The progressive sealing is a metallurgical method that involves drilling, bending, coining, and several other methods to modify the raw material of the metal, in combination with an automatic feed system.
This feed system pushes a metal strip (while unwinding from a coil) through the entire units of a progressive stamping die. Each of the stations carry out one or more operations until a finished part is made. The final station is a shortcut operation, which separates the finished part of the web that it carries. The web that it carries, along with the metal that is drilled away in previous operations, is treated as scrap metal. They are cut, beaten down (or out of the dice) and then both are ejected from the die system, and in mass production are often transferred to the piece bins via the material conveyor belts of the underground piece.
The progressive stamping die is placed in an exchange sealing press. While the press rises, the superiors die the movements with it, which allows the material to feed. When the press is lowered, the die closes and performs the sealing operation. With each movement of the press, a finished part is removed from the die.
Since additional work is done on each die "station", it is important that the strip is advanced very precisely so that it lines within a few thousandths of an inch as it moves from the station to the station. The bullet's "formed or conical" pilots enter pre-drilled around the holes in the strip to ensure this alignment since the feeding mechanism generally cannot provide the necessary precision in feed length.
Progressive stamping can also be produced in the transfer presses. These are the presses that transfer the components from one station to the next with the use of "mechanical fingers". For the mass production of sealed parts that require complicated in-press operations, it is always advisable to use a progressive press. One of the advantages of this type of press is the duration of the production cycle. Depending on the piece, productions can easily run well above 800 servings/minute.
One of the disadvantages of this type of press is that it is not suitable for deep drawing of high precision which is when the depth of the seal exceeds the diameter of the partition. When necessary, this process is carried out on a transfer press, they run at lower speeds and rely on mechanical fingers to carry out the component in place during the entire training cycle. In the case of the progressive press, only part of the forming cycle can be directed by spring-loaded sleeves or similar, which give rise to problems of concentricity and non-uniform material thickness.
Other disadvantages of the progressive presses compared to the transfer presses are: the increased input of the raw material required to transfer the parts, tools is much more expensive because they are made in blocks with very small independent regulation by the station; impossibility to carry out the processes in the press that require the license of the pieced strip (example beading, collet, curling of the flange, rolling of the thread, etc. of rotary sealing).
The dies are usually made of tool steel to withstand the high shock loading involved, to retain the sharp cutting edge necessary, and to resist the forces of the abrasive involved.
The cost is determined by the number of features, which determine what tools will need to be used. It is advised to keep the characteristics as simple as possible to keep the cost of supplies to a minimum. Features that are close together produce a problem because it may not provide enough clearance for the server, which could result in another station. It can also be problematic to have narrow cuts and protrusions.