Methods for the cold extrusion of metallic elements with dead or through holes and plant for carrying out said methods
Cold extrusion procedures for obtaining metal elements such as for example bushings, nuts or other elements with dead or through holes, screws, standard and special shape extruded or pressed products, etc. on a machining center comprising a series of hydraulic presses connected to each other with an automatic movement system. The final drilling or shearing of the elements is advantageously carried out by a dedicated drilling or shearing unit, working at high speed, which can consist of a vertical mechanical press. The use of the plant comprising several hydraulic presses together with the rapid drilling or shearing unit makes it possible to achieve a high level of productivity.
1. A procedure for the cold processing of tubular metal elements or other elements with dead or through holes, nuts, comprising the following machining steps:
(a) preparing a blank of full metal material from rolls;
(b) straightening the full metal material after unrolling from the skein;
(c) cutting the metal material into pieces of a determined length;
(d) passing each piece sequentially through a plurality of work stations of a work centre comprising several cold hydraulic presses in order to obtain a blank element presenting one or two longitudinally opposite dead holes separated by a central transverse section, wherein each piece is first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to an adjacent hydraulic press for a subsequent cold machining operation; and
(e) through drilling the blank to remove the central traverse section;
wherein the metal elements have a diameter greater than 30 mm.
2. The procedure according to claim 1 , wherein previously washed metal material is straightened by loading it on a wire-straightening unit designed to unroll the skein.
3. The procedure according to claim 2 , in which the free end of the roll is pulled through a first set of rollers and then through a system of opposite rollers designed to straighten the wire and transfer it to a cutting unit.
4. The procedure according to claim 1 , wherein the work centre comprises a series of hydraulic presses of various sizes and power levels connected by a transfer unit designed to move the pieces being machined.
5. The procedure according to claim 4 , wherein the transfer unit consists of a series of gripper units powered by an appropriate source of energy.
6. The procedure according to claim 1 , wherein the drilling is carried out by a special unit consisting of a vertical press.
7. The procedure according to claim 6 , wherein this vertical press consists of a mechanical press.
8. The procedure according to claim 4 , wherein the functioning and synchronisation of the individual presses and of the transfer unit are controlled by a PLC or a microprocessor.
9. The procedure according to claim 3 , in which the material is cut into pieces of a predetermined length, advantageously by various possible procedures by means of one or mobile blades or by a circular saw.
10. The procedure according to claim 1 , wherein the drilling is carried out by a special unit consisting of a vertical press.
11. The procedure according to claim 10 , wherein this vertical press consists of a mechanical press.
12. The procedure according to claim 4 , wherein functioning and synchronisation of the individual hydraulic presses and of the transfer unit are controlled by a PLC or a microprocessor.
13. A procedure for the cold processing of metal elements, comprising the following machining steps:
(a) preparing a blank of full metal material in the form of bars, which bars are loaded in bundles in a bar sectioning plant;
(b) cutting the metal bars into pieces of a determined length after being presented from the bar sectioning plant; and
(c) passing each piece sequentially through a plurality of work station of a cold multi-hydraulic-press plant in order to obtain a finished element with or without swarf or waste, wherein each piece if first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to an adjacent hydraulic press for a subsequent cold machining operation;
wherein the metal elements have a diameter greater than 30 mm.
14. The procedure according to claim 13 , wherein the products undergo shearing which can be carried out by means of a mechanical press.
15. The procedure according to claim 13 , wherein the bars are presented at the cutting station in a synchronized way according to the needs of a machining centre consisting of the presses.
16. The procedure according claim 15 , in which the material is cut into pieces of a predetermined length.
17. The procedure according to claim 13 , characterised in that a plant or machining centre consists of a series of hydraulic presses of various sizes and power levels connected by a transfer unit designed to move the pieces being machined.
18. The procedure according to claim 17 , wherein the transfer unit consists of a series of gripper units powered by an appropriate source of energy.
19. A procedure for the cold processing of tubular metal elements or other elements with dead or through holes, nuts, comprising the following machining steps:
(a) preparing a blank of full metal material from rolls, wherein setting up and preparation of the full blank differs according to the metal material used;
(b) straightening the full metal material after the material is unrolled from the skein;
(c) cutting the metal material into pieces of a determined length;
(d) passing each piece sequentially through a plurality of work stations of a work centre comprising several cold hydraulic in order to obtain a blank element presenting one or two longitudinally opposite dead holes separated by a central transverse section, whereby each piece is first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to an adjacent hydraulic press for subsequent cold machining operation; and
(e) through drilling the blank to remove the central traverse section;
wherein the metal elements have a diameter greater than 30 mm.
