Comparison: Swing beam shears – Guillotine shears
Shears are machine tools used for straight cuts on sheet metal. On a swing beam shear the swing beam moves with the upper blade in a circular arc. On a guiottine shear the upper beam moves straight down.
Swing beam: Upper blade penetration
The upper blade penetrates the metal sheet above the lower blade
- Clean, right-angled cuts with almost no burr
Guillotine: Upper blade penetration
Upper blade penetrates the material with an offset (blade clearance) to the lower blade
- Oblique fractured cutting line
- Bigger burr especially when the blades are not sharp
Swing beam: After the cut is made
The cut is made by a pivoting movement of the swing beam. After the cut is made the upper blade moves away from the lower blade.
- Prevents the blank from jamming between the lower blade and the backstop
Guillotine: After the cut is made
On guillotine shears the cut is made by a linear motion of the upper beam
- Part may get stuck between the lower blade and backstop
- Higher wear
Swing beam: Sharp blades
The upper blade moves away from the lower blade after cutting. Upper and lower blade do not rub on each other.
- Keeps blades sharp for a long time
Guillotine: Sharp blades
Upper and lower blade rub on each other when the blade clearance is low.
- Blades go dull (burrs)
- Frequent blade changes required
Swing beam: Blade clearance adjustment
The blade clearance can be easily adjusted by simply turning the cutting gap eccentric.
- Short setup times
- Automatic adjustment on higher capacity machines
Guillotine: Blade clearance adjustment
Tedious and costly clearance adjustment by repositioning the shear table
- Long down times
- Often compromises in the cutting quality
Swing beam: Twist-free cuts
Swing beam cutting requires a ridig shear design. The reasonis the low rake angle, which is fix for any material thickness.
- Low rake angle results in twist-free parts starting at about 10-15 x sheet thickness
Guillotine: Twist-free cuts
Guillotine shears use a variable rake angle. Low rake angle for thin materials. High rake angles for thicker materials. Machines can be built lighter.
- The results are twisted parts with narrow strips
