Used Cnc Grinding Machines for sale (64,962)

Year of construction: 1992, condition: ready for operation (used), - USED - BRIDGE-TYPE CNC GRINDING MACHINE LONGITUDINAL TRAVEL: 650 mm TRANSVERSAL TRAVEL: 450 mm VERTICAL TRAVEL: 500 mm VERTICAL SPINDLE TRAVEL: 130 mm TABLE SIZE: 770 x 630 mm MAX ADMITTED LOAD: 500 Kg DISTANCE BETWEEN THE COLUMNS: 750 mm DISTANCE BETWEEN SPINDLE AXIS-TABLE: 0-600 mm SPINDLE: 30.000 rpm Hsdpeigrvdsfx Ag Nonu CONTROL UNIT: FANUC 210 IS-M WEIGHT: 4000 Kg OVERALL DIMENSIONS: 2650 x 2000 x 3150 mm ACCESSORIES: RS 232 SERIAL PORT NOTE: MACHINE WITH SPINDLE 60/70.000rpm, SPINDLE 100/120.000rpm; MACHINE COMPLETELY OVERHAULED IN 2002

Condition: good (used), Year of construction: 1990, Year of construction 1990 Control type CNC Sanding length 600 mm Hnodei Hn U Ujpfx Ag Nou Sanding width 200 mm Workpiece height 375 mm Table load 100 kg Grinding wheel dimensions 250x25x51 mm Run at 1-24 m/min Speed 4200 rpm Drive motor 5 kW Total power requirement 7.5 kW Machine weight approx. 3.2 t Space requirement approx. 3.7 x 2.1 x 2.1 m

Condition: new, Year of construction: 2025, operating hours: 1 h, functionality: fully functional, travel distance X-axis: 4,000 mm, travel distance Y-axis: 1,000 mm, travel distance Z-axis: 1,000 mm, rotational speed (max.): 8,000 rpm, controller manufacturer: STYLE CNC Machines, number of slots in tool magazine: 24, motor manufacturer: FANUC, Delivery after consultation Ref: 24F048 Year of construction: 2025 Condition: Showroom Specifications: - X-axis: 4000 mm - Y-axis: 1000 mm - Z-axis: 1000 mm Hnsdpfxjw Ty S Ss Ag Nou - 26 kW (S6) main motor - 8000 rpm - BT-40 - Automatic tool changer (24 positions) - Remote service (IXON) + network connection - Stronger coolant pump incl. spray gun - Upgraded to the latest STYLE software available

Condition: new, Year of construction: 2025, Contact us for more information, price, delivery time and installation CNC Machining Center Working area X-axis 3,200mm Working area Y-axis 1,550mm Hsdewkvdgepfx Ag Nsnu Working area Z-axis. 140mm milling motor 9Kw ER32/ER40 (12Kw opti.) speed 1,000 / 24,000R HSK63F mounting tool change magazine multi-drill + 2 groove saws 9x vertical drills software PWood Pegasus inport: DXF, jpg, png, eps, plt,... Cad milling 3D simulation software nesting optimization Vacuum pump Becker VTLF2.250 5.5Kw Omron safety light street central automatic grease lubrication connection diameter extraction Ø150 Required extraction capacity 28m/m | 2900m3/h total capacity 21.4 Free 1 year online help desk. Teamviewer language English This service prevents unnecessary downtime.

Condition: new, Year of construction: 2024, We offer very flexible CNC Pallet nailing machines designed for production most kinds of pallets Machine available in 2 versions 1. Palletmax it is double table CNC Nailing Machine 2. Palletstar it is delta-triple table CNC Nailing Machine with stacking robot. Also for pallets 2600mm length. - Easy and quick change system and training for new pallet. - Standard and adjustable templates. - Easy maintenance and low costs Hnjdpfxjtk Dghs Ag Nsu - High capacity . - Short production period.

