ZMF’s experience has led to a wealth of in-depth knowledge not only in the field of production processes but also in press technology. This know-how makes for a flexible production system able to forge increasingly complex and heavy products.
Forging
ZMF produce their own moulds and mechanical machining equipment at their especially dedicated departments.
The know-how gained in this activity makes it possible to cut down the times it takes to manufacture equipment, and results in high quality tools at a highly competitive cost.
Forging advantages
Optimal fibre orientation (mechanical strength)
Why are non ferrous forged alloys so resistant? The hot pressing process allows for the preservation of the continuity of the fibres and the study of their orientation guarantees superior mechanical performance compared to other non-ferrous alloy manufacturing techniques.
Lower manufacturing costs
Hourly production of hot pressing allows consistent reduction of production costs. Due to the limited time needed to shape the component, there is no need for a long mechanical process, which also means reduced tool wear. A smaller quantity of materials also used since the excess metal is less than that in the fusion process.
Toughness, technical quality
It is easily verifiable that the mechanical compaction in hot forging of non ferrous materials allows products to have higher toughness and technical quality. During the design phase specific lighter geometries are developed allowing the use of smaller parts that have the same mechanical resistance. All the safety elements on cars and on airplanes are hot pressed to reduce the risks of rupture during functioning to the minimum.
High aesthetic quality. No porosity
The same compact design allows for a higher aesthetic superficial quality thanks to the lack of porosity.
Lower mould making costs
Hourly production of hot pressing allows a quick serial production.
High production speed
ZMF’s 40 year experience in forging technologies and the technological development reached leaves little space to error and allows continuous close dimensional tolerance. By eliminating internal faults through a high compression during pressing, the amount of excess material in the production phase is minimum.
Design
The simulation of manufacturing process for metal deformation has been determined as one of the most effective aids to obtain significant improvements in the design of both equipment and process. In fact, the simulation of metal moulding processes helps obtain significant savings in the design of moulds, improving the quality of moulded parts and reducing production rejects.
There are some important aspects that must be taken into consideration during the design phase for the raw forged and its pressing technology in order to guarantee an excellent final result. These are:
The draft
The draft, which is the angle of inclination for the surfaces parallel to the pressing axis. This is used to easily extract the raw pieces from the moulds at the end of the production cycle. A small draft, invisible to the eye, must be applied to the forged piece to ensure its detachment from the mould when hot.
The parting line
The parting line, which corresponds to the opening surface of the product and divides the rough component into two parts. One part will be formed by the top part of the mould and the other by the bottom part. The optimal parting line develops in a perpendicular way to avoid detachment in the production process.
Allowances
Allowances must be analysed by taking into consideration the necessary processes that will transform the raw piece into the finished product. The vary in size and according to the mechanical process, the specific load for the detachment of the shaving, the need for component holding on cnc machines and costs. For all these reasons, the quantity of allowances in raw pieces always tends to be minimized.
Tip radii
The tip radii that must be applied to the geometrical edges to allow the metal to flow into the moulds with no risk of rupture and lack of material
The cavities and the ribs
The cavities and the ribs and/or bulges in the raw pieces must be carefully studied as the first could be critical in the shaping phase and the second cool quickly because of the non ferrous metal.
Tolerance
The study of the general tolerance of the finished piece which will influence the shelf life of the moulds that due to wear must be reprocessed or completely recreated.
The Burr
The burr and its trenching process, the outer area where the moulds close. This will correspond to the outlet of exceeding material needed to completely fill the mould. It also acts as a shock absorber for the moulds. In the phase immediately after pressing it is removed with a tool, called shearing burr, that is specifically shaped.
The starting billet
Finally but equally important, the exact calculation of the starting billet that must be perfect in order to avoid excess or lack of materials.
Forging Cycle
The forging cycle is an orderly succession of technological operations that transform a bigger piece of material into a raw pressed piece.
ZMF manage forging following a series of gradual steps which allow managing high level of quality.
After a billet is appropriately sized, it is brought to a temperature close to that of plasticisation to reduce the deformation forces.
Then, the true and proper moulding stage is carried out- two (or sometimes more) togliere moulds fitted onto a press close onto the billet.
Once the forged piece is cool, all excess material is cut off. This semi-finished product can now be further machined and thermal and surface finished.
