Redefining Small-Scale CNC Production
The Sienci Labs AltMill MK2 4×4 bridges the gap between hobbyist routers and heavy-duty industrial manufacturing centers. Built on a rigid, custom-machined aluminum extrusion frame featuring HGR15 linear guides and ball screws on all axes, this machine is designed for high-speed precision. With a 49-inch by 49-inch working area and closed-loop stepper motors, it maintains highly reliable positioning while achieving production-level cutting speeds of up to 600 inches per minute.
Automating Workflow with the ATC
The most significant efficiency upgrade for the AltMill is its specialized Automatic Tool Changer (ATC). By eliminating manual bit swaps, the ATC minimizes idle machine time and prevents the z-axis offset errors that frequently ruin complex multi-tool projects.
⚬ Spindle Specs: The 2.2kW air-cooled spindle utilizes ceramic bearings and maintains constant torque from 18,000 to 24,000 RPM.
⚬ Tool Holding: It uses industry-standard ISO20 tool holders paired with ER20 collets.
⚬ Rack Configurations: The system is available in 6-tool or 12-tool quick-release racks, which only consume about 5.3 inches of rear Y-axis travel.
⚬ Air Requirements: The low-pressure pneumatic tool release requires a continuous compressed air supply filtered to 40 µm to keep the internal mechanisms free of moisture and debris.
Operating this system safely requires proper electrical allocation. The standard AltMill frame runs on a 110V circuit (48V, 10A power supply), while the robust 2.2kW ATC spindle requires a dedicated 220V/15A single-phase circuit to handle maximum loads.
Sidebar: Post-Processor & CAD/CAM Compatibility
The AltMill is driven by an SLB-EXT 32-bit controller running grblHAL firmware, paired with Sienci’s free gSender control software. This open-source backbone ensures broad compatibility across major CAD/CAM suites.
- Mastercam: You can utilize a standard grblHAL post-processor to generate your G-code. As long as the post outputs standard
M6tool change commands, gSender natively intercepts them and orchestrates the physical drop-off and pick-up at the tool rack without requiring custom macro programming. - Fusion 360 & Vectric: Both platforms offer easily downloadable, dedicated grblHAL post-processors that fully support automated ATC commands.
- Carveco: Standard GRBL posts export clean toolpaths that the AltMill executes seamlessly.