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Efficiency of size sorting of fish
intematimal journalof
production economics
ELSEVIER
Int. J. Production
Economics
48 (1997) 259-265
Efficiency of size sorting of fish A.C. Booma+*,
M.A. Parinb, A. Zugarramurdi”
“Centro de Investigaciones de Tecnologia Pesquera, Institute National de Tecnologia Industrial, Marcel0 T de Alvear 1168, 7600 Mar de1 Plats, Argentina %2entro de Investigaciones de Tecnologia Pesquera. CONICET (National Council ofkientijc and Technical Research) Marcel0 T de Alvear I 168, 7600 Mar de1 Plats. Argentina Received
5 November
1993; accepted
17 September
1996
Abstract Machine sorting can reduce production costs by increasing the yield in the heading operation, and the overall efficiency of the rest of the line. It also adds quality to end products, but in turn increases investment and process complexity. When the process involved is raw material and labour cost-intensive processes, small increases in yield and productivity lead to important cost reductions. The advantages and draw-backs of fish sorting by size are analysed as a function of parameters such as size distribution and cost structure of the industry. A general model to estimate cost variations is developed. Figures are presented for anchovy canning in Argentina. When the proportion of small anchovies is high, savings of more than 8% of the total unit cost can be obtained. For average conditions, daily production of only 3000 cans in one season is enough to pay for the sorting machine. Keywords:
Machine sorting of fish; Quality of end product; Advantages; Drawbacks
1. Introduction In Argentina, fish canning and salting industries usually process less than 20000 t of anchovy [l, 21 which still is a very small figure when compared to
the MSY (Maximum sustainable yield) that has been evaluated as 1 140000 t [3]. These industries could be expanded if significant cost reduction is achieved due to the fact that they are directly costintensive and that raw material prices are high. A usual process for canning anchovy starts with tilting the plastic boxes in a brine pool. From the pool the anchovies are fed to the heading machines, leaving apart mackerels, and some small or damaged *Corresponding
author.
0925-5273/97/$17.00 Copyright SSDI 0925-5273(96)00101-6
anchovies. Headed anchovies are then washed and scaled cooked, trimmed and placed in the cans. Then, the cans are filled with oil, closed and sterilised. A close look at the traditional process revealed that usable meat in most anchovy heads, and fish wrongly cut, flowed further along the production line. A way to increase the yield and overall line efficiency in an anchovy cannery is to sort by size first. A manual sorting operation is not feasible for reasons such as high cost of operation, longer process time at a critical stage, and poor accuracy and consistency of the manual sorting; all this add up to overwhelm any advantage in the subsequent production stages. Another way is to make or adapt heading machines to adjust automatically to the head
(Q 1997 Elsevier Science B.V. All rights reserved
260
A.C. Booman et al. /ht. J. Production Economics 48 (I 997) 259-265
length, but this means complex mechanisms and a smaller reduction in labour/kg than the one possible with a good mechanical sorting. Machine sorting can reduce production costs by increasing the yield in the heading operation, and the overall efficiency of the rest of the line. It will also add to the end product’s quality, but in turn increase both investment and process complexity. This paper describes the machine prototype and develops a general model to analyse the convenience of mechanical sorting as a function of variables such as distribution of sizes in the catch, investment, labour cost, and factory size.
2. Prototypes In-plant anchovy sorting has posed different problems in Argentina. Machines imported several years ago did not perform as expected and were returned or exported again. The problem was studied at CITEP, and so it was found that the difference between the thinnest and the thickest anchovy to be processed was too small to be properly handled by the available machine. To test the feasibility of solutions to the sorting problem, two prototype machines were built at CITEP. The first one could also be used as a washing machine. The second one was capable of washing, scaling and sorting in three anchovy sizes while taking out almost all the by-catch in one operation. Additional information can be found in Patents No. 219847 [4] and No. 288226 [S].
