Solutions for the working of the material with a delicate surface
LOWER TOOLS TR SERIES WITH AN OVERSIZE RADIUS
One of the most commonly experienced problems relevant the bending activity is the needing to avoid any abrasion, marking, dent and any other kind of damages on the product external surface.
The priority given to this matter becomes higher if the material being formed is stainless steel or any pre-painted material due to the needing to reduce/avoid any secondary polishing application.
Another one of the most widespread problem concerning the bending process is in the appearance, on the external side of the bent surface, of any mark in the form of a line, which is produced by the contact of the material against the lower dies shoulders’ radii. Our studies bring us to suppose that the mark is the consequence of the sheet rotation over a small radius (Figure 1).
To eliminate this inconvenience we were successful in testing the solution represented in Figure 2: it is possible to avoid the marks by increasing the die bending radii, on which the sheet is leant during the bending cycle, due to the larger contact points between sheet metal and die radii.
Following the excellent results noticed during our tests, we have increased the range of our standard tools with the new “TR” series, located on our catalogue at page 18 and 19; along side the drawings are the tables detailing the dimensions of the radius.
Depending on the application we can offer a personalized service of modification with precise tolerances afforded to us by our state of the art precision C.N.C. grinding machines and by our highly trained engineering department.
This solution is offered as an option on all our standard dies, either as a new die, or as a rework on customer’s existing dies.
ROLFILM PLUS CT
This product can be useful as a complement to the increased radius dies, or it can provide a cheap alternative for our customers that find marks problems only during some kind of works.
Rolfilm is a polyurethane tape, 0,6mm thin that can be placed between the sheet metal and the dies upper surface.
This kind of protection is often useful when working with damageable materials, such as stainless steel, pre-painted steel and aluminium products and, at the same time, assures the repeatability of the bending angle.
The film is placed between the die and the sheet metal, to creates a protective layer that prevents marks; moreover, the film thickness cause a 0,6mm increase of the die radius (see the advantages in the previous chapter).
Another important feature offered by polyurethane is the guarantee of the bending angle repetitiveness, due to its absence of elasticity. For this reason it doesn’t suffer from deforming or flattening but remains stable during all the bending process.
In order to optimise the use of ROLFILM we designed and manufactured holders that allow to keep the film firmly located on the die, however allowing for its movement inwards and outwards of the press brake machine; this feature decreases the set up time and reduces waste. The innovative holders positioning system, on the die body, allows the use of ROLFILM along all the machine working areas without any interference with the lower beam.