method.
Where traditional manufacturing relies on long conveyor belts and single-task CNC operations, rapid machining uses short setups designed for quick tool swaps and material changes.
Following is a brief comparison between rapid machining and traditional manufacturing.