2.1. Machine operation A cross section is shown in Fig. 1. The fish is fed into the machine hopper (1) by a conveyor. Anchovies drop into a stainless steel perforated revolving drum (2), where they are washed and scaled with the aid of water jets. The drum has a screw in it (3) which advance the anchovies to the upper end of the machine. As the anchovies revolve, scaling takes place as a result of the friction with other anchovies and with the sharp edges of the perforations in the drum. The type and size of perforations play an important role in scaling
Fig. 1. Sorting machine cross section. (1) Machine hopper; (2) Washing and scaling drum; (3) Spiralls; (4) Scale collecting drum; (5) Water with scales outlet; (6) Sorting drum; (7) Motor. (A) Belt or bin where small fish is collected; (B) Belt or bin where medium fish is collected; (C) Belt or bin where big fish is collected; (D) Bin where mackerel and other species thicker than normal anchovies are collected.
efficiency and scale wash-out. Waste water and scales are collected by another stainless steel drum (4) and driven to the scale separator through a water channel (5). At the upper end of the drum the fish comes out clean, without scales and ready to be classified by thickness. A deflecting baffle (not shown) drives the anchovies gently to the external drum (6), which rotates slowly. The external drum is made up of parallel prismatic tubes. These tubes have three sectors of different width; thus, the slots between tubes also have three different sections. The slots are narrower in the first section and wider in the last one, while the gap between tubes in each section is constant. As the drum rotates, the revolved anchovies have various opportunities to run through a slot in each section. According to their thickness, fishes drop in A, B, C, or D. Damaged and small anchovies and other little fish are collected in section A. Anchovies size 1 are those too small to be canned. Anchovies size 2 are used for canning and dropped in B. In section C, drop anchovies size 3 also good for canning but much more desirable for salting. Horse mackerel (Trachums trachurus), mackerel (Scomber japonicus marplatensis), common squid (Loligo sanpaulensis) and other species are collected in D. The variation and distribution of anchovy sizes were analysed based on published statistics from INIDEP [6,7]. The almost random variation in the lengths of the histogram’s shape was confirmed by direct observation of landings during two consecutive
A.C. Booman et al. /ht.
J. Production Economics
seasons, as well as by statistics made on boxes purchased for testing CITEP’s prototype grader.
3. Economic analysis In order to perform the economic analysis, a cannery that is only processing sizes 2 and 3 for canning and throwing away size 1 was assumed. This is considered to be the most common case when no sorting machine is used. To estimate the difference in production costs, the cost structure proposed by Zugarramurdi [S] was used. From this analysis, it is possible to develop a cost model as a function of five main variables, devising an equation such as the following, for each productive process, using annual production capacity. Eq. (1) shows the coefficients obtained for anchovy canning plants [9]. TC = 3.00 RF + 2.23 L + 1.05 E + 0.228 IF/Q, (1) where TC is the total unit cost (US$/can), RF the cost of fish (US$/can), L the direct labour cost (US$/can), E the cost of utilities: energy, water, steam (US$/can), IF the fixed investment (US$), and Q the plant capacity ( lo3 cans/y). All numerical values of Eq. (1) are dimensionless, except the last one that is a yearly coefficient. To make the results as general as possible, they are written in terms of savings per unit. The increase in yield is due to the following savings: (1) in raw material, by adjusting the heading machines to the sizes coming out of the sorting machines; (2) in labour, by not introducing the smaller anchovies in the line; and (3) in fixed costs, by the increase in output. These savings were estimated based on available statistics [7] and on the sizes that came out of the machine built at CITEP. The savings will be analysed one by one.
3.1. IZaw anchovy savings. It was observed that the smaller anchovies that came in a typical lot were anyway lost somewhere
261
48 (1997) 259-265
in the line, (i.e. fishes not fed into the heading machines, fishes taken out because they cross-over while being headed, and the ones that fell from or were left in the cooking trays because they were small), so there was no loss of raw material by disposing of size 1. When there is no sorting machine, all the heads are cut as if they were big (size 3), so, there is a loss of raw material while cutting size 2 as size 3. Since the heading machines must be adjusted to the longest head expected in a sorting line, some machines can be adjusted to size 2, so, for any lot of fish dRF = DzTz W,/(T,W,
+ T,W,)RF,
+ T,W,
(2)
where dRF is the raw anchovy savings (US$/can), D2 the proportion of fish wasted while heading size 2 as 3, T1, T,, T3 are the number of fishes size 1,2,3, and WI, W,, W, the average weight of size 1,2,3.
