Sheet metal shearing and punching Flashcards
1
Q
Sheet metal cutting methods: straight cutting
A
- Straight cutting
- Rotary shearing
- Notching
- Sawing
- Thermal cutting
2
Q
Sheet metal cutting methods: form cutting
A
- Nibbling
- Punching
- Thermal cutting
- Water jet cutting
3
Q
Shearing process
A
- elastic deformation
- plastic deformation
- breaking
- loose slug
4
Q
Shearing force calculation
A
F=1,2…1,6Ls*k
L-cutting length
s-sheet thickness
k-shearing strength (0,6—0,9*breaking str.)
5
Q
Die structures in punching
A
- outer shape
- hole
- compound die
6
Q
Progressive punching
A
dies with follow up structures to punch a part successively
7
Q
Turret punch press
A
- for nibbling
- tool magazine (20-50)
- NC
- flexible
- efficient in small batch sizes because small set up times
8
Q
Electric stroke advantages
A
- No oil, filters, gaskets (Dichtungen)
- Less need for maintenance
- Simple construction
- Silent
9
Q
Punching tools
A
- punch and die
- steel or HSS
- max d=100mm
- Tool clearance is 5 – 15 % of sheet thickness
- punch grinding to prevent sticking of slug
10
Q
Automation for workpiece handling
A
- Sheet loading is easiest to automate
- With a suction cup manipulator
Common problems:
- sticking oily sheets
- -> prevented by bending, compressed air or magnetic holding of lower sheet in stack
