How to achieve maximum productivity in Rollforming
When we were contacted by companies for a new project, this was often the only problem that was truly on the agenda.
Let me explain.
The customer’s company wanted to introduce a profile or a system of profiles and products and wanted a system that would allow them to be manufactured at a certain rate of productivity, maximizing return on investment.
Taken from the book “The Revolution of Efficiency”
As already discussed, productivity is only one of the four aspects used in evaluating an investment.
I often received folders full of drawings, accompanied by requests from customers asking me to check both their feasibility and cycle times: in fact, the norm was to compare the facilities of the various manufacturers, mainly measuring their productivity.
However, what sense did it make to produce a piece quickly if the times involved in loading and unloading the machine, production changeover, handling or packaging were much higher? Indeed, providing a solution to this problem always requires assessing lots of other factors, starting with the overall process and production mix.
I began to understand which were the right questions to ask, starting with the size of the lots, the management of production before and after the machine and from the number of production changeovers.
Productivity often, if not always, clashed with the flexibility required of the process.
There were two main production systems in the sheet metal processing sector: one was sheet-fed with numerical control punching machines (for low production and high flexibility), and the other was coil-fed with a press and progressive dies (for high production, but with low flexibility).
The introduction of the parametric coil-fed punching systems, as discussed in the case of Giovanni Maffei, introduced great benefits in terms of savings on raw materials, as well as huge increases in productivity and flexibility!
Eliminating loading and unloading times, the handling of pieces, improving logistics: all elements that influence productivity, maintaining the sort of flexibility that a system with fixed dies and a press can never provide.
On the contrary: although very productive in a continuous cycle, production changeovers on presses take a very long time – while on coil-fed punching machines they can take place in zero time – and modifying any die, should the customer ask for the position of some holes to be changed, was extremely expensive when using mechanical presses and hard tools!
Productivity and Automation: Coil to Pack e Coil to Box systems
As for roll forming, customers often limited themselves to viewing the profile as the final product of the machines, but in many cases the product offered for sale had to be packaged according to the criteria set by the target market.
On the subject of roll forming, the first high-speed lines that we began to produce were for plasterboard profiles, which became one of the Dallan’s main products – and still are!
Pushing the lines to over a hundred meters per minute was relatively simple, thanks to the expertise we had developed on thin materials. We immediately ran into the problem of how to manage the miles of profiles that the machines produced, at the speed of a thousand meters in less than nine minutes.
We began to see our customers’ problem – and the need to develop appropriate automation – at the beginning of 2000. Plasterboard profiles are C or U profiles, which are assembled and interconnected to form a frame on which plaster panels are positioned, on walls or suspended ceilings.
The problem is that profiles can only be paired in twos and then stacked to form small packages and large packages, according to different sequences based on the type of profile and market. Consequently, an enormous number of profiles is generated, which then have to be managed in the packaging and warehousing phase.
We understood that the existing packaging systems required too many employees and generated enormous confusion in the production department due to the quantities of the product. Controlling production times and costs was almost impossible.
So, in 1997, we began to introduce partial automations into the process, starting by automating the stacking of small packages and completing the system in 2002, with the creation of small packages and pairing them with profiles directly on the line. The most repetitive and tiring operation (both mentally and physically) of the roll forming process was permanently replaced by a system we now call “Coil To Pack”.
In the suspended ceiling sector, the profiles that required a huge amount of automation were, for example, the T-bars.
These profiles make up the reticular (or grid like) structure on which panels 60x60cm or 60x120cm in size are positioned and this type of suspended ceiling is widespread all over the world.
The quantities were very high and customers began to ask for very fast machines and complete packaging that could produce the profile, perform quality control and package it directly into cardboard boxes. These machines also produce more than 100 meters per minute.
We called these systems “Coil To Box” and we are still the first and only company to provide complete systems for the production and packaging of T-bar profiles. These systems will be described in detail in one of the chapters dedicated to applications.
So, achieving high productivity in this case also required specific automation for the various types of profiles.
In fact, the T-bar system consists of three types of profiles: the first is called Main Runner and is the profile that supports all the others. It is coupled to the ceiling and is over three meters in length.
Then there are the two Cross Ts, profiles that are two or four feet in length, which couple to the Main Runner and to each other.
When it’s necessary to cover a surface, usually a quarter of the length of the profiles are Main Runners, a quarter are the two foot (or 600mm) Cross Ts and fifty percent are the four foot, or 1200mm, Cross Ts.
Therefore, it is necessary to begin with the total quantity of annual profiles and, in these cases, we’re talking of millions, perhaps tens of millions of meters per year. Given these quantities, the solution, for example, is to have several lines dedicated to Cross T profiles alongside a line dedicated to the Main Runner profile.
In the case of systems with lower productivity levels, we began offering semi-automatic packaging systems, which require an operator to check the quality of the profiles and to seal the profile boxes.
Below, you can see an example of semi-automatic packaging for Main Runner:
For systems with higher productivity levels the “Coil To Box” solution means it’s possible to go from a coil of raw material to the quality controlled product, sealed in cardboard boxes and palletized. These installations devour tons of steel in a very short time: in this case, the role of the operator is to supervise the system and, above all, to supply the raw materials (steel coils and cardboard sheets) and unload the pallets of finished boxes.
Want to find out more about high-speed automatic roll forming systems?
Contact our engineers HERE!
CEO – Dallan Spa