Are your prints adhering to the build platform a little too well? Your issue might be burn-in layer exposure time. Below I’ll take you over what that means.
I’m going to split this guide into two parts: how to get your prints off when you’ve already botched them, and how to prevent the issue from happening again.
How to remove stuck resin prints from the build plate:
1. Heating the plate:
Warning: Do not apply heat to your model if your resin print has come into contact with alcohol. This could cause a fire.
If your prints are alcohol-free and you’ve moved any alcohol to a safe distance, then this is a good solution to try. It leverages thermal expansion to get your resin models to expand and soften enough to pry loose.
Use a hairdryer, heat gun or even hot water to heat the build plate, causing just enough expansion to slacken the model free. I would avoid applying the heat directly to the miniature or build platform surface to ward against damaging either. You want the build platform itself to absorb the heat, which doesn’t require direct application.
What about freezing?
I have heard rumours that freezing the plate also works through the reverse – thermal contraction. I’m not sure how effective this would be, though some have reported sticking the build plate in the freezer for a short duration has helped. I have some concerns this won’t be sufficient to release the print. You also really don’t want resin to come into contact with food areas. It’s toxic. I would stick to heat.
2. The correct scraper:
While it may sound obvious, ensure you’re using a metal scraper to remove models from the build plate, and not the plastic scraper like the type you’d use to mix the resin vat.
As far as technique goes, don’t try to wedge your scraper under a large surface area at once. Instead, try to lever the corner of your scraper under your miniature and leverage the air pocket. Approach your model from a few angles to determine where it has a point of give, and try lever the scraper up once you had a foothold to see if you can “pop” the model off.
Rather than large blows (although I understand the temptation), attempt lots of small, firm “picking” motions at one area and you should prevail.
Will applying alcohol work?
Having tested this, alcohol did not manage to slacken the 3D print in any noticeable way.
Image: Use a scraper like the metal one on the right, not the plastic scraper on the left.
How to prevent resin prints from sticking to the build plate in the first place:
1. Reduce bottom layer exposure time:
You’ll find this in the slicing settings in programs like Lychee or Chitubox. The primary way to avoid resin prints sticking to the build plate is to reduce the burn-in layer exposure time. While it differs per resin type, you generally want to keep your burn-in layer (or, bottom layer) exposure time to or under 40 seconds. Also make sure you are using “seconds”, as your slicing software often lets you choose based on a few measurement standards.
While the exact exposure time will differ per resin type, I’ve seen some pretty high numbers suggested by 3D printing companies. I use the following when printing these two primary types of resin:
Regular (including regular plant-based) resin: 40 seconds bottom exposure time
ABS-like resin: 20 seconds bottom exposure time
What is the bottom or burn-in layer?
The bottom layer is also called the burn in layer, and refers to the initial stages of your 3D print in which the base of the model is being built. These layers play a special role because they’re the ones that adhere to the build plate. For this reason, the exposure time (the amount of time a layer is exposed to UV light) for the bottom or burn-in layers are usually set much higher than the rest of the print.
2. Flexible build plate cover:
Prevention being better than cure, I have started using a magnetic flexible steel build plate cover. It’s been a great quality of life improvement, letting me remove the flexible plate and bend it to pop the models off.
To equip it, you’ll have to thoroughly clean your build plate, let the magnet set and then adjust your Z limit to calibrate for the additional volume of the plate.
Flexible Build Plate Cover
They have a few sizes available, so make sure to choose the size best suited to your 3D printer’s build plate.
3. Avoid large surface areas:
The larger a model’s surface area, the more it will adhere to the build plate. This can be avoided by splitting your prints up into smaller parts instead of printing them whole. Typically, it’s easier buying from creators who split them for you. If you only have a whole model and it’s dominating the build plate, consider a program like Meshmixer to help you split it.
Large terrain or other large surface areas are often better suited to FDM for this reason, too.
4. Try a beginner resin type:
If you are experiencing repeated failings with one resin type, it’s worth trying others to aid with process of elimination. I highly recommend starting with a basic resin and applying the slicing settings widely available on online communities. As different resins can require different exposure times and other settings, it’s worth mastering the basics. Here is the basic resin I use. I recommend checking Anycubic’s website for your exact printer’s closest match in size.
Anycubic Standard Resin
Make sure to check their website via the link above to determine the best print settings for your resin printer.
5. Level your build plate:
Another step to rule out is your build plate’s levelling. Re-level your plate to rule out this isn’t the cause of sticking prints.
I hope you get back to printing soon.
