SECTION 16 -
Trays, Tote Boxes and Slipsheets.
(Covers: Introduction, Packing a given tray / tote; Additional Challenges: Complex patterns and poor utilisation; Cost Entries; Multiple Tray/Tote Sizes.
As well as dealing with the optimal packing of product onto pallets, PALLETMANAGER is an ideal tool to use when tackling any other problems where the objective is to pack a cubic space (e.g. tray, tote box or even a shipping container) with identical products. Only when you need to load a variety of different products into a given unit does alternative software such as our CARGOMANAGER product become more suitable.
The approach taken to solve tray, tote or slipsheet loading problems is essentially identical to that illustrated earlier (e.g. Section 3 - Guided Tour for Palletisation) and typically uses Palletise (or in some situations CUBE) mode. The only difference is the format of the reports produced by PALLETMANAGER which take account of the fact that a pallet is not in use.
We would strongly recommend you study Section 3 of the manual to gain a full understanding of points relevant to both pallet & tray/tote loading which are given a more summary treatment in the section.
The remainder of this Section illustrates the specific application of PALLETMANAGER for tray / tote box loading using Palletise and CUBE modes of operation. [With Slipsheets (essentially a thin card or plastic pallet substitute), the same logic applies as for standard palletising save for the pallet height]
The types of unit into which product is to be loaded are illustrated below, although in some companies the term tote is used for cardboard boxes of various sizes used for product transportation.
16.2 Packing into a given tray or tote box.
PALLETMANAGER Palletise mode will provide you with optimal solutions to problems where you need to pack identical products in layers so as to maximise the fill achieved. What is crucial, before tackling such problems, is to ascertain the exact internal dimensions of the base of the tray / tote and the maximum permitted loading height within the tray/tote, together with the weight limit applicable for contents. The range of tray sizes available (such as those used by leading food retailers) vary significantly from retailer to retailer and accurate internal measurements for units into which you will be packing are vital.
For the purposes of the next few examples we will assume the following tray (or tote) limits: Internal dimensions: 544mm * 352mm ; maximum loading height 172mm; maximum load weight 18kg.
We will assume that we need to examine the solutions for a number of different products, and in doing so over the next few pages we will illustrate various features of PALLETMANAGER that will be useful in practice when tackling such problems.
After starting PALLETMANAGER we select the New Run and the enter the PALLETISE mode of operation - ' Pack an existing product into a given load space [pallet, tray etc] in the most efficient way.'
In PALLETISE mode we first enter details of the product size - and here we will assume our first product is 170mm * 86mm * 42mm high and each weighs 0.22kg. The product must be packed with the height dimension vertical. A completed data entry screen is shown below:
You will notice that the 42mm dimensions has been 'ticked' to show that it must be vertical. The two bottom entries are set = 1 - their default values. As will be described later these can be used to calculate an actual cost for the transport of a given quantity of product, but for the moment we leave these at their default values.
After completing entry of the product details we select Continue and the next screen contains details of the load space into which the product is to be packed.
|** When you first use the software the load space shown will NOT show the tray size detailed earlier but will contain the default load space size - Entry 1 in the pallet / load space database. To change this select Pallet Database **|
The first of 10 entries for the database is then shown and, assuming your work will 'normally' involve packing trays / totes and not pallets edit entry 1 to match the tray details detailed earlier as shown in the screen below. You could, of course, select other database entries and change as required. In time you will set up entries for other trays / totes as required into the other database entries.
Having made the necessary changes select the Use this Entry button, and the Load Space details screen will then be as below:
Having selected Pack PALLETMANAGER will then calculate the maximum number of product that can be fitted into the given load space. This shows that a total of 48 units can be fitted, with 4 layers each accommodating 12. Part of the Tabular Results Screen is shown below.
The figures in this table are explained in more detail in Section 3, but in summary show that 91% of the area of the tray/tote base are occupied by product, and that an extra 38mm of loading height would be needed for an extra layer of product to be fitted in the tray / tote.
For any given problem there may be many different ways of fitting the given number (here 12) in a layout, but sometimes there may only be one or two ways of achieving this number. Selecting Layout from the Tabular Results Screen (Screen 5), shows us that on this occasion there are 35 different ways for packing a layer of 12 product into the given load space. We can browse through these to see which is most suitable. The first two available arrangements for this product are shown below:
Either of the above might be suitable for tray loading, but in some situations (and most certainly for pallet / slipsheet loading) a more complex form might well be required which provided some 'bonding' between each of the layers, such as that shown below as a 3D stack:
The procedure once you have selected a suitable layout follows that outlined during the examples in Section 3 - If all the layers in the stack are to be the same then you can just select Print / View and obtains on Screen or Printer reports of the proposed arrangement in both 2D and 3D form. If you have the Webbase (manual, Section 14) and/or STORE (manual Section 9) modules then you can also save these specifications for future recall / re-printing.
16.3 Additional Challenges.
In the above example there were a wide range of arrangements which could be used for packing the given product into the tray / tote, and the area utilisation (at 91%) was reasonably good.
We now consider the following two situations:
(a) What if the arrangements available are all too complex to use?
(b) If the results are very poor and we need to consider a possible change to the product size?
16.4 Arrangements too Complex to Use?
If we were to perform a packing of a unit 121mm * 86mm * 42mm high into the same tray/tote size as considered previously we would obtain an optimal solution fitting 17 units on each layer. This is the best that can possibly be obtained and gives a 92% fill on the base of the tray/tote.
