OEE for Tortilla and Flatbread Lines: Count Pieces, Not Stacks

A tortilla line has no pause button after the press. Once a piece is formed, it is through the oven and onto the cooling conveyor within minutes, whether the bagger is ready or not.

This page covers flour and corn tortillas, wraps, and flatbreads such as naan, pita and chapati made on continuous lines.

We sell Fabrico, so test what we say here like any other vendor's claims.

The line in order, and the two places to count

A flour tortilla line usually runs: mixer, divider and rounder, proofer, hot press, oven, cooling conveyor, counter stacker, bagger, metal detector, case packer.

Corn tortillas and many flatbreads swap the divider and press for a sheeter and a rotary die cutter, and corn masa needs no proofer.

Count 1 is pieces formed, counted after the press.

The press cycle, or the die cutter speed, times the positions across the belt gives the most the line could have made.

Count 2 is good packs after the bagger, taken at the metal detector or checkweigher exit, so rejected packs are already out.

Between the two counts there is no buffer. That is where product gets lost without anyone booking it.

Why a packing stop becomes waste

An oven cannot hold product: stop the belt and what is inside burns. The cooling conveyor keeps delivering too.

So when the bagger jams, pieces keep arriving at the stacker. Operators pull stacks off by hand for a minute or two, then product goes to the waste bin.

A longer stop means cutting the dough feed. But the pieces already in the proofer, oven and cooler still come out, often several minutes of product.

Then the restart costs again. The first pieces through a press and oven that ran empty are often off in size or colour.

Measured only at the bagger, this is a short stop and a small availability loss. The pieces in the bin never show up.

Measured only at the press, the line never stopped at all. With both counts the loss lands where it belongs.

• Bagger or stacker stopped, oven running: book the lost pieces as quality loss, with the reason on the packing machine.
• Press stopped because packing is down: book the time as blocked by packing, not as a press fault.

Where a tortilla line loses time, speed and product

The packing rows show quality first: while the oven runs, a packing stop costs pieces. It costs press time only once the dough feed is cut.

Empty positions are a speed loss. A press that makes 10 pieces a cycle and gets 9 dough balls still cycles on time, with no stop, no alarm and 10% less output.

If count 1 is only press cycles times positions, those missing pieces land in the quality gap by mistake. A count of real pieces after the press, from a sensor per lane or a camera over the belt, puts them in performance.

Stacker and bagger jams are short, cleared in seconds and never written down. They are classic micro-stops, and on this line they also send pieces to the bin.

Stack count errors: count pieces, not stacks

The counter stacker turns a stream of pieces into stacks of 8, 10 or 20. When it miscounts, two different things happen.

• One piece too many: the pack is sellable. That is giveaway, a cost to track next to OEE and not inside quality. Our page on giveaway and overfill covers the method.
• One piece too few: the pack is short. When the checkweigher rejects it, it is a quality loss. A pack topped up by hand later is rework, not a pack that was good the first time.

This is why "packs made" is a weak output number on its own. Packs times the count on the label assumes the stacker was right.

The press makes the same pieces a minute whether they leave in 8 packs or 20 packs.

So set the ideal rate in pieces, and turn good packs back into pieces. If the rejects you counted do not explain the gap between count 1 and count 2, the rest is miscounts or dumping that nobody booked.

Setting the ideal rate and the planned time

Ideal rate

Set it per product, by diameter and recipe. A 30 cm wrap fills fewer positions across the press than a 15 cm tortilla, and may need a longer bake.

Use the best rate the line has held on that product with good quality and full positions.

Planned time

Planned time is the time you meant to run. Oven and press heat-up scheduled before the shift stays out, and any overrun into the shift is a loss.

Size and recipe changeovers go one of two ways. Keep the whole changeover inside planned time as an availability loss, or take out a standard allowance and count only the overrun.

Either works, as long as you pick one and keep it. The example below uses the first.

Worked example: one shift, two counts

These are example numbers, round on purpose, from no real plant. The product is a 25 cm flour tortilla in a 10 pack.

Planned time is 480 minutes. The press stood for 60 minutes, 35 for one size changeover and 25 for other stops, so run time is 420 minutes.

The ideal rate is 600 pieces a minute, so 420 minutes could give 252,000 pieces. Count 1 saw 226,800 pieces formed.

Count 2 saw 21,546 good packs. At 10 a pack that is 215,460 good pieces.

