Why continuum robots aren't common on CNC machining processes?

Question

So, I was searching on google/youtube about minimally invasive procedures and its tools to reach deep and delicate spaces of the human body, and it came to my mind the possibility of using it for CNC machining.

For example, these could reach deeper and produce incredibly complex shapes just like the 3D printing machines do, but without the weaknesses that normally come with the second method.

The first problems I can imagine would be the difficulty in automatic control (but that depends on the design of the robot, for example, this one would be easier to control) and how to subtract material in confined spaces (maybe fiber lasers, water jet cutter or wire EDM), but even so, why aren't continuum robots used for CNC machining?

The following picture is a cutaway metal 3d print of an Aerospike Rocket Engine.

Answer 1

Most probable reason: Speed

In CNC machining, speed is everything if you want to make money. It doesn't looks like these can be very rigid which means you can't hog out large amounts of material at high speed for roughing nor can you hold tight tolerances for finishing. You can probably imagine that the forces for cutting small amounts of even a soft material like plastic are much higher than those involved in surgery.

On top of that are problems of chip evacuation.

The difficulty in automatic control that you state is probably the second reason. I feel that when you say "difficult to control" you are thinking it is difficult to write algorithms and routines. But in this case there is something more fundamental: That there is no good way to sense, locate, or calibrate the tool to within acceptable tolerance limits for modern machining. Surgery in the human body doesn't require accuracy or repeatability within 0.005" as far as I know, and 0.005" is really sloppy by machining tolerances.

Answer 2

Continuum Robots is a kind of flexible robot, which is composed of flexible materials and many small continuum structures, which can realize highly flexible movements. In contrast, CNC machine tools usually use rigid materials and joint structures during machining, and their movements are strictly controlled to achieve high-precision machining.

Although continuum robots have advantages in some application areas such as medical surgery and flexible industrial automation, they are not common in the field of CNC machining for the following reasons:

High precision requirements: In CNC machining, it is usually necessary to process and position materials with high precision to achieve the expected geometry and size. Because the structure of the continuum robot is relatively flexible, it is difficult to achieve high-precision processing and positioning like a CNC machine tool.

Slower machining speed: Compared with rigid robots, continuum robots usually take longer to complete the same machining task. This is because the movement mode of the continuum robot is realized through the overall deformation, and the movement speed is slower than that of the traditional robot.

High cost for industrial applications: Continuum robots usually require the use of high-strength flexible materials and complex sensor and control systems, which lead to their high cost. Therefore, for some industrial applications, their cost may exceed the budget.

So while continuum robots excel in some applications, they are less common in CNC machining