SECTION 7 -
FIXED VOLUME
(Covers: Introduction, basis of operation, using Fixed Volume, FV results, FV for cylinders, Variable FV.)
In all modes of operation PALLETMANAGER will provide you with optimal pallet layouts for the given case / primary / sub-primary unit. However in doing so it is naturally limited by the dimensional values you provide for the product itself, the pallet load area and height, and the collation quantities and packaging materials used. Whilst the whole of the PALLETMANAGER suite of programs is ideally suited to you posing 'what if' questions (e.g. what is the effect of using different collation quantities), it may be that the size specified for the product itself limits the feasible options.
It may be that a change of 1mm or less to one product dimension could provide a vast improvement in pallet fill. The Fixed Volume mode of PALLETMANAGER is designed to optimise pallet fill in instances where some minor change to the product dimensions might be possible. It takes its name from the fact that when using Fixed Volume mode you can (if you wish) specify that the case / primary size must in any event have have a volume exactly equal to the volume of the original product.
Technically it is one of the most complex and powerful parts of the software suite and utilises unique and powerful optimisation techniques. However users will find that it is very easy to use.
In situations where the volume is not required to be fixed then the Do Better module may alternatively be used. This 'more automatic' function is accessed from the Summary Results Screen (Screen 5) and is described in detail in Section 16.
It should perhaps be mentioned here that even when the product size (e.g. a Case) is fixed (and thus Fixed Volume mode is not appropriate), then a palletisation improvement may be possible by simply allowing a few mm. of pallet overhang. The automatic examination of both 'standard' and 'overhang' arrangements is discussed in Section 5.
In instances where the volume of a primary unit or case is fixed, its exact dimensions may be somewhat flexible as long as the internal volume remains constant. In other instances the volume as such may not need to be fixed. Both are catered for in the Fixed Volume module.
One approach to solving such problems using the Palletise or Collation modules is to select (using a calculator and experience!) a set of possible primary or case designs and run each in turn through the appropriate module.
However, such an approach may not yield any improvement. The Fixed Volume module performs a far more powerful and systematic search for an improved solution using unique and powerful algorithms and in-built information on designs which may yield improved results.
In some instances the designs examined may have dimensions which are only fractions of a millimetre apart, but these may result in very different loading results. An approach based upon varying the dimensions in fixed steps of (say) 1mm would not be sufficient.
The Fixed Volume module can be selected following data entry for either the Palletise or Collation modules from Screen 3 (where the pallet size is selected). Normally you will first examine your chosen primary or case using the standard Palletise or Collation modules, and you may well find that these produce a satisfactory solution.
In using Fixed Volume you should select the Advanced Options screen (Screen 4) and then complete details as described below. A typical Advanced Options screen is shown below. The one shown is for a Collation of 6 primaries, the size of each being 100mm * 90mm * 60mm.
It is the entries in the bottom half of this screen which we will focus on in the discussion below.
On entry this part of the screen shows the 3 (Actual) product dimensions (100, 90 and 60) together with entries for Lower and Upper limits which that dimension may take. Initially these will be equal to the product dimensions as input. You can edit the lower and upper limit values for any or all of the values. In practice it is likely that any dimensional flexibility will be limited to just a few mm. either size of the initial values. (The program limits the range you can enter to extreme realistic values).
If you are optimising a primary (i.e. Collation mode as here), also enter the maximum number of collation tiers that you will consider. This will override the value stored for the chosen packaging specification.
The final data entry on this screen - Max. Volume Reduction - is discussed in a later part of this section - it can be left = 0 at this point. A typical completed set of entries is shown below:
Given the above information PALLETMANAGER will examine every feasible collation arrangement:-
1) with the original dimensions
2) with the height fixed at its original value and base dimensions varied within your limits
3) with the product height increased so as to provide up to three less layers on the pallet in each instance leaving little or no spare height. Once again base dimensions will be varied within your constraints.
4) with the product height reduced so to increase the number of pallet layers that can be accommodated in the available loading height by up to three, once again varying base dimensions.
During stages 3 and 4 the product dimensional limits you have specified will, if necessary, be used restrict the number of examinations carried out.
