Сrank hot forging press of new generation

Quality of machinery production depends on quality of produced parts, that is defined mainly with preparation industries as well as for vital parts, forging or hot stamping. Hot forging has been developed in mass and large-series industries, that consume more than 60% of stamped forgings.

In manufacturing of high-precised forgings great role play crank hot forging press (CHFP) that have stable trend to power increasing. Voronezh plant for building heavy mechanical presses produces CHFP of different nominal capacity. For the last years were carried out different investigations intended for designing and production of powerful crank hot forging press with nominal capacity equal to 80 and 125MN.

Scope of industrial implementation of crank hot forging press of new generation manufactured by JSC «Tjazhmekhpress» are described by statistic data of volumes, structure and supply geography on these machines, carried out in period 1985—2006. Comparison of this data with data about CHFP supplied by foreign manufacturers testifies that during this period of time TMP has become undoubted leading supplier of these hot forging presses. Volumes of supplied machines average out at the following:

TMP in period 1985—2006 — about 750 items, 50% were exported;

German company SMS Eumuco — about 500 items for the last 40 years;

Japanese company Sumitomo Heavy Industries — about 100 items for the last 35 years;

American company National Machinery — about 500 items in period from 1950 to the end of 80s, when company was forced to refuse manufacturing CHFP;

German company Hasenclever — about 200 items from 1950 to 1995.

In the sphere of heavy crank hot forging presses (with capacity 40MN and more) TMP’s advantage is more evident because its rate in quantitative manufacture is 1,5 −2 times higher. Moreover TMP as unique equipment (more than 80MN capacity) manufacturer has no rival.

It is illustrative, that about 87% of exported CHFP are machines, that was supplied in industrialized countries. These countries have the most developed forging industries with strict requirements to technology and equipment.

Designing and modernizing of these presses had demanded carrying out of investigations and experimental-constructional works in the following basic spheres:

1. better basic parts durability;

2. achieving of necessary rigidity of press-die system;

3. dynamic stability of press;

4. rational technology of producing huge basic press parts.

At present time JCS «TMP» aims to develop crank hot forging press with capacity 160 MN and automatic lines for manufacturing crankshafts and front-axle beams on its base. With maximum weight of bearings equal to 200 kg, length more than 2300 mm and technological performance up to 2800 kjoule.

Main constructive features of CHFP of JSC"Tjazhmekhpress" are the following:

— Presses with capacity 10, 16 and 25 MN are produced without middle shafts (gear drives).

— Eccentric shafts of all presses are free from flywheel’s weight. Flywheels are installed on special plugs, fixed on press frame.

— Double-piston slide hanging and presses’ rigidity on the level of modern samples help to receive high-precision forgings.

— Press slides are orthogonal, frame-construction with two counterbalances.

— Provision of necessary tightening of press frame and outlet from thrust is carried out with special hydraulic nuts, installed on tightening rods on the top of the press.

— Eccentric mechanism of shut height adjustment is moved to the slide, it has electric drive or hydraulic motor with reading accuracy up to 0,1 mm.

— All drive bearings and executive mechanism are lubricated constantly with oil with the help of centralized single-line lubrication system TRABON. This system warrants dosed lubrication in each lubricated point.

— It has two-staged shock-less clutch switch-on.

— Indicator of stamping capacity with digital readings or computer signal processing and memorizing.

— Presses are equipped with continuous monitoring system, which provides effective control of bearings temperature, lubrication system operation, electric motor load, stampipng capacity etc.

At present time all forges of the world have about 17 CHFP with nominal capacity 110, 120, 125 and 160 MN and 27 CHFP with capacity 80 MN. Manufacturing of such heavy presses was carried out mainly in countries with highly developed machine industry (USA, Japan, Germany, Russia) on plants that have sufficient technological and manufacturing potential.

Heavy CHFP serve for producing heavy forgings with weight 50—150 kg. For example it could be engine crank shafts, front axle beams of auto trucks and pipeline flanges.

As manipulating of such heavy forgings manually is rather difficult, presses are usually main part forging machines of mechanized or automatized complexes and press lines. These lines that besides hot forging presses have also forging rolls, trimming, twisting and sizing presses, industrial robots, transport system, die lubrication system, die overrunning system and other equipment are manufactured on TMP and could be supplied in full scope.

It should be noticed that modern level of hot forging production has tendency to reach high forgings flexibility, that should provide fast reaction on changing market demands. These demands are connected with increasing series production on one hand and staggered delivery of forgings due to main forging purchasers on the other hand. In these conditions full automatization of hot stamping equipment is not always cost effective.

In different cases, for example in case of small series production or rather huge series of small delivery, partly automized process is interesting. In this case automized operations that do not demand labour-intensive work during re-adjustment (heating, blank part feeding on first position, transportation of ready forgings) and manipulating of blanks during preliminary and final stamping is carried out manually or with the help of special devices, controlled by operator. Upon that certain productive increasing is achieved in comparison with non-automatic operation because of operator’s labour facility and compulsory support of stable work temp. Moreover substantial reduction of investment outlays derives (in comparison with full automatic systems). Main advantage consists in almost unlimited scope of forgings and usage percent of hot forging equipment that is 60—65% for full automatic systems and about 80% for partly automatic.

That is why level of automatization for hot forging presses TMP varies from simple feeding equipment to fully automatic complexes and optimal value in each case is defined during cooperation with purchaser in dependence on purchaser’s operation conditions.

As hot forging methods are based on inflexible principle in accordance with which could be produced only definite forging (mainly because of special tool), flexibility should be understood as decreasing of labourship and time needed for re-adjustment of all equipment in technological line in order to produce forging of new type. On other words flexibility of hot forging production is provided with according conceptions of hot forging complexes that are programmed for using appropriate variants of known hot forging methods.

As well as problem of automatization and problem of re-adjustment of heavy hot forging equipment TMP produces relevant system as hydraulic hand with manual operation for changing tools of press with capacity 80 MN (Ulma, Spain) or automatic shift for assembling and disassembling of stamps in line with 125 MN press (Forge de Monterrey, Mexico and Corea Flange, Korea).

Providing of high forging quality demands strict reproducibility of technological process that during hot forging process implies stability of temperature regime of forging and tool. Multi-level systems of program check of all elements of equipment play fundamental role. Purchaser receives non only high-reliable control systems but also necessary software, developed by TMP specialists in dependence of certain operating conditions.

High competitive ability of TMP presses and heavy machines is mostly precise indicator of efficiency of used constructive solutions, calculation methods and experimental research.

CHFP of TMP of new age are the most effective type of hot forging equipment for series production and could be considered as technical ground of development of hot forging industry in modern conditions