Advantages of rollforming over drum corrugation
For manufacture of wide panels there is really no substitute to Roll forming. Whether the panels are corrugated or come in complicated shapes or profiles roll forming gives the best products with unparalleled consistence of quality.
There are many advantages of roll forming for producing corrugated panels as against erstwhile methods including drum corrugation.
Firstly, the process can be highly automated with all benefits related to automation. The process can be coil fed and end products stacked neatly, ready for further packing, if required, and dispatched.
Secondly, roll formed corrugated sheets give the best protection against corrosion. It is common knowledge that drum corrugated sheets suffer numerous process related scratches resulting in scraping off of Zn coating. No wonder then that these sheets start to rust even within their first few months of usage. Abrasion between the gear-toothed drums and the galvanized sheet in between can in no way be avoided. Roll formed corrugated sheets, on the other hand, are as much corrosion resistant as much as the galvanized strip is. The forming process itself constitutes of bending the sheets in a progressive manner longitudinally by specially shaped rolls. The material, during the process, just glides over the rolls thus leaving the Zn coating intact. Roll forming is also the established process for manufacturing panels from colour coated strip. Roll forming does not deteriorate the quality of the mother material in any way whatsoever.
Thirdly, the quality of the finished product is absolutely uniform as long as the mother strip remains so. Aesthetically, the products are extremely appealing to the eye as because the sinusoidal profile generated by roll forming is geometrically true to size and shape, absolutely symmetrical and dent or mark free. No dent or mark is ever introduced by the process.
Fourthly, as is presently observed barrel-corrugated sheets tend to assume either a convex or a concave shape. This fact becomes evident when the sheet is laid on top of a table. Needless to say, in comparison, roll formed sheets lie absolutely flatly when subjected to the same test.
Roll formed sheets also show a minimum of width variation. In fact, all sheets from a particular coil would be of the same width if the mother strip is of consistent quality. Such consistence of quality is too much to ask from drum corrugating equipment.
Owing to the absolute consistency of roll formed sheets roofing proves to be a lot easier and economical. When lapping one sheet over the edge of another the builder will need one less wave compared with the same for barrel-corrugated products.
Roll formed sheets can be much longer; in fact, the length of roll formed sheets is restricted only by handling constraints. This means, less jointing which again amounts to more corrosion resistance.
The equipment is also highly productive requiring less manpower for equivalent output from barrel corrugation equipment. For example, a coil fed line will need only two operators per shift. Rate of output of the performance of the line operated by M/s. TATA RYERSON may be considered. The line is presently producing from 175 tons per day to 197 tons per day for strip thickness varying between 0.40 mm. to 0.63 mm.
Barrel of drum corrugating technology that employ traditional methods requires ONE SHEARING LINE to produce galvanised plan (GP) sheets from coils and THREE barrel or drum corrugators to produce 40,000 tons of galvanised corrugated (GC) sheets out of those GP sheets. Requirement of man power is also considerable. A Plant with a capacity of 40,000 tons per year would need two operators for the shearing line and four operators each for each drum corrugator. That makes a total of 14 operators per shift.
Our equipment, on the other hand, requires just 2 operators per shift to produce 50,000 tons of corrugates sheets.