The Simplicity of Shearing Cut-off Parts
Shearing plates by an iron-worker delivers simplicity. The sheet is placed in the area between the top and bottom blades. Once the ram pushes the top blades downwards to the fixed bottom blades, the sheet gets cut through the opposite cutters.
Consider such factors as rake angles, clearance between blades as well as maintaining, since they have an immediate influence on the work outcomes.
Angularity For Perfection
Angularity of rakes and movable blades as they turn to the stationary blades determine the extent of the sheet being cut at a time by blades. This has an effect on the cutting outcomes and the tonnages required for the task. Large rake angles tilt the top knife downwards, cutting off the sheet with blades. The advantages of large rakes lay in that considerably lower tonnages are needed to shear, since smaller amounts of sheet are cut at once, especially in cases when accuracy is not crucial. The disadvantages include bowing, twisting or cambering of cut parts, the reason of which is that great pressure is exposed to quite a limited area of materials while shearing. Parts of metals might fall into the cuts, producing a little recess in the roll at the upper edges of the shear.
In the lower-rake-angular shear the top blades descend almost concurrently to the bottom blades like guillotines. Here higher tonnages are needed, since more amounts of sheet get cut at once. Shear strength spreads along the cutting sheet, instead of concentrating on limited areas. This also reduces deformations.
The variable tilt angular technology allows operators to make adjustment about the tilt angles according to particular tasks. Relatively higher rakes might be needed to cut thick metal parts, and later change it to lower rake-angles not to consume excessive energy while cutting thin sheets or improving part quality.
In systems with a fixed angle of inclination, the angle of inclination stays the same as set by the manufacturers, the angles are estimated to deliver the most proper shearing quality for sheet thickness ranges, that depend on the tonnages of machines. Some iron-workers perform with lower-tilt-angular shearing without pushing or pulling work pieces. This in its turn leads to the fall-off of clean-edged and smooth pieces. Progressive machines enable a lower-rank-angular shear to cut considerably thicker metals with low tonnages. For instance, the top shearing blades on HARSLE iron-workers carry a little camber. The central part of blades gets into the contact with the sheet as soon as they bend down to the work piece, shearing with smaller tonnages, meanwhile maintaining the lower rake for cuts with the least deformity.
Importance of Blade Clearance
Suitable clearance between blades is crucial to achieve excellent cutting with stationary as well as variable-rake system. At the cutting area and the end of shearing strokes a blade clearance of only a few cms. is produced. This clearance creates space to remove little particles of sheets that fracture in the process. The clearance extent is determined by materials and their thickness.
Excessively limited clearance makes it impossible for metal particles to get removed, which brings about extra pressures on blades interfering with the proper cut process. An excessive clearance will make the sheet get pulled in it. This will create barbs upon parts when the blades come to the end of strokes.
Certain iron-workers carry stationary top blades and bottom blades, that can be adjusted according to different tasks. To gain an ideal quality for parts, the clearance has to be adjusted depending on the thickness of materials. In most cases when leaving the clearance the same as that of the manufacture set-up while processing thin and thick sheets, quality variations are seen.
Fabricators make clearance settings between the blades in an ideal position to adapt the cutting of the advised range of materials depending on the tonnages of the iron-worker. Once installed by the manufacturer, the clearance between blades generally needs no — or receives no — readjustment or maintaining unless the blades have to be replaced or sharpened.
A good feature of the shearing point on an iron-worker is that the preset manufacture clearance covers 99 % of the materials being cut, with no need of re-setting the clearance. For instance, the clearance on a design cutting utmost 1 by 12 inches and 3/4 by 20 inches is adjusted to 0.020 inches. This set-up allows the machine to cut 1 by 12 inches and 1/8 by 20 inches with no change of the gap. With certain iron-workers a small gap, from 0.007 to 0.01 inches, provides the same simplicity and accuracy to cut thick as well as thin work pieces, besides allows shaving some more cuts on a flat work piece.
Keep It Steady
The clamping system helps to fasten materials to the cutting table not to allow misalignment while cutting. Clips might be mechanical, which need adjusting after every single shift, or hydraulic system. The latter is automatically adjusted according to the thickness of the sheet. Though hydraulic system is more expensive, it increases productiveness as allows materials to cross over the system rapidly. The self-regulating characteristics of the hydraulic system provides the correct pressure to protect sheets when changing the thickness of materials with no interference of operators. HARSLE machines apply urethane rubber clamps to automatically fasten and release materials after very single stroke. Parts stay fastened throughout the whole cutting cycle to ensure precision.
The latest approach to the cutting process offered anti-torque systems built into some versions of the HARSLE iron-workers. This delivers support for fall-off pieces in the cut process preventing deformations.
Under the cutting part appears a spring-load bearing. Once the upper blade is lowered to cut the sheet, the cut piece is maintained during the cutting process. This requires more costs, however, each cut part is smooth, has no deformation or burr.
Little Maintenance Is Required
Iron-workers and their scissors do not need excessive maintenance. Lubricate or grease the machines every week or month based on their usage extent. Oil is typically recommended being changed after 2000-hour usage. Since current oils are more long-lasting, just checking visually the viscidity will prolong the lasting time.
Shearing blades require no more care as well. They might be 2 or 4-edged based on manufacturers and models of iron-workers. Edges are exposed to wearing and turn blunt, consequently, they need being rotated to ensure proper cutting. There are manufacturers that do not recommend blade sharpening, while some recommend using grinders to renew each edge. It is also advised to lubricate the blades with little amounts of grease after each 10 or 15-cycle turn.
Manufacturers are on their go to figure out new characteristics, ensure more suitable set-ups, produce renewed versions to simplify the whole working process and cutting quality parts through iron-workers. Just follow our tips on maintaining your machines properly.