Constant print failures!

So my printer is about 6 weeks old and has so far been a fairly irritable piece of kit and not exactly the experience I was hoping for.

I have been trying to print a range of parts in various setups and orientations with the following issues:

  • Complete print failures
  • Parts not sticking to the bed (although have sorted this mostly with Z-axis adjustment and increasing base thickness to 3mm)
  • Rashing and ragging on prints
  • Bits missing from print
  • Layers of jelly like substance on printed parts
  • Really poor surface finishes
  • Cured resin left floating in the tank or attached to the bottom of the tnak

I am using the latest PreForm, a clean mirror, pretty much new tanks and new build platforms.

Anybody got any suggestions of what is wrong? Just tonight I have chucked away the old resin and replaced it with new… but no improvement. Thoroughly infuriating piece of kit so far.

I have opened a support ticket with FormLabs but after going back and forth a few times very little success or improvement.

It’s dirty mirrors or dodgy laser. Did you clean your galvos mirrors as well? Are the mirrors completely streak and dust free? Have you run the laser diagnostic? If so are you getting a nice dot or something that flares all over the place?

Open a ticket. If the mirrors are reasonably clean, the resin is not old, and you’re sure the tank’s PDMS is not cloudy at all, your printer is horked.

I have cleaned the main mirror, where is the second one?
I will run a laser test tomorrow.
I have had some OK prints out of it previously but it has definitely gone downhill recently.

The galvos are at the back of the machine, it’s two galvos mirrors and 1 fixed mirror. You need to take the back of the machine of to get to them.

You should also filter your resin. If you’re having failures, the resin will be accumulating muck and half-cured sludge. Definitely clean the galvo mirrors, but also filter the resin with a funnel & paint strainer.


I have drained the resin and filtered it using a gauze… no improvement.

Taking the machine apart to clean mirrors is not really where I was expecting to be with the cost of the machine, but I will look in to doing it tonight.

I can’t say I disagree with you on your last point, but it is an issue due to the open optical system, something that had been drastically improved (I hope) in the form2. It’s actualy pretty straightforward to clean the mirrors, shouldn’t take you more than 45 minutes or so.

I (and a lot of other folks) use these filters, rather than gauze. I think gauze might be too coarse/open.

There seems to be an issue of crud on the galvos appearing somewhere between final inspection and use. Or QC isn’t catching dirt inside. Regardless…

I had similar issues on a new machine until I cleaned the galvos.

You need to get the information on how to do this from the Form folks in order to preserve your warrantee. It’s not hard, but takes a while.

I’ve found almost all my problems track back to dust on the mirrors, and it takes about an hour to clean all four. Not my favorite exercise, but reliability went way up after I made it SOP to inspect and blow off dust every week or two. And every few weeks, I go inside and clean the galvos.

And for a print that takes up most of the build volume, I’ll clean no matter how recently I’ve done it.

If you have a form1 make sure your temps are high enough, low resin temperatures can cause similar failures.

Sorry to hear about the trouble with the new machine, @Elliot_Tanner. Your conversation with Support will definitely be useful to keep the print issue moving forward. There are quite a few helpful pointers above regarding optical clarity; it’s pretty clear that something is obstructing or obfuscating the laser. I’d also ask what steps and materials you’re using to clean the mirror(s). The first surface mirrors are more delicate than standard mirrors, which is one reason Formlabs recommends only PEC*PADs and alcohol to contact the mirrors. The reflective surface is also tricky in that oils or dirt smudges may be invisible until inspected with a flashlight illuminating the mirror from a low angle. See step 2 of “Checking the Mirror” for an example.

Sounds like you have a bad batch of resin. your photos look exactly like what I was getting. I sent a support ticket, they sent me a fresh bottle and BAM!!! all fixed.

I am having a similar problem. If resin spills inside the machine during a refill of the tank while a large print is ongoing, could that cause this problem? Is there a way to clean it up? A little bit of resin spilled over the side of the tank during a refill once before this started happening. Not sure if it is a coincidence, or not…

Yes any resin spills inside the machine are absolutely critical.

Formlabs does have instructions for cleaning spills but in my experience, if resin spills on the main mirror, cleaning it is impossible and the mirror should be replaced. I’ve tried cleaning such spills and have only managed to damage the mirror further in the process.

At this point, I keep at least 2 spare main mirrors on hand (contact Formlabs support. If you are under warranty, they just send one out no charge). I will say that Mirror replacement is very easy and only takes about 20-30 min. I would, however, make a small alteration to their instructions. They say to remove the protective film only after installing the mirror and then clean it as needed. This is not ideal as the mirror is difficult to inspect and clean once in place. What I do is first remove the old mirror. Then, remove the film from the new mirror, handling with gloves and Pec pads. I and handle the mirror only by the edges with PEC pads. Inspect and very gently wipe the mirror with a fresh, dry PEC pad. I never use isopropyl as it only seems to leave streaks. Once I feel the new mirror is perfect, I install the new mirror and close up the unit. To keep things clean from there, I always keep the lid closed and a UNUSED , spare resin tank in place. This leaves very little chance for even dust getting into the compartment.

I do have a few suggestions regarding Filling. While Formlabs says it is safe to refill your tank mid build with the tank in place, I never do this. Unless it is unavoidable, I always remove the tank for filling.

First, I do whatever I can to keep my models UNDER 90ml (you can check in Preform) including supports. If the build is larger, I take it into Maya or ZBrush and split it up and add keys for assembly. This is not an easy solution and does require a fair amount of modeling experience. But it is the best way to avoid mid build filling.

Sometimes, you just cant prevent needing a mid build refill. This is what I do. I pause (quickly press the main button) the build which should raise the platform to the top of the unit. I open the lid and hold a sheet of 1mm styrene plastic (the sheet should be large enough to completely cover the compartment opening. You should be able to find it at any hobby shop, even Michael’s in the architectural aisle ) with one hand to prevent the build from dripping. With the other hand, I place the cover over the resin tank (it may be low or empty, but no reason to take the risk) and then slide it out of the dock. Once the tank is clear, I can rest the styrene sheet over the compartment opening, completely covering it. If the build drips, it ends up in the sheet of plastic and not in the compartment. I then fill the tank OUTSIDE of the unit as normal. I replace the lid on the tank (so it can’t spill during insertion), raise the sheet plastic and insert the tank. Once the tank is docked, I remove the tank lid, remove the sheet plastic, close the unit lid and DONE :slight_smile:

If, for some reason, I am not able to remove the tank, I pour some resin into a disposable plastic cup and use a 10ml nylon medical syringe (without a needle of course. Got some at walmart) with a PEC ready to cover the tip. It takes longer but there is little to no chance for spillage.

Once it is habit, there is no reason the ever have a spill inside your printer. For that matter, you shouldn’t have to do anything other than occasionally use a Giottos rocket air blaster to clear out what little dust makes it in.

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