How to optimize cutting


How to calculate how many parts of the same size can be got from the original panel.

First of all think in one dimension.
Assign the saw kerf size to 3 mm.
How many pieces can you get 200 mm from 1800 mm?Int((1800 + 3) / (200 + 3)) = 8
"Int" is used as a function to truncate the decimal part in Excel etc.
Next is the panel (2 dimensions).
How many 400mm * 300mm can be taken from the original panel of 1800 * 900 mm?
Int((1800 + 3) / (400 + 3)) * Int((900 + 3) / (300 + 3)) = 8


Changing the direction of the parts. 
Int((1800 + 3) / (300 + 3)) * Int((900 + 3) / (400 + 3)) = 10

In this case, the vertical orientation improves the yield.


When cutting multiple kinds of board materials.
When cutting the first part, the size of the later edge material changes depending on whether to cut from the long side or cut from the short side.



● If the parts can be rotated, the pattern will be doubled.
● If there are n parts, the order of cutting is n!
●  If there are multiple types of original panels (including increased edges), the combination will increase even more.
Therefore, it is impossible for a PC to find out all the patterns and to select the most efficient pattern if the number of parts is 10.

First Fit method

I have searched for google many times to produce cutting optimization software. It is one of the keywords that appeared in that. However, after all it was disappointing with just saying "to cut from large size members".
In addition, I found the keyword "Monte Carlo method", but I only generated random data in large quantities and evaluated one by one.
In addition, although a "genetic algorithm" seems to be cool, it is a technique to narrow the range by crossing relatively good patterns issued by the Monte Carlo method.
After all, the optimization equation does not exist.
Cut the largest member that can be taken from the smallest size original panel / edge material.
There is no big mistake.

Aim for further upward

Based on First Fit method,
For example, regarding the size of the standard board
1800 = 900 + 900
1800 = 600 + 1200
1800 = 450 * 4
Let's keep in mind what kind of parts we should combine with.
In some cases, it may be more efficient to allocate it to a larger original panel / edge material.

And, especially when cutting off the first large version, if you think about cutting from the longitudinal direction or cutting from the short direction, the later efficiency will change.

Rely on computers (using cutting optimization software)

Even if you do not try hard to think, PC will pick out the greatest number of patterns and pick out the best one with efficiency. Patterns exist indefinitely. Although it is impossible to put out everything, even if it is infinite, "almost this will be different sensibly" is mostly. How to remove it is an important quality of cutting optimization software.