Process Encyclopaedia
Mechanical cutting
Other names / variants: Sawing, hacksaws, bandsaws, circular sawsOverview
One way of splitting a workpiece in two is to plastically press a shape out of it, such as with blanking.
This entry deals with splitting a workpiece in two by removing a thin slice of material by mechanical means (the other main approach is removal by intense heat). These processes are usually called "sawing" and include: hacksaws, bandsaws, circular saws and friction saws.
Other specialist cutting processes include gear cutters.
Materials and shapes
- Generally speaking, sawing is only for straight line cuts all the way through a workpiece.
- Some sawing processes are capable of producing curves, and some can be used for cutting "slots".
- In general, wood and metals are easily cut - although the higher the strength of the metal the greater the rate of wear on the cutting teeth.
- Polymers can be cut, but care must be taken to avoid any melting.
- Glass can be cut by "score-and-snap" techniques.
- Composites are not usually cut (other than edge trimming) after forming as it can have a serious impact on the mechanical properties.
Economics
- If possible, avoid cutting! A surprising number of designs involve a cutting process followed by a joining process. Although this can be more economical than making in one-piece, it is not usually the case.
- The main use for cutting is to reduce stock items (usually from rolling or extrusion) to the correct length.
- For thin workpieces (up to 6mm), mechanical cutting competes with sheet process such as blanking.
- For thicker workpieces, new processes such as plasma-arc, water jet and lasers are becoming competitive because of their greater flexibility.
Typical products
- I-beams
- window frames
- joists
- architectural mouldings