CNC. Digital Manufacturing and Prototyping

CNC (Computerized Numerical Control) is probably the most powerful system to manufacture final pieces. It’s an interesting option for manufacturing in 3D but with a kind of 2D design strategy. What I used here is a 2.5-3 axes machine, where the advantages vs laser cutting are limited. With a 5 axes machine, the options are bigger. Well here you can achieve similar results, re-positioning the pieces in a different axis but it’s complicated to fix it and to do it accurately.

With a CNC, we can do geometrics that is not able to achieve with other technologies. There is a limit of around 20mm thickness for cutting in laser cutting, and here we don’t have these limits. Many pieces are not feasible with laser cutting, and here they are not complicated. Other times, it’s also possible to achieve similar results using different layers of laser cut pieces.

Here I only did a course, and I have a couple of pending projects, but I was a little bit disappointed. I expected a new world, full of new ideas, and I only found some cases or designs where this technology is better. I also have the feeling, and small experience, that the learning curve is difficult. This is my next challenge, but I didn’t find a real need or appropriate project until now.

Operations and materials

There is so much to learn, with materials, different drills, tolerances… and it’s also dangerous if you break one of the drills while spinning. Here is the limit between the professionals and the amateurs. They are industrial machines, and some knowledge about manufacturing is need.

In this Lab, what I used is the CNC with wood and plastic, making the options similar to the ones we have in laser cutting. The big difference comes using metals, stone… so working with hard materials. Here the CNC opens the door to new constructive properties, creating ready to use products with good mechanical properties. Of course, you need different drills bits for each of these materials and know the right settings. As harder is the material, the more difficult it is to work with it.

Alternatives

I never used a lathe, but I know there are digital versions of them. They are limited to pieces done by rotation but very useful and easy to use in these cases. It’s a classic tool in the workshops, something similar to the milling machine. Sometimes we try to do with CNC what it’s easier with these machines. Many times, they are included as a “CNC tool”.

Conclusions

• With this technology, many new pieces are possible to be done, from geometries to materials available. It only depends on the number of axes of the machine
• The limit is related to the needed space for the tools. We can mechanize a surface, but not create intricated designs inside a sphere, for example, they are not a 3D printer, they do not add material, there remove it, and we need place enough to let the drill work.
• They are less flexible than a 3d printer, but they can work with a wider range of materials.
• It is a tool for professionals. It means some training and experience, with a good knowledge of the tools and the materials. In the beginning, it is better to use them supervised by someone with experience.
• It is something not extremely easy to find in a maker space, few of them have these machines because of the price, the required space, and the maintenance.
• There are simpler tools, like lathes or milling machines, that represent a good alternative and that could easily solve many problems.

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