Mushroom like printing failure


I got three consecutive mushroom like part failure.  Does anyone here experienced the same?

My printer is a replaced printer. The previous one had the famous adherence problem, e.g. the printing part was not sticking to the build platform. But now, it seems over sticking. I got the replacement printer after a lengthy trouble shooting and  waiting for the replacement. With the replaced printer, I have gotten almost 90% successful rate on 6-7 batch of initial printing, but yesterday got failure like mushroom shown in the attached photos.

Before each printing, I used a paint strainer to filter the debris.  After the second failure, I changed the resin tank to a brand new one, then I got the third exact same failure. In each failed printing, there are a large area of debris sticked on bottom of resin tank. All of these three printing are the same model with PreForm generated orientation. Now I am trying to print it with clear resin to see if the problem is about that grey resin only.  But I already see the mushroom like support stick out of the main body. Clearly, resin and resin tank is not the cause.

Did anyone else experience the same situation before? Optical problem?  Thanks a lot!

Wish not suffering another two months replacement process … Hope it be a little bit reliable…

PS, a ticket has been submitted (37832).

Retro Form 1+ Guide

I should have used a smaller part to test the print.


14 hour 30 min has past since my initial inquire about this problem with FormLabs. No response at all so far.

After identified the problem is not about resin with the previous clear resin printing (last post, the clear round object), then I used a new resin tank with the same grey resin printed two small object (test #5 & #6 in attached photos).

  1. Before each test, I have thoroughly cleaned the large mirror with professional optical wet cleaning wipe (Flents Wipe’n Clear), not a single dust left on the large mirror.
  2. Before each test, all resin has been filtered with paint strainer (medium mash).
  3. This failure suddenly appeared. Before the failure, I have successfully printed 6-7 batch of objects with the replacement printer, except two consecutive occurrence of parts falling from the building platform, which is tolerable, compared with my previous defected printer. All other conditions are exactly the same, not even moved the printer to another table.
  4. The environmental air quality is good to moderate. Air Quality Index (AQI) 23 to 54, according to  in the San Francisco Bay area.
  5. After each mushroom like failure, there was same shape of derbies left on the bottom of the resin tank.
  6. Apparently, the extra mushroom like extrude has severely reduced the quality of the printing. Please see the comparison with previous successful print-out.
  7. All the six test was arranged on not single area of the build platform. Also the previous clear test has covered a large area. So we can conclude that the problem is not location sensitive.
  8. To my understanding, as a physicist, the extra mushroom like extrude is probably caused by scattering of the leaser beam. But where the scattering come from (probably not from the major mirror, since it has been cleaned twice)? How can I clean other optical devices?

None technical comments:

  1. I bought this printer in the beginning of this year. But so far, we only used it printed out three small successful design. With the endless trouble shooting, it’s too frustrated. Actually, one of my partner just quitted from our project partially due to this issue : )
  2. We bought your printer (also combined with another low resolution FDM 3D printer) is for rapid prototyping. But it turns out much slower than outsourcing to professional service.
  3. I am running a startup as well, and know the difficulties and challenges. Your initial success has been supported by almost $3M from thousands of backers. Please do not disappointing your customers.
  4. I have experienced and experiencing the speed of your response. But our project is due now. I will broadcast the trouble shooting process lively on your forum and my social media. It’s a technical problem, but also a PR opportunity. I definitely will share the story in my circle.
  5. And always, thank you!


22 hour has past since my initial inquire about this problem with FormLabs. **No response at all so far.  **

To justify my suspect about the optical system, following some post on this forum, I made a simple paper screen to replace the resin tank and triggered the magnetic cover sensor with a iPad cover magnet.  I have combined several video shot and made a short movie. The movie can be found from the following link:

Is the laser beam spot looks normal? Is the halo too heavy?


By the way, I used the following Form file to run the test.