• Availability: 420 of 480 minutes = 87.5%
• Performance: 226,800 of 252,000 pieces = 90%
• Quality: 215,460 of 226,800 pieces = 95%
• OEE: 87.5% x 90% x 95% = 74.8%

Check it the short way: 215,460 good pieces at 600 a minute is 359.1 minutes of perfect running. That is 74.8% of 480 minutes, so the two agree.

Now the 11,340 lost pieces. Bagger and stacker jams added up to about 9 minutes with the oven still running, and that sent 4,800 pieces to the bin.

That is more than all the shape and bake rejects together. A pack count alone would have shown those jams as 9 minutes of stops, and the waste as nothing.

Giveaway is not in these figures: packs with an extra piece count as good here. For the method behind the three factors, see OEE calculation.

Size and recipe changeovers

A size change touches almost the whole line: dough ball weight at the divider, press settings or the die roll, oven time, stacker guides and count, and the bag.

A recipe change adds a dough clean-out. Where it crosses an allergen boundary, your plant's own cleaning rules set the length.

• Time it from the last good pack to the first good pack. Book the slow running after that as speed loss, with the changeover as its reason.
• Split the reason by type: pack count only, size change, recipe change.
• Give start-up pieces their own reject reason. Then the cost of a changeover is the stop plus the pieces, as in the example.

What to check in OEE software for a tortilla line

Run these checks in a demo with every vendor, including us. Bring one real shift with a bagger stop in it.

1. Two counts on one line. Can pieces formed and good packs both feed one OEE, with the gap shown as quality loss?
2. Pieces per pack on the product. When the format changes from 10 to 20, do good packs still convert to pieces without anyone editing a formula?
3. Ideal rate per product. Can each diameter and recipe have its own rate, and does it switch when the product does?
4. Waste with a reason. Can lost pieces be booked as packing stop, start-up, shape or bake, by signal or by entry in pieces or kg?
5. Blocked and starved. Is a press waiting for dough, or held by packing, kept apart from its own faults?
6. Short stops. Where does a 15 second stacker jam go, and who sets the threshold?
7. Counting flat pieces in lanes. Where the press gives only a cycle signal, what are the options: a sensor per lane, a camera, a manual entry?

For a wider list of products to run these checks on, see our review of OEE software.

Where Fabrico fits

Fabrico is a cloud-based OEE and light MES platform.

• Stops: they come from the machine signal, through the PLC or a Fabrico IoT device. The operator adds the stop reason on a tablet or phone.
• OEE and downtime: availability, performance and quality by line and by shift, on the web, iOS and Android.
• Micro-stops: detected from the machine signal, so short stacker and bagger jams are not left to memory.
• Losses in money: losses can be shown in money, not only in minutes.
• Your data: REST API and webhooks, and any list exports to Excel or CSV.
• Camera: the AI camera is an add-on that counts parts. Ask us if it fits your belt where there is no usable count signal. You can open the video of a stop. In the standard setup video is streamed, not stored.
• Not in Fabrico today: production planning and scheduling. The order of sizes and recipes for the week stays with your planning tool.

A stop reason can also be set up to open a maintenance task, for example on a repeat stacker jam.

The seven checks above apply to us too, so ask us to show two counts on one line with your own pack formats.

Book a demo or Contact us.

What people ask next

Should we count tortillas, stacks or packs?

Count pieces: pieces formed after the press, and good packs after the bagger times the count per pack. Pieces stay comparable when the pack format changes.

Is product dumped during a bagger stop an availability loss or a quality loss?

Quality, if the press and oven kept running: the line made the pieces and could not sell them. Give them the reason "packing stop" so the fix goes to the bagger.

Is a pack with one tortilla too many a quality loss?

No, it is a sellable pack, so OEE counts it as good. Track the extra pieces as giveaway next to OEE.

Where should the ideal rate be set on a tortilla line?

At the press or die cutter, in pieces per minute, per diameter and recipe. Use the best rate held with good quality and all positions full.

Does a size changeover count against OEE?

It depends on the rule you pick: count the whole changeover as an availability loss, as the example here does, or take out a standard allowance and count only the overrun. Keep to one rule so shifts compare.

Is this the same as OEE on a bread or bun line?

The dough side is close, but the product is flat and fast with no buffer before a counter stacker. For bread, buns and cakes, see our guide to OEE software for industrial bakeries.