If your prints are sticking to the FEP film, getting them off can be nerve-wracking.
Often, you can simply pop them off by sliding a nail under one edge and lifting from the corner. But, every time you do, you risk a tear or a scratch on the film.
Eliminating the issue is the way to go. However, that often means diagnosing issues first.
Often, fixing resin prints sticking to the bed will mean adjusting your 3D printing settings. In other cases, it will mean cleaning the FEP. Or, if you’ve recently cleaned the FEP, you might have issues with a bed that isn’t level. In addition, you might be printing a model that is too large for your tank or that puts too much weight on any one part of the bed.
5 Causes Of Resin Print Sticking To FEP Film
In most cases, your prints should have a slight bit of adherence to the film. However, they should pop off very easily.
If your prints were loose, you’d have issues actually printing, because the model might slide around, causing deformation. However, if it’s sticking too well, you can risk tearing or scratching the FEP getting it off.
Here are some of the most common reasons that happen.
1. Vat Isn’t Level
You can probably easily tell if the vat isn’t level because the resin will not be level. However, even slight inconsistencies in vat leveling can cause one side of the model to stick too much to the bed.
For example, if the vat is slightly canted, that side of the first layer will be too thin and overexposed – which will cause it to stick.
When this happens, one side of the print should be less stuck.
2. Bottom Exposure
If the bottom exposure is too long, it will cause the print to over-adhere to the FEP. That’s also true if you have the reverse problem.
If the bottom exposure is too short, it could mean the resin is still too sticky, which could cause it to over-stick to the FEP, especially as additional model layers add weight to the base.
3. Base Layer Thickness
If the base layer is too thin, it might not provide enough support for the print, causing it to stick.
However, this issue can be difficult to diagnose.
4. Dirty FEP Film
Dirty, scratched, or cloud FEP film can all cause a print to stick.
Here, the largest issue is when the FEP becomes cloudy. This blocks much of the light from the LCD and can cause the print to fail to cure properly.
When this happens, the only fix is to replace the FEP.
However, you can get similar issues from scratched FEP. If a scratch blocks light in the right place, it might cause curing and therefore sticking issues.
That’s also true if you have a buildup of micro scratches from using paper towels or another rough cleaning material to clean the FEP.
Finally, if you’ve been printing with the same resin for some time or refilling the tank without straining and cleaning the resin, you might have issues with contamination or particulates.
Normally, this includes tiny pieces of hardened resin. You might also have resin crystals. These can interfere with your print and can cause sticking.
In addition, if your model is printed right on top of larger shards of resin stuck to the FEP, it can significantly adhere to the FEP, which might make it very difficult to remove.
5. Model Size and Design
In some cases, models stick to the FEP because they are designed without enough supports. You might also have sticking issues if the model is too big for the vat.
In each case, it can be very difficult to determine what the actual issue is.
How To Prevent Resin Prints From Sticking To FEP Film
Preventing resin prints from sticking to FEP film normally means troubleshooting and diagnosing the issue.
From there, you can take steps to actually fix the issue.
1. Get Settings Right
Base layer height and bottom exposure can both affect whether a print sticks to the FEP or not. Here, many 3D printer brands have their own recommendations.
For example, you can use 0.10 mm lift height and 0.05 mm layer height as a standard for most printers. The more detail you want, the smaller the layer height should be.
Many printers also allow you to go as low as 0.01 mm for layer height. However, the standard is 0.05 mm.
On the other hand, the base layer count or “lift height” (depending on your slicer) is the number of layers you include in the bottom exposure. If this layer is too thin, your model will stick.
Common values include 4-8 layers for the bottom layer. The thinner your layers, the more bottom layers you should have.
From there, you also have to have transition layers.
For example, if you have a high bottom exposure and a low normal exposure, your normal layers may peel from the bottom layers and the bottom layers may stick. Make sure you have transition layers, gradually changing the amount of exposure.
It’s normally a good idea to use bottom exposure settings at 8-12 times the regular exposure time. However, it should almost always be under 30 seconds.
Therefore, if you have a normal layer exposure time of 2 seconds, you could use 16-24 seconds of bottom exposure time. You can always tweak that based on actual results.
More bottom exposure time means a stronger bottom layer – which you’ll need for a bigger model. However, if you increase exposure too much, the bottom layer will get too hot and it will stick to the FEP.
On the other hand, that changes a lot depending on the printer you’re using. You’ll also want to check setting recommendations for your resin.
However, that can be an issue if you’re using a new slicer. For example, the default setting on ChiTuBox is 50 seconds. That can cause significant over-adherence to the FEP.
2. Level the Vat
Most resin printers have an auto-level setting in the settings.
Some printers also don’t have a bed leveler. Instead, they have a printer leveler and ask you to level the printer from the feet using the printer leveling function under maintenance or settings.
3. Clean the FEP Film and Filter the Resin
If your FEP is contaminated or there are a lot of crystals or particulates floating in the resin, you can reduce issues by filtering the resin. Here, you should carefully remove the resin vat from the bed.
Then, pour the resin into a plastic container using a funnel and a filter. Go slow and be careful not to splash.
Dab out the bottom of the container with a microfiber towel. Dunk the vat in isopropyl alcohol a few times to remove any stuck resin in the bottom.
Pat it dry with a clean microfiber towel. If there are any bits of resin stuck to the FEP, you can gently massage them away from the bottom of the FEP.
Once you’ve strained out the particulate, you can almost always re-use the resin. However, if you want to change resin, you should never mix the old and new resin.
4. Try a Different Model
If your model is sticking, it may be an issue with the model and not with the printer.
Here, you can try adding more supports to your slicer. You can also check the recommended maximum dimensions of prints in your printer.
If you’re still not sure, print something else and see if it also sticks.
Elegoo Mars & Anycubic Prints Sticking To FEP
If you’re using an Elegoo Mars or an Anycubic resin printer, you can try these solutions:
- Check settings for the resin you’re using; e.g., Elegoo Maroon and Black need 90 seconds of bottom exposure time, most colors need 60-70 seconds.
- Use the screws to level the build plate. The Elegoo Mars does not have an automatic leveling function.
- If you’re printing in a cold room, increase the bottom exposure time. If you’re printing in a very warm room, decrease it.
- Check the tension on the screws on the build print. Sometimes they come loose which causes prints to stick.
- Check bottom exposure levels. (The default is 80, but this may be too much for your resin.)
- Reset the Z/home parameter.
- Make sure you’re printing in a warm room, as Anycubic does not provide printers with a heated bed.
- Make sure you have transition layers in your model.
- Clean the build plate.
If your resin print is sticking to the FEP instead of the build plate or sticking too well to the FEP, it’s likely an issue with settings. Often, the easiest fix is to adjust the bottom layer settings like exposure time and layer height. In other cases, you might have issues with your build plate or vat not being level enough. In most cases, a bit of experimentation will point out the issue, which may mean troubleshooting with settings and trying several test prints in between.