WhatisMachining?
Subtractive manufacturing — the key processes of metalworking.
Machining — Definition
Machining (also: subtractive manufacturing) is the umbrella term for all manufacturing processes in which material is removed from the workpiece in the form of chips. Machining belongs to the main group Separating according to DIN 8580.
Unlike forming processes (bending, deep drawing) or additive processes (3D printing), machining involves material removal — the workpiece is carved out from solid stock. Machining is the most widespread manufacturing process in metalworking.
Machining Processes According to DIN 8589
DIN 8589 classifies machining processes by the type of cutting edge:
Geometrically defined cutting edge
- Turning — Workpiece rotates, tool is stationary. → What is Turning?
- Milling — Tool rotates, workpiece is stationary. → What is Milling?
- Drilling — Tool rotates and moves axially into the material
- Broaching — Tool with progressively arranged teeth
- Sawing — Cutting process with saw teeth
Geometrically undefined cutting edge
- Grinding — Abrasive grains remove material. Highest accuracy and surface quality
- Honing — Finishing of internal surfaces (cylinders)
- Lapping — Flat machining with loose abrasive grain
Cutting Parameters in Machining
Every machining process is governed by three main parameters:
| Parameter | Symbol | Unit | Influence |
|---|---|---|---|
| Cutting speed | vc | m/min | Tool life, surface finish, temperature |
| Feed rate | f / fz | mm/rev or mm/tooth | Roughness, material removal rate |
| Depth of cut | ap | mm | Cutting force, material removal rate |
Optimal values depend on the workpiece material, tool, and the desired surface finish. Too high a cutting speed = tool wear. Too high a feed rate = rough surface.
Cutting Fluids (Coolant)
In machining, cutting fluids play a crucial role:
- Cooling — Dissipating process heat (up to 600°C at the cutting edge)
- Lubrication — Reducing friction between tool and workpiece
- Chip removal — Flushing chips from the machining zone
- Corrosion protection — Short-term protection of machined surfaces
Modern trends are moving toward minimum quantity lubrication (MQL) and dry machining — especially for aluminum and cast iron, where the environmental impact and cleaning costs of cutting fluids are a concern.
Frequently Asked Questions
What is the difference between machining and forming?
In machining, material is removed through chips (e.g., turning, milling). In forming, the material is reshaped without material removal (e.g., bending, deep drawing). Machining enables higher accuracies.
What types of machining processes exist?
The main ones are: turning, milling, drilling, grinding, reaming, broaching, sawing, and honing. They are distinguished by the type of cutting edge (geometrically defined vs. undefined).
What is contract machining?
Contract machining means an external service provider (contract manufacturer) handles the subtractive processing. The customer supplies drawings, and the contractor manufactures the parts on their own CNC machines.
Further Topics
Ready for Your Project?
Send us your drawing or 3D model, we'll prepare a quote within 24 hours.