Microswiss CHT High Flow Hotend – hotend for 3D printer Bambu Lab A1

Microswiss CHT High Flow Hotend for Bambu Lab A1, A1 Mini, H2D, and H2S

Key advantages

• Declared up to 50% increase in maximum volumetric flow rate (high-flow) for more efficient 3D printing at high speeds.
• Official collaboration Microswiss × Bondtech and patented CHT geometry for flow separation in the melting zone.
• Compatibility with Bambu Lab A1, A1 Mini, H2D, and H2S.
• Nozzle options 0.4 mm / 0.6 mm / 0.8 mm – choice based on detail and performance.
• Package contents: hotend assembly + silicon sock.
• Documentation: available PDF assembly instructions (SKU M3121).

Who it is for and what problem it solves

Microswiss CHT High Flow Hotend is an upgraded hotend aimed at users of Bambu Lab A1, A1 Mini, H2D, and H2S who want to "squeeze" more performance from their machine without changing the workflow. In practice, the limitation in fast 3D printing is often not the kinematics, but the ability of the melting zone to feed enough material stably (volumetric flow rate) – especially when increasing extrusion width, layer height, or working with a larger nozzle.

This is exactly where the CHT (Core Heating Technology) concept makes sense: instead of relying solely on heat transfer "from the outside in," the idea is to split the flow to increase the effective surface area of heat exchange and maintain more stable melting at higher flow rates.

CHT technology and its impact on the result

According to Microswiss, the CHT design splits the filament flow into multiple "chambers"/channels as it passes through the melting zone. This aims for more even layer deposition and better adhesion between layers, reducing voids and weak spots.

Bondtech describes CHT® as a technology that divides the filament into thinner "strands" inside the nozzle, allowing the material to melt more efficiently "from the inside" and enabling higher flow rates. This is also why CHT is used as a solution for high-flow scenarios where standard nozzle geometry may start to limit stable feeding.

What to expect in performance and quality

The manufacturer declares up to 50% increase in maximum volumetric flow rate. In real settings, this is most often felt as:

• less "choking" at high speeds and/or with larger extrusion widths;
• more predictable filling of massive sections and a more stable extrusion line at loaded profiles;
• better interlayer consistency when flow rate is a limiting factor.

It is important to emphasize that the high-flow hotend is not a "magic accelerator" by itself. To gain meaningful benefits, you need to balance flow rate, temperature (within the printer's limits), cooling, and mechanical stability. At aggressive speeds/flow rates, profile adjustments may be necessary to avoid under-extrusion or surface defects.

Compatibility, nozzle sizes, and ecosystem

Microswiss CHT High Flow Hotend is designed for:

• Bambu Lab A1
• Bambu Lab A1 Mini
• Bambu Lab H2D
• Bambu Lab H2S

Compatibility is confirmed by the manufacturer.

Options with nozzle diameters of 0.4 mm, 0.6 mm, and 0.8 mm are available. Practical guidance for selection:

• 0.4 mm – a balanced option for everyday details where you want speed without sacrificing finesse.
• 0.6 mm – more suitable for functional parts and larger models when the priority is performance.
• 0.8 mm – for maximum performance and fast prototypes/cases when detail is not a priority.

For Bambu Lab A1, a filament with a diameter of 1.75 mm is specified. This is also the standard with which the ecosystem of these models operates.

The workflow in the software remains unchanged: you prepare the model in the slicer and generate G-code. The technical specification for A1 states that the slicer is Bambu Studio, and third-party slicers that export standard G-code (e.g., SuperSlicer, PrusaSlicer, Cura) are also mentioned.

Installation and initial setup

Microswiss has published brief instructions for changing the hotend (SKU M3121). It is good practice to follow the documentation step by step, starting with the following safety measures:

• unload the filament from the toolhead;
• lower the platform;
• let the hotend cool down to room temperature;
• turn off the printer and unplug the power cable.

The logic of the replacement is as follows: removing the silicone cover, unlocking/releasing the original hotend, removing it, installing the new one (first the upper part), pressing the heater core against the heater plate, locking the fastener, and returning the silicone cover/cap.

A critical step after installation is "scanning"/reading the nozzle information from the printer menu: Nozzle & Extruder > Read Nozzle Info. This helps the system to correctly recognize the installed module.

Use scenarios, limitations, and best practices

Professional scenarios (4–6)

• Rapid prototyping of housings and mechanical details: shorter cycle "idea → sample → correction" thanks to high-flow profiles.
• Functional parts with thicker walls/wider extrusion: more stable feeding at increased flow rate and potentially better interlayer consistency.
• Small series (jigs, stands, mounting elements): more predictable production time for repeatable tasks.
• Educational environments/workshops: higher throughput of a single machine during demonstrations and workshops.
• Large volumes with moderate detail: choose 0.6/0.8 mm nozzle for faster "rough" iterations.

Limitations and best practices

• High-flow settings increase sensitivity to moisture in the filament and unstable profiles. Drying and proper storage often have a greater effect than "chasing" extreme speeds.
• When switching to a larger nozzle diameter, plan for profile adjustment (extrusion width, flow rate, temperature within the printer, cooling) and create test objects.
• After replacing the hotend: check first layer and perform control tests for stable feeding before starting long tasks.
• If you notice increased "stringing" or unstable surface with high-flow profiles, take a step back: reduce flow rate/speed and adjust temperature/cooling according to the specific filament.

Technical specifications

Installation Instructions