How to adjust a roll former ??
LOTOSFORMING guides and explains many of the common issues encountered in the roll forming process and roll forming operation manual, all factors that contribute to possible problems such as material, design, and manufacture.
roll forming operation manual is a process that developed by gradually bending the metal through a series of roll stands, or passes. Each stand must produce the appropriate amount of deformation for which it was designed. when roll-forming problems occur, it is important to examine each stage of the process and not merely the stand at which the problem initially appears. The goal of a roll forming operation is achieved when there is uniform metal deformation throughout the line. Roll forming operation manual is designed to be reasonably during the operation. If run “popping” throughout the operation, the operation needs to be investigated.
Kind types of roll forming systems :
Two basic types of roll forming systems are utilized: a pre-cut line and a post-cut line. A pre-cut line snips the incoming material to a specific length prior to roll forming operation manual. During post cut line operation, the roll-formed panel runs continuously and is sheared to the required length after roll forming.
Roll forming operation :
One of the main parameters that define the success of a roll forming operation is the character of the material. for design the optimal process, the designer should be provided material information to be used prior to the tooling designing such as material mechanical property ranges, gauge tolerances and shape tolerances, different metallic coatings.
Mill alignment is critical. forming rolls and their components must be aligned to each other both horizontally and vertically. The rolls must be aligned both side-to-side and pass-to-pass. Forming material with the gauge either lighter or heavier than that for which the tooling is designed can result in problems. Using material thinner than the designed gauge can lead to finish radii greater than the intended design. This is usually offset by over-tightening the rolls, which causes a decline in tool life.
Processing heavier gauge material than intended can also lead to larger radii than designed. When running thicker material, the tooling will make contact on the side of the tool radii leaving no center contact with the tooling. Since the material is not in proper contact with the tooling, gap differences from side to side become more critical. Small side-to-side roll gap differences can result in a twist, bow or sweep problems.
setup by the roll tooling manufacturer, feeler or wire gauges are most often used to set the gaps on roll-forming stands. This should ideally be done each time the metal being utilized changes significantly in gauge. Operators must be sure to periodically check for tooling wear or machine wear.
Each stand consists of top and bottom rolls designed to provide the necessary part dimensions. The position of the top roll can be adjusted via screws to change the gap between rolls, thereby changing the forming pressure applied to the metal at each stand. The final roll gap adjustment on each stand should always be down to compensate for the gear and bearing tolerances inherent to each stand.
Cutoff dies or shears are available in many types and variations. The most common types utilized for roll forming machines are the “slugless crop die” and the “flying shear”, or “cutoff die”.The cutoff operation accurately cuts the part to the desired length in a manner that is essential to the continuous operation of the line. Slugless crop dies generally have a short stroke length, possess contoured blades, and rapidly cut-off the finished part. Since the cut-off action is extremely fast, an accurate cut can normally be performed without interruption to the continuous operation of the line. Proper set-up in this type of operation is critical.
Roll forming machine design
Line speeds, die speeds and die clearances must be closely established and monitored to prevent blade drag. This condition can result in panel buckling. Removal of the buckled panel from the line is time-consuming and may result in damage to the cutoff die, or in extreme cases, to the roll tooling. Even if the part does not buckle to the point that it jams the line, improperly timed cutting can cause problems upstream in the roll former.
Momentary interruptions in the later roll-forming stand, while the initial stands are still driving the material, can result in a wide variety of problems and/or imperfections. Minor buckling in the intermediate stands can result in oil canning type imperfections as well as other twist or dimensional issues in the finished panel. If the line is set-up with extremely loose tooling clearances, the effect of momentary line interruption from the cutoff operation may be seen all the way to the uncoiler. In this instance, the alignment of the entire line becomes integral to the cut-off operation. For example, if the uncoiler is out of alignment, the momentary line interruption could „pull‟ the material in a skewed manner from the uncoiler and potentially cause oil canning, twist or sweep problems.
Roll forming stands
A flying shear, or cut-off die, may be required with an increase in the line speed or panel height configuration. This allows the shear or die to attain the speed of the line prior to the cutoff operation. The timing of the shear is critical in this operation. Momentary interruptions in the latter roll-forming stands, as described above, will generally be larger in magnitude and more serious in nature as the speed of the cut-off operation increases. The blade or die should always be cut to an approved part. Improperly designed/machined tools must be avoided because they result in tight clearances, induce blade drag, tool drag, or lose clearances, which result in burrs on the finished panel.
