I always love seeing the joy on people’s faces when I give them a lithophane as a present, it is a unique way to impress somebody.
Usually, when we talk about 3D printing an image, we refer to lithophanes which is an engraved piece of any material that produces the effect of a photo when backlit. You can create very neat nightshades with them and there are lots of projects on the web that you can use for free.
Generating your STL from the photo
The first step is generating your STL file, there are some great tools out there and I’m going to share my favorites:
- 3D Builder – 3D builder is a great app produced by Microsoft and it’s installed by default with Windows 10. Very similar to Tinkercad, it’s very easy to work with and offers some great instruments to build and modify 3d objects. It also has a built-in plugin that will generate a lithophane when you upload a photo which is what we need.
- Cura -I essentially use Cura because it is my slicing software and like 3D builder, it generates a lithophane from a JPEG photo file, also it speeds up my workflow by slicing the file with the same software.
- Image to lithophane converter – Or you can use this free online tool which is great, you can build lithophanes of different styles and it’s free! This app is great as it permits you to create different shapes on the go.
We can achieve very good results printing a lithophane with both an FDM or SLA printer but each one has a drawback:
What is an FDM printer?
FDM printers work by fusing thermoplastics and extruding them on layers.
In your typical printing process, the nozzle hovers over the build plate and creates a layer, when finished the build plate is lowered and the next layer is started. The minimum layer height is 0.5 mm typically, which is not bad but the major drawback is that all the moving parts can affect print quality. The positive note is that FDM printers are very cheap and printed parts don’t require much post-processing. Using a common FDM printer is easier and you have a huge variety of materials from which to choose
Lithophane with FDM printer
Choosing the printing material
The first main factor for perfect lithography is choosing the proper filament, we need a fitting white. Notice that not all producers have the same tone of colors, the main things we are avoiding is plastics that have a yellowish tint and also, we need to get a filament that has a little transparency to it, For example, a silk PLA could be a bad option as it’s filled up with reflecting material and wouldn’t let light to pass.
It is very important to consider what will be your light source. PLA doesn’t stand a chance against a regular light bulb as it heats a lot.
A good option would be PETG that is much more resistant to higher temperatures.
In this example, I utilized Everyone PLA ,but any filament should work.We need to work with details so diameter precision is important!
Slicing the right way like a ninja!
In this case, I’m going to use Cura. I find it very user-friendly and you can change the visibility of some parameters. This way is more accessible to learn the basics and get accustomed and after moving on some more fine-tunings by unlocking more options.
The basic requirement to achieve a precise lithophane effect its that the model has to be printed at 100% infill avoiding having patterns inside.
Also add lots of layers, as you can in the photo below adding more layers occupies the infill space and also will make a better finish and will add more depth to your lithophane
Also add lots of wall layers, as you see can in the photo adding more layers occupies the infill space and also will make a better finish and will add more depth to your lithophane
Vertical or Horizontal?
Definitely, the best way is printing in a vertical direction. Mainly because printing horizontally means the plastic gets squished on, and some fine details on the top will ruin as the nozzle work on small areas, ruining the finished product. Another suggestion is to avoid using the axis that produces most of the movements like the bed axis, as it will most plausibly make your printer vibrate and shake. This depends from printer to printer. To avoid bed adhesion problems you can simply use some brim with a large width. If you still have problems with adhesion. Check my article on bed adhesion issues where I go more in detail on the argument and explain some great ways to avoid this problem.
What is an SLA printer
SLA printing or resin printing exists from approximately 1980 it is often used by professionals and only recently gained popularity.
The printing process involves a chemical reaction triggered by a laser that hardens a liquid resin forming a 3D object.
The difference between a plastic extruding printer is that it requires much more post-processing
- It requires a first rinse with solvent (isopropyl alcohol)
- Some resins require a curing process
- Harder time removing supports
Undoubtedly is more time consuming and the entry cost is more expensive but the quality of the print is much more satisfying and it can be used for very tiny objects.
LSA printers are great for some niche uses like jewelry casting and miniatures, but used correctly they can produce some very fine lithophanes. Which in our case is what we want. I’ve noticed that using a translucid white resin produces the best results.
Lithophane with a LSA printer
As for the resin printers, there aren’t many alternatives for the materials. You need a white resin with good transparency. It doesn’t depend if its High-Detail Resin or Standard Resin, both work great. for this test, I used ABS-like eloogo, a great product that hasn’t disappointed me once and I’ve been using bottles without a failed print
I’ve tried different print options with this kind of resin and you will see what it works for me. with these settings, I avoid wasting too much material and having sticky resin to clean off
So its time for the results!
Which one do you think did better ?
Here we have a sample of the same STL file printed on an SLA printer and a FDM one
So As you can tell it’s easy to judge by yourself
So, as result, if you strive for quality is it surely better an SLA printer, even if that means double the work, but if that isn’t your target even with a conventional FDM printer you can achieve excellent results by adjusting some options and doing some tweaks. In the end, it’s a work of trial and error
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