Warehouse layout design


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Warehouse layout design

  1. 1. ByChetan Reddy Mitta
  2. 2.  Order picking is the most time consuming operation It accounts for 55% of the warehouse operating costs
  3. 3.  Cross Aisle Structure Input and output points Number of aisles Length of the aisles Dimensions of the warehouse
  4. 4.  Concerned with unit load warehouse i.e. items are stored andretrieved in pallet quantities Dual command Cycle- a worker first stores and then picks thepallet Flow through process The angle of inclination of the cross aisles to be 45 degrees
  5. 5. The goal is to compare the average distances travelled by aworker from selected input and selected output in X layout withrespect to the traditional layout.
  6. 6.  Y-height of the warehouse X-Width of the warehouse a-cross aisle width b-sub aisle width/ picking aisle width Theta – angle of inclination x 1-X coordinate of intersection point of the sub aisle with the cross aisle y 1-Y coordinate of intersection point of the sub aisle with the cross aisle Entry i-Input i i={1,2,3} Exit i-Output I i={1,2,3} (Entry,Exit)=(coordinate x, coordinate y): ( 1,1)=((0,0),(0,Y)),(2,2)=((X/2,0),(X/2,Y)),(2,3)=((X/2,0),(X,Y))
  7. 7.  H-total number of aisles along horizontal V-Total number of aisles along the vertical Aisle offset_H-Aisle offset along horizontal Aisle offset_V-Aisle offset along vertical. I_x1,I_y1-x,y coordinates of point of intersection of first x . I_x2,I_y2-x,y coordinates of point of intersection of first x . Zone-1,2….8,9..12 Perzone_H-Number of sub aisles / picking aisles in eachhorizontal zone. Perzone_V-Number of sub aisles / picking aisle in each verticalzone.
  8. 8.  Finding the intersection points of the picking aisle line with thecross aisle line by using simple coordinate structure.For e.g.: If we consider Zone 2 : LocalAisle = aisle - (zone-1)*perZone_H; x_1 = AisleOffset_H+(zone-1)*perZone_H*b+ LocalAisle*b; ymax = Y - AisleOffset_H + (-m)*x_1; ymax = Y - m*(x_1 -AisleOffset_H); perzone _H=X-4*Aisle offset_H*a/8*b perzone_V=Y-a-2*a*aisleoffset_V/4*b
  9. 9.  Calculate the total number of aisles i.e. sum of horizontal andvertical aisles. We number the aisles from zone 1 to zone 8 in anti clockwisedirection and the zone 9 to 12 for vertical aisles . We generate two random aisle number s . Then we identify the zone in which the two random aisle numberlie the aisle number is converted into the local aisle number. This isformulated as below for zone 2 : LocalAisle = aisle - (zone-1)*perZone_H;
  10. 10.  The point of intersection of this randomly generated aisle and crossaisle is found. LocalAisle = aisle - (zone-1)*perZone_H; x_1 = AisleOffset_H+(zone-1)*perZone_H*b+ LocalAisle*b; ymax = Y - AisleOffset_H + (-m)*x_1;------------1 ymax = Y - m*(x_1 -AisleOffset_H);-----------2 It can lie in any of the two coordinates. We assumed a variable to take value between (0,1). So, if the value is < 0.5 takes one side or else the other (Just liketossing the coin). Now ,we know that a random number on this aisle should betweenthe two known points .
  11. 11.  y_1 = ymax+ rand(1,1)*(Y/2-a/2-ymax); The same methodology is used for the zones 2,3,6,7.And for thevertical zones the random point varies along the X-axis. After generating two random points and two random aisle number wecan calculate the total travel distance from entry to point 1 to point 2and then to exit. E.g.: Entry 1 exit 1 and the two zones are 1 and 3 . Pick1_dist = distance(Pick1_x,Pick1_y,Pick1_x,Pick1_ymax);- Pick2_dist = distance(Pick2_x,Pick2_y,Pick2_x,Pick2_ymax); Travel_dist =A1+A8+2*A9+2*Pick1_dist+2*Pick2_dist+2*distance(I2_x,I2_y,Pick2_x,Pick2_ymax);
  12. 12.  The X-layout model is programmed in matlab and run for 500different points by fixing 3 different input and 3 different out putpoints i.e.11,22,23.
  13. 13. sub aisle width"b"Cross aislewidth "a"Entry 1 Exit 1 -avg distEntry 2 Exit 2-avg distEntry 2 Exit 3-avg dist2 4 436.8473627 412.359603 469.96210783 6 458.9083926 421.9085264 440.20559964 8 438.8048983 403.970392 444.63491165 10 464.4144204 413.390739 472.15341356 12 438.0494148 431.7415695 485.23149067 14 459.9804163 436.8815879 466.5468598 16 479.5830189 429.3905281 481.52698189 18 467.6955873 414.8935882 424.159999310 20 488.820164 445.4807398 488.8825158
  14. 14. 02004006008001000120014001 2 3 4 5 6 7bDistance
  15. 15. 02004006008001000120014001 2 3 4 5 6 7bDistance
  16. 16.  The average distance is low for the entry 2 and exit 2 comparedto the other input and output points as the b is varied The average distance decreases as we increase the dimensionsof the layout In a traditional layout, the average distance increases as the b isvaried Also, the average distance increases with the increase in thedimensions of the x Comparing the two layouts, the X layout would be much betterwhen the length of the warehouse is more and also the averagetravel distances are low for X compared to the traditional layout
  17. 17.  The X layout can be extended by increasing the X’s appropriatelywith respect to the length of the warehouse , I/O points and thestorage space Finding an optimal angle of inclination for X Finding optimal number of inputs and output points at properlocation