Roll forming machine configuration :
With a working knowledge of the roll forming machine configuration and the roll former setup procedures, the root cause of many problems can be determined at the plant level. Generally, the most important factor to keep in mind is that roll-forming issues must be approached from a systematic point of view. That is, everything must be considered from the incoming material properties, lubrication, roll former setup, uncoiler, and cut-off methods to the inspection details of the finished product. All or any of these factors can impact the acceptance of the finished part.
Important questions about adjusting the roll forming machine :
What are the Tool Gap Settings?
Gaps should initially be set at the material gauge with final adjustments made to achieve the desired final dimensions.
Does It Hold Dimension?
Ensure that the material is within the ordered width and property tolerances. Check the gaps in the overbend stands for proper gauging.
Where Does the Imperfection Appear?
Inspect and check the tooling and gap settings where the imperfection occurs and in the stands upstream. Adjust to appropriate settings.
Are There Tight or Loose Areas on the Finished Panel Radii?
These imperfections typically denote improper tooling adjustment or worn tooling or bearings. Ensure that the tooling has proper gap settings. Inspect the tooling for worn areas (chrome coating loss or increased radii due to wear). Inspect the line during operation for bearings with excessive movement. Occasionally, a worn bearing will make noise during operation. If bearing wear is isolated and is consistently in one stand, it would be prudent to inspect the tooling in the entire line for alignment, wear and proper gap settings.
Do the Radius Lines Appear to Wander Down the Length of the Panel?
Dry material, worn tooling, and improper tool alignment can cause this problem.
Does the Tooling Run Eccentrically or Wander with Respect to Other Stands?
This is an indication of bent shafts, worn bearings, worn or misaligned tooling. If the tooling visually wanders from side to side, either the bearings are worn or the shaft locknut has come loose, or a shim has worn or fallen out. When the tooling is running in an elliptical pattern (egg shape, or up and down) the shaft itself may be bent. This will require checking the shaft for run-out with a dial indicator for the amount of movement.
Are There Areas Where Excessive Material Has Been Stripped Off During Forming?
This normally indicates dry material, tight clearances or improper tooling setup. Tooling stands where material slivers and/or debris accumulate should be closely monitored, as this can lead to premature wear and finished panel imperfections. Material run with insufficient lubrication (dry areas) will run with increased friction in these areas during forming. This can cause the material to be scrapped during the roll-forming process, especially on the panel edges. In some cases, running dry material can raise the temperature of the tooling sufficiently to reduce the die clearances from heat expansion.
Tooling that is gapped to less than the material being formed, or tooling that is out of alignment from stand to stand, can also cause this problem. Although it is sometimes not possible to prevent material debris accumulation on some stands, tooling should be gapped and checked for alignment frequently.
Portable roll forming machine
Does the Material Track Properly into and from the Line?
Material that has differential lubrication edge-to-edge, the material with significantly different thickness edge-to-edge or tooling that is out of adjustment can cause tracking issues.
Does the Imperfection Appear at One Stand?
If this is the case, ensure the tooling is gapped properly at both the imperfection stand and also at the stands prior to where the imperfection occurs.
Does the Cut-Off Operation Run Transparent to the Line?
Drag or an out-of-time cut-off operation can induce a variety of imperfections or problems. In a post-forming cut-off process, the cut-off should not alter the continuous forming of the panel. Dull cut-off dies or knives can impart sufficient drag in the cut-off operation so that the formed panel actually begins to buckle in the cut-off operation. A similar condition is possible if a flying shear is out-of-time with the speed of the forming operation. Both of these conditions should be addressed when they first appear, as permitting them to continue will eventually cause the panel to buckle in the line prior to the cut-off.
Does the Material Pop, Crackle, or Wrinkle at One Stand?
This is often the result of either tooling misalignment of the material entering the rolls in a skewed fashion. Roll-forming should be approached from a systematic point of view; each stand is designed to perform a specific amount of forming.
Roll forming machine for sale
Successful roll-forming relies on a combination of factors, including material properties, tooling set-up, and roll former operation. As problems arise, it may be difficult to ascertain which factor is negatively impacting the finished panel to the point of rejection. This is why it is imperative to view the roll-forming process from a systematic point of view. With this approach, it is possible to determine the root cause of the problem and take the appropriate corrective course of action.
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