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How To Resin Print Flat Surfaces (Best Settings)

SLA or resin 3D printers are great for printing a smooth surface. However, it might give you some issues when trying to get the surfaces completely flat. If you're having trouble printing flat surfaces with resin, you need to know these tips!

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SLA or resin 3D printers are great for printing a smooth surface. However, it might give you some issues when trying to get the surfaces completely flat. If you’re having trouble printing flat surfaces with resin, you need to know these tips!

Here 7 easy tips for printing flat surfaces with resin: 

  1. Calculate print angle using flat surface formula. 
  2. Adjust the print angle. 
  3. Always tilt flat surfaces. 
  4. Know how to print multiple flat areas. 
  5. Print the flat surface directly on the plate. 
  6. Fill in the stair steps. 
  7. Keep the printer bed level. 

As you gain more experience with resin printing, you’ll learn how to adjust the printer settings to get the results you want. Once you know how to calculate the tilt of the printer bed, you’ll have no issues getting it set up. Here’s all you should know about printing flat surfaces. 

1. Calculate Print Angle Using Flat Surface Formula

If you want to print flat surfaces with your resin printer, you need to print them at an angle. You can use the flat surface formula to determine what your print angle should be: 

Tan-1(layer height/ pixel width) 

You can plug the formula into a calculator using the printer settings, so the value shouldn’t be too difficult to find. The layer height is the layer thickness you plan to use when printing. You’ll want to take the number from your slicer settings. 

The pixel width is the XY resolution of your resin printer. This value can be different in each resin printer. You can find the resolution online or in the manual that came with your printer. 

This formula will always get you the best setting for your resin printer. Once you know what angle you need, you’ll want to know how to adjust it.

2. Adjust the Print Angle

You can adjust the model’s angle by rotating it in your slicer program. There are different ways to rotate the model, depending on the program. Many have a “Rotate” setting that you can find in the toolbar. 

In the “Rotate” setting, input the angle to which you want to tilt the model. This number should be the one you calculated using the flat surface formula. Then, slightly raise the model to add your raft and supports– which are essential for printing flat. 

Adjusting the print angle shouldn’t be too hard, although it’s under different menus depending on the software. 

What’s the Best Print Orientation With Resin Printing?

The best print orientation in resin printing is 45 degrees. Using this number should help you achieve better prints. You want to angle the print so all of it can fit on the build plate without hanging over.

Rotating your print to 45 degrees will help orient it correctly. However, you’ll also want to make sure you have it scaled and in the correct place on the build plate. 

Even though 45 degrees tend to be best for most resin printers, yours might differ slightly. Make sure to check your pixel width with the brand first. That way, you can determine what the correct angle will be.

The way you orient the print impacts the quality of the surface finish. For example, not placing it correctly could cause blobbing and more profound steps to appear. Always make sure to consider the angle when placing the model in your slicer program. 

3. Always Tilt Flat Surfaces

It’s a good idea to get early on into the habit of tilting flat surfaces. Tilting flat surfaces even slightly can significantly increase the success odds of your final print. Plus, printing at an angle lets you reduce the layers’ surface area, which reduces the peel force on the print. 

If you don’t tilt the resin print, you’ll end up running into many problems. It can collapse or peel away from your building plate easily. Tilting the print can also shave a lot of the printing time off. Since it’s angled, the layers build much faster. 

In short, you’ll need to tilt your resin prints if you want to have them turn out correctly. Skipping tilting will increase the odds that your print fails drastically. 

Why You Should Print Resin at an Angle

Printing resin at an angle will get you the best possible results. Doing so reduces layer lines on the final print and gives it a better finish. You’ll have a higher rate of success with the print, too, even though it takes longer to finish and needs more support. 

Printing at an angle also lowers peel force, which causes the print to peel away from the build plate. You want to reduce the peel force as much as possible. This short YouTube video explains peel force and how it impacts resin prints: 

Getting the right print angle is essential to 3D resin printing. If you get it right, your print will have flat, smooth angles. Most people recommend using an angle of between 30 and 45 degrees, but this measure can vary from printer to printer. 

You can tilt the 3D object in your slicer program. Each program will have a different place where you can do this. In most cases, you simply have to enter the angle you want, and the object will tilt to that degree. 

Most resin prints will need to be at an angle. The process reduces layer lines (stair steps) and the peel force. 

4. Know How To Print Multiple Flat Areas

Suppose you’re printing an object with many flat surfaces. In that case, you’ll need to take an additional step after using the flat surface formula. After all, the formula only calculates the best printing angle for a single flat side on an object. 

If you want the best angle setting for multiple flat surfaces, then match the layer height and the pixel width (the XY resolution of the printer). Plug these numbers back into the above formula, and you’ll get an angle to use in the “Rotate” or “Angle” settings in your slicer software. 

