Quick Calibration test (0.2mm)

This is a small and very quick calibration tool for 0.2 profiles. 

Use it to determine the quality of layers, walls, tolerances, bridging, threads, and more. See the supplied images (and the text below) for a quick guide to what to check for.

Based on your findings, here are some general tips to get you started.

Please note: While these tips should help, they are not the be 'all end all' of troubleshooting. I'm no expert, but have done my best to help as much as I can.

First layer issues

Achieving a perfect first layer requires a precise balance between the Z-offset and bed conditions. 

If you see gaps between lines or round, spaghetti-like strands, your nozzle is too high and "dropping" the filament; you must decrease the Z-offset in small increments to press the plastic into the bed. 

Conversely, if lines are transparent and paper-thin - or if the extruder makes a "clicking" sound - the nozzle is too low and choking the flow. 

If the surface shows ripples or waves, you are slightly too low, as the excess plastic has nowhere to go but up, creating ridges that require you to back off the nozzle height.

When a layer looks good initially but peels at the corners, you are likely dealing with surface contamination or thermal contraction. While Isopropyl Alcohol is common, washing your build plate with warm water and dish soap is often more effective because it physically breaks down and removes oils rather than just spreading them around. You can further improve grip by slowing your First Layer Speed to 15–25 mm/s and increasing the First Layer Line Width to 120–140% to create a wider footprint. Using a slightly thicker First Layer Height (e.g., 0.24mm) also helps by making the print more forgiving of minor bed height inconsistencies.

Thermal settings must be tailored to your specific material. For PLA, a bed temperature of 55–65°C is ideal with the cooling fan disabled for the first few layers. PETG requires a hotter bed of 70–85°C and prefers a "laid" layer rather than a "squished" one, meaning the nozzle should sit slightly higher than it does for PLA. For high-temperature materials like ABS or ASA, you must maintain a bed temperature of 100–110°C, and an enclosure is almost mandatory to prevent ambient drafts from causing the print to warp and lift off the plate.

Tolerance issues

In 3D printing, "tolerance" refers to the intentional gap designed between two parts (like a peg in a hole or a drawer in a frame) to ensure they fit or move as intended. If your models are fusing together or your parts simply won't fit, your printer is likely suffering from Dimensional Inaccuracy.

The most common cause of poor tolerance is the Flow Rate (or Extrusion Multiplier). If your flow is even 5% too high, a 0.2mm clearance will disappear. Try adjusting the Flow Rate in your slicer

Other culprits are Plastic Ooze (Over-extrusion), where if the nozzle pushes out too much plastic, it "bulges" past the intended boundary and/or Thermal Expansion, where plastics like ABS or PETG shrink/warp as they cool, which can distort past the intended dimensions.

Brigde- and overhang sagging

Bridging and overhang failures occur when molten plastic fails to solidify quickly enough to resist gravity. To ensure a clean transition from liquid to solid the moment filament leaves the nozzle, your Part Cooling Fan is the most vital tool; for PLA, this should always run at 100% for all bridges and steep angles. If you notice that only one side of your print looks poor, you are likely dealing with Directional Cooling, where a single-sided fan duct fails to reach the "blind side" of the model.

Inside your slicer, you can optimize these moves by enabling specific Bridge Settings to modify flow and speed. Reducing the Bridge Flow Ratio to 0.8 or 0.9 (80–90%) creates tension by slightly stretching the filament as it crosses a gap - much like a guitar string - which prevents drooping. While bridges benefit from faster speeds (60–80 mm/s) to "zip" across the void before gravity takes hold, overhangs require slower speeds to give the cooling fan sufficient time to harden the plastic being deposited on the edge of the previous layer.

Thermal management and wall strategy provide the final layer of stability. Dropping your nozzle temperature by 5–10°C can drastically improve performance by reducing the heat the fan must dissipate. Furthermore, your Wall Ordering plays a critical role in overhang success; printing Inner Walls first provides a physical "shelf" for the outer wall to anchor to. If you print the outer wall first, the plastic often has nothing to stick to and will inevitably curl or collapse.