Condition: as good as new (ex-display), Year of construction: 2024, operating hours: 10 h, functionality: fully functional, machine/vehicle number: 8046723D038, spindle motor power: 11,000 W, turning diameter over cross slide: 380 mm, spindle speed (max.): 3,000 rpm, overall weight: 2,000 kg, type of input current: three-phase, total width: 1,800 mm, total length: 2,500 mm, total height: 1,800 mm, torque: 373 Nm, Equipment: documentation/manual, CNC LATHE STYLE 350 [850 dbc] Hedpfxevvwblo Ag Njnu - main spindle motor power 11kW - main spindle bore Ø54 mm, 3,000 rpm - manual universal with 3 jaws D200mm - VDI30 turret with 8 positions - Coolant gun, including high-pressure pump - Work area lighting (LED) - Cooling system - Automatic lubrication - Ball screw protection - Full fairing with sliding doors - Speed potentiometer - Coolant control button - Handwheel - Remote support on machine – allows remote diagnostics

Condition: new, Experience unmatched precision and performance with ROBBI cylindrical grinding machines. Our machines offer grinding lengths starting from 600mm and are available in semi-automatic and CNC versions. With a grinding diameter of 300-1000mm, you have endless possibilities. Some machines are available from stock! Discover our extensive range of special accessories that make your cylindrical grinding machine even more versatile. Whether for complex workpieces or challenging tasks, our machines always deliver the best results. Trust in ROBBI's years of experience and let us optimize your machining processes together. Invest in quality and precision - contact us today! Our selection of conventional or controlled machines with grinding length up to 2m (further models available upon request): TECHNICAL MAIN DATA: Model Omicron CNC 60 or semi-automatic series Grinding diameter 595/695 mm Grinding length 1000 - 3000 mm max. workpiece weight between centers 1200 kg TECHNICAL MAIN DATA: Model Omicron CNC 36/32 or semi-automatic series Hjdpfx Agogay T Do Nonu Grinding diameter 320 / 355 / 455 mm Grinding length 630 - 2030 mm max. workpiece weight 120 (250/300 opt.) kg CONVENTIONAL MACHINES: TECHNICAL MAIN DATA: Model Omicron E Series Grinding diameter 360 - 430 mm Grinding length 630 - 1530 mm Workpiece weight between centers 200 - 300 kg ACCESSORIES (EXAMPLE FOR OMICRON CNC 60): CNC control: Siemens 840D Glass scales: in the X-axis Coolant system: with coolant collection tank Grinding wheel dresser: mounted on the tailstock (without diamond) Telescopic cover: for the fabric table Machine oil: 5l for the spindle Frequency converter: for spindle motor and workpiece drive (stepless) Hydraulic unit: for controlling the tailstock quill Ball screw in axes: X and Z Optimized cycle with geometric and operational parameters - CNC grinding machines meet the requirements for producing medium-sized workpieces. - The machines are equipped with the latest generation SIEMENS 840Di sl system. - The machine can be equipped with automatic measuring systems. - It is possible to design the grinding wheel for geometries specifically created for the required production type. - High-precision machining can be carried out when the grinding machines are equipped with a third interpolated axis and specially designed software. EASY PROGRAMMING Complex programs can be created without the need for knowledge of ISO programming. The input of parameters is facilitated by a series of messages and symbols that explain the meaning of the different parameters step by step. Programming of work cycles is done by entering the same cycle parameters. The order of execution of the various cycles can be changed quickly and intuitively. By the way, in addition to affordable new machines and tested used ones, you can expect more from us: • Consultation and problem-solving on-site at your location • Organization of transport of your machine to your factory • Installation, assembly, commissioning, and operational handover and more.

Condition: good (used), Year of construction: 2014, center height: 180 mm, center width: 600 mm, grinding diameter: 260 mm, Sinumerik 840D sl cnc control tail stock measuring device diamant roll portal loading device Technische Daten / technical details: Spitzenweite / center to center 600 mm Spitzenhöhe / center height 180 mm max. Schleifdurchmesser / max. grinding diameter 260 mm Schleifscheibenmaß / grinding wheel dimension 600x80x304,8 mm Reitstock / tail stock MK4 Hnsdpfxevygwws Ag Nju Antriebsleistung Schleifspindel / drive capacity grinding wheel 12 kW Gewicht der Maschine / weight 7500 kg Technische Daten, Zubehör und Beschreibung der Maschine sind unverbindlich - Technical data, accessories and description of the machine are not binding.

