Модернизация кузнечного оборудования

national and international level, concluding that the functioning and construction of presses

used for the manufacture of ceramic plates and refractory products are directly dependent on

two factors: the manufacturing technology and the quantitative and qualitative evolution of

these products on the market. Thus, starting with the ’80s, the conventional technology for the

manufacture of ceramic plates was abandoned to a great extent. Today, we speak of rapid

double burning or porous products obtained by single burning.

The rapid double burning and the single burning of porous products have benefited since

their appearance from a series of complementary technologies, intended to improve technicaleconomic

and aesthetic factors, in order to help define the ideal plates for all exigencies.

Aesthetic results are due in the first place to graphic techniques that have significantly

improved over the past years.

The adoption of large sizes of ceramic plates (especially for sandstone) is due to the

worldwide tendency to mimic natural marble.

These manufacturing technologies and the large sizes of ceramic plates were dictated by

the energy crisis of the ’80s, not by the market demand. This is demonstrated by the

appearance of special plates (parts) that are increasingly demanded on the market, with a high

energy consumption.

The most important aspect remains the recovery of waste material and energy losses,

using new competitive technologies and equipment.

Lately, Welko (Italy) has developed a new technology for the manufacture of Ekotile

ceramic plates.

Essentially, ceramic plates, whether demolition waste material or manufacturing rejects,

are devitrified in the first stage, in order to change their physical structure in an optimal way.

This material is ground and sifted until granules less than 1 mm in size are obtained. Then, the

normal process of drying and preparation follows. This material is mixed with clay and

additives, in order to obtain the ceramic mixture. The wet mixture will be ground and dried in

atomizers, in the hot area, in order to reach a humidity of 4-6%.

This technology allows to recover 70%, sometimes even up to 90% of the material.

Ekotile ceramic plates, also called ecological plates, show high resistance characteristics

(70 N/mm2), water absorption less than 1%, and are superior to those produced by “classic”

technologies. These are the best monoporous ceramic plates.

A new technology for the manufacture of ceramic plates appeared, called FLEXCROME.

What is specific for this system is that dosage, granulation, grinding and feeding of the press

are directly performed with a colored ceramic mixture. The essential difference that

distinguishes this system from other systems is that regranulated powder plates may be

obtained. The FLEXCROME technology has the following advantages: -it reduces the costs

of the manufacture installation; -it ensures a flexibility of production by a wide variety of

plate types; -it eliminates intermediate storing silos of the mixture; -it uses to the maximum

extent possible the production capacity of the press (12-13 strokes/min for 300 x 300 mm

plates).

The application of the FLEXCROME technology requires changes in the auxiliary

installation of the press.

Regarding refractory products, technological manufacturing problems are of a completely

different nature. Over the past decade, market demands for special refractory products in

terms of composition and shape have increased.

The international tendencies in the field of refractory products are:

- increase in the production of unformed refractory materials;

- increased production of special materials to the detriment of “standard” materials;

- further concentration of the great producers of standard refractory materials and

maintenance of the small producers of special materials.

Chapter 3 presents the current stage of the international production of presses for the

manufacture of ceramic plates and refractory products. In the first part of this chapter, the

current developmental stage of presses intended for the manufacture of ceramic plates and

refractory products in Romania and at international level is presented, the achievements of top

companies such as Welko, SACMI, SITI and LAEIS BUCHER being mentioned. Data are

presented under the form of tables regarding the distribution of presses used for the refractory

ceramic sector, the types of existing presses, their export and import, the sales turnover of the

great producers (Italy, Germany, France, Spain, China, United Kingdom). The conclusion is

that due to the fact that over the past three years (2003, 2004, 2005) the annual production of

ceramic plates has decreased by approximately 4-5% and that of refractory products by

approx. 6-10%, the production of presses has also diminished. This is due on the one hand to

the international economic crisis, and on the other hand, to the saturation of the world’s

market with these products.

The appearance on the world’s market of states with a real potential for the manufacture

of ceramic plates and formed refractory products such as Russia, China, the Arabian

Republics, South Africa, Brazil or Australia has seriously affected traditional companies.

The modernization of presses for the manufacture of formed ceramic plates and refractory

products should take into account the changes occurring at international level.

The most important and the most extensively presented part in this thesis is included in

Chapter 4, entitled “Industrial design in the modernization of presses for the manufacture of

ceramic plates and refractory products”.

It should be understood from the beginning that industrial design represents the fulfillment

of a need. It is not a rigorous process, which is why each design is different. Therefore, this is

the first aspect to be understood.

