Various constraints on destacking
The use of Automatic destacking can have a big effect on the type of patterns the optimisers produce they must also allow for the rules of the destacking machinery.
Allocating parts to stations - A part can go to an AUTOMATIC station if the entry in the part information box for automatic/manual allows automatic destacking and the stacking arrangement fits the size of the station, for example:
Part A 500 x 400 - destack picture 2x2 lengthways.
Station size must be no less than 1000 x 800
Automatic stations are not cleared at the end of a pattern - A part can go to a MANUAL station if the entry in the part information box for automatic / manual allows manual destacking. Neither the destacking picture nor the part size is required to fit the station size.(The operator can change the destacking picture to X (or something else) so that the part fits OK).
A manually destacked part can always be allocated to a manual station and there is usually no requirement to use the overflow station. The overflow station (99) is used in the following situations.
- Part books that cannot be destacked at an automatic station
- Pattern amendment changes that have created illegal destacking
The first part out of a new pattern does not go to the same station as the last part of the previous pattern. This gives time for the station receiving the last part from the preceding pattern to be cleared and loaded with the new baseboard before a new part in the next pattern comes through.
Part books - A Part book is a book of parts that is less than the maximum book height (e.g. a stack of 3 pieces where the maximum book height is 5 pieces).
If a part is assigned to an AUTOMATIC station there may be part books at the end of some of the patterns in which the part appears, for example:
Part A cut 10 high, 663 pieces, automatic destacking
Pattern 1 - 1xA, run qty 1, 1 part book
Pattern 2 - 6xA, run qty 75, 42 full books, 6 part books
Pattern 3 0xA
Pattern 4 2xA, run qty 100, 20 full books
Pattern 5 0xA
Pattern 6 12xA, run qty 1, 2 part books
Total number of full books: 62
Number of pieces in full books: 620
Number of pieces in part books: 43
If the destacking parameter: PART BOOKS TO OVERFLOW STATION is set to No, all these pieces are allocated to one automatic station.
If the parameter is set to Yes, the part books are assigned to an overflow station (99), even if the destacking picture is not defined [x].
Sorting within strips - The position of manually destacked parts in a pattern depends on the destacking parameter: MANUAL PARTS TO FRONT OF STRIP. Setting this parameter to Yes makes the program sort manual parts to then front of each strip. Note that the Saw parameters controlling the minimum size of the last cut are still followed.
Sorting strips - Strips containing parts that are automatically destacked are usually sorted to the rear of the pattern.
Sets of strips are placed at the rear in the order.
strips with all automatic parts
strips with mixture of automatic and manual parts
A set of strips that are destacked in the same way (e.g. automatic) are sorted in descending order of strip width (widest towards the rear of the pattern).
Notes
Any set of strips moved to the rear does not violate the saw parameter: MIN WIDTH OF LAST SET OF STRIPS
Any strip moved to the rear does not violate the saw parameter: MIN LAST RIP CUT
Sorting patterns - the standard rules for sorting patterns are NOT used for runs that use the automatic destacking optimisers
Station size - the size of both manual and automatic stations are checked when parts are allocated to stations.
Parts to large for destacking - Part lists containing parts which are too large to be destacked can still be optimised. The program reports any oversize parts before optimising and if optimising continues the parts are allocated to the overflow station (99).
Semi automatic stations - Automatic parts can be allocated to these stations if there are no free automatic stations. Also manual parts can be allocated to semi-automatic stations if there are no manual stations available. The size of these stations is checked when allocating parts.
Restricting the number of board types - If there are more than 3 different board sizes for each material you must set the Optimising parameter: MAX DIFFERENT BOARDS to 3.
Overflow station - Parts can be forced to the overflow station by entering a * (star)character in the additional information box used to specify whether a part is to be destacked at a manual or automatic station. This is especially useful when using pattern amendment to add new parts to patterns. Entering a *in the relevant information field ensures that the new part is destacked at the overflow and the existing allocation of parts to stations remains unchanged
Parts which cannot be destacked by the Automatic Destacking optimiser are allocated to the overflow station (99).
