Formula Batch Size

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Posted on by Tim Schofield

Hi I'm looking at the classic batch processing problem where I am trying to schedule production orders onto two vats, one is 1250L and the other is 2000L. So these are the only planned order sizes that I want. I thought that if I created two formula versions and set that size on each version that those would be the only production order quantities I could use - but I'm getting confused by the setting of Formula multiple. The system's letting me create a production order for any order size that fits in with the multiple - and planned orders don't seem to be looking at the formula settings at all.

For planned production is the only control I have got the Default order settings or have I missed something in the formula setup?

Is there a way to constrain the system so that it only allows you to use specific production order quantities?

Thanks

Tim

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RE: Formula Batch Size

I don't think you can quite get there trying to enforce binary order multiples like that, even with creative use of min max and multiple order quantities. If you set min at 1250 and max at 2000 without a multiple, you'll get as you've noted any number in between. To resolve this, you'd need to set a multiple, but multiple of 1250 would prohibit an order of 2000, and multiple of 2000 would prohibit an order of 1250. Multiple of 1000, I think, would prohibit the 1250 minimum enforcement and round it up to 2000.

You can use BOM/route versions to establish the materials and resources needed for each of these batch sizes, but that won't help generating the appropriate planned order quantity, just dictates which BOM/route is used after that order is generated.

The only way I can think of to work around this would be to create two separate products, one for 1250 batch and the other for 2000, then you could try monkeying with higher level BOM's and setting up large and small quantity versions pointing to the respective lower level product.batchsize products, but this wouldn't fit well where you want the consolidated requirements grouped into planned batch orders.

You're basically trying to enforce a multiple-order-multiple strategy, which is definitely not something standard MRP methods support. It's probably not a complex customization, though--you'd set up a special coverage group name, then code an algorithm to figure out how to most efficiently break up consolidated demand into orders of 1250 and/or 2000, then feed that back into AX as planned batch orders in the background. The logic would say something like if REQ<=1250, Oqty=1250, else if REQ<=2000, Oqty=2000, then if REQ>2000 you'd need to incorporate some multiple/remnant logic to optimize the minimum total order quantity using combinations of 1250 and 2000 towards total REQ. Might be as simple as limiting to a single 1250 with the rest 2000 or a single 2000 with the rest 1250, but I'm not monkeying with the math to figure this one out this morning :-)

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Tim Schofield on at

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RE: Formula Batch Size

Thanks Chan - I'm trying to avoid customising. So in this case I think I'll try to push back on the requirements. But I appreciate you taking the time to respond.

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ColbyGallagher 3,666 on at

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RE: Formula Batch Size

Hi Tim,

You can do what you are trying to do. Sounds like you didn't set your formula multiple = to your formula size. See screenshots below.

Formula versions for 1,000 lb batch and 2,000 lb batch. Note that formula multiple = formula size.

Here is what DOS inventory tab looks like. Standard is just in there for costing.

Here is some dummy demand forecast data:

And this is what Net Requirements looks like, picks the correct formula version based on the quantity required:

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Tim Schofield on at

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RE: Formula Batch Size

Thanks Colby - I'm not sure this will work unless you're using quantities that are multiples of each other (so you are using 1000 and 2000, but what if we have 1250 and 2000) - and also the actual question I got asked was "if I need 5000 - can the system give me 2 * 2000 plus 1 * 1250"? And we can do that with the default order settings (almost). Multiple = 250. Minimum = 1250. Maximum = 2000. Of course that will generate some orders of 1500 and 1750 - so we will have to handle those manually. But thanks again for the reply.

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ColbyGallagher 3,666 on at

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RE: Formula Batch Size

Tim, yes, it will do the scenario you describe.

Formula versions

DOS - set a max.

Net Req:

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Tim Schofield on at

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RE: Formula Batch Size

Got it!

Thanks - you're a genius. My setup error was setting the 'From formula size' on the smaller Formula version - once I set that to zero as per your screen shot it worked perfectly.

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