3.2. Labour savings With mechanical sorting, size 1 is neither fed to the heading machines nor separated, so the savings in labour AL are due to savings by not feeding size 1 into the heading machines, plus by not taking out anchovies size 1 (always defectives), plus by increase in the yield by not cutting T2 as TJ: AL = TdT, +
+ T, +
D~TzW~I(TIWI
T3bhU
+
+
T2W2
B)
+
T3W3L-,ci
(3) where LHG is the labour for heading and gutting (US$/can); and /3 the relationship between labour to take out defective anchovies and labour for heading and gutting.
3.3. Investment savings If a machine like the one built that washes, scales and sorts in the same unit is utilised, no washing or scaling machines are needed. The space requirement wiI1 be about the same as that for a washing/scaling machine. The same can be said on the maintenance cost, which is related more to the numbers of motors than to the price of the machine.
262
A.C. Booman et al./Int.
J. Production Economics
In turn, the investment is about 60% higher than that of a scaling/washing machine. Also, the heading machines that work with sorted fish do not waste capacity cutting fish that will be taken apart later on, and since they are adjusted to the right weight, the saving in investment will be dZr = A CZHG- (Zs -
= IHG
TILTI
+
Iw)l Tz
+
T3)
QD/QHG
- Us QdQs - hvQ~/Qw), Table 1 Data used for obtaining
(4)
48 (1997) 259-265
where AZr is the Investment savings (US$), Zuo the investment for 1 heading and gutting machine (US$), Is the investment for 1 sorting/washing/scaling machine like the proposed prototype (US$), Zw the investment for 1 washing machine (US$), Qn the plant capacity (lo3 cans/day), Qno the capacity of the heading and gutting machine (lo3 cans/day), Qs the capacity of the sorting machine (lo3 cans/day), Qw the capacity of the washing machine ( lo3 cans/day). Summarising, these savings can be expressed mathematically as ATC = 3.00ARF + 2.23AL + 0.228 A&/Q.
Figs. 2-5.
1
Labour to take out defective anchovies/ Labour for H&G (&o); B = 0.95 2 Raw material cost (RF) = 5OOG600 US$/t or 0.13- 0.15 US$/can Labour cost (L) = 1.552 US$/h or 0.0550.07 US$/can 3 Investment for heading and gutting machine (I,,) = 4 100000-150000 US$ 5 Investment for sorting machine (Is) = 4000-8000 USS 6 Investment for washing machine (Iw) = 2OOG 4000 USS 7 Plant capacity (Q) = 20000 cans, 170 gea./day 8 Annual production: 200 days (average for fish canning plants in Argentina) Anchovy production season for canneries in Argentina: 50 9 days/year 10 Processing yield: 45% 11 Net filling content: 25% 12 Process time: 2 min/can _
0.2
0.3
PROPORTION
The economic data used for calculation are shown in Table 1. Costs and prices of equipment correspond to the 1992 anchovy season in Argentina.
4. Results and discussion
In Figs. 2-4 is shown how the variables related to size distribution and heading machine correlate to savings in raw material, labour and investment using values defined in Table 1. Finally, the total unit cost curves in Fig. 5 show the maximum and minimum savings expected. In Fig. 2 it can be seen that savings in raw materials increase when the proportion of smaller
0.4
0.5
OF MEDIUM SIZE ANCHOVIES
Fig. 2. Savings
(5)
in raw material
costs.
(in weight)
A.C. Booman et al. /ht.
J. Production Economics
48 (1997) 259-265
263
0,006
-z
0,005
II ;i 9 -
0,004
4 P 4
-
AL (TZ=O.l),DZ=lO%
-
AL (T2-0.3)
- - AL (T2=0.5) 0,003
I
-
AL (T2=0.1),02=2%
z z 0,002
0,001 0.1
0.2
0.3
0.4
QUANTITY OF ANCHOVIES SIZE 1 (small)/TOTAL
Fig. 3. Savings in labour costs.
E
0.06
k
0.06
5 z,
0.05
23 _.
AI/Q
0.07
0.04
2% 02.
