CNC Machining & Rapid Prototyping : Which is better?
Is CNC really better than Rapid Prototyping (RP)? This questions were always asked by peoples, when comparing the merits of rapid prototyping and CNC machining, opinions abound. RP and CNC machining both have staunch supporters that tout the benefits of their preferred technology. However, those who are familiar with both technologies generally agree that each has its own merits.
Both technologies have changed significantly compared to the past years. In the early days, most RP technologies offered an obvious speed advantage, but were limited by accuracy and material property issues. Since the launch of RP, CNC has advanced, in part due to the competitive threat, to become faster while offering many well-known benefits. Likewise, RP has improved in areas such as accuracy, material properties and surface finish.
As the technologies come closer in capabilities, the selection process becomes increasingly difficult. However, knowledge of both technologies is important for the selection of the right tool for the job. Hence, we will be discuss on some general guidelines on both CNC and RP.
CNC Machining
Machining centers are capable of milling almost every material imaginable. In case of maximum part size, CNC machining can fabricate parts and molds of virtually any size from small desktop units to large gantry systems. Practically speaking, size is only limited by the capacity of the available machine tools.
In the aspect of part complexity, CNC machining must deal with every feature in a part, and this can add time and cost. As the complexity of the part rises, so do the number of setups and tool changes. High aspect ratio features, deep slots and holes and square corners can challenge the most expensive CNC milling machine. However, in feature detail, CNC has the advantage over RP. Sharp edges, smooth blends and clean chamfers are among the details where CNC excels. This is especially true when evaluating detail in terms of accuracy and surface finish.
In case of leadtime, CNC with many jobs will take longer than those done in RP. But, CNC could be faster when the design is simple and straightforward, and when high spindle speeds and feedrates are an option.
Rapid Prototyping
The materials selection for RP is still limited compared to CNC. The maximumpart size RP could process is 24 x 36 x 20 in. (600 x 900 x 500 mm). Compared to CNC limited part complexity, it is possible for RP to build it with little impact on time or cost if a prototype can be modeled with design software. The ability to quickly and cost-effectively produce complex parts is one of RP's biggest benefits.
There are situations in which RP can produce features that CNC cannot. For example, RP can produce sharp inside corners and features with high aspect ratios, such as deep, narrow channels or tall, thin walls, ribs and posts.
With less labor, fewer steps and an insensitivity to design complexity, RP reduces leadtimes not only for the physical build, but also for the entire process. Overall, the RP process is more efficient in both time and labor. However, this does not mean that RP is the fastest for all parts.
Both technologies are having their own benefits in different aspects, hence, it is more important to choose the suitable technology for different kind of projects. Kindly contact Worthy Hardware if you are looking for some help in CNC Machining or rapid prototyping.