Course project - mechanical assembly workshop

Contents

Contents

Introduction

1 Workshop program and operation mode

2 Equipment calculation and selection

3 Calculation and selection of states

4 Calculation and determination of areas

5 Layout, layout and layout of the workshop

6 Technical and economic indicators of the project

7 Business Case for Design Efficiency and

reconstruction of mechanical assembly shop

Literature used

Applications

Introduction

The project contains the production annual program of the designed workshop in the main areas

Ship repair (SR) - ship representatives, their main characteristics and number per year by repair category are indicated;

Shipbuilding (SS) - the ships to be built, their main characteristics and number for the year are indicated;

Replacement and spare parts (S3H) - the total machine labor intensity of their manufacture in man-hours (person-hour), the main types of manufactured parts and the ratios between types as a percentage of the total machine labor intensity of MHF are indicated; shows the quantity of materials (casting, forging, grade) for the production of FWD.

Besides, other directions of the program in processes from total labor input and a consumption of the main materials in the first directions (SR, CC, SZCh) are set:

Navigation repair;

Mechanical engineering;

Own needs;

Other orders.

A special task to be developed during design may also be specified.

The Course Project provides a milestone and protection schedule for the project.

The course project consists of a calculation and explanatory note (RPZ) and a graphic part (WP).

The calculation and explanatory note provides calculations and explanations of the decisions made in the draft.

Programme and mode of operation

1.1 Based on the initial data of the design task, we fill in the table of form 1, where the load (labor intensity and material intensity) is determined for each direction of the program. Table forms are given in Appendix I of the course design (forms F1, F2 and FZ).

Using reference data, the labor intensity of manufacturing each given type of parts is distributed according to the types of work (turning, boring, milling... etc.), the results are entered in the table in form F2.

The total labor intensity from the table according to form F2 is transferred to the row "Total by FWD" of the table according to form F1.

In the row of the table on form F1 "Total by SR, SS, NWH," the labor intensity and material intensity of the work are calculated in total by ship repair, shipbuilding and replacement-spare parts. From the values ​ ​ of these amounts, other program directions are given as a percentage (clauses 1.4... 1.7 tasks for the course project). Based on these percentages, labour intensity and material intensity of navigation repair, mechanical engineering, auxiliary needs and other orders are determined and recorded in the table according to form F1.

To record the shop totals in the table in form F1, two lines "total workshop" are provided. We write the totals in the first line without rounding, in the second (below) - with rounding with an accuracy of 1.0% of the rounded number.

1.2 "Operation mode" includes the following components: intermittent or continuous production; the number of holidays per year; Number of working days per week Working week duration (in hours) number of work shifts per day; Working shift duration (in hours) Adopted work schedule.

In mechanical assembly workshops (MSC) of ship repair enterprises, usually intermittent production, work in the workshop is carried out in at least two shifts. On ships, one shift is provided. 

We choose the time funds of the equipment and workers based on the working conditions in the workshop and the accepted mode of operation.

Equipment Calculation and Selection

The number of main metal cutting machines is calculated by the labor intensity of the machine work, auxiliary machine equipment (grinding machines, table machines, etc.), as well as the equipment of the locksmith compartment, we choose according to technological need.

Based on the total labor intensity of the machine work, we determine the total number of machines, and then distribute them by types, using the percentages between the types of machines.

Layout, layout and layout of the workshop

For the obtained design value of the total area of ​ ​ the workshop, it is necessary to determine the type and dimensions of the overall layout of the workshop, as well as the layout of its spans. If the standard span width L0 is selected, the calculated span length may not be a multiple of the column pitch B0. In this case, it is necessary to select the nearest multiple step of columns B0 of the span length. At the same time, if the remainder from division of the calculated length of spans by B0 is equal to or more than 0.5 B0, the selected span length is increased (against the calculated length) to the nearest multiple of B0 value, and if the remainder is less than 0.5 B0 - reduced to the nearest multiple of B0 value.

