The Best Buyer’s Guide for 3 Roll Plate Bending Machine and Profile Bending Machine
3-Roll Bending Machine
3-roll initial-pinch, 3-roll double-pinch, 3-roll variable translating, 3-roll top roll horizontal movement, and 3-roll pyramid bending machine
What Is 3-Roll Bending Machine?
The three-roll bending machines are ideal for fabricators working with a wide range of material types. 3-roll bending machines are offered in two distinct categories: single and double-pinch. General 3-roll bending machine types are three-roll initial-pinch, three-roll double-pinch, three-roll variable translating, top roll horizontal movement, and three-roll pyramid.
Working Principle: 3-roll bending machine work by “pinching” the flat workpiece between two rolls and bending it as it comes in contact with a forming roll. This bends the workpiece into a cylindrical form, where it is welded together to produce a cylinder.
Five Types Of 3-Roll Bending Mmachine
Plate or metal profile 3-roll bending machines are offered in two distinct categories: single and double-pinch, but they may vary in geometry or style. General machine styles are three-roll initial-pinch, three-roll double-pinch, three-roll variable geometry, top roll horizontal movement, and three-roll pyramid.
The 3-roll bending machines are also built in a vertical format for special applications. Matching the most appropriate machine style to the application is important.
Double-Pinch 3-Roll Bending Machines
Double-pinch 3-roll bending machines are available in light to very heavy capacities. The terminology can be confusing as these units also may be referred to as double-pinch pyramid plate rolls or double-initial-pinch plate rolls.They have fixed-position top rolls and two offset, or lateral, rolls, one on each side.
Three-roll bending machines generally require pre-bending the leading end, running the sheet through the machine to prebend the trailing end, and then switching roll rotation direction to roll the cylinder body.
Smaller machines can be mechanical, but most are hydraulic and include drop-end yokes for easy extraction of the workpiece.
Variable-Geometry 3-Roll Bending Machine
Variable-geometry 3-roll plate bending machines are built to handle medium to extremely heavy plate rolling applications. Easy-to-remove end yokes can make material removal a quick process.
A metal fabricator doesn’t have too many machine tools that are dedicated to one job or one type of material. The nature of low-volume, high-mix work typically means a shop needs equipment that is versatile enough to tackle a range of jobs. When it comes to plate rolling, variable-geometry, a three-roll bending machine is that tool.
This type of plate roller differs from more traditional techniques in that it doesn’t have a fixed roller. The equipment is designed so that the top roll moves up and down and the two lower rolls move horizontally and independently of each other. The equipment’s flexibility makes it a suitable choice for medium to thick materials, say more than 1 in. thick.
The top roll moves up and down while the lower two rolls each move horizontally. This lower roll movement increases the offset distance from the top roll and in so doing delivers a distinct mechanical advantage in bending. A machine of this type works well over a wide range of material thicknesses. With varying geometry, these rolls can be used like a single-pinch, double-pinch, or pyramid-style machine that requires minimal sheet movement during pre-bending.
Top Roll Horizontal Movement 3-Roll Bending Machine
The top roll horizontal movement 3-roll bending machines top roll crowning and adjustable Back-Up Rolls enable to achieve precise circularity and cylindricality to application with a wide range of material thicknesses.
Being formed in the procedure that top roll moves front/rear direction, the ends of the material plate are firmly bent as well as the one was done by the ordinal press. Top roll crowning and adjustment of back-up roll help correct deflection of both Top Roll and Back-Up Rolls to be more precise circularity and cylindricality of applications, which reduces the time of post-procedure.
Pyramid 3-Roll Bending Machine
True pyramid machines are rarely used in cutting-edge facilities.
They have three rolls with both lower rolls fixed in position and the top or bending, roll moving up and down. The pyramidal bending machine‘s upper roller can move vertically up and down to pressurize the lower roller, so it cannot be pre-bent. In general, they leave a very long unbent flat and are not as user-friendly as other types of rolling machines.