0.03
I g
0.02
z
0.01
I
0.3 QUANTITY
OF ANCHOVIES
r
0.4
(1 HG, 1 HG&
-
-
AI/Q (10000,lO)
-
Al/Q (100000.50)
-
AI/O (100000,100)
-
Al/Q (150000.75)
h’d)
I 0.5
SIZE 1 (small)/lOTAL
Fig. 4. Saving in capital investment.
anchovies increases and when the proportion of size 2 anchovies headed as size 3 rises. In Fig. 3 it is shown that savings in labour are increased with the increase in proportion of small fish and that differences in size 2 have little influence on these savings. In Fig. 4 it is shown how investment savings correlate with size distribution plotted as proportion of anchovies size 1 (smaller) and prices of machines. It can be observed that savings are higher when size of anchovy is proportionally
smaller. Also, it can be seen that the price of the heading and gutting machine influences savings more than the price relation to washing machine. Besides, when th three figures are compared, the component that has the major influence on total savings is the saving in investment followed by savings in labour and in raw materials. Overall results are shown in Fig. 5. It can be seen that total savings of more than 0.04 US$/can can be reached when the proportion of intermediate size fish is 0.5, the proportion of size 2 headed as size 3 is
264
A.C. Booman et al. /ht.
J. Production Economics 48 (1997) 259-265
~. ..:
.mw.s .
..I
ATC
(D2=21;.2=0,
-
ATC (DZ=WqT2=0.3)
, )
-
ATC (DZ=Z%;T2=0.5)
111
ATC (D2=1 O%;TZ=O.l)
-_-
ATC (D2=1 O%;T2=0.3)
-ATC
(D2=lO%;T2=0.5)
I
0.2
0.3
0.4
QUANTITY OF ANCHOVIES SIZE 1 (small)/TOTAL
Fig. 5. Saving in total unit costs.
10% and the amount of small fish in the production line is higher than 0.2. Taking into consideration that in Argentina the total unit cost of canned anchovies is around 0.5 US$/can, the above values result in savings greater than 8% of the total unit cost. Considering that the plant is working at 100% capacity (Q = 20000 can/day) and with uniform catch size (Point A: T1 = 0.1, T2= 0.1 and D2 = 2%) the unit saving is minimum and equal to US$ 0.0056. Thirty-six days are needed to pay off the investment on sorting machine, one season (50 days) if the plant is operating at 70% capacity (Q = 14000 can/day) and only one week for Point B (Tl= 0.1, T2= 0.5 and D2 = 10%) where the unit saving is equal to US$ 0.036. For average conditions (Point C: dTC = 0.027 US$/can, Tl= 0.2, T2= 0.3 and D2 = 10 %), daily production of only 3000 cans in one season will be required. This shows the profit of buying a sorting machine even if catch size is uniform.
Results presented in this paper show that the convenience of the utilisation of a sorting step in a processing line depends mainly on the industry’s cost structure and fish size distribution. Savings of more than 8% of the total unit cost can be achieved, depending on the cost structure of the process involved, investment in machine and size distribution of the fish. On the other hand, considering uniform catches and a minimum of unit saving, a production of 14 000 cans/day (170 g each) is enough to pay for the sorting machine. For average conditions, daily production of only 3000 cans in one season will be required. Since, uniform size is a quality factor that leads to better prices, the increase in profits may actually result higher than that estimates based on the cost reduction figures hereby presented.
Acknowledgements 5. Conclusions It was found that almost always, a washing/ scaling machine reduces production costs.
This work was supported in part by National Institute of Industrial Technology (INTI) and by National Council of Scientific and Technical Research (CONICET).
A.C. Booman et al. /ht.
J. Production
References Cl1 Parin,
M.A., Musmeci, S. and Zugarramurdi, A., 1990. The pelagic fishery of Argentina. Infofish Internat., 5: 24427. I21 Captura’94, 1995. Revista Redes de la Industria Pesquera Argentina. Aiio 8, No. 81. A., Boeri. R., Parin. M.A. and Musmeci, S.. c31 Zugarramurdi, 1988. Dimension y perspectivas de1 mercado de exportation de productos argentinos de la pesca. SECYT Proyecto Pilot0 de Innovation Agroindustria Exportadora, Anexo VI-2, Buenos Aires. c41 Booman, A. Lupin, H. and Inti. Patent. No. 219,847 ‘Maquina clasificadora de pescado por espesor’. cv Booman, A. and Inti. Patent No. 288,226 ‘Maquina lavadora, descamadora y clasificadora de pescado por espesor’.
