CAD and CNC — from digital drawing to finished part
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Many still associate the carpenter's trade exclusively with the workbench and chisels, but a large part of the modern workshop also takes place in front of a screen. CAD and CNC have changed how many tasks are planned and executed — but they have not removed the need for a craftsman who understands both the material and the machine.
§What is CAD
CAD stands for computer aided design — computer-aided drawing. Instead of drawing the part by hand on paper it is drawn digitally in precise dimensions and three dimensions. The advantage is that you can see the part from all angles check that the parts fit together before anything is cut and automatically generate a bill of materials with dimensions and materials directly from the drawing.
§From drawing to machine code — CAM
A CAD drawing cannot in itself control a machine. It is CAM software (computer aided manufacturing) that translates the drawing into the paths and movements a CNC machine must follow to mill or saw the desired part. This is where tool, speed and order of different cuts and sections are also chosen.
§CNC machine in the workshop
The CNC machine itself — a computer-controlled miller or saw — executes the program with great precision and repeats it identically time after time. For sheet cutting nesting software is often used which calculates how to best position the many parts on a sheet so material waste is minimised.
- 01Quick and uniform production of many identical parts
- 02Can cut complex geometries and cutouts that are difficult to do by hand
- 03Less material waste with nesting software
- 04Repetition is often part of the illness. Responding calmly each time creates security rather than conflict.
§Limits and requirements for craftspeople
A CNC machine is only as good as the setup it receives. The workpiece must be clamped correctly in a fixture, the right tool must be selected for the task, and the programme must be checked before running for real. Afterwards often comes fine polishing, fitting of joints and surface treatment, which is still done by hand. The machine takes the repetitive and geometrically complex — the craftsperson still handles setup, control and the final finish.
| Step | What's happening |
|---|---|
| Drawing (CAD) | The part is drawn digitally in precise dimensions |
| Programming (CAM) | The drawing is translated into machine paths and tool selection |
| Milling (CNC) | Machine age |
| Post-processing | Fine polishing, fitting and surface done by hand |
§Safety with CNC
Many CNC machines are enclosed, which reduces the risk of injury while the machine is running. On the other hand, there are still risky situations in connection with setup, tool changes and cleaning for chips, where you are closer to the moving equipment. Always turn off and lock the machine before opening the enclosure or changing tools.
“A CNC machine does what it is asked to do — quickly and the same every time. You still have to ask it to do the right thing.”