With any 3D printer, the most important layer is your first, as any inconsistencies and mistakes in this layer will cascade and affect every subsequent layer; it’s the foundation for the entire 3D print. An essential part of 3D printer preparation is preparing the build plate and ensuring that not only is the gantry parallel to the build plate, but that the build plate itself is “level.” Within 3D printing, you will often hear the term “level,” which doesn’t mean breaking out the bubble level and checking that it’s parallel with the ground, but that the nozzle or screen is the same distance from the build plate at any point along its surface. More accurately this would be called “tramming” your bed.

Now, not only is keeping your bed parallel important, but having a surface as flat as possible is the other half of the equation. It’s common for cheap 3D printer build plates to be dished or bent, which is where automatic bed levelers (ABL) come in. They pick up the slack and constantly adjust the nozzle’s distance from the bed so it doesn’t change and you have uniform adhesion. In the case of resin printing and how it works, that’s just impossible. Instead, you have to rely on the surface being truly flat in order for it to work. What’s flat to your eye or for general use, like a desktop, may in actuality be a wavy mess that would perform terribly as a 3D printer’s build plate. Fortunately, with a little elbow grease you can bring even the worst build plate up to par.

We are going to do two things: achieve the flattest possible surface we can and add texture, both of which promote print adhesion and lead to better resin 3D prints

Required materials

  • Sandpaper - 120 grit as a single sheet the size of your build plate to create flatness
  • Sandpaper - 80 grit as a single sheet the size of your build plate to add texture
  • Very flat surface - while a surface plate made of granite is one of the flattest pieces of equipment anyone could find, most will not have access to one. Instead, take a metal straight edge and lay the side against a surface you want to test for flatness. Shine a flashlight from behind and toward the bottom edge, looking for any spots where light peeks out from underneath. If you can’t see the light at all, great! This is a fantastic surface that is as flat as we need for this process. Be sure to rotate the ruler a couple times to make sure it’s not just that specific area that’s flat, but the entire surface.

Using a straight edge metal ruler to find the flattest surface we can.
Using a straight edge metal ruler to find the flattest surface we can.

Safety precautions

  • Wear gloves - general cleanliness as well as avoiding getting leftover resin or metal dust on your skin
  • Wear a mask - breathing aluminum dust is not recommended

Nitrile or latex gloves are an essential precaution for any resin 3D printer maintenance.
Nitrile or latex gloves are an essential precaution for any resin 3D printer maintenance.

Procedure

  1. Remove your build plate from the 3D printer
  2. Clear your build plate thoroughly with isopropyl alcohol, and dry it with a lint free cloth.
  3. Place your piece of 120 grit sandpaper down on the flattest surface you can find
  4. Press down lightly on the build plate as evenly as you can and slide it away from you.
  5. Lift the plate off the sandpaper, bring it back to you, and repeat four times.
  6. Take a look at the buildplate. You should see the high spots as the parts showing scratches and the low spots should be untouched and a clearly different finish.
  7. Rotate the build plate 90 degrees and repeat the process.
  8. Continue rotating the build plate until you have sanded in each direction.
  9. Clean away any dust from the build plate.
  10. Inspect the sanded surface and look for unsanded areas. Continue the sanding process until these disappear.

Slow and steady wins the race here. Don't apply too much pressure or you can induce a bend in the build plate; let gravity do the work here.
Slow and steady wins the race here. Don't apply too much pressure or you can induce a bend in the build plate; let gravity do the work here.

It should be clear that you are done when the surface of the build plate is sanded such that no low spots are visible and the entire surface is roughed. Swap out the 120 grit sandpaper sheet for an 80 grit sheet and this time diagonally slide the build plate to put some deep scratches into the build plate. This will add texture for prints to grab onto. Go back to the 120 grit sandpaper and once again slide the build plate. This will remove any burrs created by the lower grit 80 sandpaper while still leaving its deep gouges.

You can clearly tell that the build plate has been sanded flat when it has a uniform color.
You can clearly tell that the build plate has been sanded flat when it has a uniform color.

Once you have sanding and roughed your resin printer’s build plate, you need to give it a good cleanup with isopropyl alcohol and a lint-free cloth, then reinstall it back on your printer. Perform the normal leveling routine for your 3D printer and take as much time and adjusting as you need to leave your build plate as parallel to the LCD as it can feasibly be. From there you are ready to print! I would recommend starting conservatively with your print settings and work your way up to the limits of your machine; give your layers more time to cure and have peel speeds slower than usual. That way you can really test things one at a time and know that your bottom exposure time is causing problems, not the level of your bed. In our experience. Sanding and roughing up our build plates has made a huge improvement in the bed adhesion for resin 3D printing, even the resins that are more temperamental with sticking to the bed.

A couple quick swipes on the 80 grit sandpaper will introduce some gouges to give 3D prints more bite.
A couple quick swipes on the 80 grit sandpaper will introduce some gouges to give 3D prints more bite.

At MatterHackers, it is our goal to guide you to success in 3D Printing through providing superior products and knowledge. Hopefully through the help of this guide your resin 3D prints have a much higher success rate than before and have turned resin 3D printing into a much more enjoyable process. Interested in some resin 3D printing accessories? Check out the resin collection here.