3D Printing The Perfect First Layer

The most important step in 3D printing is, without question, a great first layer. When browsing forums or helping customers, we see endless posts about adhesion issues, warping, and spaghetti monsters. I would estimate that 90% of those 3D printing issues can be traced back to an incorrect first layer.

For 3D printing, it is vital that your first layer is perfect—or at least very close to it. If you don't get that foundation right, the rest of the print is structurally destined for failure.

In this guide, we are going to move beyond "guessing" and use a specific, repeatable process to get your print off on the right foot.

The Physics of Adhesion

There are several variables involved in a great first layer, but if you break them down sequentially, the process is easy to master. We will cover:

1. Bed Leveling (Tramming)
2. Temperatures (Hotend & Bed)
3. First Layer Speed
4. First Layer Height
5. Fan Speed
6. Calibrating Z-Offset

By the end of this guide, you won't just "hope" your print sticks—you'll know it will.

Step 1: Bed Leveling (Tramming)

The first step is ensuring your nozzle travels parallel to the build plate. This is often called "leveling," though "tramming" is the technical term.

Some machines feature automatic bed leveling (ABL) wizards that move the nozzle to the four corners and the center. If your machine doesn't have this, you can download our Bed Level Wizard (in the downloads section) or manually move the print head via the LCD menu.

The Paper Method:

1. Preheat: Set your bed to your normal printing temperature. Metal expands when heated; leveling a cold bed will yield poor results when it heats up.
2. Clean: Ensure the nozzle tip is free of hardened plastic.
3. Home: Run a "Home All" command.
4. Test: Slide a standard piece of paper between the nozzle and the bed at the first corner.
5. Adjust: Tighten or loosen the bed knobs until the paper just starts to drag. You want to feel slight friction, not a vice grip.

Repeat this for all four corners. Then, do it again. Adjusting one corner affects the others, so it usually takes two full rounds to get the bed perfectly flat.

Step 2: Optimizing Temperatures

Your printing temperature affects two things: layer strength and bed adhesion.

Hotend Temperature

Filament can extrude at lower temperatures, but it often comes out "dry" rather than "molten." For the first layer, you want the plastic effectively liquid so it fuses into the build plate's pores.

• Strategy: If your PLA recommends 190–220°C, print the first layer at 210–220°C. You can drop to 205°C for the rest of the print. This ensures a strong initial bond while maintaining good overhang performance later.

Bed Temperature

Generally, follow the filament manufacturer's recommendation. Even if a heated bed is listed as "optional," we recommend using it. It prevents warping and, critically, allows the part to "pop" off automatically once the bed cools down. However, avoid overheating the bed. Excessive heat keeps the bottom layers too soft, causing them to bulge out under the weight of the print—a common defect known as "elephant's foot.

Step 3: The Golden Rule of Speed

This is where many hobbyists get impatient, but this rule saves hours of frustration.

Print your first layer at 15 mm/s.

Yes, that is slow. But at 15 mm/s, you ensure the filament has ample time to melt in the heat block and bond to the surface. It eliminates the "dragging" of filament around sharp corners. Considering a print has hundreds of layers, slowing down the first one adds a negligible amount of time to the total job—but it dramatically increases your success rate.

Step 4: First Layer Height & Cooling

Many guides suggest "squishing" the first layer with a low height (e.g., 0.16mm) to force adhesion. We disagree. This usually masks other issues like an unlevel bed.

Our Recommendation: Use a 0.24mm initial layer height (for a standard 0.4mm nozzle). A thicker layer holds more heat energy, giving it more time to bond before cooling. It is also more forgiving of slight imperfections in your bed's flatness.

Fan Speed Strategy

Fans are the enemy of adhesion. You want the plastic to stay molten as long as possible on that first pass.

• Layer 1: 0%
• Layer 2: 0%
• Layer 3: 50%
• Layer 4: 75%
• Layer 5: 100%

Step 5: Calibrating Z-Offset (The Precision Method)

Many people think leveling the bed and setting the Z-offset are the same thing. They are not.

• Leveling: Ensuring the bed is flat relative to the nozzle.
• Z-Offset: Telling the printer exactly how far the nozzle is from the bed when Z is at "0."

To do this scientifically, you need Digital Calipers. (We recommend the Neiko 0-6" Digital Calipers—an invaluable tool for under $20).

The Process:

1. Slice the First Layer Test STL (from our downloads) with a 0.24mm layer height.
2. Print the file. It should be a single layer thick.
3. Once finished, peel it off and measure the thickness of the plastic with your calipers.

The Adjustment Math: Ideally, your calipers should read 0.24mm.

• If you measure 0.20mm, the nozzle is too close. You need to raise your Z-offset by 0.04mm.
• If you measure 0.28mm, the nozzle is too high. You need to lower (more negative) your Z-offset by 0.04mm.

Repeat this test print until your measured thickness matches your slicer setting.