Industrial design, which appeared in the ’80s, represents a relatively new, continuously

developing discipline, created because of the problems occurring in industrial production. The

responsibility of a designer, as well as his/her ethics, can be compared to those of an engineer.

The two professions frequently intermingle. One cannot speak of designers without engineers

in industrial production, but one can speak of designing engineers.

Design methods aim to decompose an ensemble into small items. This is why designers

must cope with multiple manufacturing technologies, the interaction between the different

components, and the changes undergone in time.

The large number of elements and details, as well as their dispersion, automatically results

in arbitrary decisions. This is why the factors that contribute to the design of a quality product

must be known. Because several construction variants are possible or in order to be sure that

the variant obtained is the adequate one, the stages of synthesis, analysis and control must be

followed.

In a complex interactive system, the design of a press is the result of a series of

component principles. These should be in unity, which is derived from a certain will for order,

a certain harmony of the ensemble, a combination and ordering of the components. A good

“design” for a press represents a global composition. Unity does not mean monotony but, by

paraphrasing W. Gropius, “unity in diversity”.

The functional dimensions of the press correctly reveal the functions for which it has been

conceived. These dimensions obtained from purely mathematical calculations (resistance,

mechanisms, machine organs, hydraulic drives, value analysis, etc.) express the concept of

utility and they cannot omit aesthetic elements (shape, color, proportion, contrast, etc.). The

press as a whole is a structure formed by “component elements”. Component elements

include: press body, movable traverse, driving mechanism, feeding mechanism, etc. These

component elements should result in the creation of a sense of fulfillment, satisfaction,

security and truth.

After a presentation of the history of the evolution of presses for ceramic and refractory

products, the author gives an analysis of shapes in the design of a press. The 5 laws of the

Gestalt theory are detailed, which allow an analysis of the perception of the complex shapes

of presses. These laws are: the law of transposition, the law of figure and ground, the law of

unit segregation, the law of the reproduction concept, and the law of hierarchy.

Then, the value of use and the functions of the press are analyzed, the stages of a value

analysis study being defined.

In what follows, the concept of “quality in design”  and the ecosystem and design of the

press are mentioned, after which the aesthetic components and artistic elements used in the

construction of the press are presented. According to Jacques Viénot, there are 13 laws that

govern industrial aesthetics, namely the law in economy, the law of the ability for use, of

unity and composition, of harmony between appearance and use, of style, of evolution and

relativity, of taste, satisfaction, of movement, of hierarchy, the commercial law, the law of

probity and committed art.

Artistic elements are materialized in: symmetrical, dissymmetrical elements, rhythm,

contrast, proportion, composition, optical illusion, color, graphics, stylism.

In order to draw up the necessary documentation for a design study, some questions

should be answered, related to: identification of the problem, analysis (technical, functional,

economic data) and synthesis of the proposed subject.

The determining factors of aesthetics must be correlated with the culture and religion of

the area for which the product is intended.

In what follows, fields such as ergonomy, philosophy, sociology, semiology, psychology

and micropsychology, sciences involved in the design of presses, are referred to.

Speaking of the functionality and technologization of presses, the thesis relates these

concepts to a new discipline, called bionics. Defined in 1960 by J. E. Steele at the first

congress of bionics held in USA, this discipline is presented as a science of systems that have

a functionality reproducing that of natural systems or are analogous to them.

The following paragraph of Chapter 4 mentions creativity, logic, intuition, and team spirit

as stimulating factors in the design of a press. Then, management and marketing are referred

to, as relatively new fields in the design of presses.

An activity that must be treated with patience and seriousness in the process of conceiving

and designing presses is related to evaluation and quantification methods in design. The

following are presented: the method of semantic differences with its three stages, the

Christopher Jones method based on checking lists, on selection, ordering and evaluation

criteria, mention of specifications, and on Quirk’s reliability index, the method for the

evaluation of the aesthetic quality proposed by the mathematician D. G. Birkoff, based on the

measurement of balance, equilibrium, symmetry, sequence of figures in an image,

measurement of cohesion, measurement of unity, measurement of proportion, measure of

simplicity, density, regularity, economy, homogeneity, measure of rhythm, order and

complexity, all these supported by specific mathematical relationships. Then, the method for

the evaluation of aesthetic quality proposed by K. D. Bodack is presented, which defines the

measure of the aesthetic quality of a product, introducing the concept of aesthetic redundancy.

