Shaken.. not stirred!

I noticed my print quality was degrading a little. Details were getting lost. This was partially due to a slight misty spot in the middle of my tank. Though I also noticed my grey prints were starting to look a little on the light side in comparison with the prints I did a month or so ago. I stir the resin regularly in the tank to ensure the pigment is mixed in, though doesn’t have much of an effect.

So I filtered the resin into a black chemical screw-top container flask and gave it a really good shake and poured back in the tank. The print quality after, was much better and the details that failed to print with the lighter prints showed up. The print was noticeably darker. Just wondered if anyone else does this and how often do you find it necessary? I’m thinking I will need to do this shaking in the bottle every week to to get the best out of my prints, even though I find the task of pouring the resin out of the tank a daunting one as it can be a bit messy.

Could you ask this to Formlabs Support?

Normally it’s the job of the mixer to…er… mix the resin in the tank before printing and it’s the user’s job to mix the resin in the cartridge. I don’t use standard resins. Maybe the shake routing in the firmware needs update?

I don’t ever shake or stir the tank (nor the cartridges!) (maybe a couple of times tumbling the cartridge before inserting it).
I am not seeing problems with any of my prints (T2000/T1500/Elastic/F80A/Durable…)
I do store the cartridges 90º rotated related to the upright position on the printer

But the issue of ensuring the resins are homogeneously dispersed is obviously important for print quality.
The thing is, the components of each resin types have probably different settling times.

I have read people making machines for tumbling the cartridges or shaking cartridges (“vigorously”) for more than 10 minutes before using it. It seems a pity to waste time if not necessary…

I’d hope there was official recommendation for this, per resin type…

Shaking the resin absolutely helps. I used to do it by hand and recommend at least 10 straight minutes. I’m one of those folks who hacked together a mixing appliance, and now use it for cartridges that have been sitting a while (letting them rotisserie for 30 minutes to a few hours depending on my rush). My usage pattern often entails long periods of time between prints (weeks / months / even excess of a year).

What you did accomplished two things:

  • filtered out any bits of cured resin or other contaminants
  • mixed the components of the resin

The pigments settle over time. Some resins even stratify into layers if left standing long enough (e.g. months), forming a gooey consistency on the bottom or top (I’ve found Black v4 is notorious for this).

I’m sure if you stir long enough and very thoroughly it will accomplish the same thing. I don’t bother to drain the tanks myself unless I think they need filtering, but I do stir until I see all the resin is completely consistent, then double that amount of time to be sure. Sometimes I do this if it’s been more than a week since my last print, and certainly if there’s any obvious inconsistency looking at the contents of the tank. The wiper or mixer alone doesn’t seem to achieve the same level of homogeneity. (It also doesn’t take care of the thin, sticky layer I’ve found forms over time and needs to be gently scraped from the bottom of a tank containing Rigid 4000). I’ve suggested Formlabs give us a “mix” procedure we can perform under the Maintenance menu that heats the resin a little and just moves the arm back and forth for like 30 minutes.

I don’t have a regular “agitation schedule” for cartridges in storage. Once and a while I might cycle them all through my rotisserie (couple times a year?) but primarily I just do it before I use them. Before the contraption, I used to go and flip my stored cartridges upside down now and then for what it was worth (very slow mix).

One thing to watch out for is an excess of air bubbles that have formed right after you shake (especially if you were vigorous, then remove the cap and pour the resin out into the tank manually). If I shake by hand, I typically let the resin stand for about 10-30 minutes afterward (either in the tank or the cartridge) before starting the print to give the bubbles a chance to dissipate.

All this has helped me get more lifetime out of some of the resins (Black in particular).

If you’re in a rush or lazy you can certainly take a less conservative approach as to duration and frequency.

Interesting as I never noticed my prints looking particularly bad, just lighter colour and decrease in detail visibility (I’m printing human heads, so wrinkles and scars were very faint in places. I did stir the resin, probably not as long as I should, though I’m not keen on this as touching the pdms layer is a little daunting.

I didn’t even need to shake the resin that long, about a minute, and the difference was huge. I think once shaken a good stir is like you guys said enough to mix. Though if left for too long in the tank I think a good shake in a container will really get the pigment mixed in. Probably also good to give the cartridge a shake before every print too.

I would like to know how you guys filter your resin? I use a cleaned out penut butter small bucket and tape the filter to it then pour in. Only tricky bit is scooping the last of the resin out from the bottom. Probably a disposable spoon should do it.

I used to just rest the filter in a red plastic beer cup. Then I built a holder out of a coat hanger. I finally got a laboratory retort stand like this and it makes it easier:

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Hi @FormBeast ,

As others have mentioned, giving the resin a good, long shake before printing is a great way to improve color and detail in a printed part—especially if the resin has been sitting for an extended period of time. However, if this ever does not resolve the issue, be sure to contact our support team. They’ll be able to more accurately diagnose the issue!