Economics
48 (I 997) 259-265
265
[6] Cousseau, M.B, Castello, J.P, Cotrina, C.P. & Silvosa, J.M. 1973. Informe sobre el muestreo bioestadistico de desembarque. Enero 196%diciembre 1971, Contribuchn No. 224, Instituto de Biologia Marina. [7] Cousseau, M.B, Castello, J.P. and Cotrina. C.P., 1977. Informe sobre el muestreo bioestadtico de desembarque. enero 19722diciembre 1972, Contribution N330, Instituto de Biologia Marina (last published raw data). [E] Cerbini, J.M. and Zugarramurdi, A.. 1981. Cost correlations for the fish canning industry. Eng. Costs Prod. Econom., 5: 217-223. [9] Zugarramurdi, A., Parin M.A., Lupin. H.M., 1995. Economic engineering applied to the fishery industry. FAO Fisheries Technical Paper. No. 351, 295 p.
production economics
ELSEVIER
Int. J. Production
Economics
48 (1997) 259-265
Efficiency of size sorting of fish A.C. Booma+*,
M.A. Parinb, A. Zugarramurdi”
“Centro de Investigaciones de Tecnologia Pesquera, Institute National de Tecnologia Industrial, Marcel0 T de Alvear 1168, 7600 Mar de1 Plats, Argentina %2entro de Investigaciones de Tecnologia Pesquera. CONICET (National Council ofkientijc and Technical Research) Marcel0 T de Alvear I 168, 7600 Mar de1 Plats. Argentina Received
5 November
1993; accepted
17 September
1996
Abstract Machine sorting can reduce production costs by increasing the yield in the heading operation, and the overall efficiency of the rest of the line. It also adds quality to end products, but in turn increases investment and process complexity. When the process involved is raw material and labour cost-intensive processes, small increases in yield and productivity lead to important cost reductions. The advantages and draw-backs of fish sorting by size are analysed as a function of parameters such as size distribution and cost structure of the industry. A general model to estimate cost variations is developed. Figures are presented for anchovy canning in Argentina. When the proportion of small anchovies is high, savings of more than 8% of the total unit cost can be obtained. For average conditions, daily production of only 3000 cans in one season is enough to pay for the sorting machine. Keywords:
Machine sorting of fish; Quality of end product; Advantages; Drawbacks
1. Introduction In Argentina, fish canning and salting industries usually process less than 20000 t of anchovy [l, 21 which still is a very small figure when compared to
the MSY (Maximum sustainable yield) that has been evaluated as 1 140000 t [3]. These industries could be expanded if significant cost reduction is achieved due to the fact that they are directly costintensive and that raw material prices are high. A usual process for canning anchovy starts with tilting the plastic boxes in a brine pool. From the pool the anchovies are fed to the heading machines, leaving apart mackerels, and some small or damaged *Corresponding
author.
0925-5273/97/$17.00 Copyright SSDI 0925-5273(96)00101-6
anchovies. Headed anchovies are then washed and scaled cooked, trimmed and placed in the cans. Then, the cans are filled with oil, closed and sterilised. A close look at the traditional process revealed that usable meat in most anchovy heads, and fish wrongly cut, flowed further along the production line. A way to increase the yield and overall line efficiency in an anchovy cannery is to sort by size first. A manual sorting operation is not feasible for reasons such as high cost of operation, longer process time at a critical stage, and poor accuracy and consistency of the manual sorting; all this add up to overwhelm any advantage in the subsequent production stages. Another way is to make or adapt heading machines to adjust automatically to the head
(Q 1997 Elsevier Science B.V. All rights reserved
260
A.C. Booman et al. /ht. J. Production Economics 48 (I 997) 259-265
length, but this means complex mechanisms and a smaller reduction in labour/kg than the one possible with a good mechanical sorting. Machine sorting can reduce production costs by increasing the yield in the heading operation, and the overall efficiency of the rest of the line. It will also add to the end product’s quality, but in turn increase both investment and process complexity. This paper describes the machine prototype and develops a general model to analyse the convenience of mechanical sorting as a function of variables such as distribution of sizes in the catch, investment, labour cost, and factory size.
2. Prototypes In-plant anchovy sorting has posed different problems in Argentina. Machines imported several years ago did not perform as expected and were returned or exported again. The problem was studied at CITEP, and so it was found that the difference between the thinnest and the thickest anchovy to be processed was too small to be properly handled by the available machine. To test the feasibility of solutions to the sorting problem, two prototype machines were built at CITEP. The first one could also be used as a washing machine. The second one was capable of washing, scaling and sorting in three anchovy sizes while taking out almost all the by-catch in one operation. Additional information can be found in Patents No. 219847 [4] and No. 288226 [S].
