Used Dmg Ctx Beta 500 for sale (383)

Condition: excellent (used), Year of construction: 2014, operating hours: 11,440 h, DMG 5 axis Simultaneous HSC 30 Linear Year 2014 Heidenhian TNC640 Control Travel X320 / Y 300 / Z280mm B axis +/- 120 degree C axis 360 x 0.001 degree HSK-E40, 40,000rpm Swivel rotary table Codjw Hxiwepfx Addeaa Touch Probe BLUM Tool Measuring system 3D Quick Set Application Tuning Cycle Air Blast through spindle Super Fine filter system c/w tooling ----- Clearance Sales -----

Condition: ready for operation (used), Year of construction: 2017, Control Unit Brand SIEMENS Model 840D sl Operate with CELOS® Movement X-Axis Movement 560 mm Y-Axis Movement 560 mm Z-Axis Movement 660 mm Media Chip conveyor Yes Additional Equipment Tool breakage control system in the tool magazine Cjdpoxwz Afefx Addeaa Two pallets with threaded holes Automatic turning APC with 2 stations Direct distance measuring system Rotating viewing window in the work area door Coolant rinsing gun I/F for oil mist separator Knoll KF110/700 compact filter system Spindle sensor measuring system with optical signal transmission / Cooling unit for spindle Signal light (red, yellow, green, blue) This 4-axis DMG MORI NHX 4000 was manufactured in 2017. A robust horizontal machining center, it features a travel range of 560x560x660 mm and a clamping surface of 400x400 mm. The spindle was completely overhauled in May 2023. It has a tool magazine with 60 slots. The tool Holder is HSK 63 HSK-A63 motor spindle and the spindle speed range is 20 - 20,000 min-1. The machine includes a CELOS® control system with Siemens 840D sl Operate, enhancing usability with a multi-touch screen. For more information about this horizontal machining center, please reach out to us. Application Types Milling

Condition: good (used), Year of construction: 2019, operating hours: 8,173 h, functionality: fully functional, turning length: 12,025 mm, turning diameter: 480 mm, spindle speed (max.): 3,250 rpm, travel distance X-axis: 308 mm, travel distance Y-axis: 120 mm, travel distance Z-axis: 1,240 mm, bar passage: 102 mm, overall weight: 7,200 kg, controller model: DMG MORI SLIMline Multi-Touch Control, control type: CNC control, CLX 550 V6 2-axis universal lathe with driven tools incl. C-axis, Y-axis, and counter spindle Standard equipment: 1. Ergonomic DMG MORI SLIMline operating panel 2. Main spindle A2-8 with AC motor, drive power 22 / 33 kW (100/40% DC), 3,250 rpm 3. Counter spindle A2-6 with ISM 52 synchro, drive power 13 / 14 kW, torque 171.5/192 Nm (100/40% DC), 5,000 rpm 4. 12-position servo turret, VDI 40 mounting with Trifix® precision interface and 12 driven tool stations per DIN 5480 5. Y-axis ± 60 mm 6. Chip tray 7. Hollow clamping device, max. bar capacity D 80 mm 8. Electronic handwheel Drive power (100%/40% DC) 22/33 kW Hydraulic clamping device with bar capacity diameter 102 mm, surcharge Differential pressure clamping for main spindle Bar package & interface option includes: - Workpiece unloader for parts up to D 80 x 200 mm long (D 100 x 200 mm with option C-B7000G) Max. workpiece weight 4 kg - Interface for bar loader or bar feed unit (DMG MORI standard interface) - Hinged belt chip conveyor instead of chip tray - 4-color signal tower Recommended additional option: Double cartridge filter for coolant, especially for production environments with very high chip volumes. Automatic workpiece ejector for counter spindle with internal coolant supply for clamping device flushing. Note: Option recommended for machines with workpiece unloader option. External flushing for counter spindle, option recommended for machines with automation Differential pressure clamping for counter spindle Tailstock function for counter spindle, mechatronic force control programmable in the software (force 250-600 daN), including foot switch (only for CLX 550 V6) Direct measuring system for X- and Y-axis (option only available for V4 and V6 versions) Manual tool measuring device in the working area, brand Marposs Documentation according to 'Technical Documentation Delivery List' – included in the machine price. Software option: DXF import for converting DXF files into NC programs (SIEMENS control) Tool monitoring system: Easy Tool Monitor 1.0, monitors each cutting operation against a set limit. Simple learning function for determining the monitoring limit per tool and cutting operation; manual adjustment/correction possible. Technology cycle: Alternating speed (turning) for vibration-sensitive applications Csdsxx Tcmepfx Addoaa Note: We offer flexible financing solutions for all machines as well as a professional relocation service. Dismantling, transport, and professional installation – everything from a single source. Billing based on individual terms and duration. Contact us for your personal offer.

