An Easier Way to Get 95% Nesting Material Efficiency

Material Waste - Programming Time - Inventory Expenses

Material Waste - Programming Time - Inventory Expenses

I recently heard about a manufacturer, who had an extraordinary material efficiency.  They consistently got 90-95% material efficiency on every sheet they ran.  Further, this was achieved with exceptionally complicated patterned/grained material.  It was an amazing feat!

First I’ll tell you how they did this and the problems they encountered.  Then I’ll walk through an easier solution.

How did they get the material efficiency?

The first question is, naturally, how did they do it?  They could be doing manual nesting and spending a great deal of time on each nest, but that’s only half the equation, they still need the right part selection to make a highly efficient nest.  They could be running lots and lots of the same or rectangular parts which lend themselves to static nests with high efficiency.  Or they could be making very large sheet-sized parts that have very little waste.

But as it turns out, none of that was the secret to their amazing material efficiency solution.  Although, they did have large parts, there was still plenty of trim. And they did do manual nesting, but even with the time spent that really didn’t account for the minimal waste.

Their solution to nesting efficiency

The very ingenious programmers tackled this problem – to get the greatest material efficiency from the expensive material with two tools.

Step 1. Use Filler Parts

The use of filler parts is a clever nesting strategy that leverages smaller parts that aren’t of a first priority nature to “fill in the holes” or use up the scrap left by other, larger parts.  Filler parts can be used applying one or more of three strategies.

 

  1. Part InventoryFiller parts can be those smaller piece-parts that you keep on hand or in inventory because you use lots of them, and it doesn’t make sense to do a whole run (nest or multiple sheets) of just these parts.  They make excellent parts to fill in the gaps on a large sheet, then throw in the “bucket” for future use.  Stocking a KanBan system would be a perfect application of filler parts used for inventory management.
  2. Future Orders – If your nesting software can be sensitive to part order due dates, you can use parts with a future due date as filler parts.  Let’s say you fill your nest with parts due today; however, you have an unsatisfactory amount of scrap left.  You can “pull forward” orders due tomorrow or even next week as filler orders to be used when and only when there is room in the nest.
  3. Premium Materials Most shops have different grades of material – some “good stuff” and some “okay stuff.”  The good stuff is naturally more expensive than the okay stuff.  In the case of filler parts, parts designated for manufacture out of the okay stuff, could be made from the good stuff – if and only if there is sufficient scrap in the good stuff to warrant its use.  This can be easily done in the case of using brushed stainless steel for the back panel of a cabinet instead of the regular material.  The cabinet customer gets an upgrade and the better quality material is not wasted.

Inventory Problem

This manufacturer took used filler parts to supplement part inventory (option #1 above).  But there was a problem.  It seems that a quick check of the filler part inventory led them to discover that they had a 6.2 -year inventory of some parts.  And while using the filler parts is great for material efficiency, what is it doing to their cash flow and inventory costs to see that much money literally sit on the shelf?

Step 2. Use Static Nests

The programmers took the time, energy and effort to create very tight static nests (a nest that is created once, saved, and run multiple times without change) with very high material efficiency. This also contributed to the material efficiency.

 

 

Static Nest Problem

However, the problem they encountered is not unusual for static nests.  Because they are by definition static, there isn’t much if any room for change or adaptation as circumstances change – which they always do.  For example, they created a nest with parts 001, 002, & 003.  Then Part 003 gets damaged, and they need a new one.  However, this manufacturer created a whole nest with all of the parts (oo1, 002, & 003)  to get a new “Part 003.” Now they have the “Part 003” they needed, plus two extra parts – 001 & 002.  What do you do with the extra parts 001 & 002?  Put them in inventory.  [I’ve heard of another manufacturer, who had a similar situation.  His solution was to remake the whole nest, but to scrap the additional parts 001 & 002.]

The Nesting Solution

The solution to the problem is to first look at all of the costs – sheet material efficiency, programming time, and inventory – and assess the best approach to managing all of the costs at one time.  It’s very easy and naturally human to sacrifice the “off book” costs of inventory and programming time, which often aren’t as transparent and as accountable, to the much harder cost of material.  This may mean a reassessment of policies and or procedures beyond the actual tools of nesting software.

The next step is to turn to an automatic nesting software that can handle the grain pattern on the material and nest dynamically to eliminate the problem of schedule rigidity inherent in static nesting.  Dynamic nesting considers a variety of parts for each nest, and evaluates them based on several qualities including urgency, order cohesion, and material efficiency. Dynamic nesting would enable this manufacturer to create a Part 003 – and only a Part 003 – as it is mixed with other priority parts in the next nest or batch of nests.  They would not need to superfluously recreate parts 001 & 002 and put them in inventory.

Finally, if the approach of filler parts still seems viable based on the above reassessed policy, part of the solution may be using this automatic nesting software to automatically fill nests with filler parts – and track the quantities used and needed – to prevent excess inventory.

In Conclusion….

The lesson for most of us is that manufacturing is a fluid, dynamic process, which juggles many priorities and often warrants a nesting software  solution with similar fluidity and adaptability. For a perfect solution, which is in tune with the needs of the plant, the nesting solution needs to be calibrated to the environment it which it serves.  It needs to honor material efficiency, programming time, and the flexibility to change.

How about you?

Does this story ring true?  Have you or someone you know been in a similar situation?  Let us know and share your story.

If we can be of assistance in improving the fluidity or efficiency of your nesting process, let us know.

 

Notice: This work is licensed under a BY-NC-SA. Permalink: An Easier Way to Get 95% Nesting Material Efficiency

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