2.1. Machine operation A cross section is shown in Fig. 1. The fish is fed into the machine hopper (1) by a conveyor. Anchovies drop into a stainless steel perforated revolving drum (2), where they are washed and scaled with the aid of water jets. The drum has a screw in it (3) which advance the anchovies to the upper end of the machine. As the anchovies revolve, scaling takes place as a result of the friction with other anchovies and with the sharp edges of the perforations in the drum. The type and size of perforations play an important role in scaling
Fig. 1. Sorting machine cross section. (1) Machine hopper; (2) Washing and scaling drum; (3) Spiralls; (4) Scale collecting drum; (5) Water with scales outlet; (6) Sorting drum; (7) Motor. (A) Belt or bin where small fish is collected; (B) Belt or bin where medium fish is collected; (C) Belt or bin where big fish is collected; (D) Bin where mackerel and other species thicker than normal anchovies are collected.
efficiency and scale wash-out. Waste water and scales are collected by another stainless steel drum (4) and driven to the scale separator through a water channel (5). At the upper end of the drum the fish comes out clean, without scales and ready to be classified by thickness. A deflecting baffle (not shown) drives the anchovies gently to the external drum (6), which rotates slowly. The external drum is made up of parallel prismatic tubes. These tubes have three sectors of different width; thus, the slots between tubes also have three different sections. The slots are narrower in the first section and wider in the last one, while the gap between tubes in each section is constant. As the drum rotates, the revolved anchovies have various opportunities to run through a slot in each section. According to their thickness, fishes drop in A, B, C, or D. Damaged and small anchovies and other little fish are collected in section A. Anchovies size 1 are those too small to be canned. Anchovies size 2 are used for canning and dropped in B. In section C, drop anchovies size 3 also good for canning but much more desirable for salting. Horse mackerel (Trachums trachurus), mackerel (Scomber japonicus marplatensis), common squid (Loligo sanpaulensis) and other species are collected in D. The variation and distribution of anchovy sizes were analysed based on published statistics from INIDEP [6,7]. The almost random variation in the lengths of the histogram’s shape was confirmed by direct observation of landings during two consecutive
A.C. Booman et al. /ht.
J. Production Economics
seasons, as well as by statistics made on boxes purchased for testing CITEP’s prototype grader.
3. Economic analysis In order to perform the economic analysis, a cannery that is only processing sizes 2 and 3 for canning and throwing away size 1 was assumed. This is considered to be the most common case when no sorting machine is used. To estimate the difference in production costs, the cost structure proposed by Zugarramurdi [S] was used. From this analysis, it is possible to develop a cost model as a function of five main variables, devising an equation such as the following, for each productive process, using annual production capacity. Eq. (1) shows the coefficients obtained for anchovy canning plants [9]. TC = 3.00 RF + 2.23 L + 1.05 E + 0.228 IF/Q, (1) where TC is the total unit cost (US$/can), RF the cost of fish (US$/can), L the direct labour cost (US$/can), E the cost of utilities: energy, water, steam (US$/can), IF the fixed investment (US$), and Q the plant capacity ( lo3 cans/y). All numerical values of Eq. (1) are dimensionless, except the last one that is a yearly coefficient. To make the results as general as possible, they are written in terms of savings per unit. The increase in yield is due to the following savings: (1) in raw material, by adjusting the heading machines to the sizes coming out of the sorting machines; (2) in labour, by not introducing the smaller anchovies in the line; and (3) in fixed costs, by the increase in output. These savings were estimated based on available statistics [7] and on the sizes that came out of the machine built at CITEP. The savings will be analysed one by one.
3.1. IZaw anchovy savings. It was observed that the smaller anchovies that came in a typical lot were anyway lost somewhere
261
48 (1997) 259-265
in the line, (i.e. fishes not fed into the heading machines, fishes taken out because they cross-over while being headed, and the ones that fell from or were left in the cooking trays because they were small), so there was no loss of raw material by disposing of size 1. When there is no sorting machine, all the heads are cut as if they were big (size 3), so, there is a loss of raw material while cutting size 2 as size 3. Since the heading machines must be adjusted to the longest head expected in a sorting line, some machines can be adjusted to size 2, so, for any lot of fish dRF = DzTz W,/(T,W,
+ T,W,)RF,
+ T,W,
(2)
where dRF is the raw anchovy savings (US$/can), D2 the proportion of fish wasted while heading size 2 as 3, T1, T,, T3 are the number of fishes size 1,2,3, and WI, W,, W, the average weight of size 1,2,3.