Redundancy defines the relative surplus of signs, being a measure of the intelligibility of a

structure. Bodack defines redundancy as the difference of the highest possible number of

signs and the number of signs received by humans.

The variation of selective and structural information is illustrated on a number of 12

switchboards, to which the calculation algorithm presented in the thesis was applied regarding

the determination of the current number of structural information, selective information,

maximum structural information, structural and relative redundancy of the structure and value

of aesthetic measure. The numerical data obtained, presented under the form of tables, allow

the choice of the construction variant of electric switchboard with the best aesthetic

appearance.

After the fascinating field of industrial design, including evaluation and quantification

concepts and methods in design, the thesis proposes a modernization of mechanical presses

with a screw mechanism, starting by showing a modality of involving industrial design in the

conception of presses for the manufacture of ceramic and refractory products.

The management of the process of conception of the press with a screw mechanism

requires a sequence of feasibility study phases including the strategy, the establishment of

principles, preliminary data, the rationale for the choice of the modernization of the press, the

situation of the market of screw presses; then a preliminary or a definition study is performed,

followed by detail and development studies, as well as by the achievement and evaluation

study.

The preliminary study is performed in order to identify the problem, which is done

through the answers to the questions: For what? For whom? These answers are introduced in

tables, in order to justify the choice made. Also, tables with positive and negative criteria are

drawn up and scores from 1 to 5 are assigned. Value 1 corresponds to the case when there is

no practical importance, value 5 corresponds to an important exigency. This evaluation grid

was used for the analysis of four constructive-functional solutions of mechanical screw

presses, conceived by the author of the doctoral thesis.

The conception process in the design of the mechanical screw press spans all phases of the

management of the press design. This thinking process is based on four stages: identification

of the problem, analysis, synthesis and validation.

The new driving system of the mechanical screw press is based on an invention patent of

the author of the thesis and results from the feasibility study.

Subsequently, the author shows methods for the rationalization of energy consumption in

the case of the modernized mechanical screw press. One of the modalities for the

rationalization of energy consumption is an optimal design of the electric driving of the press,

consisting of: optimal sizing of the wheel and the electric drive motor, and adaptation of the

consumed power to the necessary energy value in a different technological process from that

for which the wheel was sized, for which purpose the PADAPT program was elaborated.

Starting from the patented press variant, the mechanical screw press was modernized,

being described in the thesis as a manufacturing cycle for the variant used for the fabrication

of ceramic plates and refractory products.

Then, the thesis presents a complex study for sizing the body of the screw press,

illustrated by calculations, tables and graphics, and the analytical and finite element

calculation of the press body is also performed.

Chapter 4 closes with the presentation of some models of modernized mechanical presses

with a screw mechanism, designed by the author using Solid Edge, with conclusions.

Chapter 5 deals with the dynamic study of screw presses. The dynamics of screw presses

is analyzed in the following cases:

- mechanical screw press with two friction discs, for which the diagram of variation of the

peripheral speed of the discs and the wheel is considered in two variants: in the case of the

first variant, the disadvantage of driving is the low efficiency due to sliding between the disc

and the wheel, both during lowering and lifting, while the second variant involves several

phases during a work cycle, which ensures the correct choice of the pressing force value.

The calculations performed are laborious, those for the second variant of the peripheral

speed diagram belonging exclusively to the author of the thesis. For numerical applications,

the functional-constructive data of the 4MN FORTPRES mechanical press were used, and

experimental measurements were also performed.

- coupling-driven mechanical screw press

- mechanical screw press with a mixed drive mechanism.

Chapter 5 closes with the conclusions.

Chapter 6 includes experimental researches on the dynamics of mechanical screw presses.

Thus, the means used for the performance of these researches, the development of

experiments, the processing of results, the experimentation of the device for the

rationalization of electric consumption in the modernized mechanical screw (wheel) press are

reviewed.

Chapter 7 deals with the economic aspects regarding the modernization of mechanical

screw presses. Calculations are performed regarding the reduction of energy and material

consumption. The expenses involved by the modernization of the mechanical screw press are

mentioned, and conclusions are drawn at the end of the chapter.

In Chapter 8, the author presents conclusions, contributions and suggestions.

The thesis addresses a subject of actuality and importance for the machine building

industry, regarding the conception, design and manufacture of new presses used in the

industry of ceramics and refractory products or for the modernization of existing presses.

Drd. Eng. CONSTANTIN CAIREDDIN ŞARAMET