PLA+ layer adhesion problems can turn hours of printing time into wasted filament and frustration. Unlike standard PLA, eSUN’s PLA+ formula improves toughness and layer adherence through modified polymer chemistry, but only when your printer settings match the material’s requirements. This guide walks you through the exact configuration changes needed to fix delamination, using the manufacturer’s specifications to eliminate layer separation once and for all.
Understanding PLA+ Layer Adhesion Issues
Why Layers Fail to Bond in PLA+
Layer adhesion failures in PLA+ occur when each printed layer doesn’t fuse properly with the layer below it. While eSUN’s PLA+ formula is specifically designed to resist this problem with improved toughness and layer adherence characteristics, the material still requires precise environmental and speed conditions. When a new layer deposits onto partially-cooled plastic below, they need adequate time and temperature to bond at the molecular level. If your nozzle moves too fast or the previous layer has already begun hardening, the new material slides across the surface instead of melting into it.
The mechanical properties confirm this material’s potential: a flexural strength of 74 MPa and elongation at break of 20% indicate a formulation designed for strong interlayer bonding. However, achieving these properties depends on following the precautions in eSUN’s technical documentation, which emphasizes that “appropriately reducing the printing speed and optimizing the slicing printing path” are essential steps.
Common Signs of Poor Layer Adhesion
Inspect your prints for these specific delamination indicators. Horizontal cracks appearing between layers—especially visible on the sides of tall prints—signal inadequate bonding. Parts that snap cleanly along a horizontal line rather than breaking through layers show complete separation. If you can peel layers apart by hand or see visible gaps when looking at a part’s edge, the bed temperature or print speed is likely the culprit. Warping at corners while layers still separate in the middle suggests uneven bonding across the print platform.
Build Platform Temperature Fixes
Minimum Bed Temperature for PLA+ (45°C)
eSUN specifies a 45°C minimum build platform temperature for PLA+ printing. This temperature serves a critical function: it keeps the previously-printed layer in a slightly softened state long enough for the next layer to fuse into it. At temperatures below 45°C, each layer hardens too quickly, creating a mechanical bond through pressure rather than a true molecular weld. The print test conditions in eSUN’s technical data confirm this baseline, listing 45°C as the platform temperature used during official mechanical property testing.
Set your build platform to exactly 45°C as your starting point if you’re experiencing delamination. This is the minimum threshold where eSUN’s PLA+ formulation performs as designed. If your printer reports platform temperatures in a range (like 40-50°C), confirm the actual target value in your firmware or printer’s control interface—many budget printers have calibration drift that causes real temperatures to be 5-10°C lower than displayed.
Optimizing 45-60°C Range for Your Printer
The recommended printing parameters show a 45-60°C range for build platform temperature. This 15-degree window exists because different printer designs transfer heat differently. A printer with a thick aluminum bed retains heat better and can use lower temperatures. A printer with a thin steel plate or glass bed may need temperatures closer to 60°C to maintain the softness required for layer fusion.
Test within this range systematically. Start at 50°C (the middle of the range) and print a small test piece. If you see layer separation, increase to 55°C for the next print. If bonding is poor only at corners or edges (where the bed is cooler), move to 60°C. If the print shows good adhesion but the surface becomes slightly textured or sticky, reduce back to 48°C. Document which temperature eliminates delamination for your specific printer, and maintain that setting for all future PLA+ prints on that machine.
Critical Slicing Configuration Changes
Enable Z Seam Alignment Function
eSUN’s precautions section states: “When slicing, it is best to turn on the Z seam alignment and starting point alignment functions.” This instruction appears first in the precautions list for good reason—Z seam alignment directly impacts layer adhesion quality by controlling where the nozzle completes each layer loop.
In your slicing software (Cura, PrusaSlicer, Simplify3D, etc.), locate the Z seam or seam position setting. This typically appears under “Advanced” or “Shell” settings. Change it from “Random” or “Shortest” to “Aligned” or “Sharpest Corner.” When Z seam alignment is enabled, every layer ends and starts at the same location (usually a sharp corner of your model). This creates a consistent vertical line on your print instead of random dots scattered across the surface.
Why this matters for adhesion: When seams are scattered randomly, the nozzle travels erratically between layer endpoints. These unpredictable path changes cause uneven cooling and variable layer compression. A consistently aligned seam lets the plastic cool uniformly and maintains predictable compression force as each layer ends exactly where the previous layer ended.
Starting Point Alignment Setup
Paired with Z seam alignment, the starting point alignment function ensures the nozzle doesn’t move unnecessarily between layers. In your slicer, look for “Starting Point” or “Layer Start Position” options. Set this to align with your Z seam location—typically the same corner where seams terminate.
Some slicers bundle these functions together under a “Seam” menu. Others separate them into “Z Seam” and “Extra Start Position” options. Regardless of how your software names them, the goal is identical: the nozzle should travel from the seam endpoint directly into the infill, without backtracking or making unnecessary moves before engaging the next layer.