Condition: as good as new (ex-display), Number: AAL 130426 Length: 1,000 mm Storage diameter: 170 mm Hjdpfx Aod Nlagsg Nenu Cone intake: 46 to 64 mm diameter 70 mm length Speed: 8,000 U/min Condition: Unused Use: For large Chevalier grinding machine FSG 2460 CNC

Year of construction: 1990, condition: ready for operation (used), Working width: 900mm, length: 2600mm, width: 2600mm, height: 2000mm, weight: 1.8t, operating hours: 5866h. Including wet suction. Documentation and maintenance reports available. On-site inspection is possible. Hnjdpouzlg Djfx Ag Neu

Condition: new, Experience unparalleled precision and performance with ROBBI's range of cylindrical grinding machines. Our machines offer grinding lengths starting from 2000mm and are available in semi-automatic and CNC versions. With a grinding diameter range of 300-1000mm, the possibilities are endless. Partly available from stock! Hedpetximvefx Ag Njnu Discover our extensive range of optional accessories that make our cylindrical grinding machines even more versatile. Whether it's for complex workpieces or demanding tasks, our machines always deliver the best results. With ROBBI's years of experience, trust us to optimize your machining processes. Invest in quality and precision - contact us today! MAIN TECHNICAL DATA: Model: Omicron CNC 80 Grinding diameter: 795/895/955 mm Grinding length: 3000-6000 mm Center height: 400/450/500 mm Center distance: 3000-6000 mm Swing over bed: 795/895/955 mm Max. workpiece weight between centers: 4 t Additional technical data in the appendix MAIN TECHNICAL DATA: Model: Omicron CNC 60 Grinding diameter: 595/695 mm Grinding length: 1000-3000 mm Center height: 300/350 mm Center distance: 1150-3150 mm Swing over bed: 600/700 mm Max. workpiece weight between centers: 1200 kg Additional technical data available on request or in the appendix MAIN TECHNICAL DATA: Model: Omicron CNC 36 Grinding diameter: 355/455 mm Grinding length: 630-2030 mm Center height: 180/230 mm Swing over bed: 355/455 mm Max. workpiece weight: 250 (300 opt.) kg Additional technical data available on request or in the appendix ACCESSORIES (EXAMPLE FOR OMICRON CNC 80) CNC control: Siemens 840D Glass scales: in the X-axis Coolant system: with coolant collection tray Grinding wheel dresser: mounted on the tailstock (without diamond) Telescopic cover: for the table made of fabric Machine oil: 5l for the spindle Frequency converter: for spindle motor and workpiece drive (stepless) Hydraulic unit: for controlling the tailstock quill Ball screw in the axes: X and Z Optimized cycle with geometric and process parameters - The CNC grinding machines meet the production requirements for medium-sized workpieces. - The machines are equipped with the latest generation SIEMENS 840Di sl system. - The machine can be equipped with automatic measuring systems. - It is possible to design the grinding wheel for geometries specifically created for the required type of production. - High-precision machining can be performed when the grinding machines are equipped with a third interpolated axis and specially designed software. EASY PROGRAMMING Complex programs can be created without the need for ISO programming knowledge. The input of parameters is facilitated by a series of messages and characters that explain the meaning of the various parameters step by step. The programming of work cycles is done by entering the same parameters of the cycle. The sequence of execution of the various cycles can be quickly and intuitively changed. By the way, in addition to affordable new machines and tested used machines, you can expect even more from us: • Consultation and problem-solving at your location • Organization of machine transport to your facility • Installation, commissioning, and turnkey delivery, and more.

