Introduction
When you’re comparing two packaging equipment bids, a lower Factory Acceptance Test line item can look like an easy win.
The machine specs seem similar, the vendors both look capable, and output promises are close. Then one quote shows a much lower cost for Factory Acceptance Testing and fewer factory-tested sizes. On paper, it feels like savings. In practice, it often is not.
If you’ve been through a packaging equipment startup before, you know what happens when testing is too light: Startup drags on, operators struggle with changeovers, maintenance chases recurring issues, and line performance misses expectations for months. What looked cheaper during procurement ends up costing more in downtime, rework, lost throughput, and frustration.
At Douglas, we’ve seen how often buyers underestimate the value of a thorough FAT. The reality is simple: The FAT is the last point in the project where the OEM still owns most of the debugging cost. Once the machine ships, that burden starts transferring to you.
What a Factory-Tested Size Actually Means
A factory-tested size is a specific product or package format that has been fully validated on the machine before shipment.
That should mean more than “the machine ran it once.”
It should mean that a true factory-tested size has been…
-
Run long enough to produce useful performance data
-
Measured against clear acceptance criteria
-
Documented in detail
-
Signed off as meeting expectations
It should also mean any meaningful issues were resolved before the machine leaves the OEM’s facility. That is very different from a quick demonstration.
Some low-cost FAT scopes include brief setup checks that prove the machine can run a size for a few minutes without immediately faulting. That may confirm basic functionality, but it does not prove the size is production-ready. And it certainly does not eliminate startup risk.
Why Cheaper FAT Scope Is So Risky
When a machine is not thoroughly tested at the factory, the work does not disappear. It simply moves to your site. And that shift is expensive.
Instead of uncovering problems where engineers, parts, and technical resources are close at hand, you discover them during installation or startup. Now the machine is on your floor, your team is involved, your production timeline is affected, and every delay has a cost attached to it.
A reduced FAT scope often saves money in the quote and adds cost everywhere else. Those costs usually show up in a few predictable places…
A well-executed Site Acceptance Test should confirm that the machine performs at your facility the way it performed at the OEM’s plant.
However, if factory-tested sizes were only lightly validated, SAT turns into a troubleshooting event. Your team ends up resolving format-specific issues that should have been found and fixed earlier.
That kind of situation can add days or even weeks to startup.
Under-tested sizes often lead to repeat (and more painful) service visits after startup. The machine runs one size fine, then struggles on another. A changeover takes too long, rejects climb, and faults show up inconsistently.
Every visit costs money. Even worse, the original cause gets harder to trace, and what began as a weak FAT scope starts looking like an operations or maintenance problem.
“I see this all the time. When a customer wants to run a size we never factory tested, the pain is real and I feel for them because they have a new machine and high expectations. But that frustration is actually proof of why factory testing matters so much. Everything they’re struggling through on their floor is work that should have been done on ours.”
– Travis K, Field Service Manager
When operators do not trust a machine, performance suffers. They run it slower, they want to avoid difficult sizes, and they allow extra time for changeovers. Maintenance teams overcompensate, and schedulers work around the line instead of relying on it.
Those decisions are understandable, but they reduce OEE and limit output long after startup is over.
What a Thorough FAT Looks Like
If you want to know whether you are paying for real risk reduction, look at the details of the FAT process.
A strong FAT typically includes several things…
A meaningful factory-tested size should be run at or near rated speed for long enough to surface real-world issues. In an ideal world, that means hours of run time, not minutes. In practice, most CPG producers can only provide a limited quantity of product and packaging materials for factory testing, which means even 10 to 15 minutes of cumulative run time can be difficult to achieve.
Given those constraints, the more important question becomes: Does the OEM have a rigorous testing process, and do they actually follow it? The quantity of run time matters, but so does what the OEM does with it. A disciplined process — one that is documented, consistently applied, and honestly evaluated — will produce far better results than a longer but loosely managed run.
The difference between a serious OEM and a careless one usually becomes obvious quickly. One treats factory testing as a controlled validation. The other treats it as a formality.
