Xtrench Run

What Xtrench Run Actually Is

Xtrench Run is a calibration and diagnostic G-code routine used primarily in FDM/FFF 3D printing. It was originally designed as part of the broader 3D printer tuning workflow, specifically to help dial in extrusion multipliers, estimate step/mm values for your X and Y axes, and catch mechanical issues before you waste material on a long print. The scripts come from the RepRap community and have been adapted over the years by various firmware developers and slicer profiles. It prints a smallish calibration object — usually a rectangular block with internal features, holes, and measured walls — that lets you check dimensional accuracy and extrusion consistency in one shot. You measure the output with calipers and adjust your printer settings accordingly. That's the whole idea.

Where to Get It

The original Xtrench files live on GitHub repositories and 3D model sites like Printables and Thingiverse. The most common source is the PrusaSlicer-compatible Xtrench calibration files hosted on GitHub under the 3dbenchy and printer-tuning communities. Search for "Xtrench Run calibration gcode" and you'll find both the STL models and pre-generated G-code files. There's also a standalone G-code version that works in any slicer where you can import custom start/gcode templates. I recommend grabbing the version that matches your slicer profile if you can find one. The G-code versions are more universal but less optimized for your specific printer configuration.

Running Xtrench Run Step by Step

First, make sure your printer is homed and heated to normal operating temperature. A cold extruder or a bed that hasn't stabilized will give you bad calibration data, so don't skip the warmup. Bed level first. If your auto-level mesh isn't populated, do a quick manual four-corner level at print temperature. Load the G-code into your slicer or send it directly via USB or network. If you're importing into PrusaSlicer, Cura, or SuperSlicer, set the layer height to match your normal print settings. I usually run it at 0.2mm for general calibration, though some people prefer 0.1mm for finer detail work. Be consistent — you're trying to replicate normal print conditions, not create a showpiece. The print itself takes anywhere from 20 to 45 minutes depending on your printer's speed and the specific Xtrench variant. Don't walk away from it. Watch the first three layers closely. If the first layer doesn't stick properly, abort and fix your bed adhesion before the calibration is even worth doing. Messed-up first layers invalidate everything that follows.

Once it finishes and cools, pull out your calipers. The Xtrench model has specific reference dimensions printed on it — linear measurements on the outer walls and through-hole diameters. Compare measured values to the nominal values. That comparison is what drives your adjustments. For extrusion calibration, look at the wall thickness measurements. If your measured walls are consistently thinner than the design specifies, your flow rate is too low. If they're thicker, you're over-extruding. The formula is straightforward: new extrusion multiplier = old multiplier × (design dimension / measured dimension). Take three measurements and average them to reduce human error. For axis step calibration, measure the X and Y dimensions and calculate your steps/mm using the same ratio method. This is where people get sloppy — make sure you're measuring the actual printed part, not the build plate dimensions or some reference number from the model description.

The Problem I Ran Into

Last year I was calibrating a printer that kept showing inconsistent extrusion results on the Xtrench Run. The first half of the print looked fine — walls were within tolerance. The second half, maybe 15 minutes in, the extrusion started creeping high. Measured dimensions went from 0.02mm under spec to 0.08mm over spec. I thought the extruder gear was slipping, so I checked tension, cleaned the filament path, replaced the bowden tube — nothing fixed it. The issue turned out to be that the print started at 220°C and the bed was at 90°C, but the ambient room temperature in my shop was dropping below 15°C during the night cycle. The hotend was struggling to maintain temperature during the slower second-half moves, causing slight under-extrusion early, then thermal recovery bursts that over-extruded. I added a simple enclosure — just acrylic panels taped around the printer — and the inconsistency vanished. The lesson was that Xtrench Run exposes thermal issues that you'd never notice on a normal print because those prints run faster and the thermal differential is smaller.

Common Pitfalls

The biggest mistake I see is using Xtrench Run results from a single print to adjust settings. Printers drift. Calibration objects are sensitive to environmental factors, filament moisture, and even the direction the printer heads move during the job. Run it twice before making any changes. If the second run gives you different numbers than the first, something is unstable and calibration isn't going to fix it — you need to diagnose the root cause first. Another issue is measuring wrong. The Xtrench model has internal holes and thin walls that are easy to misread with cheap calipers. Use digital calipers with at least 0.01mm resolution. Don't try to estimate with a tape measure or a ruler. Your adjustment values will be garbage and you'll just chase your tail. People also tend to over-adjust. If your measurements are off by 1-2%, that's within normal tolerance for most FDM printers. Don't change your extrusion multiplier by more than 2-3% at a time. Make the change, print again, measure again. Big jumps in settings often make things worse because you're compensating for one error while introducing another.

When Xtrench Run Won't Help You

This tool assumes your printer is mechanically sound. If your belts are loose, your rods are binding, your stepper motors are skipping steps, or your nozzle is partially clogged, Xtrench Run will give you calibration numbers that look reasonable but your actual prints will still be bad. Use it as part of a maintenance workflow, not as a substitute for basic printer health checks. Clean your nozzle. Tension your belts. Grease your linear rails. Verify your stepper currents are set correctly. It also doesn't account for material variation. Different spools of the same filament type can have different flow characteristics. If you switch brands or batches, run Xtrench Run again. Your old calibration numbers won't transfer reliably. For printers with direct drive extruders that have significant retraction behavior, the calibration can skew slightly because the retraction tests in the model interact with your retraction settings. If you're using aggressive retraction values, consider tuning those separately first before running the full calibration.

What to Do After You Calibrate

Once you've adjusted your settings based on Xtrench Run results, don't just call it done. Print a real model — something you'd actually use — and verify that the improvements carry over. Calibration prints are artificial test cases. They tell you about your printer in a controlled scenario, but real prints have different thermal loads, different travel distances, and different wall-to-infill ratios. If the real print looks good, your calibration worked. If it doesn't, go back and refine. I usually keep a log of my Xtrench Run results along with the settings changes I made. After six months of tuning and logging, I could see patterns — my X-axis step value drifted in one direction during summer, my extrusion multiplier needed seasonal adjustments, and certain filament brands consistently required a 1.5% flow reduction compared to the baseline. That kind of historical data is more useful than any single calibration run.