Forging and finishing process.

The basic technology in the production of forgings made at Kuźnia Polska Sp. z o.o. is the hot forging of die forgings weighing up to 25 kilograms using forging presses, air hammers and headers.

High quality forgings intended primarily for the automotive industry are made by means of:


process 1 - heating of sheared pieces of steel, called charges, to a temperature of 1,200 oC in electric induction furnaces or gas-fired furnaces and their subsequent plastic forming of the required element in a die-cast. In the forging of forging-crank-operated forging presses of 10 to 25 MN pressure, air hammers with a striking forth (hit energy) between 1,600 to 10,000 KGm and vertical and horizontal forging machines with 2 to 12 MN pressure are used. It is also possible to manufacture small mass forgings - i.e. from as little as 0.25 kilograms using PS-type screw presses.

process 2 - removal of excess material in the form of fins - this is a dubbed trimming operation on crank or eccentric presses. During this stage of the production process aperture swaging, bending and calibrating is performed.

process 3 - heat treatment of the forgings aimed at giving the forging high strength. In carbon and alloy steel forgings heat treatment in the form of quenching and tempering (quenching in water, oil or polymers), normalizing or isothermal annealing is used. Strength is also attained through a controlled cooling after forging.

- shot blasting operation - cleansing of the forging's surface of so-called scales (hard surface bloom resulting from steel oxidation at high temperatures). This operation takes place on special machines called shot blasters, which use steel pellets of great hardness and with a shot diameter ranging from 0.8 to 1.2 mm.

process 5 - finishing operations including cold calibration, straightening, marking, grinding and burnishing.

process 6 - the majority of manufactured forgings intended for the automotive industry, require 100% monitoring for reasons of safety with regard to material defects such as cracks, lapping, scratches and overlaps. This monitoring is performed by so-called magnetic defectoscopes.



process 7 - Meticulous visual inspection of each item in order to ensure 100 % faultless forgings: with underfills, joggles, scale pitting, cold shuts.

process 8 - final control aimed at statistical checking of the quality of manufactured forgings and to provide a quality warranty through quality certification in accordance with the client's requirements.

Machining.

I n order to meet customers' expectations, Kuźnia Polska Sp. z o.o. has broadened its range of ready-made machined products. At present our stock of machining tools includes vertical machining CNC centers, CNC lathes with powered tools which also perform drilling and threading, vertical and horizontal milling machines, turning lathes, drillers, relieving lathes and hydraulic presses. We produce mainly ready-made elements such as levers, flanges and towing hooks. Any process engineer who designs the process must also take into account a number of important parameters, which cover both the technological possibilities of forging the element (in other words giving it the desired shape) and the functional qualities that the client stipulates, such as hardness, resistance, hardenability, structure etc.

Tool-making shop/facility.

Kuźnia Polska Sp. z o.o. has its own Tool-Making Shop, which was completely modernized in 2005 and provides the company with all the tools it requires and supplies tools and services to meet external demand as well. Continuously modernized and up-dated machinery equipment and the latest IT systems are capable of meeting even the most demanding requirements of the market. The designing, constructing and programming of CNC machines is performed using highly advanced CAD/CAM platforms and a leading CATIA system. State of the art milling centers using HSM technology, lathe centers and electric hobbing and wire hollowers guarantee the shortest possible die-performance time with full continuance of production repeatability. Thermal treatment and the nitriding of impression surfaces is carried out in a vacuum furnace socket. Continual research aims to optimize pad welding during tool regeneration. Thanks to the development of tool building and tool regeneration durability is improved steadily, while labor costs are being reduced as a result of this.

Both from a construction and manufacturing perspective it is worth mentioning here that the company has at its disposal all types of instrumentation providing full production capability: from simple forging trimming and punching tools, through to simultaneous tri-operational tools equipped with nitric springs to component forging and machining tools.