Form3 - Use RFID for Cartridge and Tank Identification on the Next Generation

The physical connectors for the current tank and cartridge sensing are prone to intermittent connection failures. Switch to using a non-contact method of tank and cartridge sensing so there are no physical connectors to get fouled, lose spring tension necessary for making good contact, etc.


That seems an excellent idea. Over the three years or so using the Formlabs 1 and now the 2+, I’ve encountered this very problem.

Yes please, this seems to be the “Achilles heel” of the system, it would save so many failed print attempts where there is a perfectly good cartridge, often a freshly opened one, that the system refuses to recognise.
Shimming the cartridge to try to push the contacts to make a decent connection is a sort of half baked fix that works half the time, but given the cost of the resin, and time spent messing about trying to get our 3 Form2s to actually see the cartridges, it would be a “no brainer”.
Does anyone know if the newly announced printers will use the same unreliable detection system?

The form 3 and form 3L uses the same cartridge as it is cross-compatible with the Form 2.

I’d argue that “hassle-free” attribute isn’t as reliable as they would lead you to believe, especially when it comes to cartridges not being recognized or losing connection while printing. The two pin connector that is used and the way it is supported don’t lead to the most robust system. A simple RFID could have been added to new cartridges without removing the chip for very, very little additional manufacturing cost and this problem would have been completely eliminated.

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even cheaper- just use an optical sensor and a printed serialized marker on the consumables.
no radio transponder, no complex gizmo inserted into each cartridge.

or- make it reverse compatible by printing a pattern on one corner of the tray that the Resin Sensor can read when the carriage is all the way to one side.

Or, why not use spring loaded push pins from the base up. The weight of the tank will assure connection.
The vertical connection is 90% if not 100% of the fault in the design.

Whatever part of the system is on the tray has to be writable as well as readable.

I don’t see why that would be true. The Form 2 has to be able to communicate with Preform to set materials and identify the resin and the tray.

All you need is a unique serial number for each cartridge and tray… and the material can be assigned to that serial number in a look up table stored either in Preform- or memory on the Form 2 - or even online in your dashboard…
Just as heat maps for trays and how much resin you have left is stored online.

All you need is a means of serializing the cartridges and trays in a way that the User can not discern the serial number- to prevent users from spoofing the system.

Sliding contacts are the correct way to do a reliable connector. 95+% of commercial connectors work this way. The problem with push pins is that if they get corroded or dirty, they have to be cleaned manually. The sliding action of most connectors works to clean them every time they inserted and removed.

The problems with the Form 2 are in the details of the implementation, as there are similar connectors with 10,000+ mate cycle ratings.

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I disagree.

My cordless phone uses push-pin contacts. As does my electric tea kettle in the base. My Motorola walkies use them in the base as well. BUT even using your statement, place them on the horizontal and allow the weight of the tank to keep the connection.

As luck would have it, I just had a tank of flex resin do this exact same thing. Took me way too many times of removing and reinserting the tank for it to register. It ended up losing mid print but by then it didn’t matter.

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Sliding contacts are fine if implemented properly and used in a clean environment, no argument. Unfortunately they’re not ideal for a machine that produces thigs dripping with insulating resin. A little residue ( and I do mean just a little residue, not even a drop) on your gloves is all it takes to foul those contacts and what makes it worse is that the matching fingers in the machine are in a location that makes them exceptionally difficult to clean.

Its all a moot point now though… Maybe its not enough of a problem that Formlabs thinks it needs to be addressed.

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The headaches associated with the poor reliability of the tank and cartridge sensors is my main reason to not buy Form3.

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They seem to have changed this design aspect in that it now has guides that cover the pins, ostensibly to prevent anything from contaminating them although this can still occur if the carrier is the cartridge itself. The housing is also thicker and more rugged, at least in appearance. How it plays out in terms of positive functionality, is anyone’s guess right now.

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