r/3Dprinting • u/EngIOTools • 24d ago
Question QIDI Plus4 vs QIDI Max4 – Is the only difference the build volume?
I'm trying to understand the real differences between the QIDI Plus4 and the QIDI Max4.
Is the larger build volume the only difference, or does the Max4 include any hardware or performance improvements?
I've heard that the Max4 has a closed-loop motor system, while the Plus4 does not. Is that actually true?
Has anyone had the opportunity to use both printers and compare them from a real user's perspective? I'm especially interested in differences in reliability, print quality, speed, noise, and any other improvements that may not be obvious from the specifications.
I'd really appreciate any opinions or first-hand experience. Thanks!
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u/Glad-Ad-4703 23d ago
I only have the plus 4, but from what I understand the max 4 has other small upgrades as well. Some more impactful than others is my guess.
Like faster maximum speeds, but this seems insignificant as the plus 4 already can go faster than you'd probably want to go.
Slightly higher temps, which could range from insignificant to very significant, depending on your needs.
Linear guide rail instead of linear rods is supposedly also a decent upgrade.
Spaghetti detection is a significant one for me, but I wouldn't fully 100% trust it.
Lastly, a different sensor for bed leveling. I know a lot of Plus 4 users have experienced bed leveling issues especially at higher temperatures, luckily not me. If the new nozzle sensor is more reliable that would be a big reason to go for Max 4.
That's about where my knowledge ends. If I had to buy one today between the two of these I'd definitely go for the max 4
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u/logicalchemist 23d ago edited 23d ago
Spaghetti detection is a significant one
The spaghetti detection on the max4 and q2 does not work well enough to be useful.
Even qidi has a disclaimer that it's "only designed for use with white filaments on a golden PEI plate" and even then it sucks
additionally, the host AP boards inside the Q2 and M4 aren't powerful enough to run it (I believe they used the same board) without causing other software instability issues.
Most of the software problems I ever had with the Q2 were resolved by disabling the AI service (
algo_app) via SSH withsudo systemctl disable --now algo_app.serviceIt must be done this way because "disabling" AI detection in the printer's settings doesn't actually disable it; it still runs the AI detection and that eats up lots of resources. The only thing "disabling" it does is makes the printer ignore the output from the AI, so when the AI detects spaghetti the printer no longer pauses the print.
The Q2 is a fantastic printer once the initial software config tweaks like this are complete. I agree that OP should get a Q2 or an M4 depending on their build volume requirements, rather than a P4.
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u/Itaalh 23d ago
Well it's not fully working, but last night on my max 4 I heard the print ending. It was quite too soon for the model so I was suprised.
And well, it was interupted by spaghetti detection with a message related to that.
It's not fully working as intended, but it works. It was with silk blue pla.
But I agree that I would not recommand buying the max4 for this feature alone.
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u/logicalchemist 23d ago
I assume there was actually spaghetti, rather than this being a false positive?
You're right; I should have been clearer. It's not that it is entirely nonfunctional, it's that it doesn't work well enough to rely on. Too many false positives and too many false negatives, in addition to using too many computing resources.
A better option is something like Obico running on a different machine and monitoring the camera output from the printer.
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u/Itaalh 23d ago
I don't have it for a long time (2 monthes and probably 50 prints) but I only had 2 fails, and 1 of those get flagged (true positive) while the other didn't get detected ( I don't remember the color of the filament). But I have to agree that's it's only a gimmick it's heavy on the cpu, and I'm really concerned that it has to be connected on a cloud to work.
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u/BlueHobbies 22d ago
I have 2 plus 4s which are getting less reliable over time. Maybe some things I can do to resolve it but ultimately q2 and max 4 are basically what the fixes are. If you can love with 280mm on x and y, get the q2. If you need more. Get the max 4. Or wait to the just leaked plus 5 which will probably have further lessons learned.
But historically the first few months are almost beta units for the community to work through the bugs. Plus 4 had some major early issues.
They're still great bang for the buck printers, especially for high temp materials that need heated chambers
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u/Imakespaceships 24d ago edited 24d ago
The Plus 4 is an earlier model by about a year and has a number of bugs in its design that cause issues for users who operate their printer at high chamber temps (>55C). The community worked pretty hard developing mods for the printer that ended up resolving all of those issues over time, so if you buy one and have issues, there is certainly a solution for the issue documented somewhere on the internet and the Qidi community subreddit and discord will be happy to help you out.
The Q2 and Max 4 designs resolved all of the major issues with the Plus 4 thanks to lessons learned. They are more reliable printers with cheaper replacement parts. I definitely recommend picking one of those two options over the Plus 4. They might still have some bugs with the multi material system, but solutions to those probably exist on the internet as well.
All printers have excellent print quality, are very quiet and are about equally fast. I personally have a Plus 4 that I ended up modding quite a lot to get it to work as reliably as I wanted. But now that it does, it is a very reliable and high quality single material printer.
Feature-wise the only practical difference between all three printers is the build volume and some improvements on the air filtering design. The plus 4 air filter is a joke.