We choose the longitudinal layout of the workshop, that is, the machine and locksmith compartments are arranged in spans sequentially one after the other.

GOST 23 83779 approved unified dimensional diagrams of buildings of industrial enterprises.

GOST 2383879 regulating the parameters of industrial buildings. Establishes the coordination dimensions of buildings (modular steps on transverse and longitudinal coordination axes and modular height of floors), rules for linking structural elements to the coordination axes of buildings and dimensions of inserts in places of temperature joints, rules for adjoining mutually perpendicular spans and height differences, etc.

The standards (GOST 2383779 and GOST 2383879) apply to the overall diagrams and geometric parameters of the ground part of single-storey buildings of industrial enterprises, service-technical and production buildings of railway, automobile, sea, river and air transport.

Deviations from the dimensional diagrams and parameters established by GOST 2383779 and GOST 2383879 are allowed when developing reconstruction and expansion projects of existing buildings built without observing the provisions of modular coordination of dimensions in construction, i.e. without observing the provisions of these standards.

In the overall diagrams, the span width L0, the pitch of the columns B0, the span height (from the clean floor to the bottom of the supporting structures) H0 are unified, and for the schemes providing support bridge cranes, the load capacity of the latter (QK) and the nominal elevation of the crane rail head (height to it from the clean floor, Nr) are indicated.

The dimensions of the spans and the pitch of the columns adopted in the unified standards are two or more times larger than that of most workshops built earlier, which allows to reduce the number of columns, improves the use of inter-column space, and ensures a significantly more efficient use of the production area of ​ ​ the workshop. With the pitch of columns B0 = 12 m, the flexibility of redevelopment of equipment is increased, associated with a possible change in the technological process, which is especially important in the subsequent reconstruction of the workshop.

Multi-span buildings should be designed (GOST 2383879, item 1.2), as a rule, with spans of the same direction, of the same width, with the same pitch of the columns, without a height difference.

When choosing a unified overall layout of the housing (shop block), it should be borne in mind that the width (or number of spans) and length of the buildings are not regulated. This makes the operation much easier and makes it possible to widely use the unified elements of the building in combination with the requirements of the technological process .

During process planning of equipment and workplaces in mechanical assembly, diesel repair and other specialized workshops, it is necessary to observe the characteristic sequence of their technological process and avoid returns.

The scheme of organization of production in the mechanical assembly shop of the ship repair plant should provide for:

1 Disassembly of mechanisms and assemblies delivered from ships to the workshop in specialized areas for disassembly. Folding areas for incoming products shall be provided in front of these areas.

2 Washing and cleaning of parts and assemblies in a washing (preferably mechanized) area.

3. Defectation of washed parts and assemblies and their distribution either for selection, for repair, or (suitable parts) in the picking storage room for further assembly;

4 Treatment of repaired parts and manufacture of new parts in the machine section of the shop. At the same time, parts undergoing machining on several machines, after each operation, are returned (except for large heavy parts) to the interoperative storage room, and after processing and acceptance of the CTC, to the picking storage room. Here, the parts are assembled by units and mechanisms and delivered to the assembly in the locksmith compartment;

5 Performance of repair and assembly locksmith works in specialized areas with maximum possible mechanization of these works.

6 General assembly of mechanisms on assembly stands.

7 Running and testing of all mechanisms repaired in the workshop on specialized stands.

8 Mechanization of transport and warehouse works.

9 Centralized tool sharpening.

10 Location of storerooms (material, interoperative, picking, instrumental, etc.) closer to the places of their greatest use.

There are three ways to plan machine tools at MSC.

In-line - machines are arranged strictly sequentially according to the production process of products (in-line lines).

This method is used in large-scale and mass production, sometimes

- in serial.

Group machines of different types are arranged in groups of equally machined parts. It is used in serial (sometimes in small-scale) production (areas and workshops of replacement parts, etc.).