3.2. Labour savings With mechanical sorting, size 1 is neither fed to the heading machines nor separated, so the savings in labour AL are due to savings by not feeding size 1 into the heading machines, plus by not taking out anchovies size 1 (always defectives), plus by increase in the yield by not cutting T2 as TJ: AL = TdT, +
+ T, +
D~TzW~I(TIWI
T3bhU
+
+
T2W2
B)
+
T3W3L-,ci
(3) where LHG is the labour for heading and gutting (US$/can); and /3 the relationship between labour to take out defective anchovies and labour for heading and gutting.
3.3. Investment savings If a machine like the one built that washes, scales and sorts in the same unit is utilised, no washing or scaling machines are needed. The space requirement wiI1 be about the same as that for a washing/scaling machine. The same can be said on the maintenance cost, which is related more to the numbers of motors than to the price of the machine.
262
A.C. Booman et al./Int.
J. Production Economics
In turn, the investment is about 60% higher than that of a scaling/washing machine. Also, the heading machines that work with sorted fish do not waste capacity cutting fish that will be taken apart later on, and since they are adjusted to the right weight, the saving in investment will be dZr = A CZHG- (Zs -
= IHG
TILTI
+
Iw)l Tz
+
T3)
QD/QHG
- Us QdQs - hvQ~/Qw), Table 1 Data used for obtaining
(4)
48 (1997) 259-265
where AZr is the Investment savings (US$), Zuo the investment for 1 heading and gutting machine (US$), Is the investment for 1 sorting/washing/scaling machine like the proposed prototype (US$), Zw the investment for 1 washing machine (US$), Qn the plant capacity (lo3 cans/day), Qno the capacity of the heading and gutting machine (lo3 cans/day), Qs the capacity of the sorting machine (lo3 cans/day), Qw the capacity of the washing machine ( lo3 cans/day). Summarising, these savings can be expressed mathematically as ATC = 3.00ARF + 2.23AL + 0.228 A&/Q.
Figs. 2-5.
1
Labour to take out defective anchovies/ Labour for H&G (&o); B = 0.95 2 Raw material cost (RF) = 5OOG600 US$/t or 0.13- 0.15 US$/can Labour cost (L) = 1.552 US$/h or 0.0550.07 US$/can 3 Investment for heading and gutting machine (I,,) = 4 100000-150000 US$ 5 Investment for sorting machine (Is) = 4000-8000 USS 6 Investment for washing machine (Iw) = 2OOG 4000 USS 7 Plant capacity (Q) = 20000 cans, 170 gea./day 8 Annual production: 200 days (average for fish canning plants in Argentina) Anchovy production season for canneries in Argentina: 50 9 days/year 10 Processing yield: 45% 11 Net filling content: 25% 12 Process time: 2 min/can _
0.2
0.3
PROPORTION
The economic data used for calculation are shown in Table 1. Costs and prices of equipment correspond to the 1992 anchovy season in Argentina.
4. Results and discussion
In Figs. 2-4 is shown how the variables related to size distribution and heading machine correlate to savings in raw material, labour and investment using values defined in Table 1. Finally, the total unit cost curves in Fig. 5 show the maximum and minimum savings expected. In Fig. 2 it can be seen that savings in raw materials increase when the proportion of smaller
0.4
0.5
OF MEDIUM SIZE ANCHOVIES
Fig. 2. Savings
(5)
in raw material
costs.
(in weight)
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0,006
-z
0,005
II ;i 9 -
0,004
4 P 4
-
AL (TZ=O.l),DZ=lO%
-
AL (T2-0.3)
- - AL (T2=0.5) 0,003
I
-
AL (T2=0.1),02=2%
z z 0,002
0,001 0.1
0.2
0.3
0.4
QUANTITY OF ANCHOVIES SIZE 1 (small)/TOTAL
Fig. 3. Savings in labour costs.
E
0.06
k
0.06
5 z,
0.05
23 _.
AI/Q
0.07
0.04
2% 02.
