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ROLLA-V Dies

Rolla V dies are distinguished from the traditional ones by the presence of 2 oscillating rotors which support the sheet metal before the bending process. Their peculiarity consists in the rotation of the rotors that accompanies the sheet metal during the bending with a drastic reduction of the friction resistance and of the length of the minimum edge. This type of tool applies the concept of tangential bending whereby the behavior of the sheet is different: this is more noticeable if holes and slots are present near the bending areas. Thanks to this concept, these areas do not undergo the classic deformations more commonly known as "slurries".

Advantages

VERY SMALL EDGES

Consumption of material is a factor that modern manufacturers must take into consideration, even a 5% reduction of the edges of the profiles can lead to considerable savings in material costs. When using conventional dies, the sheet must remain well supported on the opening radius of the die to obtain a good bend without deformation. Furthermore, many profiles may have holes near the fold line or require very small minimum edges; with Rolla V the bending process is different so that the sheet is always supported by the inserts of the die.

BENDING NEAR HOLES , INCLUDING PROFILES WITH OBLIQUE SIDES, AVOIDING DEFORMATIONS

Some profiles have edges that shrink as you approach the end of the piece. When these profiles are made using conventional dies, the final part of the fold remains more open because the edge is too small, it is not adequately supported by the die and slips into the slot. Since the inserts of the Rolla-V matrices guarantee constant support of the sheet metal edges cut obliquely up to almost the bend line, the deformation of the profile is kept to a minimum and often not even noticed.

REDUCTION OF BENDING MARKS

Thanks to the fact that the inserts of the Rolla-V dies support the sheet during the entire bending process, the friction between the sheet metal and the die is significantly reduced and consequently the marks on the sheet are significantly less. Moreover, the lateral movement of the sheet metal on the inserts is minimal and, contrary to what happens with conventional matrices, the sheet does not slide along any edge of the die, preventing almost all the bending marks on the sheet metal.

AVOID FURTHER OPERATIONS AND SAVE TIME

Many profiles must be aesthetically perfect and without signs because they must be positioned in view or because after bending they must be painted. Thanks to the use of Rolla-V dies it is possible to significantly reduce the expensive polishing operations that follow the bending, since the traditional straight mirroring marks along the bending line that usually appear after bending with traditional dies are absent and other scratches are reduced to a minimum mark. Thanks to the elimination of further processing steps, production costs decrease and, more importantly, delivery times are reduced.

Other models

ROLLA-V adjustable

All the advantages regarding the internal bend radius obtainable with Rolla-V matrices also apply to the variable V models which, as their name indicates, have an adjustable groove opening. Each model (HD, 2, 2.5, 3 and 4) has its own parameters and Rolleri can provide special punches according to the radius to be made; unfortunately there's no universal variable size punch (yet). All adjustable models have 3 types of interchangeable inserts depending on the type of bend you want to make: flat inserts for standard folds, concave inserts for bending radius U-profiles and V-inserts for obtaining square U-profiles. The same die can make all these types of profiles just by changing inserts.

NON-STANDARD ROLLA-V DIES

Although there is a standard Rolla-V matrix for most of the applications, an ad hoc solution may sometimes be required for particular projects. Thanks to the production of each single component with cutting-edge machinery, we can produce special dies for the creation of particular profiles. Rolla-V offers a complete range of models, each of which corresponds to an die opening which is measured with the distance between the centers of the inserts. Whether you need to bend from 0.5mm to 30mm thick, or you need to make a 2.7mm edge on 1mm sheet metal or a 40mm edge on 30mm thick material, there is a Rolla-V die capable of accomplish what is required. There is a range of dies with different sizes and suitable for different thicknesses: normally each model can be used for at least 3 different  thicknesses. Another characteristic is their high resistance (up to 2500 kN / m). They are tools with a special anti-corrosion coating and do not require special maintenance.

Useful references for working with Rolla-V matrices

Model

A [mm]

B [mm] 

C [mm]

Z [mm] 