Avoiding Z-Axis Lift and Exit Commands
The precautions section explicitly states to “turn off the Z-axis lift and exit.” This refers to settings that tell the nozzle to rise vertically before traveling between layers or before retracting. While Z-axis lift prevents nozzle crashes in poorly-tuned machines, it introduces a gap between the nozzle and the previous layer during the critical moment when new plastic should be flowing onto it.
Disable these settings in order: First, find “Z Lift on Retract” or “Z Hop” and set it to 0mm. Next, locate “Extra Restart Distance” or “Z Lift Before Retraction” and disable it. Finally, check for “Nozzle Lift on Layer Change” and turn it off. If your printer experiences crashes after disabling these features, the issue is likely underextrusion or incorrect nozzle height—address those separately rather than re-enabling Z-axis lift, which directly causes poor layer adhesion.
Perimeter and Shell Optimization
Setting 4 Outline/Perimeter Shells
Both the recommended printing parameters and print test conditions specify exactly 4 outline/perimeter shells for PLA+. This number isn’t arbitrary—it represents the wall thickness that balances structural integrity with printability for this material.
| Parameter | eSUN Specification | Why It Matters for Adhesion |
|---|---|---|
| Outline/Perimeter Shells | 4 | Creates thick walls that resist layer separation stress |
| Top/Bottom Layers | 4 | Thick solid layers bond strongly to infill |
| Infill Percentage | 20% | Reduces internal stress that causes delamination |
| Fan Speed | 100% | Cools outer layers uniformly for better bonding |
With a standard 0.4mm nozzle, 4 perimeter shells create approximately 1.6mm of wall thickness. This thickness ensures that when one layer bonds to the next, the adhesion strength distributes across multiple overlaps rather than relying on a single thin wall. If you’re using a different nozzle diameter, recalculate shell count to maintain roughly 1.6mm of wall thickness: divide 1.6 by your nozzle diameter and round to the nearest whole number.
Top and Bottom Layer Thickness Requirements
The specifications call for 4 top and 4 bottom layers, matching the perimeter shell count. With standard 0.2mm layer heights, this creates 0.8mm of solid plastic at top and bottom surfaces. This thickness is critical because top and bottom layers bond to infill material underneath them, and thin top/bottom layers create weak interfaces that delaminate easily.
If your slicing software uses a “Top/Bottom Thickness” setting instead of layer count, set it to 0.8mm (4 layers × 0.2mm). If you’re printing with non-standard layer heights (0.1mm or 0.3mm), multiply your layer height by 4 to find the equivalent thickness. For example, 0.3mm layers × 4 = 1.2mm total top/bottom thickness.
Printing Speed Reduction Strategy
Slowing from 100 mm/s to Improve Bonding
The recommended printing parameters specify 40-100 mm/s, but the print test conditions used for official mechanical property testing employed 40 mm/s. This significant speed reduction directly impacts layer adhesion because slower nozzle movement allows more time for plastic to fuse with the layer below before the nozzle moves away.
When filament extrudes onto an existing layer, it needs approximately 0.5-1 full second of contact before sufficient molecular bonding occurs. At 100 mm/s, the nozzle completes a 1cm travel distance in 0.6 seconds—barely enough time for fusion. At 40 mm/s, that same 1cm takes 1.5 seconds, allowing complete molecular integration. The eSUN technical data emphasizes that “appropriately reducing the printing speed” is a precaution specifically mentioned for achieving the best printing effect.
Start at 60 mm/s if you’ve been running near 100 mm/s. Print a test piece and evaluate layer strength by trying to flex the print or applying controlled thumb pressure to test for cracks between layers. If delamination persists, reduce to 50 mm/s for the next test. Most users eliminate adhesion problems between 40-55 mm/s with PLA+.
Speed Adjustments by Layer Type
Fine-tune speed settings differently for different parts of the print. Set perimeter/outline speeds 10-20% slower than infill speeds—the outer walls need maximum bonding strength. For example, use 50 mm/s for perimeters and 60 mm/s for infill. Set the first layer speed to 30-40 mm/s (half your normal speed) regardless of height—first layer bonding to the build platform affects every layer above it.
Top and bottom solid layers also benefit from reduced speed. Many slicers let you set “Top/Bottom Layer Speed” separately. Use 50-60 mm/s for these layers even if internal infill runs at 80 mm/s. The mechanical properties tested by eSUN (flexural strength of 74 MPa, impact strength of 9 kJ/m²) were achieved at 40 mm/s, so matching or exceeding that speed reduction for critical layer types guarantees you’ll hit those performance targets.
Advanced Slicing Path Optimization
Avoiding Shell Passing Through Idle Zones
eSUN’s precautions specify to “avoid passing through the shell when idling, optimize the slicing printing path.” This means the nozzle should never travel across already-printed perimeter walls when moving between infill sections. When the nozzle travels across a finished shell surface without extruding, it can drag cooled plastic and disturb the layer bond that’s still setting.
In your slicer’s path planning options, enable “Avoid Crossing Perimeters” or “Avoid Shells” (naming varies by software). This setting forces the nozzle to travel through infill cavities or around the outside of the part entirely, never across solid walls. This simple checkbox change dramatically reduces adhesion problems because it eliminates the mechanical dragging that disrupts layer fusion.