A proper FAT does not just prove the machine can run different sizes. It proves your team can move between them in a repeatable way.
That means timing changeovers, documenting the steps, and validating the procedure against the promised target.
If only the OEM technician can do the changeover quickly, that is not a proven process. That is a demonstration.
Each tested size should have its parameters captured and saved as a usable recipe. That includes timing, servo settings, pressure settings, HMI values, and other format-specific adjustments.
Without that documentation, your site team is forced to rediscover settings that should already have been locked in.
A serious FAT tracks alarms, stoppages, and faults by size. Problems are root-caused, corrected, and closed out before shipment whenever possible.
If issues are casually deferred to commissioning, the FAT is not doing its job.
When an OEM charges more for FAT scope, that does not automatically mean the price is inflated.
Often, it means the scope is real.
A thorough FAT takes more machine time, more technician hours, more controls support, more documentation effort, and more coordination with customer witnesses. It may also require more product, more changepart handling, and more retesting before release.
That work costs money, and it should. Higher FAT pricing is often a sign that the OEM is doing the testing you actually need, not just the testing that looks acceptable in a proposal. In many cases, the cheaper alternative is cheaper because the scope is abbreviated.
“Customers who’ve been through FATs with other machine builders have told me that sometimes it feels like the first time the cases were being run, and that the OEM was discovering issues and making adjustments on the fly. I understand how that happens. Real testing takes time and material. That’s why our sample requests sometimes catch new customers off guard. We ask for as much as we can get, because that’s what it takes to do this right.”
– Scott T, Project Management Manager
The Real Comparison Is Not Quote Price, but Realized Cost
The key mistake buyers make is comparing FAT line items instead of comparing total downstream cost.
A vendor may be $10,000 to $20,000 cheaper on FAT scope, but if weak testing adds startup delays, field service visits, engineering hours, and scrap, that savings disappears quickly.
In many cases, it does more than disappear. It reverses.
The “more expensive” FAT often becomes the lower-cost choice once the machine is installed and running. That is especially true when you have multiple SKUs, difficult changeovers, demanding production rates, or limited tolerance for startup disruption.
What to Ask Before You Sign the PO
If you are comparing vendors, do not stop at the FAT price. Ask what is actually included.
You should know:
-
Which sizes will be fully factory-tested
-
How long each size will run
-
Whether runs happen at rated speed
-
Whether changeovers will be timed and documented
-
What acceptance criteria will be used
-
What recipes and settings will be saved
-
What documentation you will receive
-
How punch list items are tracked and resolved
-
Whether customer sign-off is required for tested sizes
-
What happens if a size fails during FAT
These answers should be documented before award, not negotiated later.
If a vendor is vague here, that is useful information. It tells you something about how they approach accountability after shipment too.
How to Evaluate the Right FAT Scope
Not every size has to be tested with the same level of rigor, but the sizes that matter most should be obvious.
Focus on the formats that are highest volume, hardest to run, most mechanically demanding, or most important to production success. Those are the sizes most worth fully validating before the machine leaves the factory.
It also helps to look beyond the total FAT price and ask a better question: How much are you paying per meaningful factory-tested size, and how much startup risk does that remove?
That framing gives you a much more honest comparison.
The Bottom Line
Factory-tested sizes are easy to undervalue because they appear on a quote as a service cost. But they are not just a service cost. They are a risk-reduction investment.
The machine may still ship on time, but the unresolved problems ship with it.
When FAT scope is too light, the machine may still ship on time, but the unresolved problems ship with it. Then your site pays the price through delays, troubleshooting, lower performance, and long-term frustration.
A thorough FAT costs more because it requires more effort, more discipline, and more accountability. That is exactly why it is often worth it.
If you are deciding between a cheaper FAT scope and a more thorough one, the best question is not, “Why does this vendor charge more?” The best question is, “What will it cost us later if this testing is not done now?”
In most packaging projects, that answer makes the smarter investment clear.
Set Up Your FATs for Long-Term Payoffs
Need to discuss FAT expectations? Douglas consultants can help you get on track so that testing sizes today ensures successful packaging in the future.