How To Choosing
Machine capacity is equally if not more important than style. Bending machine manufacturers commonly rate their machines according to baseline material yield strengths of 36,000 to 38,000 pounds per square inch (PSI). However, you need to realize that steel mills are producing materials with ever-increasing yields.
When choosing a machine, you must refer to your bending machine certificates and verify the average yield strength of the metal profile (sheet metal, H-beam, angle iron, U-channel, pipe/tube, steel bar, etc) you are buying. It is not uncommon to find that the “mild“ steel you are rolling will have actual yields in the 48,000- to the 58,000-PSI range.
Remember, machine capacity must match your material, and most bending machine manufacturers can provide detailed capacity-versus-yield tables to assist you.
Pre bending is performed on the 3-roll bending machine at the leading and trailing edges of the metal profile, and eventually the seam.
A metal profile cannot physically be bent right to the edge, and thus what remains is referred to as the unbent flat. The minimum flat you can expect is 1.5 times the material thickness and often 2.5 to 3.5 times the material thickness for the heavier metal profile.
It is the pre-bending operation, in attempting to minimize the unbent flat, which takes the most power. That’s why pre-bending ratings are lower than rolling capacities for any given machine.
3 Roll Profile Bending Machine/Section Bending Machine
PR 3-Roll Plate Bending Machines
PRT Top Roll Horizontal Movement 3-Roll Plate Bending Machine
High rolling power combined with maximum pre-bending precision: PRT is the series of top roll horizontal movement 3-roll bending machines at the highest level of its category by performance and versatility.
PRT 3-roll bending machines designed, manufactured and marketed by BIT deliver performance equivalent to that obtained with the more expensive 4-roll plate bending rolls and are therefore ideal for medium-heavy duty machining.
PRT series models feature a very fast and secure pre-bending stage because the plate is never tilted but always parallel to the ground.
Thanks to the special configuration of PRT electronic plate bending machines, the machine’s top roll moves vertically and horizontally, by minimizing the length of the straight part, they offer better quality pre-bending. More Detail
Four Benefits of Double-Pinch 3-Roll Bending Machines
Pre-bending at both ends
The two lower rollers of the PRD Double Pinch three-roller plate bending machine can be lifted and lowered independently in an arc.
During operation, one lower roller is lifted and the upper roller is clamped to the sheet material, and the other roller is placed at the bottom for support. That is, an asymmetric sheet rolling process method is formed, so as to pre-bend one end of the sheet material; One side of the roller is lowered and the other side of the lower roller is raised, so that the metal plate on the other side can be pre-bent.
It is necessary to install a rolling cone device roll device at the end of the upper roll body on the discharge side of the equipment.
The device consists of a sleeve, a fixed ring, and a friction key. The principle of the roller is to decelerate by friction, to achieve the same speed at the large and small ends of the fan-shaped plate, and to complete the roll forming of the tapered roller-shaped workpiece.
Sheet center alignment
Ordinary three-roller plate bending machine center alignment mainly depends on the operator’s experience, low work efficiency, and easy-to-produce waste. On one side of the PRD Double Pinch three-roller plate rolling machine, there is a hydraulically-operated overturning centering mechanism. Accurately realize that the axis of the sheet is parallel to the axis of the work roll to avoid skewing of the sheet.
Wide roll bending range
The two lower rollers of the ordinary three-roll plate rolling machine are the main driving work rollers, and the upper roller is the driven roller, which is easy to slip when rolling thin plates and small-diameter workpieces. Generally, the thickness of the plate can be less than the maximum plate thickness specified by the parameters 1/3, the minimum rolling diameter is 2.5 times the diameter of the upper roll.
The upper roll and the two lower rolls of the PRD Double Pinch three-roll plate bending machine are the main drive work rolls. That is the three-roller full drive. Allows to roll metal sheets with a minimum thickness of 1/5 of the maximum coil thickness specified by the parameters, and the minimum roll diameter can reach 1.25 times the diameter of the upper roll. It can also be equipped with inner brackets and outer brackets to meet the needs of large thin plate drums. Rolling of diameter workpieces.