Condition: used, Year of construction: 2008, x-travel 500 mm y-travel 450 mm z-travel 400 mm Control HEIDENHAIN iTNC 530 Table dimensions 500 x 380 mm table weight 500 Kg c-axis 0.001º ( ± 360º) 0 b-axis 180 ° rapid traverse X-axis 80 m/min Csdpsxluf Aefx Addeaa feeds 50 m/min spindle turning speed range 18.000 U/min spindle taper BT- 40 spindle drive 30 kW Internal cooling system 40 bar handwheel HEIDENHAIN HR-410 Working hours 51.770 h Spindle hours 14.627 h total power requirement 50 kVA weight of the machine ca. 6,5 t

Condition: excellent (used), Year of construction: 2012, operating hours: 3,540 h, functionality: fully functional, travel distance X-axis: 700 mm, travel distance Y-axis: 420 mm, travel distance Z-axis: 380 mm, rapid traverse X-axis: 60 m/min, rapid traverse Y-axis: 60 m/min, rapid traverse Z-axis: 60 m/min, feed rate X-axis: 60 m/min, feed rate Y-axis: 60 m/min, feed rate Z-axis: 60 m/min, nominal power (apparent): 16 kVA, controller manufacturer: Siemens, controller model: 840D SL, table load: 300 kg, spindle speed (max.): 24,000 rpm, spindle nose: BBT Big+, number of slots in tool magazine: 25, Equipment: documentation/manual, DMG Mori Milltap 700 machine for sale, in new condition. Caodpfxjxghpwj Addea Siemens 840 D SL control. We bought the machines because of the small space requirement, 24,000 spindle, fast tool change and 60 meter rapid traverse. The machine can be viewed and tested under power. We can help with packaging and loading onto a truck.

Condition: good (used), Year of construction: 2010, Ref. -No.: 10287 Manufacturer: DMG Type: DMC 210 FD Year of construction: 2010 Type of control: CNC Control: Heidenhain Mill Plus Storage location: Halberstadt Country of origin: Deutschland X-Travel: 2100 mm Y-Travel: 2100 mm Z-Travel: 1250 mm Machine length: 11.000 mm Machine width: 5.000 mm Machine Height: 3.500 mm Max. Workpiece diameter: 2500 mm Max. Workpiece Weight: 6.000 kg Max. rotary table diameter: 1.850 O Table speed range: 250 min/-1 Tool Taper: HSK-A100 Tool Piece Magazine With: 600 Pcs./pcs. Spindle Speed: 20.000 RPM Max. Torque: 8.600 Nm Casdpjxxn Uksfx Addea Feed Speeds X/Y/Z Axis: 60.000 mm / min Max. Workpiece height: 1.460 mm axes: 5 Further information: Turning and milling center incl. pallet changing system Gear spindle Coolant treatment system, with belt filter, 710 x 50mm 1 Knoll 600S2 chip conveyor 2 Losma oil mist extraction units 1 steel platform (storage space for clamping device): 5,300 x 2,900 mm - Axes renewed 11.2024 - New encoder, electrical components renewed - Geometry protocols available Machine is still in production and under power. The machine can be viewed at any time by appointment.

Condition: good (used), Year of construction: 2020, spindle speed (min.): 12,000 rpm, Machine type: CNC Vertical Machining Center Model: CMX1100V Manufacturer: DMG MORI Control: DMG MORI HEIDENHAIN TNC 620 Year of manufacture: 2020 Location: Germany Travel Range X-axis: 1100 mm Y-axis: 560 mm Z-axis: 510 mm Table size approx. 1400 x 560 mm Max. workpiece weight approx. 1000 kg Max. spindle speed approx. 12,000 rpm 13/9 kW Number of tool pockets: 30 Rapid traverse X / Y / Z: 30 m/min Tool holder: SK40 Footprint (L x W x H): approx. 4.04 x 2.8 x 2.95 m Equipment - Main spindle 12,000 rpm 13/9 kW SK40 - Direct absolute measuring system X-Y-Z - Separate electronic handwheel - 30-position chain-type tool magazine Csdpfexx Athjx Addjaa - Bed flushing via M-function - Coolant tank 600 liters - Internal coolant supply (IKZ) pump 20 bar - Coolant spray gun - Enclosure roof (M-function) - Touch probe set for Heidenhain - 4th axis interface (Subject to errors in technical data and specifications)

