The next product to be manufactured by MP Lifts has enabled the Special Machinery department to form part of this project for the design and manufacture of means of punching door shutting frames and panels. The frame and the panels are both made of steel and are installed on each floor of the building. Both parts are made from surface treated or stainless steel sheets.

Design and manufacture of means of punching
door shutting frames and panels

Punching involves cutting a sheet of material by applying pressure to a cutting punch and the action of the cut-off die on the other side of the sheet. Together, the cutting punches and the cut-off die are referred to as punch.

This project has been quite challenging given the large amount of different door types that exist and that require very specific punching techniques. Furthermore, these techniques must be simultaneous with all other operations in order to reduce the time it takes for each part and must quickly adapt to the various models being manufactured. Each machine has an in-built quick change system which enables them to adapt to the different lengths and widths of the parts or to omit certain punches depending on the type.

PUNCHING MACHINES FOR FRAMES
There are two very similar machines for punching the frames which punch and carry out all other operations simultaneously on the frame. Both machines are designed for a specific type of frame and its variations. Three punches carry out the various sets of punching. These are activated by hydraulic cylinders capable of supplying a maximum force of approximately 48 t per punch and high speed up and down action. Choosing which hydraulic system to use, depending on the production requirements is extremely important. It is equally essential that the structural rigidity of the unit can withstand the great forces generated in each cycle.

PUNCHING AND FORMING MACHINERY FOR DOOR PANELS
First, this machine punches the panels and finishes by bending one of the ends into an L shape. This machine is capable of working with six different models of metal sheet, depending on the lift part being made. Each model has 25 different variations, which may be different in length, width and in terms of punching requirements. It is clear that the machinery must be adaptable. Therefore, this machine has 6 mobile manual units that allow the punches to be positioned as required.

The machine is equipped with four main presses, each of 18.5 t that activate both punches. Some must be changed depending on the type and others adapt automatically with a quick punch change. For smaller punching processes, there are six extra machines which have less force.

The parts are placed on a guided cart for loading and unloading. The operator pushes the cart to the punching area where cutting is carried out. The operator then feeds the sheet into the forming machine, pulling the cart backwards. There is an additional 18.5 t press for forming.

The requirements of the cycle time determine the characteristics of the system and require an additional feature to those less specific production techniques; this together with the need to adapt to the different variations of lifts demanded by the market, once again highlight the importance of turnkey engineering projects for providing highly specialised production techniques that focus on a product’s specific needs.

Lucas Girela Baena
Technical Department of Special
Machinery. Engineering Division.