Bean Cutters, Part Deux

So, let’s look at the numbers for bean cutters in a potato strip application (see last week’s entry), and draw some conclusions, OK?

My model is admittedly simplified. For example, it assumes that all strips that contain peeled surfaces substantially on their ends are 75mm long. And strips that contain peel surfaces substantially on their sides are 60mm long. Yes, I will make a more detailed model later, but for now this will do.

The results? When running through a sort-then-bean-cut-then-sort line, defect removal is 65.8% maximum, roughly the same as a sort-then ADR cut line (64%). Compare that with an ADR-only line (80%) and ADR-First (93%). If your need is product quality, and/or your incoming quality exceeds 20%, ADR-first or ADR-only is clearly what you need. The bean cutter? Only if your incoming defect is under 20% (everyone busts that barrier sometimes, these days) or your product quality requirements are not as high as your competitors, does bean cutting make any sense from a removal perspective.

Now let’s look at yield. The total cubes coming out of the bean cutter (including cubes put into the blancher) is over 62% white, less than 38% defect. Now, if you have a bean cutter system you might measure your white cube rate at “only” 50-55%. But you are not seeing the rest of your losses. Take a peek at what is going into your blancher, what you see may surprise you.

Now, the typical modern ADR outputs a cube stream of about 80% defect, 20% white cuts. Many folks achieve better, but let’s go with those numbers. And let’s focus on comparing a sort-then ADR cut vs. sort-then-bean-cut-then sort line; as we mentioned above, if your need is high defect removal, you have already made your decision.

The total flow rate of cubes out of the sort-then-ADR system is about 1/5th of the defect flow in. For example, if you are running a 15 metric ton per hour (finished) line, and the defect level averages 15%, your incoming flow of defect into the sorters is 4.5 tons per hour. And your cube stream is 900 kg per hour.

Now, the total cube generation of the sort-then-bean-cut-then sort line is 2.1 times that of the sort-then ADR system. So, for that same 15 ton/hour line at 15% defect, the cubes total 1890 kg per hour. The difference is 990 kg/hour.

Now you have enough to do the rest of the math. What is the value difference to you between cubes and strips? What is your flow rate? What is the nominal defect level you wish to target? My bet is that the installed cost of an ADR looks to have a handsome payback for you, even if the bean cutters would be free.

Let’s just use some rough numbers. Assume 8 months of storage crop, running at capacity 23 hours per day, running 13 of every 14 days. Total bean cutting operational hours are then 5126. Assume you don’t need defect control on fresh crop. If you run a 15 ton/hour line, your loss due to the difference between a bean cutter and an ADR is 5075 metric tons per year. Now, if the difference in value between cubes (going to formed or flake) and strips is "only" €0,10 per kg, the value loss due bean cutters is €507.500 per year. At 10% MARR simple annual compounding, the present value of that cost over 7 years (minimum life of equipment) is about €2.500.000!

That is enough to buy the ADR AND the yacht!

And this doesn’t yet address the other costs: you need more sorting capacity with a bean cutter line, due to the need to re-sort the cut strips, then resort again and again. And the other matter: With the bean cutter, your average strip length drops like a rock. You have many more short pieces in the line. You would probably struggle to make length grade for many products. You can do the math on that issue, as well.

That cheap bean cutter doesn’t look so cheap now, does it? Like I said in my last post, you can pay now or you can pay later.

So, we’re back to somber, serious, hard numbers after a blog entry that was perhaps a bit of fun last week. Which style do you prefer?

Tim

Stumble It!

Bookmark on del.icio.us