If your slicer doesn’t offer this setting explicitly, check for “Travel Path Optimization” or “Path Planning” menus. Some premium slicers like Simplify3D include extensive path planning controls that let you specify exactly which zones the nozzle can traverse during travel moves.
Path Planning for Consistent Layer Contact
Beyond avoiding shells during travel, optimize the order in which perimeters and infill are printed. Most slicers default to “Perimeter First” or “Infill First” sequencing. For PLA+, use “Perimeter First” to ensure outer shells print onto fully-set layers before infill adds internal stress. This sequence reduces the chances of infill pressure deforming perimeters during bonding.
Additionally, check for “Combing” or “Smart Wipe” settings. These features minimize retractions by keeping the nozzle inside the model whenever possible. Fewer retractions mean more consistent plastic flow and fewer pressure fluctuations that interfere with layer fusion. Enable combing and set retraction length conservatively (3-4mm for Bowden extruders, 1-2mm for direct drive) to maintain layer consistency.
When to Seek Replacement Filament
Quality Control Issues in Manufacturing
If you’ve implemented all the settings above and still experience delamination, the filament itself may have absorbed moisture or suffered manufacturing defects. eSUN’s material status is “Mass Production,” but even production materials occasionally have batches with inconsistent polymer chain length or contaminated resins. Moisture absorption is the most common culprit—PLA+ can absorb up to 0.3% moisture by weight when exposed to humid environments, which disrupts layer bonding by creating a thin water layer between fused plastic.
Before replacing filament, dry your current spool in a filament desiccant box or oven. Set an oven to 50°C and place the sealed spool inside for 4-6 hours. Do not exceed 60°C—the material’s heat distortion temperature is 53°C, and excessive heat can degrade the polymer. After drying, print another test piece immediately. If adhesion improves, your filament was absorbing moisture; store future spools in an airtight container with silica desiccant.
Testing with Fresh eSUN PLA+ Stock
If a dried spool still produces delamination and you’ve verified all printer settings match the specifications, request a replacement from your eSUN supplier. Include the lot/batch number from your spool packaging with your request. Provide photos of failed prints showing layer separation. eSUN monitors quality across production batches, and they can verify whether your batch was affected by quality variance.
When you receive replacement filament, confirm the spool label matches eSUN’s current packaging (Nov. 2021 Version 4.0 is the latest technical data sheet version). Store the new spool in a dry container immediately and retest using the settings documented in this guide. Consistent layer adhesion across multiple prints with fresh filament confirms the original spool was the issue.
FAQ
What build platform temperature should I use if my printer doesn’t reach 60°C?
eSUN specifies 45-60°C for build platform temperature. If your printer’s maximum is 50°C, use that setting and focus on the other adjustments: reduce print speed to 50-60 mm/s, enable Z seam alignment, and set 4 perimeter shells. The combination of temperature plus speed reduction often compensates for lower platform heating. If you cannot reach 45°C even, PLA+ may not be suitable for that printer without a heated build platform upgrade.
Can I print PLA+ at 100 mm/s if I increase the bed temperature to 60°C?
No—speed and temperature work together but don’t fully substitute for each other. The eSUN test conditions used 40 mm/s at 45°C to validate mechanical properties. If you increase temperature to maximum (60°C) but keep speed at 100 mm/s, you’re still moving the nozzle too fast for complete molecular fusion. The filament stays hotter longer at 60°C, but you haven’t solved the fundamental timing problem. Reduce speed to 50-60 mm/s and you’ll see immediate adhesion improvement regardless of temperature within the acceptable range.
What happens if I use fewer than 4 perimeter shells?
With only 2-3 shells, wall thickness drops below 1mm and delamination stress concentrates at the thin shell-to-infill interface. The mechanical properties tested by eSUN (74 MPa flexural strength) were achieved with 4 shells and 20% infill. Using fewer shells reduces actual tensile and flexural strength, making the print more prone to both external stress failures and layer separation. Always maintain 4 perimeter shells for PLA+ printing.
Should I disable the part cooling fan to improve layer adhesion?
Absolutely not—keep fan speed at 100% as specified. The cooling fan cools the outer perimeters while the nozzle is in contact, helping new plastic fuse into the layer below before hardening. Without the fan, plastic cools too slowly and droops, reducing contact pressure. The recommended printing parameters explicitly list 100% fan speed. Layer adhesion improves with the fan on because uniform, controlled cooling creates consistent bonding.
How do I know if poor adhesion is from my printer settings or a bad filament spool?
Test with a print designed specifically for adhesion checking—a simple cylinder 50mm tall with 4mm wall thickness and 20% infill. Use the settings from this guide (50°C bed, 50 mm/s speed, 4 shells, Z seam aligned). If that test cylinder shows clear layer separation, dry your filament spool for 4-6 hours at 50°C and retest immediately. If adhesion improves after drying, the problem was moisture absorption. If adhesion remains poor, the filament itself likely has a manufacturing defect and warrants replacement from eSUN.