1.4 Metal Wasting Processes Flashcards
What is metal milling
A cutter moves into the workpiece and chips are produced as material is removed.
What is the makeup of metal milling machines
The majority of milling cutters are two or four fluted solid cutters made from High speed steel (HSS) which can cut slots, plunge (drill), machine contours etc.
What type of operation is metal milling and turning
Manual or CNC
What in metal milling is used to reduce heat build-up and what 2 -ves does it cause
Liquid coolant is used to reduce heat build-up which can affect tool wear and surface finish.
What is metal turning
The single cutting edge of a lathe tool effectively shears material from a rotating workpiece as chips or swarf (a continuous chip).
What is flame cutting metal
Oxy-acetylene gas is mated to a flame-cutting torch to produce an intense, focused flame that is used to cut plate steel. The flame cutting is achieved with a jet of oxygen.
What in metal turning is used to reduce heat build-up and what 2 -ves does it cause
Liquid coolant is used to reduce heat build-up which can affect tool wear and surface finish.
What are solid tools and tipped tools made from in metal turning
Solid tools are forged from high-speed steel (HSS) whilst tipped tools use inserts e.g. tungsten carbide that are brazed or mechanically attached to the tool holder.
What are the 2 adv and 2 disadv of flame cutting metal
+ Low capital costs and suitable for remote locations without electricity.
+ Very thick metal cut be cut.
- Deformed and brittle cut edge.
- Manual operation is slow, inaccurate and inconsistent (CNC systems used for repetitive cuts).
What is laser cutting metal
A 2D CAD file is used to direct a high-powered focused laser beam that can cut through a range of metals. High pressure gas or compressed air forces the melted material through the sheet.
What is plasma cutting metal
An electric arc is combined with a super-heated ionized gas that is electrically conductive, to form a jet of plasma (similar to a lightning strike) that can cut through a wide range of metals.
What are the 2 adv and 2 disadv of plasma cutting metal
Faster than flame cutting.
Cannot cut through very thick plate metal.
Some thermal distortion and embrittlement at the cut edge.
Manual operation is slow and inconsistent (CNC systems used for repetitive cuts).
What are the 2 adv and 2 disadv of laser cutting metal
Fast and accurate cuts.
Limited thermal distortion
Limited to cutting flat sheet metal
High capital cost
What is the Cutting kerf (lost material) order for the 4 metal wasting processes excluding milling and turning
Plasma cutting c.a. 4mm
Flame cutting c.a. 1mm
Laser cutting c.a. 0.5mm
Punching 0mm
What is punching/stamping metal
Hardened punches are directed, via a CNC program or 2D CAD drawing, to punch out sheet metal that moves around under the punch.
