CNC and CAD/CAM: digital manufacturing in precision mechanics

CNC stands for Computer Numerical Control and means that the machine's movements are controlled by a program rather than a hand-operated wheel or handle. It does not change what a precision mechanic must be able to do — understand material, drawing and tolerance — but it shifts part of the work from hand to screen.

§From CAD drawing to CAM path

Work starts in a CAD program (Computer Aided Design) where the part's geometry is drawn in 3D. That file is imported into a CAM program (Computer Aided Manufacturing) where you define which operations the machine should perform — face milling, contour milling, drilling, threading — and in what order. The CAM program then calculates the tool paths based on the chosen cutter, material and cutting parameters you set.

§G-code: the language the machine understands

The CAM program translates the paths to G-code — an instruction language for positioning speed and functions standardized internationally through ISO 6983 (and the German version DIN 66025 which many European controls build on). Although most machines today have manufacturer-specific additions the basic structure with G and M codes is common enough that you can recognize the logic across machines.

§Simulation and test drive

Before a program runs in actual material, it is simulated — either in the CAM program or in the machine's own control — to catch collisions, incorrect tool choices, or inefficient paths. Many shops also run the program in air or at reduced speed the first time as a final check before the piece is really clamped.

§Zero point, clamping and tool data

A programme is only as good as the references it is built on. You must set the item's zero point correctly in relation to the machine's coordinate system enter precise tool lengths and diameters and ensure the clamping holds the item fast without deforming it. A small error in the zero point propagates to the entire item — therefore start-up control is just as important as the programming itself.

• 01CAD draws the geometry, CAM calculates the tool paths
• 02G-code (ISO 6983/DIN 66025) is the language that controls the machine's movements
• 03Simulation catches collisions and errors before the workpiece is destroyed
• 04Correct zero point and tool data is the prerequisite for a correct result
• 05Target points in the subject Anatomy physiology and behavior require that the apprentice can explain the horse's skeletal muscle nerve blood vessel and digestive systems as well as identify structures below the knee and front knee on both living horse and specimen.

Automation does not remove responsibility from the precision mechanic but shifts it. Instead of controlling each movement by hand, you control the process: you choose strategy, check the simulation, set up the machine correctly and measure the result. The one who understands both the craft and programming gets the most out of a CNC machine.