XT1

5,7

5,04

4,57 

0,8 

XT2

10 

9,21 

8,66 

0,95 

1

7,17

6,59 

2

15 

13,92

13,16 

1,3 

2.5

28 

26,34

25,17 

3

36 

33,44

30,22 

5,5 

3.5

60 

57,1

55,05 

3,5 

4

85 

80,03

76,51 

Model

Maximum recommended thickness

 V ➀

Max. resistance  ➁

Sheet thickness ➂

Minimum angle ➃

Force required for iron with max. 450 N / mm2➄

Force required for stainless steel with max. 700 N / mm2➄

Minimum outer edge➅

Max. Outer radius ➆

XT1

1,2 mm

5,7 mm

500 kN/m

0,5 mm

1,0 mm

60°

60°

50 kN

180 kN

75 kN

260 kN

2,7 mm

4,0 mm

1,7 mm

1,3 mm

XT2

2,3 mm

10 mm

500 kN/m

1,2 mm

2,0 mm

60°

60°

120 kN

320 kN

170 kN

450 kN

4,9 mm

6,0 mm

3,3 mm

2,4 mm

1

1,5 mm

8 mm

1000 kN/m

0,7 mm

1,1 mm

1,5 mm

40°

35°

35°

50 kN

130 kN

270 kN

70 kN

200 kN

410 kN

3,0 mm

3,0 mm

4,2 mm

3 mm

2,6 mm

2,2 mm

2

3,2 mm

15 mm

1500 kN/m

2 mm

3 mm

3,2 mm

59°

47°

47°

210 kN

550 kN

650 kN

320 kN

850 kN

1000 kN

8,5 mm

9,3 mm

9,3 mm

6 mm

5 mm

4,8 mm

2.5

6,3 mm

28 mm

2500 kN/m

2 mm

4 mm

6 mm

46°

46°

55°

100 kN

470 kN

1270 kN

150 kN

730 kN

1960 kN

18,6 mm

18,6 mm

18,6 mm

13,2 mm

12 mm

9,8 mm

3

6,3 mm

38 mm

2500 kN/m

2 mm

4 mm

6 mm

68°

47°

50°

70 kN

340 kN

900 kN

110 kN

500 kN

1300 kN

22,5 mm

22,5 mm

22,5 mm

13,9 mm

11,9 mm

9,9 mm

3.5

8 mm

60 mm

2500 kN/m

6 mm

8 mm

75°

75°

440 kN

850 kN

610 kN

1190 kN

39 mm

39 mm

20 mm

20 mm

4

16 mm

85 mm

3000 kN/m

6 mm

8 mm

12 mm

78°

76°

73°

260 kN

500 kN

1290 kN

440 kN

840 kN

2150 kN

56,6 mm

56,6 mm

56,6 mm

36,4 mm

36,4 mm

36,4 mm

 


 CORRESPONDING V➀

For each model of Rolla-V die, the equivalent opening of the V in a conventional die is ​​indicated. This value is measured as the distance between the centers of the inserts.


MAXIMUM RESISTANCE ➁

This value represents the maximum tonnage that the matrix can support.


SHEET METAL THICKNESS➂

For each model, the table indicates the series of thicknesses that it can bend. Searching on the basis of the thickness, allows to identify all the models capable of bending the selected thickness and, by checking all the following parameters, it is possible to decide the most suitable model based on the type of bending.


MINIMUM ANGLE➃

For each thickness, it's indicated the narrowest angle obtainable for the selected die


BENDING FORCE➄

The table indicates the tonnage needed to bend the indicated thickness with the selected die, here's how to calculate the tonnage:

FN (kN/m) = [(Rm x thickness²)/C] x {1+[(4 x thickness )/C]}

Aluminium: Rm=200-300 N/mm2
Steel: Rm=370-450 N/mm2
Stainless steel: Rm=650-700 N/mm2

Example: aluminium 2 mm  with model 2

FN (kN/m) = [(30 x 2²)/13,16] x {1+[(4 x 2)/13,16]}

 

MINIMUM EXTERNAL EDGE➅

For each material thickness, the minimum external edge that can be obtained with the selected die is indicated in the table


BEM (kN/m) = √B² /2

Example: min. External edge with model 1

BEM (kN/m) = √7.17² /2
Min. Edge= 5.07 mm

 

MAXIMUM EXTERNAL RADIUS➆

For each material thickness, the maximum external radius that can be obtained with the selected die is indicated in the table. By subtracting the sheet thickness from the maximum external radius, it is possible to obtain the maximum internal bend radius and therefore the maximum tip radius of the punch. It must be taken into account that during the bending process the sheet is wrapped around the tip of the punch and therefore tends to form an internal radius equal to the tip radius of the punch if its characteristics allow it.

Rule #1: RE (kN/m) = √(C² /2) - (s+Z)

Rule #2: if External radius > B/2.2, ER=B/2.2

regardless of the thickness of the sheet, the maximum external radius is a consequence of formula 2. Beyond that dimension, it is not possible to bend

Example: thickness 3 mm with model 2.5

Rule #1: 17.8 - 5 = 12.8
Rule #2: 26.34 /2.2 = 11.97
Max. external radius = 11.97

 

PUNCH RADIUS

In order to obtain the correct punch radius based on the external radius of the sheet, the following formula must be applied:


Models 1 e 2
Rp = (ext.radius-Material thickness) x 0,9
Models 2.5, 3, 3.5 and 4
Rp = (ext.radius-Material thickness) x 0,8

 

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