Zheng, thank you for the comprehensive troubleshooting outlined here…it will definitely be helpful for us to diagnose. Please note that your ticket was submitted on a Friday and so we have no yet gotten to it yet. We will be sure to jump on this first thing on Monday.

Your patience is appreciated and we’ll make sure you get sorted out!


I fully understand that and really APPRECIATE your help!


Update: on Monday evening, 6/9/2014, 41 hours after my initial inquire about this problem with FormLabs.



Thanks so much for contacting us with these issues. I want to first say that I appreciate your patience in awaiting a response. It is our policy to respond as soon as possible; in this case, it has taken some extra hours to evaluate. I also spoke to Meg, and she said to tell you hello.

It seems that you have provided quite a bit of data and information from your own attempts to troubleshoot, which I appreciate. I have taken the time to thoroughly review your images, text, and video. Typically, with these “mushroom like failures” I would like to see the results of a laser test, which it seems you have attempted already. I would prefer to see the laser operate with Formlabs own diagnostic tool. Can you let me know what operating system your computer uses to connect to your Form 1? I’d like to provide relevant instructions for you to run our laser spot test as soon as possible.




My reply:


As one of the early-adopters of your cutting-edge technology, I fully understand the potential risk and am willing to assist you to make it better. But as a customer, who has paid $6000+ for a product, but without the promised function, the frustration is increasing over time. I believe Maxim, Natan, David and your team would also understand that.

If my interpretation is right, you would want me to run PreForm in its diagnostic mode on Windows. I already run the test with the following command:

“C:\Program Files (X86)\Formlabs\PreForm\PreForm.exe” -diagnostic

Please see the results in the attached photos. (I believe from the color/shape of the laser beam, you could see the experimental condition.)"


more photos about the laser beam.


Update: on Tuesday evening, 6/10/2014, 1 hour 25 min after my last reply to their email. I got this:



I can entirely understand your frustration, and that is why I am committed to responding as soon as possible to this conversation. I’m here to support you and your Form 1, and I will do what it takes to resolve this problem. The reason I could not state the diagnostic directly is that it is different for Windows and Mac users.

You have followed the correct instructions, and I’m sharing these laser images with some of my team members. It would be very abnormal and we have never seen this laser fail within 1 month of use. I will be expecting some more information shortly, once our day at headquarters has started, but I didn’t want to delay my reply.

I know that you indicated that you have replaced the resin tank and experienced similar issues, but the resin tank is a critical optical component. If there are any smudges, scratches, fingerprints, or foggy areas, these would all have a significant impact to print quality. I know that you are a very active user of your Form 1, but it is essential that I communicate the importance of a clean resin tank. To be certain that we can eliminate this variable, please follow our instructions for cleaning your resin tanks:





Update: my reply to Stephen on Tuesday 6/10/2014, 4:36pm PST.


Thanks a lot for the prompt reply! And also glad to see the introduction of Form1+, with new optical system. Hope it will be better and more reliable!

Since my previous printer had the adherence problem, so I have been extremely careful about the resin and the resin tank. I did follow the resin tank cleaning instruction to clean the resin tank. In a sum:

  • Before each print, all resin (both previous remaining resin and new resin from the bottle) has been filtered with paint strainer (either 125micro or medium mash, see the attached photos).
  • After each print, the bottom of the resin tank has been gently cleaned with comb, which lift the bottom sticking debris.
  • All these operation was conducted in a pollution controlled environment; with all  window-blinds closed; with nitrile exam gloves on all the time.
  • Before each print, any dust stick bellow the resin tank is cleaned by soft micro fiber or optical air duster (see the attached photos).
  • Six test on three resin tank (#A, #B & #C, see the annotation in the attached photos).  #A & #C was slightly used less than 5 printing; #B was brand new. (Before the failure, we just ordered $1700+ resin and resin tank.)

With the evidence above, I believe you can make a conclusion.