This angle should be perfect for use on objects with many flat surfaces- like a cube or block. Your print will turn out flat and smooth, with limited step marks. 

5. Print the Flat Surface Directly on the Plate

You can orient your print directly against the build plate when printing a flat surface. If you choose to go this way, you won’t need to use any formula. However, this measure is not very useful for objects with more than one flat side. 

Printing against the build plate also works well when you don’t want to use a raft or as many supports. However, it will need to be large and flat enough to resist peel force. 

It will be up to your personal preference whether you should print directly against the plate. Not everyone likes it, but you can use it to get a flat side on any object that you want to print. 

This YouTube video covers how to get your resin print to stick to the build plate: 

6. Fill In the Stair Steps

If you try all the above steps, but there are still some minor stair steps on your resin print, don’t worry! You can quickly reduce the visibility of the steps by coating the object in resin. Simply dip it in the resin or paint it over the entire object. 

Either way, your final print will have a much more finished look to it. Plus, you can smooth over any other deformities. Adding a coat of material also makes the print much stronger. 

While this isn’t a setting on your printer, it’s still an essential step for when your print doesn’t entirely turn out flat. The additional material fills in the tiny gaps, making for a completely smooth surface. 

If the steps are very noticeable, you can also use sandpaper to reduce them before applying more material. Smoothing out the steps should take no time and will give you a flatter print overall. 

7. Keep the Printer Bed Level

Finally, you’ll want to check the settings on your printer bed. It needs to stay level at all times. If you don’t level it every five to ten prints, then it’s not going to be flat anymore, causing your surfaces not to turn out completely flat either. 

Here’s how to keep your resin printer level: 

  1. Start by cleaning the build plate. 
  2. Remove the resin container, then loosen the screws that hold the build plate. 
  3. Use a piece of paper to tell how close the bed is to the nozzle. The paper should be loose enough to wiggle but not too loose. 
  4. Lower the build plate with the paper still in place. 
  5. Set your Z-axis to 0 and tighten the screws. 

If your printer comes with automatic leveling settings, you can use that instead of adjusting the printer bed. 

What Are the Best Settings To Keep Resin Objects Flat?

The best settings for keeping resin objects flat require that you know your resin printer’s pixel width (XY resolution). Keeping the layer height as close to this number as possible will help you determine the angle to keep your resin object flat.

Once you have your angle from the flat surface formula, you can enter it in the settings under the “Rotate” option in your slicer program. Let’s work through an example and figure out the best angle for a print.

If your printer has a pixel width of 0.050mm, you want the layer height to be around 0.050mm as well. Enter that into the formula. You will get 45 degrees for the answer. That’s how much you should rotate your object to get the flattest possible surface. 

The best angle to print flat surfaces with your resin printer is something you’ll have to figure out on your own printer at home. Every printer comes with a slightly different pixel width, but a 45-degree tilt works well for most 3D objects. 

Can You Print Perfectly Flat on a Resin Printer?

Resin printers are great for making flat, smooth surfaces on any 3D model. If you want multiple flat surfaces, you’ll need to properly angle the model to reduce the number of steps. 

You can create flat prints using resin. It takes a bit of work to ensure the settings are right, but it’s perfectly possible. You’ll want to do a few test prints before making your final model. 

If the test prints don’t turn out well, make sure you readjust the angle and check the rest of your print settings. 

Do You Need To Angle 3D Resin Models?

You don’t need to angle every resin print, although it’s a good practice to do so. Turning the model will give you better results by reducing layer lines and peel force. However, some simple prints with one flat side may not need tilting. 

Tilting your print will make it turn out a lot better than leaving it flat. You’ll need to ensure it has enough support and a reliable raft. When done printing, remove the supports and buff the object with sandpaper—no one will know they were ever there! 

Flat prints tend to have higher peel force, which can easily ruin a print. To combat this, you’ll want to use thicker supports on the outside, with thinner ones in the middle. 


You can print flat surfaces when using resin. Just make sure that you tilt the object to the correct angle. Doing so can help you avoid steps that might appear otherwise. 

Here is what you should remember when trying to print flat surfaces with your resin printer: 

  • You should know the flat surface formula to determine the print angle. 
  • Tilting the object helps to ensure the flat surfaces come out smooth. 
  • You should check the printer bed angle every five to ten prints. 
  • You can always coat the object in resin to help smooth out the surface. 
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About Ben

I started 3D printing since 2013 and have learned a lot since then. Because of this I want to share my knowledge of what I have learned in the past years with the community. Currently I own 2 Bambulab X1 Carbon, Prusa SL1S and a Prusa MK3S+. Hope you learn something from my blog after my years of experience in 3D printing.