Willey explains how to maximize efficiency in your screen department.
By Jane Willey
Plugging in the numbers from the table for this shop, you have LF = SRF x ODF x MCF
LF =1.75 x 1 x 1.75 = 3.06 (or 3) If you change the variables to account for an additional production shift, a total of three screen ODs, and four different mesh counts, the calculation would change as follows: LF = 2.75 x 1.5 x 1.85 = 7.63 As you can see, supporting two production shifts with one screenmaking shift, plus adding more screen ODs and mesh counts can easily double the size of the frame loop. Once you have determined your loop size (total number of screens required), the next step is to determine the scale of your screen department. Remember, the steps in the screen loop are constant, but the space and equipment required are dictated by the loop size and frame ODs. Obviously, a screen loop of 1000 frames rather than 500 frames, or a frame OD of 50 x 70 in. rather than 23 x 31 in., will require a larger facility and more equipment. For an example of how to determine the screen-loop size (SL), let's assume the operation is one shift, uses three mesh counts, has a loop factor of 3, and includes the information in Table 2. Using the estimation formula, the calculations for the screen loop will be as follows: * for machines A & B, SL = C x SU x LF x M x S SL = 6 x 3 x 3 x 2 x 1 = 108 * for machines C-F, SL = 8 x 3 x 3 x 4 x 1 = 288 The total loop size is 396 (rounded to 400) frames for all six machines. This uses the loop factor of 3 to compensate for two frame sizes and three different mesh counts. Again, the two different ODs are dedicated to specific machines and are always in the same ratio.
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