Optimising parameter to set a cost for offcuts produced
Set the balance for the cost of offcuts between full cost and zero.
The offcut allowance is a percentage of the original board cost from the board library, for example, 40% of board cost. Use this to say how much an offcut is worth.
The program does not use a single percentage because in many cases a large offcut is worth more than a small one. So, for example, a large offcut may be worth 60% of the original cost but a small offcut may only be worth 40% of the cost.
It is possible to set different percentage values for large and small offcuts to encourage the optimiser to produce large offcuts rather than small ones (all other things being equal).
The largest offcut is the largest board size for that material in the run, and the smallest offcut is the smallest offcut allowed by the optimising parameters. The maximum and minimum percentages are associated with the largest and smallest possible offcut sizes and all other offcut sizes are then automatically allocated a percentage based on this range. For example:-
Maximum offcut size: 2440 x 1220 mm
Minimum offcut size: 300 x 200 mm
Board cost 4.25 per square metre
Maximum offcut percentage: 70%
Minimum offcut percentage: 30%
Percentage cost of offcut 1237 x 420 =
Range in square metres = 2.97-0.06
Range in percentage points = 40
Percentage points per square metre = 40/2.91
Square metres in offcut above smallest = 1.237x.42-0.06 = 0.459
Percentage applied to this offcut = 0.459 x 40/2.91 = 6.3
Percentage value of offcut of 1237 x 420 = 30 + 6.3 = 36.3%
Cost per square metre of 1237 x 420 = £4.25 x 36.3/100 = £1.54
For a larger offcut a different percentage applies, for example, for an offcut 1500 x 900 the percentage is:-
1.500 x 0.900 -0.06 x 40/2.91 = 17.73
Percentage value of offcut 1500 x 900 = 30+17.73 = 47.73%
Cost per square metre of 1500 x 900 = £4.25 x 47.73/100 = £2.02
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