The management of innovation: implementing new technologies and products in industrial organizations.

Titu, Mihail ; Oprean, Constantin ; Bucur, Viorel 等

1. INTRODUCTION

There are numerous references in the literature to mechanical "conventional" procedures for cutting metallic materials. However, in the case of materials with specific, exceptional properties, i.e. highly alloyed steels, the operation is very difficult, and in most cases it is performed by means of electric arc with coal electrode, steel electrodes, wheels or delivery lattice which are not at all cost-effective.

The CBEE with TO-metallic strip is a modern, nonconventional technology which can solve some problems related to the processing of hard and extra-hard materials under optimal economic-efficiency conditions. (Gavrilas & Marinescu, 1993)

CBEE, as a dimensional nonconventional processing method, is based on complex, discontinuous, local erosive effects of certain impulse electrical discharges, induced between two electrodes (transfer object TO and processed object--PO), the former one being a wheel-shaped or a metallic strip, the erosive agent, and the latter the eroded object.

The erosion processing procedure is based on the destruction of the integrity of the processed material and the take-off of redundant material (tooling allowance) from the surface of the processed object through the action of certain erosive agents. (Marinescu & Gavrilas, 1993)

2. THE PHYSICAL MECHANISM OF CBEE

In CBEE the energy is transmitted through the PO, discontinuously as electrical impulses developed mechanically in the restricted space 8ml between the electrode TO, the working environment WE and the processed part PO.

Under the contact pressure (p), new contacts are established on a new surface (a) with a statistic distribution between micro-irregularities TO-PO, which determine an increase in the power density and generates a high quantity of heat Q (because of the Joule-Lenz effect); Q=[I.sup.2] x R.t [J]

This heat developed and located in the mass of elements TO, PO causes the surfaces to heat up to the melting temperature. (Marinescu & al., 2000)

Because of the mechanical action of the TO upon the PO, of the contact pressure generated and of the relative velocity between TO and PO, the process becomes dynamic and continuous, contact bridges break and thus the circumstances under which the electric erosion process occurs are created, i.e. the discharges in non-stationary arc. (Nichici & al., 1983)

By removing the micro-volumes of material, as erosive products, the configuration of the contact surfaces changes, and thus new contact points, new contact bridges appear and new processes basic erosion occur because of the relative movement between TO and PO (the metallic strip and the part).

The CBEE processing procedure with TO-metallic strip is based upon the initiation of the non-stationary arc discharges by breaking the electric contacts, occurring temporarily between the PO and the TO-metallic strip, connected to a power supply (SA). The impulses are mechanically generated through the TO-metallic strip, which performs translation movements in relation to the PO and moves tangentially to its surface.

Non-conventional installations CBEE are required for the cutting of steels which are difficult to process; most of these installations contain an alternative to conventional technologies, i.e. a TO- a metallic wheel.

There are several phenomenological, construction and technological constraints which restrict the use of such installations; the most important restrictions are the following:

--The large-size semi-finished parts are difficult to handle during processing;

--The "erroneous arc" appears between the lateral surfaces of the tool (TO-metallic wheel) and the semi-finished part (PO), which cause power waste.

Experts in the field are not fully aware of most of the constant preoccupations regarding the possibility to change the shape of the TO (i.e. the metallic wheel) with a more appropriate one, i.e. the metallic strip.

Applying a creative study and engineering analysis to different solutions (construction alternative), allows scientists to successfully apply the general flow of the "creative-scientific engineering planning" to the CBEE installation using a metallic strip as TO.

All components of the cutting installation have been subjected to an engineering analysis, and for each analysis we have developed diagrams and morphological matrixes.

The installation allows wide variation limits to certain technological parameters, as well as the development of the process, by using the metallic strip as TO. (Figure 1, Figure 2 and Figure 3).

3. PARAMETER CATEGORIES AND MATERIALS

The equipment composing the (experimental) CBEE installation have produced real-life parameters during the entire processor each section of the processed object.

The following parameters have been measured during the research program:

--Current strength I [A];

--Voltage; U [V];

--Relative voltage, TO-PO, Vr[m/s];

--Pressure force; F[N];

--Pair TO-PO;

--Surface quality, Ra[[micro]m];

--Cutting time; Tt[s];

--Cut width; Lt[mm];

--Area influenced by temperature; ZIT[mm].

Analyzed and processed materials:

--34MoCrNi15--[empty set] 40mm;

--RUL -1--[empty set] 26mm.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

Several other categories of steel or sections have been processed: (E.g. OLC-45-[empty set] 45mm, 41MOC11-[empty set] 22mm, 38MOCA09-[empty set] 22mm, AlCu4Mg1-[empty set] 28mm).

4. ADVANTAGES OF THE NEW TYPE OF CBEE/TO-METALLIC STRIP INSTALLATION. ECONOMIC EFFECTS

The (experimental) CBEE/TO-metallic strip installation brings significant innovations to the field of construction concepts, in comparison to "traditional" cutting machine tools (FCA-710; FCA-810):

--Given its components, the installation modifies the "traditional" structure of the existing conventional tools;

--The configuration of the "tool" is totally different from the conventional ones, and the costs it involves are considerable lower than those involved by conventional installations;

--Several conventional and expensive sub-assemblies (change gear, feed mechanism etc.) are no longer used in the structure CBEE/TO-metallic strip installation;

--The construction solution selected as a result of the "creative study," is different from that of the conventional types (FCA 710, FCA 810) being more cost-effective and viable;

--The toothed gears which generate the cutting force and uses power to produce the contact pressure between the TO and the PO have been replaced with a cost-effective solution.

In international transactions, the price of the material for some categories of machine tools is higher than 5$/kg.

The construction solution for the CBEE/TO metallic strip cutting installation proposes and installation which is lighter by up p 750kg than the traditional type (FCA 810).

For an annual production of 100 pieces, the economic effects/kg may reach an approximate amount of 4,000$/installation produced, i.e. 400,000$/p.a.

The resulted values are irrefutable arguments which cannot be ignored. In addition, by replaced the traditional "cutting tools" one can save up to 500,000$/p.a.

5. CONCLUSIONS

Conclusions resulted from the analysis of the parameters considered:

--The quantity of material saved during the processing with metallic strip is considerably bigger than in the case of traditional installations;

--The costs related to materials consumed during cutting, depending on the number of operating hours shows that;

--The cost of the blade 50% higher than that of the material necessary for manufacturing the metallic strip;

--The amount of savings reflects the financial advantage of using the CBEE/TO-metallic strip installation.

The implementation in industrial organizations (metallurgy, engineering) of CBEE/TO-metallic strip installations will solve technological problems and will help reduce costs related to materials, energy and labour. (Titu & Nanu, 2002)

6. REFERENCES

Gavrilas, I. & Marinescu, N.I. (1993). Nonconventional Processes in Machine Manufacturing. Vol.1, Ed. Tehnica, Bucuresti

Marinescu, N.I. & Gavrilas, I. (1993). Nonconventional Processes in Machine Manufacturing. Vol. II, Ed. Tehnica, Bucuresti

Marinescu, N.I. & al. (2000). Nonconventional Technologies. Dictionary, Ed. INID, Bucuresti, 2000

Nichici, A. & al. (1983). Electrical discharge machining ]n Machine Manufacturing. Ed. Facla, Timisoara, 1983

Titu, M. & Nanu, D. (2002). The Bases of Processes with Concentrated Energy. Ed. Lucian Blaga University of Sibiu, Sibiu, ISBN 973--651--513--3