Shop - machines of the same name are located nearby - used in single, and sometimes in small-scale production. The method is most common in mechanical assembly workshops of shipbuilding enterprises. In this method, groups of machines of the same name are arranged in a sequence that takes into account the most characteristic (predominant) general sequence of technological processes.

The layout is most often started from the place of storage of materials and blanks (material storeroom) from lathes, then boring, milling and other machines are placed, finished finishing. 

Larger machine tools are located first from main passageways and passageways in area of cranes operation. This will facilitate the installation of large parts on them. Special folding platforms should be provided near these machines (they are depicted in dotted lines on the plan of the workshop).

Large lathes, boring and other "long" machines are usually located along the axis of the span of the workshop, and not across.

To comply with the workshop method of arranging large and small machines of the same name (for example, large and small carousel or boring), they are located in different spans (large machines - in a large span, small machines of the same name - nearby in a small span). The classification of the span to small or large is most often determined not by its size (large and small spans can be the same sizes), but by the lifting capacity of crane vehicles, the concentration of heavy (or light) parts, assemblies and mechanisms.

Near the carousel machines should be located long. It usually receives large parts after carousel machines; in addition, multi-site service is possible.

Small machines (especially small lathes and grinding machines) tend to position closer to the windows and orient them, achieving better illumination of working areas. When arranging lathes, it should be possible to use the spindle cavity to process rod material, pipes, etc.

Finishing machines (grinding, honing) and especially accurate (coordinate boring, etc.) must be located further from dynamic machines (strict, long). In addition, it is desirable to shield these machines with light glazed bulkheads for greater safety and possibility of additional ventilation.

Drilling machines, sometimes strict, are preferably located on the border with the locksmith compartment. They are not always loaded in the machine compartment and can be additionally used by locksmiths, especially if the drilling machines of the machine compartment are occupied.

Depending on the ratio of width and length of the span section, small machines can be arranged along, at an angle and across the span axis.

For the convenience of passage of people and the supply of blanks and parts to distant ones, from the main passage, machines should provide local passages inside large machine sections (masses), sometimes driveways for trolleys and car cars.

In areas involving the manufacture of any special groups of parts, the machines should be placed according to a group method - several different (determined by the technology of manufacturing parts).

You can combine workshop and group methods of arranging machines.

The in-line method of placing machine tools in the mechanical assembly shops of shipbuilding enterprises is not used. Flow lines can be used only when organizing specialized workshops of large-scale and mass production (workshops of fuel equipment, replacement parts, etc.).

In accordance with the procedure for organizing the repair of mechanisms in the locksmith department of the workshop, the following are distinguished: a folding area for mechanisms coming for repair, a disassembly and washing area, defects (usually it is separated by racks or slips from the first dirty areas), a part repair area, a knot, general (bench) assembly, rolling and testing (on special stands), as well as a finished product site (sometimes with the possibility of preservation). In addition to these, specialized sections can be provided; repair of hinged mechanisms, valves, fuel equipment, hydraulic tests, repair of propellers, etc.

A site should be allocated for locksmiths working on ships.

When planning the locksmith compartment, the equipment is arranged in accordance with the principle of direct flow of the process (i.e. exclusion or minimum returns).

Pantries are located closer to the places of their greatest use. It is necessary to ensure that the ratios of the dimensions of the pantries, (length and width) their location do not divide the workshop into separate, almost isolated, zones, do not interfere with the transportation of large parts and mechanisms.

During the layout and layout of the workshop, it is necessary to monitor the linkage between the machine and locksmith compartments. So, in a large (in terms of crane lifting capacity) span there are large machines and sections of the locksmith compartment, on which there may be mechanisms assembled (disassembly sections, general assembly, tests, finished products, etc.), as well as sections where heavy parts are repaired (propeller shafts, screws, etc.).

It is necessary to strive for the smallest possible number of transfers of blanks, parts, products from span to span.

Technical and economic indicators of the project

When calculating the technical and economic indicators, the capital costs for the construction of the workshop, the cost of production, etc. are consistently calculated.

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