RM 028
We created the RM 025 because we wanted to tackle the circle in all its roundness, and its creation supplied us with the technical foundation for developing the automatic movement of the RM 028. Cased in a slightly smaller diameter of 47 mm, this creation has all the hallmarks of its uncompromising character.
RM 028 AUTOMATIC WINDING
CALIBRE RMAS7
Automatic winding movement with hours, minutes, central seconds, date and variable-geometry rotor.
POWER RESERVE
Around 55 hours (± 10%).
BASEPLATE AND BRIDGES MADE OF GRADE 5 TITANIUM
Production of these components in grade 5 titanium with black PVD or Titalyt® coating confers great rigidity to the entire assembly, as well as precise the surface flatness essential for perfect functioning of the gear train.
The baseplate and bridges were subjected to separate and extensive validation tests to ensure it met optimal strength requirements.
DATE DISPLAY
Semi-instantaneous, the calendar disc of sapphire crystal is treated with non-reflective coating on both sides.
VARIABLE-GEOMETRY ROTOR
The Richard Mille RM 028 uses variable geometry to optimise the rotor’s winding motion.
Rotor specifications
• Arm in grade 5 titanium
• High palladium content 18K white gold weight segments
• Weight segment with 6 possible positions adjusted by screws in grade 5 titanium
• Ceramic ball bearings
• Unidirectional; anti-clockwise winding direction
This exclusive Richard Mille design makes it possible to effectively adapt rewinding of the mainspring to the user’s activity level, in sporting or non-sporting environments. By adjusting the six-position rib, the rotor’s inertia is modified to either speed up the winding process in the case of leisurely arm movements, or to slow it down during sporting activities.
MOVEMENT CHARACTERISTICS
Movement dimensions: 30.25 x 28.45 mm
Thickness: 4.14 mm
Number of jewels: 32
Barrel arbour: AP 20 steel
Balance: Glucydur®, 4 arms, moment of inertia 4.8 mg•cm2, angle of lift 53°
Frequency: 28,800 vph (4 Hz)
Balance spring: elinvar by Nivarox®
Shock protection: INCABLOC 908.22.211.100 (transparent)
Escapement wheel jewels: Rubifix (transparent)
Three-position stem: manual winding, date adjustment, time setting
Finishing
Movement
• Baseplate and bridges in hand-ground, wet-sandblasted grade 5 titanium, black PVD or Titalyt® treated
• Burnished pivots
• Diamond-polished sinks on the bridge side
• Pinions with undercuts
Steel parts
• Sapphire-blasted surfaces
• Anglage and polishing by hand
• Screw slot and screws bevelled and polished with rounded and polished tip
Wheels
• Sandblasted and rhodium-plated, bevelled wheels (before cutting the teeth)
• Minimal corrections applied to the wheels in order to preserve geometry and performance
Other features
FREE-SPRUNG BALANCE WITH VARIABLE INERTIA
This type of balance wheel represents the ultimate in innovation. It guarantees greater reliability when subjected to shock and also during movement assembly or disassembly, hence better chronometric results over time.
The regulator index is eliminated, and a more accurate and repeatable calibration is possible thanks to 4 small adjustable weights located directly on the balance.
DOUBLE-BARREL SYSTEM
The double-barrel system helps to improve the stability of torque over a longer period. This is achieved by distributing the stored energy across two winding barrels instead of one, which increases the number of rotations and reduces pressure on the teeth, bearings and pivots, resulting in better long-term performance.
SPLINE AND EIGHT-POINTED SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES AND CASE
These types of screw permit better control of the torque applied to screws during assembly. These screws are unaffected by physical manipulation during assembly or disassembly and age well.