20. The procedure according to claim 19 , carried out on material consisting of stainless steel, wherein the stainless steel is initially treated by solution annealing and pickled in a balanced solution of sulphuric acid, hydrofluoric acid, potassium permanganate and hydrogen peroxide, and subsequently washed repeatedly by means of immersion in a salting tank in order to facilitate the pressing.
21. The procedure according to claim 19 , carried out on material consisting of low-alloy steel, wherein this material is pickled in sulphuric acid and subsequently washed in a phosphating tank in which, by chemical reaction, a layer of zinc phosphate is created on the surface of the piece, then immersed in a sodium stearate tank where, again by chemical reaction, a thin layer of zinc stearate forms on top of the previous layer of zinc phosphate.
22. A plant for the implementation of a procedure for the cold processing of tubular metal elements or other elements with dead or through holes, nuts, comprising the following machining steps:
(a) preparing a blank of full metal material from rolls;
(b) straightening the full metal material the material is unrolled from the skein;
(c) cutting the metal material into pieces of a determined length;
(d) passing the pieces sequentially through a plurality of work stations of a work centre comprising several presses in order to obtain a blank element presenting one of two longitudinally opposite dead holes separated by a central transverse section; and
(e) through drilling the blank by removal of this central traverse section;
wherein the metal elements having a diameter greater than 30 mm,
wherein the plant comprises a series of cold hydraulic presses adjacent to each other, designed to carry out a successive series of pressing operation on pieces to be machined wherein each piece is first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to and adjacent hydraulic press for a subsequent cold machining operation.
23. The plant according to claim 22 , wherein the plant also comprises a drilling or shearing station.
24. The plant according to claim 23 , wherein this drilling or shearing station consists of a vertical mechanical press.
25. A procedure for the cold processing of metal elements, comprising the following machining steps:
(a) preparing a blank of full metal material in the form of bars, which bars are loaded in bundles in a bar sectioning plant, in which the setting up and preparation of the full blank differs according to the metal material used;
(b) cutting the metal bars into pieces of a determined length; and
(c) passing each piece sequentially through a plurality of work station of a cold multi-hydraulic-press plant in order to obtain a finished element with or without swarf or waste, wherein each piece is first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to an adjacent hydraulic press for a subsequent cold machining operation;
wherein the metal elements have a diameter greater than 30 mm.
26. The procedure according to claim 25 , carried out on material consisting of stainless steel, wherein the stainless steel is initially treated by solution annealing and pickled in a balanced solution of sulphuric acid, hydrofluoric acid, potassium permanganate and hydrogen peroxide, and subsequently washed repeatedly by means of immersion in a salting tank in order to facilitate the pressing.
27. The procedure according to claim 25 , carried out on material consisting of low-alloy steel, wherein this material is pickled in sulphuric acid and subsequently washed in a phosphating tank in which, by chemical reaction, a layer of zinc phosphate is created on the surface of the piece, then immersed in a sodium stearate tank where, again by chemical reaction, a thin layer of zinc stearate forms on top of the previous layer of zinc phosphate.
28. A plant for the implementation of a procedure for the cold processing of metal elements comprising the following machining steps:
(a) preparing a blank of full metal material in the form of bars, which bars are loaded in bundles in a bar sectioning plant;
(b) cutting the metal bars into pieces of a determined length; and
(c) passing the pieces sequentially through a plurality of work station of a multi-hydraulic-press plant in order to obtain a finished element with or without swarf or waste;
wherein the metal elements have a diameter greater than 30 mm,
wherein the plant comprises a series of cold hydraulic presses adjacent to each other, designed to carry out a successive series of cold pressing operations on pieces to be machined wherein each piece is first cold machined by a hydraulic press, then extracted from said hydraulic press by means of a suitable manipulator robot and conveyed to an adjacent hydraulic press for a subsequent cold machining operation.
29. The plant according to claim 28 , wherein the plant also comprises a drilling or shearing station.
30. The plant according to claim 29 , wherein this drilling or shearing station consists of a vertical mechanical press.