‘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 Diver's watch
RM 028
DEVELOPMENT GUIDED BY EXTREME SUBMARINE CONDITIONS
Following the direction set out by the first diver’s watch created by Richard Mille, the RM 025, the RM 028 uses a number of key elements that demarcate the theme of diving within the collection. Its exceptional tripartite case with a unidirectional bezel and water resistance to 300 metres follows ISO diver’s watch norm 6425, creating a perfect environment to house the skeletonised movement with variable rotor geometry, a Richard Mille exclusive.
RM 028 AUTOMATIC DIVER'S WATCH
Calibre RMAS7
Skeletonised automatic winding movement with hours, minutes, central seconds, date and variable-geometry rotor.
POWER RESERVE
Circa 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 skeletonised 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
MOVEMENT CHARACTERISTICS
CASE
The watch is water resistant to 30 atmospheres (300 metres) per ISO 6425 diver’s watch norms.
This is achieved with a unique, curved, tripartite case design using torque screws that can be individually and precisely tensioned with high accuracy around the exterior circumference of the case. This is complemented by a screw-lock crown construction.
BEZEL
This component is constructed of three layers connected with 22 screws, turning unidirectionally per ISO 6425 norms to avoid timing miscalculations.
The use of an additional screwed system attaching the bezel to the watchcase makes it absolutely stable, as well as impossible to inadvertently dislocate or loosen. In addition, the use of screws makes perfect adjustment possible, since the bezel is not tensioned into position.
For clearer visibility under murky conditions, starting at 12 o’clock, the five-minute markers of the first quarter are highlighted in red.
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.
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