The history of subsizes
The history behind subsizes
Back in the early days of MaxCut we had no concept of “subsize”, each sheet material had just a supplied length and width.
At the time we were working with a cut-n-edge company to see if the program was useful for them. A need they had was that they would sell boards in full, half or quarter sheets.
How it worked was when you ordered panels from them, sometimes on the last sheet the panels didn’t take up the full sheet. In these cases they would only charge the customer a half or quarter sheet of the last sheet (depending on how much of the last sheet was used). They wanted some way to cater for this which is where subsizes emerged.
We added the ability to set subsize for each sheet. This allowed you to specify what portions of the last sheet you could supply. To set it up you would enter your supplied dimensions and then the subsizes which was just a length and a width (there was no concept of quantity).
For example, if your supplied sheet size was 2750 x 1830 and you sold the last sheet in half and quarter sheets you would have two subsizes of 2750 x 1375 and 2750 x 688
The subsize solution worked well for them.
An unexpected use
Later on, we had users who came to us and wanted to solve a different problem. Their scenario was they have offcuts from a job in a certain material that they would like to use before buying new material. They wanted some way of inputting their left over material sizes and for MaxCut to use these before using a new sheet.
This sounded very similar to the subsizes problem, the only difference was they had a limited quantity of the stock material. Instead of adding a new section to handle stock, we simply added a quantity field to subsizes.
Let’s say you had you had a 2750 x 1830 sheet with five 1000x1000 stock pieces. The idea was you would add 1000x1000 subsizes and set the quantity to five. This sounded like it would work and in many ways it does.
Where this falls down
While this approach kind of works for stock, there are two big draw backs we are aware of.
First off, it's not clear if MaxCut will use the subsizes first or the main supplied sheet. When MaxCut decides to use whatever size it looks for the least wastage. If it can figure out that it can fit things better on a supplied sheet instead of a stock sheet it will do this (even though you may want it to use the stock you already have bought and paid for first).
Secondly, it mixes the concept of stock with sub sizes which means you can't do stock and subsizes together. You either have to pick one or the other.
Going forward
Where do we go forward with this. We realise that users have a need for stock pieces. We also realise that while subsizes may work in some instances, it’s not a perfect solution.
To build the stock pieces management part is a significant amount of work and so we need to be sure there is enough commercial value in doing it to warrant the work.
The alternative is we add a setting that says prioritise subsizes over full sheet sizes. That may work for some of the situations but feels clunky.
We would love to hear from you if you use subsizes and for what scenarios you use them for.
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Official comment
Hi Timo,
Thanks for the feedback on this.
When we added sub-sizing, the original intention not to be used as offcut management, although it looks like at lot of our users are using it for this
We are looking to separate offcut management from sub-sizes at some point in the future, but we don't have anything planned for this in our short term road map.
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I use subsizes to handel the offcut from previous projects. Unfortunately, Maxcut use the offcut-sizes only, if it can place all needed pieces onto these offcuts instead of a new panel, so it can save one hole panel. For me, it would be gainful, maxcut would use the offcut first and put the rest of the pieces on a new complete panel, so you have one bigger offcut instead of having several smaller offcuts. For example, if you have a panel of 2000x1000 an two offcuts of 1000x500. You need three parts of 900x500. Maxcut places all three parts onto the big panel, so you have at least three offcuts of 1000x500. It should be better, you use the offcut first an place the remaining part onto a new panel, so you have at least only one offcut with a bigger size, in our example of 1500x1000.
best regards
Timo Hoß
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Hi John,
Could you not just add in a field that allows you to input the QTY of "full sheets" you have in stock - that way your optimization code would then be able to reference how many of the full sheets to use before switching to the offcuts?
By doing so - the user could create a new material and input the sheet size as their largest offcut, set the QTY to X, and then enter the subsizes as normal.
Does this sound do-able?
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Hi Damo,
Thank you for your suggestion. Although this does sound like a simple solution, unfortunately it is significantly more complex than this as the core logic of the optimisation algorithm uses the fact that there are an unlimited number of sheets available.
We are currently looking at what development to do next, and recently sent out a survey with some options - offcuts being one of the options. If you feel this is an area worth developing, please submit this on the survey. Here is the link to take the survey:
https://docs.google.com/forms/d/e/1FAIpQLSd3vsRn9rMG_xtWZzhWv41BQBHrUX2pJ8XKPz6N78sJmR9h7g/viewform
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