Make rules for mechanical processing technology, in the same technology can satisfy the request of the workpiece, usually can be worked out several different processing schemes, and produce power of these plans and production costs will be different. In order to select the best plan, technical and economic analysis is necessary. The so-called technical and economic analysis, that is, by comparing the production costs of different technical plans, select the most economical processing technology plan.
The cost of production is the sum total of all the necessary costs for making a part or a commodity. The cost of production includes two categories: the first category is directly related to the cost and process cost technology called technical costs, production costs accounted for about 70%~75%; the second category is unrelated to the technical process of the cost, such as administrative staff salaries, depreciation of plant, lighting heating etc.. Because in the same production condition, the cost unrelated to the technological process is basically equal, so when the part technical plan is analyzed economically, it is only necessary to analyze the technical cost directly related to the technological process.
1, the composition of technology costs
The technology cost consists of two major variables: variable cost and constant cost.
(1) variable costs
Variable costs are related to the annual output value and are proportional to the cost, and are indicated by "V" (yuan / piece). Include: material cost, operation worker's salary, machine tool electricity fee, general machine tool depreciation fee, general machine tool repair fee, tool fee, general jig fee.
(2) constant cost
Constant costs are not directly related to changes in annual output value. When the output value changes in a certain scale, the annual cost remains basically the same, and is indicated by "S" (yuan / year). Including: machine management personnel, auxiliary workers in the workshop, adjust the wages of workers, special machine tools depreciation fees, special machine repair fees, special fixture fees.
2. Calculation of technical cost
(1) annual technical cost of parts;
In E, the technical cost (yuan / year) of a part (or part of a part) for the whole year;
V -- variable cost (yuan / piece);
N - annual output value (unit / year);
S - constant cost (yuan / year).
From the above formula, the annual technical cost E and the annual output value of N are linearly related. It states that changes in the annual technological cost are proportional to delta N of annual output value, and that S is the capital fixed value, no matter how much it is produced, the value of E is constant.
(2) the technical cost of a part of a piece
Single piece technical cost E and annual output value N is hyperbola connection. In the A section of the curve, the N is very small, the equipment load is low, that is, the single piece small batch production area, the single piece technical cost E is very high, at the moment, if the output value N slightly adds (delta N), will cause the piece capital to decline rapidly (E). In the curve B section, N is large, that is, a large number of producing areas. At the moment, the curve is becoming horizontal, but the annual output value has changed greatly, but the influence on the technical cost of a piece is very small.
This clarifies that in terms of a technical plan, when the S value (mainly the cost of the dedicated equipment) must be punctual, there should be a scale of output that is compatible with the equipment. When the output value is smaller than this scale, the technical cost is added because the S/N ratio increases. At this time, the use of this technology plan is obviously uneconomical, should be reduced by the use of special equipment, that is, to reduce the S value to reduce technology costs. When output exceeds this scale, because the S/N ratio is getting smaller, then larger and higher productivity equipment is needed to cut V and achieve very good economic results.