A foundry twin is a living model of your process, fed by your own instruments, that keeps the record your best people currently keep in their heads.
The honest version
Strip the marketing away and it is a simple idea. A twin is a model of your plant that stays honest because your own instruments feed it. Every heat becomes a record with the sand test, the chemistry, the pour and the outcome held together, so a rejection can be walked backwards to the stage where something first went out of range.
The knowledge that prevents scrap already exists in your foundry. It sits with the two or three people who have been there longest. When they are not on shift, it is not available, and when they retire it leaves. A twin is how that reasoning gets written down while they are still there to correct it.
Versatile has built foundry sand testing instruments since 1967, and they run in more than 9,000 foundries across 40 countries. The twin was built the way it was because we have spent decades watching what the bench actually measures and what gets lost between the bench and the rejection note.
How it is put together
A twin is only as honest as the readings underneath it. These are the five stages the loop needs, and what covers each one today.
Compactability, green compression strength, permeability, moisture, active clay and grain fineness. Tested at the line by V-CAT, or on the bench by the instruments you already run.
A number is only evidence if the instrument that produced it was in calibration. Every instrument carries a code, and the certificate can be checked by anyone, including your auditor.
Results reach the record without anyone retyping them, with the time they were actually taken. Roughly 193 machines across 82 foundries report this way today.
The fettler photographs the defect and taps what it is. No typing, no email, works without a network, in six Indian languages. Free for every foundry.
With the four above in place, each process parameter can be ranked against each defect on your own heats. Not an opinion in a meeting, an ordered list with the strength of each link.
Most plants are sold stage five first, and it disappoints, because a correlation drawn over readings nobody trusts tells you very little. Stages one to four are the slow part and they are where we can help most. Start there and the fifth stage becomes worth switching on.
Reference library
Free, no sign-up, no gate. Seven cover calibration and what an auditor will ask for. Ten cover the defects themselves, and what the sand was usually doing when they appeared. Three deal with reading a rejection record once you have one.
Before you ask anyone for a quote
These get asked on every call. The answers are here rather than behind a form.
There is no single price, and any supplier who gives you one before seeing your plant is guessing. The cost breaks into three parts, and most foundries already carry the first.
Instruments. If your bench is sound and in calibration, this may be nothing. If the strength machine is thirty years old and reads high, that gets replaced before anything else is worth doing.
Connecting them. Charged per machine, once. This is the part that stops results being retyped.
The platform. Charged by use, monthly, and it can be stopped. Defect logging on CaRe 101 is free for every foundry with no user limit, so a plant can begin recording outcomes today at no cost while it decides about the rest.
Less than most people expect. Nothing is rewired and no controller is reprogrammed. The twin reads a copy of signals your machines already produce, and where a machine produces none, the reading can be typed in or photographed from the log sheet.
What it genuinely needs is three things: instruments in calibration, somebody who records the rejection rather than only sweeping it up, and one person who owns the question. The third is the one plants underestimate.
It will not run your plant. It will not tell you the cause of a defect in week one, because it has not yet seen enough of your heats to have an opinion worth acting on. It will not turn a plant that does not record its rejections into one that can explain them.
And it will not make a badly calibrated instrument produce a good number. That is worth saying plainly, because a twin built over readings you cannot defend produces confident answers that are wrong, which is worse than no answer at all.
From our own instruments
We went back through every reading our connected V-CAT II units produced over the five years to early 2025. Around 5.6 million individual readings across roughly 1.38 million test cycles. Compactability, moisture, green compression strength and permeability were taken on the same sample in the same cycle, so these are honest pairs rather than readings matched up afterwards.
Pooling every plant together, the firmest relationship we can find is green strength against permeability, and it comes out at r = -0.27 on about 136,000 paired tests. Denser, wetter sand passes less air and takes more load, which is what any foundry man would tell you. Every other pooled pair is weaker still.
That result is worth stating plainly, because it is the opposite of what most digital plant software implies. There is no industry constant sitting in this data waiting to be sold to you.
Four units carry enough paired readings to stand on their own, each on its own moulding line. Moisture against compactability, measured by the same instrument model running the same test on the same kind of green sand, gives a different answer on every one of them. On one line it runs the other way entirely.
| Moulding line | Correlation r | Paired tests | Reading |
|---|---|---|---|
| Line A | +0.60 | tens of thousands | Water drives compaction hard |
| Line B | +0.28 | hundreds of thousands | Present but muted |
| Line C | +0.07 | hundreds of thousands | Almost no relationship |
| Line D | -0.42 | tens of thousands | It runs the other way |
On line A, adding water raises compactability sharply, which is what the textbook says should happen. On line C the same change barely moves it. On line D it pushes compactability down.
If your control rule came from a handbook, a seminar or another plant, this table is the reason it may not be working for you. The physics does not change between foundries. The muller, the return loop, the cooler, the ambient conditions and the way water is dosed all do, and on this evidence they change the relationship enough to reverse its direction.
A reversal like line D can also mean an instrument that has drifted rather than a line that behaves differently. We cannot tell which from the readings alone, and we are not going to pretend otherwise.
That is the honest reason calibration sits at stage two rather than as an afterthought. Either your lines genuinely differ, or one of your instruments needs attention. Both are worth knowing, and neither becomes visible until somebody is keeping the record.
None of the above links sand behaviour to a specific casting defect, because the readings and the rejection notes are not yet held in the same place. That is exactly the gap CaRe 101 is meant to close, and it is why defect logging is free. Once a plant records both, the same arithmetic can be run against real rejections instead of against other sand properties.
Where to start
You do not need a platform to begin. Pick the defect that costs you most, check that the instrument which should have caught it is in calibration, and start writing down the rejection. We can help with all three, and the first two are ordinary work we have done for decades.