The Roll Forming Process
What advantages do roll formed parts offer, compared to other methods of manufacturing?
Roll forming is a precise, progressive bending and shaping operation that can streamline and simplify parts production. It reduces turn-around times and is compatible with close tolerance requirements roll formed parts also provide a greater strength-to-weight ratio, compared to ordinary sheet, so thinner walls can often be specified, and material costs reduced. Also, the production of rolled formed parts generates less scrap than competitive methods – a critical advantage in this era of high commodity prices.
What advantages can Rollformers offer us as a supplier of roll formed parts?
Rollformers 2000 Ltd has a broad experience base manufacturing roll formed parts for the door manufacturing, construction, steel framed buildings and many other industries. We are geared to producing highly uniform products. Our lead times are generally substantially shorter than other producers of roll formed parts. And with machinery set up for jobbing work our ability to manufacture a wide range of profiles ensures our place as a truly unique NZ manufacturer.
What roll formed parts do you offer?
Simple and complex angles, Purlins, Cees, Zeds, U-channels, hat sections, C-channels, Studs, Noggins, Ceiling battens, Roof and Tile Battens and many other special profiles.
See our pictures of previous custom profiles of what we do in the product pictures.
What materials can be roll formed?
Roll-formed parts we manufacture include low and medium carbon steels, galvanised steel, stainless steels, and pre-painted colour steels.
We also, on request, can look at materials such as aluminium, copper, bronze, and brass.
Do you offer prototyping?
Yes, we often produce rollformed parts as prototypes prior to production, and can do this on a fast track basis.
What post-manufacturing services do you provide for roll formed parts?
Hole punching, slotting and notching can be offered on request and at time of rollforming.
Rollforming vs Press Brake Forming
Which method would compare to be the most cost effective press? Brake forming or rollforming?
Rollforming in most cases where large volumes of parts are to be made. The tooling cost is usually more for the rollformed products initially but spread over a larger quantities the per piece tooling costs less. If it is a short run and the shape is compatible for forming on a press brake it is less costly to use a press brake.
So press brake is always better for small runs?
This depends. press brake forming generally requires making of more test blanks – which is scrap – and if the part is complex and precisely cut, and is made from a costly material, the expense of that scrap may tip the balance toward roll forming for a different reason. Many times the shape of the part is too intricate to do on a press brake. In addition the increased labour of brake pressing can make big runs uneconomical.
Is there any difference in total material cost between roll forming and press brake?
The cost of the material is generally higher for press brake forming because material has to be slit and sheeted-cut-to-length; roll forming accommodates very long parts lengths because the material is in coil form.
Which method delivers the greatest parts accuracy?
Press brake forming is universally regarded as an “art,” and varying levels of quality are a reality. Out-of-tolerance parts are salvaged or scrapped. Roll forming produces consistently higher accuracy, and a much lower percentage of out-of-tolerance parts. This uniformity being weighting factor in the decision to roll form products.
Why does press brake forming produce less accuracy in parts than roll forming?
The bend angles attempted with press brake forming are dependent on the specific material, its spring back properties, and the friction between the die and the blank during forming. In roll forming, metal is progressively bent, and it’s in contact with the forming dies for a longer time. The shape is reinforced by this lengthened contact, virtually eliminating spring back and making roll forming less affected by process variables.
Do roll forming and press brake forming have similar set-up times?
No – the set-up for press brake is usually less than for rollforming but the production rate piece per hour is much higher for rollforming. The reason for this is that each piece does not have to be handled individually.
We have a 90 degree angle requirement on an 800mm part. We tried press brake forming; the dies marked the part – and we had to split the part in three sections. Will rollforming work for this application?
With press brake forming, the part length can’t be any longer than the width of the brake press die. Rollforming can do the full 800mm length – and will not mark the part.
Does either method offer an advantage in reducing the number of production steps?
Depending on the shape of the part, rollforming can be done in one operation whereas using a press brake can require more than one hit. Also, depending on the part, holes and cut-outs can be done with an inline pre-notch or the cut-off operation, and that will reduce the number of operations needed and is significant in reducing cost and overall production time.
What about colour steel or plated material? Will either method accommodate this?
Both operations can be done on pre-plated or coated material although roll forming usually leaves less marks on the part.
Why is radius bending such a difficult application for press brakes?
One reason is the metal’s spring back may not be consistent from one sheet to another. Spring back is more of an issue for metals with higher tensile strengths. And the problem is exacerbated if the gauge or temper on long sheets of material has some variation. Radius bending is one task where roll forming is virtually always a better alternative.
Does the number of bends help determine whether press brake or rollforming is the better choice?
A single bend is accomplished easily with rollforming or press brake. The advantage of rollforming is that it can produce multiple precision bends over thousands of feet of material, quickly and very efficiently.
Metal Stamping vs Rollforming
Are there certain shapes that are more suitable to metal stampings than rollforming?
Most often, parts can be manufactured using either method. A more important consideration is quantity – when quantities are substantial, the tooling for rollforming can be amnitised over the production run and total cost for the program will be less than for metal stampings.
How does the set-up cost for metal stampings compare to rollforming?
The set-up cost for rollforming will always be less than metal stampings. And, if different parts widths are needed, the difference is very great. In this instance, metal stampings would require multiple set-ups. Rollforming different widths can be accomplished with just a simple timing adjustment.
With a long run, tool maintenance is a factor. How do metal stampings compare for this?
Tool maintenance is much less for a rollformed section than for metal stampings.
Why is this?
One major reason is that only one set of tooling is required for parts of various lengths.
How does production output compare between metal stampings and rollforming?
The pieces per hour will be higher for a roll formed part.
Can you tell the difference between metal stampings and a rollformed part strictly by appearance?
Quality rollformed parts look like metal stampings.
What about Colour Steel or plated material? Does either method accommodate this?
Rollforming and most metal stampings can be produced using pre-plated or coated material.
Please contact the Rollformers 2000 Ltd Engineering department on +6492744898 if you require any further information.