5) with dimensions for the primary / case having the exact values specified by you as upper and lower limits.
As you would expect, the number of calculations involved is very substantial and many hundreds / thousands of potential solutions may be examined so a short wait may be expected.
The results which are obtained from this powerful module require some detailed explanation.
For a given problem, if you had not selected Fixed Volume, but had run Palletise or Collation with the specified dimensions, a number of solutions would have been obtained, each being based upon the stated product dimensions. In Fixed Volume the first stage performed is the examination and subsequent display of the results obtained using the exact dimensions specified. Up to 1000 different case sizes can be examined in a single run.
In addition, for each of the case sizes examined in stage 1, Fixed Volume considers other cases sizes which might provide a solution which is as good as, or better than, that achieved when using the specified dimensions. In doing so it examines all variations of case / primary size which fall within your stated constraints and whose case height provides either the same number of pallet layers, or values within +/- 3 of this value. In all instances the internal volume of the case / primary will be fixed to be equal to that of the case or primary originally specified, and the collation arrangement within the case will remain unchanged.
Thus the results obtained from Fixed Volume will include the set of results which would have been obtained had the Fixed Volume option not been selected (i.e. from Palletise / Collation) and, in addition, solutions which provide an improvement over those results. These latter solutions will retain case / primary volume whilst varying dimensions within constraints you have specified.
The number of possible solutions examined may be very large, and the time taken may be significant. However, the restriction of dimensional ranges to those which would be practically acceptable will of course reduce computation time.
The dimensions displayed on the Palletisation Report are, as with all modules, displayed to the nearest millimetre, and, because of this, two (or more) similar (or apparently identical) solutions may sometimes be displayed. These are, in reality, solutions which may vary by a fraction of a millimetre from one another. Frequently, a minor change in product size can yield a very substantial cost saving.
As stated earlier the Fixed Volume module can examine up to 1000 case sizes (each meeting dimensional / stability constraints) in a single run. As with the standard Collation report, the 'best' 99 solutions are displayed and printed.
The Fixed Volume module can be used to investigate problems where cylinders (e.g. cans, drums) are to be packed either directly on the pallet (Palletise mode) or are to be collated. The Advanced Options screen (Screen 4) not only provides for Fixed Volume data entry but also provides a tick-box for cylindrial selection. Full details on patterns for nesting and other aspects of Cylindrical Nesting are provided in Section 10 of this manual.
The discussions so far in this Section assume that the user has specified:
A maximum and minimum value within which each dimension may vary.
A set of primary or case dimensions which define the VOLUME to be retained in any Fixed Volume analysis.
The former parameters are typically somewhat arbitrarily selected on the basis that the user will eventually be able to choose from a variety of possible solutions. The latter values are typically the dimensions of an existing unit for which a modified and more efficient set of dimensions may be required.
PALLETMANAGER is also able to tackle problems where the volume of the existing unit need not precisely define the volume actually required. There may be a little scope for volumetric change - perhaps a one or two percent reduction. As part of the data input phase the user may define a percentage volume reduction which may be considered. As described above the default value is zero percent.
If a reduction is allowed then Fixed Volume analysis will be carried out using firstly the volume as specified (by the primary / case size entered), and then be repeated using the specified reduction percentage. Thus there will be two sets of solutions - one relating to the original volume and one to the reduced volume problem. In both instances the ranges on dimensions will be strictly adhered to. The results from these two runs will be merged together and ranked in the usual manner on both screen and printer reports.
It is obviously important that those results associated with a reduction in volume can readily be identified on both screen and printer and for this a V code is displayed following the Reference Number on both screen and printer. (This may be in addition to other codes described elsewhere relating to Cylindrical items). Thus a comparison may easily be made between solutions in which the volume is strictly retained and those which are obtained as a result of a slight volume reduction.
The printed report also indicates the percentage reduction which you specified as being permissible.
It is important to note that improved solutions utilising 'Reduced Volume' can only be obtained if the dimensional constraints are reasonably wide. Otherwise solutions will be identical to those obtained without reducing volume.
Once again we should mention the Do Better module which may be used where volume is not a major issue. This 'more automatic' function is accessed from the Summary Results Screen (Screen 5) and is described in detail in Section 16.