When we view the layouts available (there are 5), we see that they may be too complex to adopt in practice. What is probably the simplest of the available arrangements is shown below:
What if this in not acceptable. Unfortunately the answer is that there is no simple way of fitting 17 and we may therefore need to reduce the quantity fitted to 16. This can quickly be done from Screen 5 - the Results Summary Screen - by selecting firstly the Advanced button and then the Subopt button. This reduces the number you wish to fit to 16 and you can once again select Layout to get layouts which now fit 16. The first solution obtained (one of 27) is shown below.
Thus PALLETMANAGER can adapt to meet the practical situation where the 'technical' best does not meet the practical needs.
16.5 Results Very Poor - Can we Improve Design?
PALLETMANAGER will ALWAYS give you the best solution for a given problem. However there will be instances where the best solution that can be achieved results in a very poor tray / tote utilisation. PALLETMANAGER has a number of tools available to help you make what may be very small changes to the sizing and yet achieve major load improvements.
Consider the packing of units 245mm * 120mm * 42mm high into the tray / tote size considered earlier.
If you carry out this analysis you get an optimal (best possible) solution which fits 4 units on each layer and a total of 16 units / tray / tote. The (very poor) solution - one of a number fitting 4/layer - is shown below:
We must once again emphasize that there is no way at all that extra / layers can be fitted.
Is there any way in which we can fit more by making small changes to the case dimensions?
PALLETMANAGER has two tools which will help solve this. If all the 3 dimensions of the product could be changed slightly then the Fixed Volume toolkit (Section 7) could be used. This is designed to help design products to make best use of height, length and width of the load space whilst (normally) retaining the volume of the product.
Here we will use a rather simpler - but equally powerful tool - the Do Better module. This is described in detail in Section 15 of the manual but is illustrated brifly below:
Once again we start from the Results Summary Screen (Screen 5) this looks as below:
The Do Better option is shown as a button towards the bottom right.
If you select this then, after a few seconds, a new results screen is displayed as shown below:
The line 0 of this display (245*120*42), shows the current solution, 4 layers of 4 fitting in total 16 units / tray or tote.
The lines below this are various alternate unit sizes which fit more units / layer and per tray / tote, this being achieved through changing the length and width.
A full explanation of the process is given in Section 15.
Thus it we packed a unit 352*108.79 we would fit 20 units, whilst if we packed the entry we have highlighted - 272*117.33 we would fit 24 units.
When using Do Better you should browse through the results shown and find those that are close to your current unit size - the example shown has a width just 3mm less than we had initially (117 rather than 120) and yet fits 50% more even if using a length dimension 27mm greater than that input.
Do Better will NOT change the data you have input but will highlight how improvements might be achieved.
16.6 Cost Entries during Palletise.
During the examples described above (16.2 onwards) we always have used the default values (1) provided for two of the data input values - Primaries / Case and Annual Case Volume. The relevance of these values is normally only for the loading of cases onto pallets, but they could be used, as described here, to provide costing for tote based or tray based loads.
In a pallet loading situation we might want to convert the quantities of product we are shipping / year into an equivalent number of pallet loads, and then convert this to a cost based on the average cost of storing and transporting a pallet load. This average cost is held in the Pallet / Load Space database for each entry.
In tray / tote loading we could translate the quantity of product transported / year in the tote/tray into a quantity of trays / year and place a cost per tray/tote figure into the appropriate Pallet / Load Space database entry. In the examples given above the cost value held in the database was set = zero (see page 3 of this Section).
16.7 Packing Multiple Sizes of Tray/Tote.
The Palletise module of PALLETMANAGER is designed to tackle problems where the size of the load space (pallet, tray, tote, container etc) is known and fixed. However there are situations where one may be interested in the relative performance of several different sizes of load space for packing a given product. This might be comparing which of a number of different tray sizes is best used for a particular product (in terms of % utilisation of the cubic load space), or to determine which of a larger set of standard tote boxes (say 50+ different sizes) is best used for a particular product. Once again the criteria would be the % fill achieved, subject in most instances weight limits.
The CUBE mode of operation (as with Palletise selected from the New Run Menu), is a tool specifically designed to deal with such problems. It differs from Palletise in two distinct ways. Firstly it has its own link with what is termed a 'Shipper database' - a database which you can provide with up to 600 different tote / tray / box sizes and weight limits. Whenever the CUBE module is run a product can be packed into each of these shipper sizes and the best 30 solutions (i.e. the highest utilisation trays / totes etc) are then identified. Secondly, as well as allowing the product being packed to always be placed with a particular dimension as vertical (as with the earlier examples), it also allows the user to remove this restriction and, in doing so, allow any combination of
Full details of the CUBE mode are given in Section 8 of the manual, but below we illustrate briefly what might be involved for those tackling tray or tote packing.
Step 1: The CUBE Shipperbase is entered from the Opening Screen:
Step 2: Database entries are made for each tray / tote / shipper size - up to 600 can be held in the database.
Step 3: From the Opening Menu New Run is selected and then CUBE mode selected.
Step 4: Details of the product to be packed are entered in the same way as in Palletise mode - we entered a size of 245mm * 120mm * 42mm (the product which earlier gave us a poor packing in the tray / tote size specified at the start of the Section.
Step 5: After entering the product size we are then faced with the Load Limits screen: Details of one of the database entries is shown (the first alphabetically), and by ticking the appropriate box all the others will be examined.
Step 6: Pack is selected and a results screen is subsequently displayed:
This has ranked the performance of the various database entries and lists the top 30 results ranked according the Volume Utilisation. This table can be printed or the required entry can be highlighted and pattern(s) available to achieve the packing can be displayed.
Thus the performance of various tray / tote / shipper sizes can be compared for the given product.
Once again full details on the CUBE mode of operation can be found in Section 8 of the manual.