Procedure for Successful Printing PDF

I’m not aware of anything like this from FormLabs, so I put one together. It’s a PDF so it prints nice.


Nice work, Josh. It’s very clear and concise. The only thing I didn’t see was that might cause confusion for someone new to the Form 1+: always remove the build platform before the resin tank to make sure no resin drips on the mirror.

Thanks. I added that. Hopefully this PDF can help new users avoid some common mistakes that make prints fail.

I took my name out of the topic title, it was there as an ode to “IMHO” but when I saw it hours later, it kinda had the opposite effect…

Josh, this is a good start, I have some stuff I’d like to add. I have been working with Alex, one of Formlabs support technicians and had a very faborable experience. I’ve owned my form1+ for 3 months now. Upon receiving the printer I had some success making parts, but had not developed an intuition for what makes parts print successfully. There is no big red easy button, but there are some tips that will get you the 90% solution. For starters, the Mirror must be absolutely 100% clean.

First: If you’re one of those people like me that tried to clean the large mirror and checked with a flash light and were convinced that it is 100% clean, you may still have a dirty mirror. For under $100, formlabs will send you a new mirror if your printer is out of warranty and it can be installed in about 30 minutes. Well worth the time and cost.

Two: For large models, make sure you have a clean resin tank. And by clean I mean spotless, hold it up to a light it must be spotless I tell you!

Three: Never ever ever ever use isopropyl alcohol on ANY of the acrylic, it will crack, guaranteed, just a matter of time. Also, don’t clean the build platform with it either! Use a paper towel. You can never have too many paper towels or nitrile gloves in stock.

Four: Always generate supports for your model with a spacing of 7.0, not the default. Furthermore, set the density to the lowest value. Do not use the defaults! Finally, you want to orient your part such that the Axis Aligned Bounding box (the box that encompasses your geometry) is close to the same value on all sides. In other words, don’t orient a 3d printed pencil vertical or side ways, put it along a diagonal.

Five: Use 100 micron resolution on large parts. The longer your part takes the print, the greater the chance of failure. Save 50 micron and 25 micron for small figurines.

Six: This machine is not for production runs. Make a master part, perfect and shiny. Spend a weekend and learn how to make 2-part silicone molds using castable resin, i.e. smooth-on castable resins and mold making silicone. This is a very cheap and effective way of doing medium scale manufacturing of parts for a small business.

Seven: When you wash the parts with isopropyl alcohol, do 1 rinse in the bath, 1 rinse of water, pour some fresh isopropyl over the part into the isopropyl tub/container (helps to replenish it), then a final rinse of water. Always wear gloves. Try to handle by the support structure. If you have a hair dryer, set it to low heat and get all the water off. Always post cure the model using a UV oven or an hour out in the sunshine. If the parts of thin fragile pieces, remove the support structure AFTER the part has cured. There will be some minor shrinkage of the part after curing, very important if you are building functional/mechanical parts. Don’t forget to calibrate your optics in the Fine Tuning. Grab some calipers from harbor freight if you don’t already own a pair and get it right!

Eight: You will need to do some minor sanding on your part. There is no water soluble support structure . It’s more important that the print come out looking right and sand a few support nubs off, than spend half a day trying to orient the part so that support structures don’t ruin the part.

Nine: Third party resins from maker juice do work, but that doesn’t mean they will work for you! Each resin is different, know their properties before starting a print job. Don’t forget to stir the resin in the tank before the print, it’s super important!

Ten: Using Sylgard 184 to remove and replace the PDMS liner does work, but make sure you replace with exactly 64 grams of PDMS (silicone). PTFE (teflon) liner sheets do not work. The PDMS works well be cause of 2 things. Low surface energy and the fact that it is compliant. During the peel process the separating peel force will concentrate along a line that propagates toward the hinge. The teflon liner sheet is not compliant and will do less pealing and more pulling (tensile force) and generate violent separations between layers. You’d think PTFE is the way to go, but compliant materials trump low surface energy.

Eleven: Finally, if you get frustrated or stuck, e-mail the support people at formlabs, they are VERY helpful. If you are out of warranty, send it in for a recalibration every 6 months to 1 year, keep it working like new. That’s how the big boys operate, we have an Eden 260 and Fortus at work, what we spend on the support contract for one of those machines will buy (2) form1+ printers! You bought an expensive tool, plan to spend some extra money maintaining it!

