If the operator wishes to continue cutting sheets smaller than 5 mm thickness, the cylinders that support the holding system in the front

retract, leading to the platform tilt, which in turn leads to the sheet discharge by gravity (Fig.  21).

If it is necessary to turn off the guillotine or to cut plates higher than 5 mm thickness, all cylinders retract, placing the platform in the rest position (Fig. 22).

This system presents many benefits such as stop at intermediate positions or controlling the holder movement speed between stages. Other advantage of this option is the frontal discharge capability, because it is possible to give the order to raise the holder slightly above the “upper” position  (Fig. 23).

The back gauge automatically pushes the plate to the front side and the operator can receive the cut strip at the guillotine frontal side, avoiding wasting time to collect the plate at the back    side.

Fig. 16. Conventional cylinder – discharge position.

Fig. 17. Conventional cylinder – rest position.

Fig. 18. Servo-pneumatic cylinder – upper position.

2.4.3. Option 3 – mixed  version

Option 3 is a combination of the previous ones. This solution was idealized to enable the plate extraction by the machine front, which consists of using two sets of two cylinders with two multi-position kit and two servo-pneumatic cylinders. Thus, the operation is identical to that described in option 2, however, when the operator wishes to remove the plate by the machine front side, the servo-pneumatic cylinders are placed slightly above the “upper position”, causing the holder to be positioned somewhat in ramp (Fig. 24). This ramp position is very important to avoid the collision between the plate and lower blade when this is pushed to the front side. Furthermore, the servo- pneumatic cylinders will allow more accurate movements during the system operation.

2.5.  Comparing different  solutions

Regarding the different options considered in this work, it is time to summarize the advantages and limitations of each device model allowing choose the best set of characteristics depending on the application and customer requirements. Thus, Table 1 intends to condense the main ideas about all the developments   made.

3. Conclusions

This study is proposing a novel technical device for new shearing machines or machines already in service that will increase their productivity. The device consists of a novel holder which can be assembled in the back side of the shearing machines and, provided

Fig. 19. Servo-pneumatic cylinder – intermediate position.

Fig. 20. Servo-pneumatic cylinder – final cutting stage.

Fig. 21. Servo-pneumatic cylinder – discharge position.

Fig. 22. Servo-pneumatic cylinder – rest position.

Fig. 23. Servo-pneumatic cylinder – frontal discharge position.

Fig. 24. Option 3 – upper position and frontal discharge   position.

Table 1

Comparative table regarding the different options considered in this work.

together or separately with the shearing  machines.

• The final price of the system will be competitive, allowing strong savings in finishing operations when cutting thin sheet metal  plates.

Conventional

cylinders

Servo-

pneumatic cylinders

Mixed

solution

• The problem of sheet metal deformation on the last portion of the

cut  strip  was   eliminated,  giving   more  profitability  to     shearing