Layering (line differences)

When a print resembles a stack of unevenly protruding pancakes, you are likely witnessing the effects of mechanical resistance or inconsistent extrusion. Z-Binding occurs when the Z-axis becomes physically difficult to move at specific heights, causing the layers to "stutter" and squash together. To fix this, clean the lead screw thoroughly with a toothbrush and degreaser before applying a thin coat of PTFE-based grease; avoid WD-40, as it acts as a solvent rather than a lasting lubricant.

Thermal instability, often called a PID issue, is a frequent hidden culprit for wavy walls. If your nozzle or heat bed temperature swings by as much as 5°C, the plastic expands and contracts at varying rates, making some layers appear fatter than others. Most modern printers can solve this through an automated PID Tuning command, which stabilizes the heating cycle to ensure a uniform flow of material.

Internal extrusion problems can also mimic mechanical faults. Wet filament causes moisture to turn into steam inside the nozzle, resulting in "micro-explosions" that leave the surface rough and inconsistent. Similarly, a partial nozzle clog caused by tiny debris can create a "pulsing" flow where the volume of plastic varies from second to second. If your layer lines look random rather than rhythmic, check for these issues before adjusting your hardware.

Stringing

To eliminate stringing, you must synchronize the mechanical "vacuum" of retraction with thermal control and rapid travel moves. Retraction stops the flow by pulling filament back - usually 0.5–1.5mm for Direct Drive or 3.0–6.0mm for Bowden setups - at a speed of 35–45 mm/s. Since excessive heat makes plastic too runny, lowering your nozzle temperature in 5°C intervals helps find the point where plastic stays viscous enough to remain in the nozzle without sacrificing layer strength.

Maximizing your Travel Speed to 150–200 mm/s further reduces ooze by minimizing the time the nozzle spends suspended over open gaps. You can also utilize advanced slicer features like Combing or Avoiding Crossing Perimeters, which keep the nozzle path over already-printed areas to hide any residual drips. While Wipe while Retracting cleans the tip before it jumps, you should generally turn Z-Hop OFF, as the vertical lift often creates the very opening that allows a string to form.

If persistent "hairy" strings or surface zits remain despite these settings, your filament is likely wet. Materials like PETG, TPU, and Nylon absorb moisture that turns into steam, creating internal pressure that bypasses retraction. If you hear tiny "pops" during printing, dry the filament in a dehydrator at 45–55°C for at least six hours to restore its properties.

Corner issues (seam issues)

Corner and seam blobs typically stem from residual pressure inside the nozzle. When the print head slows down for a corner or stops for a layer change, molten plastic continues to ooze even after the extruder motor has stopped. If your acceleration settings are too low, the nozzle dwells too long at these junctions; increasing your Jerk or Junction Deviation helps maintain enough speed to prevent this "dwell time" ooze.

Seam blobs occur at the Z-Seam, where the nozzle starts and ends each layer. Always ensure Retract at Layer Change is enabled to manage this transition. For printers without modern pressure control, Coasting can act as a "legacy fix" by stopping the extrusion slightly before the path ends, using the remaining pressure to finish the line. You can further hide these artifacts by setting the Outer Wall Wipe Distance to 0.2–0.4mm, which "smears" the end of the line back into the start.

Setting your Seam Alignment to Sharpest Corner hides the seam within the model's natural geometry. For the most advanced results, the Scarf Seams feature in most modern slicers ramps the extrusion up and down to create a slanted overlap rather than a vertical stack, making the seam nearly invisible to the naked eye.

Thread issues

Because threads require high dimensional accuracy, even minor calibration errors will cause the nut and bolt to bind. If your threads don't fit, it’s usually because the printer is "over-extruding" slightly, making the male thread too fat and the female hole too small.

Try adjusting the "Horizontal Expansion" to a smaller negative value. This shrinks the outer dimensions of the print slightly, providing the necessary "air gap" for the threads.

Slow down your Outer Wall Speed. High speeds cause "corner cutting" due to inertia, which rounds off the sharp peaks of the threads, causing them to bind.

If your bolt fits halfway and then gets stuck at the bottom, you have Elephant's Foot. The first few layers are squished too much, making the base of the thread wider than the rest. Try reducing the "Initial Layer Horizontal Expansion" setting in your slicer.

Best of luck :-)