I would appreciate that if you can give me a time-line/schedule, e.g. when will the trouble shooting end? how many iteration? when are you going to send someone to repair it, or replace it? when can I have the problem fully resolved? so we can arrange our project accordingly. Again, we will mutually benefit from it.



Hi Zheng - certainly your issue does not look like a galvo issue, your parts are coming out the same size, and that laser spot does looks very wrong.

However - the laser spot does not look wrong in the typical way when the laser fails, and this is where you need to understand path of the laser beam from the laser through the galvo mirrors, off the large mirror under the resin tank and up. This video from the minute 1:00 mark illustrates it perfectly

Now when a laser fails in the normal way (like mine and several others confirmed on the forums) it loses coherence and starts shining more and more like a torch rather than a tight beam - and when this torch beam passes through the two narrow galvo mirrors it gets trimmed off - one mirror trims the sides and the other mirror trims the top and bottom - so that by the time it reaches the build surface it has a characteristic square shape.

The thing that makes your laser spot look so odd to me is that it seems larger than the square spots that one normally sees off a final stage failed laser - which doesn’t fit with the normal failed laser profile - since it should be squared off by the galvo mirrors.

Did anything about your printer change on or just before the 6th June? eg new build platform? The fact that you can show prints that work previously and are now failing, and the type of the failures makes it looks like a laser issue - but those laser spot photo’s don’t look right, it’s puzzling…

So - I can think of a few possible explanations, none of which I’m very confident in I’m afraid - as I say your case is puzzling…

a) the pictures are accurate and there’s something on one of your galvo mirrors, or something large on the big mirror under the resin tank

b) you might have a laser issue, but perhaps your laser spot photos are misleading because your camera is too light sensitive, or for some other reason…

c) if your camera pictures are misleading, then another possibility is a wobbly build platform - when the locking lever is down the build platform should be completely solid on the metal bracket. It should take some force to push the locking lever all the way down - if it flicks down easily, your build platform is probably loose.

To look at the mirror under the resin tank is easy, but to get a decent look at the galvo mirrors you’ll need to remove the back cover. That’s easy enough too, as long as you have a set of allen keys - there’s a couple of hex screws under the cover hinge, and the two middle hex screws on the back sides - careful with those last two - they can be stiff and it’s easy to round out the head…


Re-reading your original post I see that this was a replacement printer that started failing after only 6 or 7 prints? were your first prints small?

My replacement printer came with a loose build platform, and it was ok for the first few small prints  - and then the failures started looking like yours  - so it’s definitely worth checking:

Of course that wouldn’t explain your laser spot photos which still puzzle me…




Stephen (Formlabs)

Jun 11 10:56 PM


Thank you, again, for your patience in awaiting my reply. As you are aware, Formlabs introduced the Form 1+ yesterday and we have been handling a higher volume of inquiries, and it has taken me longer than expected to address this.

Typically, with the data you’ve provided, I would advise that the mirrors are cleaned following Formlabs instructions ( however I can see that you have followed these instructions between each print. I hope there is no dust on the large or small mirrors inside your printer. I’ve asked our engineering team to give this situation special attention, and we’ll be relying on the great feedback and data you have provided to determine a conclusion. There are very few additional options to troubleshoot. I can understand this is urgent and I will speak with them directly tomorrow.


Replied by me:



Zheng Yang

Jun 11 11:35 PM

Hi Stephen,

Thanks for your help!

First of all, the link you provided is not working (Page not found: I assume that you were referring to this mirror cleaning instruction:

Yes, I have followed the mirror cleaning instruction and cleaned the large mirror withe the “Wet Contact Cleaning” method and the smaller mirror with “ Dry Contact Cleaning” method. I did these cleaning processes twice before the test #3 and test #4. As you can see from my photos, it was not helpful at all.

Looking forward to a final conclusion from your engineering team!




Stephen (Formlabs)

Jun 11 11:40 PM


So sorry about that - the link should have been

This is the new location of our support site with resources to help our customers use their printers. We’re working hard and continuing to improve the information we offer here.

