Hydraulic shears are of two types; swing-beam shears (fix-angle shears) and guillotine shears (shears of changeable angles). What do they differ
The main difference of QC12 swing beam shears and QC11 hydraulic one is shown in the following chart.
Hydraulic Swing-Beam Shear
Hydraulic Guillotine Shear
|Knife carrier cut movement||Mono-pivoting assist, lever principles|
Makes arch-shape curve movement round rearward.
|Triple point assisting roll guidance (Down eccentricity shaft, ahead assisting and top eccentricity shafts).|
Makes straight perpendicular movement.
Hydraulic oil-cylinder makes slanted motion.
75 percent working strength, 25 percent waste.
|Hydraulic oil-cylinder makes direct perpendicular movement.|
100 percent hydraulic stress act upon the cut edges.
|Knife styles||Prism-shaped upper knife uses just two-angled cut edges.|
Rectangle-shaped down knife uses four cut edges.
|Top and down blades are rectangle-shaped.|
All of the four cut edges are used.
|Setting of cut angles||Static cut and knife carrier angles|
Cuts certain angles regardless of the sheet density.
|Controllable cut angles, cutting angle depends on the sheet density.Adopting small angles efficiently reduces plate metal deformation and increases velocity to cut.|
As well as increases shearing angles increasing shear strength.
|Lubricating points||Bevel gear gets heavy wear-out, it needs to be lubricated frequently to provide long life.||Mostly has self-lubrication spherical bears and requires no manual lubrication.|
|Knife holder returning devices||Nitrogen returning cylinder, easily leaks and needs to be repaired.||Accumulator returning is steady and dependable.|
|Application ranges||Regular little and medium-size work pieces, regular demands for cut surfaces.||Big and medium long plate shearing, requires accuracy for cut surfaces.|
|Supporting frame||500 W AC engine combined with multi-purpose connecting twist shaft|
Easily causes raptures, no springing damper, no retraction function.
|Combines inverter, speedy engine, encoder, electronic numeric monitor.|
Velocity adjustment, little roar, spring retract and damper functions.
|Oil tanks||In case of inappropriate sheet application for a considerable period, hydraulic components get rusted, blocked and worn.||No rust exists in the whole processing, does not get into reaction with oil.|
Swing beam as well as guillotine shears have got the same blade gap of 0.04 mm. But it is impossible to entirely eliminate the bearing connective gap amongst swing arms and pendulum bodies of beam shear machines. Accuracy error amongst the clearances is more than 0.1 mm. Thus, swing-beam shearing machines perform with less precision compared to guillotine ones. Guillotine back guiding rails get compressed by the pressure of spring chock and no clearance exists amongst the head and back guiding rail. The clearance amongst blade edges is less than 0.04 mm. which provides smooth shearing with no burr.
Swing beam tool carrier is curved, this is why arch relation ensures directness of shearing materials. Guillotine shears guarantee directness through a direct tool carrier and it is far more accurate. In case of swing beam shears material gets burred and it is inevitable.
In case of processing sheets below 20 mm, swing beam shearing angles are not regulated and the shearing sheet gets slanted torsion. If the sheet thickness is less, the deformation will be more.
Guillotine shears suggest controllable shearing angles. Shear materials are not inclined to distortion or deformation which ensures processing precision of work pieces. Shearing strength is higher in the aftermath of increasing of shearing angles.
Swing beam shears are not capable of using four blades altogether while cutting plates as their blades provide curve movement. So, just the diamond-shape cut edges produce a double-side cut.
Guillotine tool holders make direct movement upwards and downwards. Their top and bottom blades realize four-edged cutting. This also ensures a longer working life for guillotine blades as compared with swing beam ones.
Guillotine shears do not realize returning of blades through nitrogen and this helps to escape the inconveniences brought about airflow.
The acting cylinders are double-operating ones. Other disadvantages of a swing beam shearing machine imply the following:
- Ensuring blade carrier force with a breadth above 3200 mm is challenging.
- Lubrication oil filling in the cylinder semi circular blocks is quite hard.
- Cylinder repairing requires big efforts.
- Rack does not get compressed evenly.
- Adjusting precision for gap blades makes difficulties.
- Materials possessing shorter shear length than 20 mm do not use the rear gauge.
- This type of machines has some restrictions in cutting thicker sheets. Plates thicker than 8 mm are preferable to process with guillotine shears.
These days most popular producers of shearing machines mostly produce guillotine shears, which are a bit more expensive. In comparison with swing-beam shear machines, these machines provide higher shear accuracy, controllable shearing angles as well as long-lasting serving life for cut edges. In a word, guillotine shear machines are advanced options of swing-beam shear machines.