0.03
I g
0.02
z
0.01
I
0.3 QUANTITY
OF ANCHOVIES
r
0.4
(1 HG, 1 HG&
-
-
AI/Q (10000,lO)
-
Al/Q (100000.50)
-
AI/O (100000,100)
-
Al/Q (150000.75)
h’d)
I 0.5
SIZE 1 (small)/lOTAL
Fig. 4. Saving in capital investment.
anchovies increases and when the proportion of size 2 anchovies headed as size 3 rises. In Fig. 3 it is shown that savings in labour are increased with the increase in proportion of small fish and that differences in size 2 have little influence on these savings. In Fig. 4 it is shown how investment savings correlate with size distribution plotted as proportion of anchovies size 1 (smaller) and prices of machines. It can be observed that savings are higher when size of anchovy is proportionally
smaller. Also, it can be seen that the price of the heading and gutting machine influences savings more than the price relation to washing machine. Besides, when th three figures are compared, the component that has the major influence on total savings is the saving in investment followed by savings in labour and in raw materials. Overall results are shown in Fig. 5. It can be seen that total savings of more than 0.04 US$/can can be reached when the proportion of intermediate size fish is 0.5, the proportion of size 2 headed as size 3 is
264
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~. ..:
.mw.s .
..I
ATC
(D2=21;.2=0,
-
ATC (DZ=WqT2=0.3)
, )
-
ATC (DZ=Z%;T2=0.5)
111
ATC (D2=1 O%;TZ=O.l)
-_-
ATC (D2=1 O%;T2=0.3)
-ATC
(D2=lO%;T2=0.5)
I
0.2
0.3
0.4
QUANTITY OF ANCHOVIES SIZE 1 (small)/TOTAL
Fig. 5. Saving in total unit costs.
10% and the amount of small fish in the production line is higher than 0.2. Taking into consideration that in Argentina the total unit cost of canned anchovies is around 0.5 US$/can, the above values result in savings greater than 8% of the total unit cost. Considering that the plant is working at 100% capacity (Q = 20000 can/day) and with uniform catch size (Point A: T1 = 0.1, T2= 0.1 and D2 = 2%) the unit saving is minimum and equal to US$ 0.0056. Thirty-six days are needed to pay off the investment on sorting machine, one season (50 days) if the plant is operating at 70% capacity (Q = 14000 can/day) and only one week for Point B (Tl= 0.1, T2= 0.5 and D2 = 10%) where the unit saving is equal to US$ 0.036. For average conditions (Point C: dTC = 0.027 US$/can, Tl= 0.2, T2= 0.3 and D2 = 10 %), daily production of only 3000 cans in one season will be required. This shows the profit of buying a sorting machine even if catch size is uniform.
Results presented in this paper show that the convenience of the utilisation of a sorting step in a processing line depends mainly on the industry’s cost structure and fish size distribution. Savings of more than 8% of the total unit cost can be achieved, depending on the cost structure of the process involved, investment in machine and size distribution of the fish. On the other hand, considering uniform catches and a minimum of unit saving, a production of 14 000 cans/day (170 g each) is enough to pay for the sorting machine. For average conditions, daily production of only 3000 cans in one season will be required. Since, uniform size is a quality factor that leads to better prices, the increase in profits may actually result higher than that estimates based on the cost reduction figures hereby presented.
Acknowledgements 5. Conclusions It was found that almost always, a washing/ scaling machine reduces production costs.
This work was supported in part by National Institute of Industrial Technology (INTI) and by National Council of Scientific and Technical Research (CONICET).
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References Cl1 Parin,
M.A., Musmeci, S. and Zugarramurdi, A., 1990. The pelagic fishery of Argentina. Infofish Internat., 5: 24427. I21 Captura’94, 1995. Revista Redes de la Industria Pesquera Argentina. Aiio 8, No. 81. A., Boeri. R., Parin. M.A. and Musmeci, S.. c31 Zugarramurdi, 1988. Dimension y perspectivas de1 mercado de exportation de productos argentinos de la pesca. SECYT Proyecto Pilot0 de Innovation Agroindustria Exportadora, Anexo VI-2, Buenos Aires. c41 Booman, A. Lupin, H. and Inti. Patent. No. 219,847 ‘Maquina clasificadora de pescado por espesor’. cv Booman, A. and Inti. Patent No. 288,226 ‘Maquina lavadora, descamadora y clasificadora de pescado por espesor’.
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