I hope this information helps new users have a smooth ride with their new form1+. Mine is working perfectly and I know a lot of people have had frustration, but once you figure out some of these idiosyncrasies, it’s very reliable and easy to get things working on the first print, it just takes a couple weeks of learning.

Here is a picture of some stuff I printed within the last 24 hours using Maker Juice Black. The formlabs resin works perfectly as well. There are all printed on the first try as 5 separate prints as there are 5 separate objects here.


Thanks Justin, that’s some good stuff. It is a relief hearing 5 and 6, I often feel alone on those! If you or anyone else has more good stuff, add it on!

Thanks guys for taking the time to share this… its gold dust.

I been FFF printing for 2 years on a modifies Replicator R2X and received my Form1+ 4 days ago… 2 weeks soon then expected :-).

I’ve printed 3 of my own designs in clear resin and they have come out great. Only one failure, the 1st as I never removed the fine plastic film covering the build plate surface.

Most of my early questions have been answered in your posts, thank you.

Justin with point four, could you explain further why it’s important to position the pencil diagonally. I would have orientated it horizontally because there would have been minimal surface area for each peel and fewer supports.

With FFF printing you would just print this vertical, off the build plate, with no supports.

Thanks again,


With FFF/FDM processes there is negligible tensile force applied to the part during the build process. For inverted SLA technology you have a peeling process. The peeling process requires that you have a build platform with high surface energy (things stick to it very well) and another interface that has low surface energy (things don’t stick to it, i.e. silicone and teflon) AND compliant (elastic). If you place the pencil such that it is coplaner with the build platform, then a lot of peeling (tensile) force will occur for each layer. The fact that the silicone is compliant (elastic) concentrates force in along a line that propagates toward the hinge during each peel, focusing the pulling force instead of distributing it across the entire part. Thing of pulling 2 magnets apart. If you try to pull then apart along the magnetic axis it’s virtually impossible. If you tilt one of the magnets so they are no longer coplaner, then it’s very easy to separate the magnets.

The bottom line is you look at each slice, you want to minimize the cross section. Now, this must be balanced with the AABB (axis aligned bounding box). In your second image, with the pencil vertical, you have 2 bad things happening.

  1. There is very little support material holding the pencil to the platform, easy to pull off during the peel operation.

  2. You have a high aspect ratio, your AABB has 2 very large dimensions and 1 very small dimension. Therefore, the pencil may start off printing well, but as it gets taller (toward the end of the print) you will find that, much like a fulcrum, any movement at the tip of the pencil will be amplified (in terms of torque) to the supporting structure and may not return to it’s original position, in other words it may move a few microns from layer to layer. By orienting it like you have in picture 1 you get the following benefits:

  3. each layer has a relatively low surface area

  4. The support keep the pencil firmly and rigidly in place, it will not move

  5. As the peel occurs from opposite hinge side to hinge side (Y axis) you are spreading out the tensile force throughout the peel and not focusing all that force into one small cross sectional area.

The downside is that you have support nubs to remove. But again, as I mentioned in my previous post (item 6), this is not for production runs, sand the part, polish it, then make some silicone molds for small production runs.

If you work like this your prints will come out perfectly each time. Don’t forget to use Spacing of 7.0 and density of 0.5, and typically you’ll one 1 or 2 extra manual supports for good measure (this is the intuition you develop as to where to put those manual supports)

Thanks a bunch Justin!

That all makes perfect sense :smiley:

This is a fantastic thread. Wish I would have read this before I started printing. Would have saved me a bunch of headaches.

Great to hear, that makes it worth while for all of us to hear that :smiley:

Good guide :slight_smile: One thing though, I would definitely not touch the resin tank with that metal scraper the printer comes with. It’s sharp edges can easily cut the delicate silicone layer at the bottom. We use a rubber spatula to mix the resin in the tray.

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Hi Edward,
I always put the scraper down at the edge of the tank. Nothing can print out there anyway. Then as I drag it across there is no risk of the corner stabbing the silicone where it matters. I can’t say I have ever seen silicone damage though.

This thread is the best one I’ve read yet! Thanks Justin_Shumaker!

Reviving this topic as it seems like this document could be very helpful but unfortunately the link no longer works. @JoshK or someone else have a copy of this still? Is it still relevant to Form 2?

Reviving this topic as it seems like this document could be very helpful but unfortunately the link no longer works. @JoshK or someone else have a copy of this still? Is it still relevant to Form 2?

I second that. Missed that file and would love to check it out!