I’ll be in touch tomorrow.




Hi Zheng, another possibility occurs to me:  the new galvos that go in the Form1+ and replacement machines might have wider mirrors, and hence laser failures don’t show the squared off shape you get with the old galvos.  Have you thought about opening the back of your F1 and checking the galvo mirrors for dust/contamination? If so at the same time it would be great if you could measure the width of the new galvo mirror… it’s ok to free rotate them when the machine is unplugged (I’ve done this many times while installing replacement galvos) - they auto-reset when a print starts.

The old galvo (PT-20K) mirrors are 6mm wide (see below) - if the new ones are wider and you have a laser failure, then that will explain your laser spot shape…


Hi Kevin,

Thanks a lot for your help!

Probably because of my poor camera (iPhone 5 back camera), the laser spot was not clear on my photos. It definitely not a single spot as you described for a normal printer. I can see the halo(or diffraction pattern) with naked eyes. It more or less liked a diamond shape.

Nothing changed before and after 6/6. Everything is the same. The actual turning point was the day they released PreForm 1.4. After upgrading the firmware to 1.3f, I got two consecutive adherence failure, one on white resin, the other on grey resin (one part was completely missing). Then, I changed the fine tuning parameters, by decreasing platform height 0.1mm. After that, I sent three batch of printing. The adherence seems restored to normal. Finally, on 6/6 six consecutive mushroom like printing failure.

Yes, it is a replacement printer. After receiving this printer and before firmware 1.3f upgrading, the successful rate was 100% on about 4-5 batch of printing, sized from 10mm to 70mm objects.

I have cleaned the large mirror withe the “Wet Contact Cleaning” method and the smaller mirror with “ Dry Contact Cleaning” method after the initial failure. But they are not helpful.

I just checked the build platform, it’s pretty solid. The build platform was coming with the replacement printer, quite new.

Then, as you said, the problem was highly probable on the galvos if not on the laser. If there is another round of “Merry-Go-Round”, I will open the back to clean and check the pair of galvos; will let you know the dimension.

Let’s see what their engineering team going to say today, as Stephen promised.

Again, Thank You!

P.S., we have outsourced all our printing jobs to Shapeways. The turnaround time is about two weeks.  Shapeways is little bit picky about the parts’ thickness. But they have many choices in material/color selection.

We used Quickparts once last year. Quickparts seems more professional, but the actual printing quality was not comparable with Shapeways. (warping and uneven surface)

I also found a nearby Form1 user on 3D Hubs ( and sent parts to their hub (still waiting for response). Hope their Form1 have no problem or defects.


There’s a lot of great information on this thread, but I want caution anyone reading this against opening up their printer and poking around in the internal components.

Opening up your machine can make diagnosis challenging for our support team, making it extremely difficult for us to isolate the actual problem, and will void your warranty. Zheng, our support team will continue to work with to resolve the issues you’re seeing!




Stephen (Formlabs)

Jun 12 03:24 PM


I spoke to our engineering team. We do have an option to more thoroughly clean the small galvanometer mirrors, but unfortunately this is not something that can be completed by users in the field. Since this cleaning process is very sensitive and specific to your machine, and because it would void the warranty of other Form 1 users if the instructions are shared, Formlabs needs to return your Form 1.






Stephen (Formlabs)

Jun 13 10:30 AM


I can start the return process, but I was hoping you might want to look at the mirrors more closely. I’ve recently learned that smudges can go unnoticed on the mirrors (even after the cleaning procedure is followed) under normal lighting conditions. It shouldn’t require you to touch any of the mirrors but if you can shine a flashlight around, I’m wondering if you’ll come across hidden scratches or smudges. I have heard the light from an iPhone works great, if you have one. This type of issue could bend a perfectly good laser spot slightly out of ordinary.

If you still prefer the return, I am attaching the instructions, but I need to confirm your shipping address before coordinating the shipment and return.


Repacking Instructions.pdf