Condition: new, Year of construction: 2025, functionality: fully functional, workpiece weight (max.): 170 kg, grinding spindle speed: 45,000 rpm, spindle speed (min.): 5,000 rpm, spindle speed (max.): 45,000 rpm, clamping diameter: 140 mm, clamping length: 1,100 mm, warranty duration: 12 months, Workpiece Clamping Diameter : ø 3 – 140 mm Workpiece Length : 50 – 1.100 mm Centre Hole Diameter : ø 1 – 100 mm Workpiece Weight : max. 170 kg Center Hole Angle : 60 ° Accuracy : < 1 µm (Submicron accuracy) Spindle Speed : 5.000 – 45.000 rpm Grinding Cone Movements : 3+1 Rotation Orbital rotation Stroke movement +1 Workpeice rotation Quirlig Grinding Technique : Included (Cross-hatched grinding pattern) Grinding Process : Robotic, Complete-CNC Control Panel : Beckhoff CNC Movements : Z1-Axis, Z2-Axis, Workpiece clamping Feeding : Stäubli robot arm for loading, unloading and aligning Automatic Grinding Cone Dressing : Included Automatic Compensation After Dressing: Included Indurstry 4.0 Compatibility : Available Workpiece Rotation : Available (as a option) Dust Extraction And Filtration : Available (as a option) Sectors: : Precision Grinding, Aviation, Automotive, Machinery etc. Benefits: Sub-micron Precision: Achieve sub-micron (< 1 µm) precision in grinding thanks to Swiss engineering and a robust machine design. Sustainable Reliability: Ensure reliable and sustainable processing. Non-Stop Production: Achieve continuous production with robotic arm feeding, automatic dressing, and automatic compensation features, eliminating the need for constant operator oversight. Quirlig Grinding Technique: Experience an optimized grinding process with the Quirlig Grinding Technique. Properly ground center holes that have cross-hatched grinding pattern. The cross-hatched grinding pattern ensures that oil is retained when the workpiece is placed between the centers during the cylindrical grinding process, creating a micro oil layer. The micro oil layer prevents unwanted "dry running" during cylindrical grinding. Easy to Use Complete-CNC Control Panel: Utilize a full CNC control panel that allows you to control all axes of the machine, manage robotic feeding, and perform automatic dressing with the Beckhoff control panel. Easily save all grinding programs and monitor machine working times, efficiency, and errors. Industry 4.0: Fully compatible with Industry 4.0 applications, thanks to the Beckhoff control panel. Low Maintenance Costs: Enjoy low maintenance costs throughout the machine's service life, thanks to Swiss-quality construction. The Zentroflex A-series center hole grinding machines are designed to deliver high-precision cylindrical grinding in the aviation, automotive, and machinery sectors for mass-production. Additionally, the Zentroflex A-series is the ideal solution for recovering parts distorted after heat treatment or for reducing cylindrical grinding costs. With 6-Axis robot arm and servo motors on all axes of the machine, Zentroflex A-series center hole grinding machines operate completely autonomously. All loading and unloading operations are performed by the robot arm. All axis movements of the machine are also performed autonomously with servo motors. Cone dressing and compensation are also performed automatically. All movements and measurements of the machine are performed from the CNC control panel. Hnedpfxju Nmi Ne Ag Neu Contact us for more details.

Condition: new, Year of construction: 2025, center height: 160,200,250 mm, workpiece weight (max.): 750 kg, grinding length: 100,020,003,000 mm, grinding wheel diameter: 500,600 mm, total width: 2,000 mm, total length: 6,000 mm, total height: 2,000 mm, grinding diameter: 320,400,500 mm, quill stroke: 50 mm, spindle speed (max.): 560 rpm, spindle speed (min.): 1 rpm, grinding spindle speed: 1,400 rpm, warranty duration: 24 months, Equipment: rotational speed infinitely variable, Main technical data : Swing diameter mm 320,400,500 Distance between centres mm 1000,1500,2000,3000 Standard wheel size (diameter x width x bore) mm 500 x 200 x80 Maximum wheel width mm 100 Peripheral wheel speed m/sec 45 Hnodepy A Iujpfx Ag Nou Wheelhead swivel (°) +10/- 30 Workhead swivel (°) 90 Tabel swivel (°) 0 Workhead spindle speed, infinitely variable RPM 2-500 Workhead sleeve taper bore Morse 5 Tailstock sleeve taper bore Morse 5 Minimum programmable increment : in axis X /related to diameter./ (grinding wheelhead) mm 0,001 in axis Z (table) mm 0,005 Maximum weight of workpiece Workhead motor kW 2.5 Wheelhead motor kW 11 Total power demand of machine kW 45 - between centres kg 500 Weight of machine with standard accessories kg approx 10000 Dimensions of machine approx. mm 8 000x 2 980 x 2 200

