Wednesday, August 19, 2009

Automatic sheet selection for nesting

Given a set of parts, selecting a right sheet size manually is always a menace to the manufacturing engineers. Because, material utilization for the same set of parts on different sheet sizes are not same. Further, there are other challenges faced by manufacturing engineers such as

1. Sheet selection from standard sheets
2. Sheet selection from standard sheets as well as Remnant sheets
3. Combinatorial sheet selection
4. Unique sheet selection

Given all such challenges, manual sheet selection would prove laborious and inefficient in selecting the optimal sheet. Very often manufacturing engineers settle for sheets with suboptimal material utilization, which increases scrap and thereby increases manufacturing cost. With the present day need for cost cutting, these are potential problems that can be easily addressed by automating the sheet selection process. Nestlib's inventory forecasting module provides such an automated sheet selection option.

1. Sheet selection from standard sheets
Standard sheets sizes such as 48"x72", 60"x72", 72"x72", 72"x144", 96"x144", etc., are commercially available. Manufacturing engineers have to choose a sheet with maximum material utilization from these standard sheets, which requires lot of iterations. Nestlib can automatically choose the right sheet for a given set of parts.

2. Sheet selection from standard sheets as well as Remnant sheets
In certain manufacturing runs, the nested layout for a given set of parts may not consume the whole sheet. In such cases, the remaining sheet, which is called as remnant sheet is generally used for nesting the next lot of parts. Sheet selection task can get more complicated when remnant sheets from previous manufacturing runs are also to be analyzed for utilization. For a given set of parts, Nestlib can choose the right combination of standard sheets as well as Remnant sheets. Nestlib can also give remnant sheets automatically for each nested layout, which can be used for nesting in consequent manufacturing runs.

3. Combinatorial sheet selection
As multiple standard sheet sizes are available, a combination of various sheet sizes for a given set of parts may lead to maximum material utilization. For example,it might turnout profitable to select 2 numbers of 48"x72" sheets and one 72"x144" sheet for a given set of parts. Nestlib provides such a combinatorial sheet selection which automatically selects a combination of various sheet sizes with maximum material utilization as the decision criteria. Nestlib includes remnant sheets also in such combinatorial selection.

4. Unique sheet selection
Sometimes it may be necessary to nest in same sheet sizes. For manufacturing large lot sizes, identical layout in same sized sheets will render use of same die, which will reduce setup time and tooling cost. The problem is to identify the unique sheet size from among the standard sheet sizes. For example if a set of parts need 50 numbers of 48"x72" sheets and 30 numbers of 72"x144" sheets, it may be profitable to nest all the parts in either 48"x72" sheets or 72"x144" sheets depending on maximum material utilization. Nestlib offers such unique sheet selection as well, where nesting is performed on same sheet size for all the parts and the unique sheet size that gives maximum material utilization is selected.