Condition: new, :Omicron CNC 3206 | Omicron CNC 3210 grinding diameter:315 mm grinding length:600|1000 mm Hnsdod Ed S Iepfx Ag Nsu centre height:160 mm swing over bed:315 mm max. workpiece weight:120 kg grinding headstock:_____ __ grinding wheel size:450 x127 x min.20-max.50 mm grinding spindle speed:600-1600 (stufenlos) 1/min feed per revolution of handwheel:0,001/ 0,01 / 0,1 mm grinding head swivellable +/-:±180 ° automatic feeds:0,2-3000 mm/min workhead:_____ __ workhead - spindle speed:0-600 (stufenlos) 1/min swiveling workpiece drive:±90 ° workhead - center taper:4 MK tailstock:_____ __ tailstock quill adjustment:50 mm tailstock quill diameter:70 mm taper in tailstock:4 MK table:_____ __ table speeds:1-5000 mm/min swivellable angle of table:+9°/-5° | +8°/-4° ° table adjustment - longitudinal:680|1080 mm motors:_____ __ grinding wheel motor:4 kW workhead motor:0,75 kW hydraulic motor:0,75 kW coolant pump:0,18 kW machine dimensions:_____ __ weight of the machine ca.:3700 | 4900 kg Machine size (LxWxH):2900x1350x1750 | 3700x1350x1900 mm CNC controller:Siemens 840 dsl complete cooling system:mit Auffangbecken für Kühlmittel Scales:X-Achse ball screw in axes:X und Z :montiert auf dem Reitstock (ohne Diamant) Telescope cover for guideways:für den Tisch aus Stoff machine lubrication:5l für die Schleifspindel hydraulic unit:zur Steuerung des Reitstockpinolenhubs

Condition: new, Year of construction: 2025, center height: 315,425 mm, grinding wheel diameter: 750 mm, grinding diameter: 630,850 mm, grinding spindle speed: 1,000 rpm, overall weight: 17,000 kg, Main technical data : Swing diameter mm 630-850 Distance between centres mm 3000,4000,500 Standard wheel size (diameter x width x bore) mm750/570 x 100 x 305 Maximum wheel width mm 100 Peripheral wheel speed m/sec 45 Wheelhead swivel (°)+10/- 30 Workhead swivel (°)90 Tabel swivel (°)+6/-4 Workhead spindle speed, infinitely variable RPM 8 – 156 Workhead sleeve taper bore Morse 6 Tailstock sleeve taper bore Morse 6 Minimum programmable increment : in axis X /related to diameter./ (grinding wheelhead) mm 0,001 in axis Z (table) mm 0,005 Maximum weight of workpiece Workhead motor kW 7,5 Wheelhead motor kW 22 Total power demand of machine kW 45 Hnsdpfx Agopy A Iqe Nou - between centres kg2 500 Weight of machine with standard accessories kg approx 17 500 Dimensions of machine approx. mm 12 000 x 2 980 x 2 200

Condition: ready for operation (used), Year of construction: 2002, functionality: fully functional, center height: 225 mm, controller model: Fanuc 16T, TECHNICAL DETAILS Hnedpfx Aexlix Dsg Nju Centre height: 225 mm MACHINE DETAILS Control: Fanuc 16T

Condition: ready for operation (used), controller manufacturer: Heidenhain TNC 360, total height: 2,850 mm, total length: 4,800 mm, total width: 2,440 mm, empty load weight: 12,200 kg, Maximale afstand van kolom tot midden van spindel: 1270 mm (diepte van de kiel) Max longitudinal travel X-axe: 3550 mm Max cross-travel Y-axe: 1050 mm Max travel Z-axe: 1016 mm Power on spindle: 15 HP Admission in boring head (ISO): ISO 50 Spindlespeeds: 28 > 1800 rpm Hedjv Tan Njpfx Ag Nenu Table size: 4100 x 1000 mm

Condition: ready for operation (used), total height: 2,100 mm, total length: 1,235 mm, total width: 1,500 mm, empty load weight: 1,000 kg, Chevalier FM 3VS X: 762 - Y: 305 - Z: 406 mm Max longitudinal travel X-axe: 762 mm Max cross-travel Y-axe: 305 mm Hnodpfx Agexpgfco Neu Max travel Z-axe: 406 mm Max height workpiece: 70 > 476 mm Power on spindle: 3 HP Admission in boring head (ISO): ISO 30 Spindlespeeds: 3750 rpm Table size: 1220 x 230 mm

Condition: ready for operation (used), empty load weight: 1,300 kg, Holke F-10-V X: 815 - Y: 400 - Z: 420 mm Max longitudinal travel X-axe: 815 mm Max cross-travel Y-axe: 400 mm Max travel Z-axe: 420 mm Power on spindle: 2 HP Hnodpfx Agoxpgfio Nsu Admission in millinghead: ISO 40 Max quill travel Z': 130 mm Spindlespeeds: 57 > 2275 rpm Table size: 1120 x 255 mm

Condition: ready for operation (used), Elgo CNC controlled machine, very easy and user-friendly max tube cap: dia 76 mm x 4 mm thickness max square tube: 70 x 70 mm max radius: 600 bending angle: 180° Hnodoxpghqspfx Ag Nsu Standard tooling 3D Special tooling on request Length: 1200 mm Width: 800 mm Height: 1300 mm

Condition: ready for operation (used), controller manufacturer: Heidenhain 355, empty load weight: 11,500 kg, total length: 7,500 mm, total width: 3,500 mm, total height: 3,800 mm, Butler Elgamill X: 3000 - Y: 1670 - Z: 1050 mm Longitudinal travel X-axe: 3000 mm Cross travel Y-axe: 1050 mm Travel Z-axe: 1670 mm Dimensions clamping space- table: 3100 x 1200 mm Power on spindle: 30 kW Hnsdpfx Asxpgh Reg Nou Admission in millinghead (ISO): ISO 50 Max speedrange: 16 > 2000 rpm

Condition: ready for operation (used), table: 1270 x 250 mm Max longitudinal travel X-axe: 864 mm Max cross-travel Y-axe: 406 mm Max travel Z-axe: 406 mm Hnodpfjxpginex Ag Nju Power on spindle: 5 HP Admission in boring head (ISO): ISO 40 Table size: 1200 mm

Condition: ready for operation (used), controller manufacturer: Heidenhain 355, empty load weight: 8,400 kg, total length: 5,000 mm, total width: 2,720 mm, total height: 2,420 mm, CN 3 assen horizontale en verticale freeskop T-sleuven: 18 x H8 Afstand tussen T-sleuven: 80 mm Met de kop in de hoogste positie kan het werkstuk een maximale hoogte van 955 mm hebben. Longitudinal travel X-axe: 1800 mm Cross travel Y-axe: 800 mm Travel Z-axe: 800 mm Hnsdpfxoxpgiuj Ag Nou Dimensions clamping space- table: 2000 x 630 mm Power on spindle: 15 hp Admission in millinghead (ISO): ISO 50 Max speedrange: 25 > 3250 rpm

Condition: ready for operation (used), controller manufacturer: Heidenhain TNC 410, empty load weight: 9,000 kg, total length: 2,800 mm, total width: 2,540 mm, total height: 2,500 mm, CME BF-01 X: 1800 - Y: 700 - Z: 600mm Longitudinal travel X-axe: 1800 mm Cross travel Y-axe: 700 mm Travel Z-axe: 600 mm Dimensions clamping space- table: 1800 x 600 mm Power on spindle: 30 hp Admission in millinghead (ISO): ISO 50 Hjdpfx Agjxpgizs Nsnu Max speedrange: 3000 rpm Power needed (KVA): 11 kW

Condition: ready for operation (used), chuck outer diameter: 3,200 mm, total height: 7,155 mm, controller model: Siemens 840D, empty load weight: 65,000 kg, Type: SKD 32B Siemens 840D CNC-besturing 2017 Tafeldiameter: 3200 mm Maximale zwenkhoek: 3500 mm Maximale belasting op tafel: 50 ton Hydrostatische tafel!! Vermogen op tafel: 120 kW Torsiesterkte: 132 Kn 2 variabele snelheidsversnellingsbak: ,8 80 tpm Verticale verplaatsing van de dwarsbalk: 2100 mm Maximale werkstukhoogte: 2550 mm Hnsdov Rwh Ispfx Ag Nju 2 gereedschapskoppen op dwarsbalk CNC gestuurd - horizontale beweging van gereedschapskop nr. 1: 1400 mm - verticale beweging van gereedschapskop nr. 1: 1500 mm - horizontale beweging van gereedschapskop nr. 2: 1980 mm - verticale beweging van gereedschapskop nr. 2: 1350 mm - rotatiehoek van de gereedschapskop: -/+ 30° Max turningdia -- passage: 3500 mm Power on the spindle: 120 kW Number of speeds: 1 > rpm / > 80 rpm Power needed: 195 kVa Long: 10045 mm Wide: 8120 mm