Condition: ready for operation (used), Year of construction: 2022, operating hours: 8,574 h, General Data Machine weight 9200 kg Control Unit Brand SIEMENS Main Drive Spindle speed range 5000 Number of axis 5 Movement X-Axis Movement 750 mm Y-Axis Movement 200 mm Z-Axis Movement 1100 mm Workpiece Cjdpfx Adexu Rufodsaa Workpiece drm 400 mm This 5-axis DMG MORI CLX 450 TC was manufactured in 2022, featuring a max. X-axis stroke of 750 mm, Y-axis stroke of 200 mm, and Z-axis stroke of 1,100 mm. It handles a max. workpiece diameter of 400 mm and length of 1,100 mm, with a bar capacity of 65 mm. Spindle speeds reach up to 5000 rpm. Weighs 9200 kg. If you are looking to get high quality turning capabilities consider the DMG MORI CLX 450 TC machine we have for tact us for more information. Application Types Turning

Condition: used, DMG HSC 55 linear is a 5-axis machining center designed for precision, high accuracy and reliable performance. Travels X 450 mm, Y 650 mm, Z 460 mm; A-axis -10/+110°; tool magazine 120 places; tool Ø max 80 mm, length 250 mm, weight 6 kg; spindle taper HSK 63. Spindle speeds 2–28,000 min⁻¹; spindle power 38/28 kW; supply 3x400 V 50 Hz; total power 70 kVA; machine weight ≈9500 kg; dims L3210×W2930×H2900 mm. Delivers tight tolerances; typical applications: automotive, aerospace, medical, watchmaking and toolmaking. Caedpfxoxx U Iwj Addoa

Condition: used, Year of construction: 2014, Opportunity to buy a DMG vertical machining center from 2014 in very good condition, with 23571 spindle hours. Caodpfx Ajw Spqhjddja Immediately available for delivery (in Europe as well). Extra: Direct measuring system X, Y, Z - inclusive air purge for measuring system Electronic handwheel Active cooling unit for electrical cabinet additional ventilator for control panel actice cooling unit for motor spindle Video available on request. X-AXIS Movement 635 mm Y-AXIS Movement 510 mm Z-AXIS Movement 460 mm Tabel dimensions 790 x 560 mm Max spindle speed 12000 rpm Tool changer 20 places Tool taper SK40 Cnc Control Heidenhain TNC620 - Slimline panel Tool clamping BT40 , for pull studs DIN69872 Spindle hours 23571

Condition: excellent (used), Year of construction: 2018, Traverses XYZ 1150 x 700 x 550mm, Casdpfxjw Nq Hxe Addsa table size 1460 x 750mm, table load 1,500kgs, spindle speed 12,000 rpm, 20 station ATC, Siemens 840D control, swarf conveyor, and coolant.

Condition: excellent (used), Year of construction: 2013, functionality: fully functional, travel distance X-axis: 600 mm, travel distance Y-axis: 500 mm, travel distance Z-axis: 500 mm, DMG-Mori DMU 60 Evo Linear Control: Heidenhain ITNC 530 HSCI NC swivel rotary table 600 mm x 500 mm B-axis swivel range: -5° to +110° C-axis 360°, including table cooling Spindle speed: 20 - 24,000 rpm, HSK 63 A Tool magazine with 120 positions Infrared measuring probe Renishaw OMP 60 Dynamic package, Laser tool measurement ICS with 40/80 bar, with paper band filter 980 l, chip conveyor Electronic handwheel, 3D Quickset Cjdjxvhtnopfx Addsaa ATC, programmable coolant nozzles via M-function Operating mode 4 Tropic package

Condition: used, Year of construction: 2017, spindle speed (min.): 12,000 rpm, Machine Type: CNC Vertical Machining Centre, 5-Axis Model: DMF260/11 linear Manufacturer: DMGMORI Control: CELOS Siemens 840D sl Operate Year of Manufacture: 2017 Location: Germany Travel Range X-axis approx. 2,600 mm Y-axis approx. 1,100 mm Z-axis approx. 900 mm B-axis (head): ° Rotary Table within Table: 1,050 mm Table Size: approx. 3,200 x 1,100 mm Workpiece Weight on Rotary Table (max.): approx. 1,200 kg Max. Spindle Speed: approx. 15,000 rpm Caodpjxw N A Tjfx Addea Spindle Motor Power: approx. 46/30 kW Number of Tool Stations: approx. 60 Rapid Traverse: approx. 80/60/60 m/min Tool Holder Taper: SK40 Power Consumption: approx. 143 kVA Machine Weight: approx. 28,000 kg Options: - Main spindle 15,000 rpm, 46/30 kW, SK40 - Dynamic package, rapid traverse x-y-z: 80/60/60 m/min - X-axis with linear motor - Separate electronic handwheel - 60-position chain magazine - Bed flushing via M-function - ICS pump 40 bar - 600 l coolant tank with paper band filter - Rotary table integrated in the machine table - B-axis in head - Automatic door - Coolant gun - Spindle probe - 2x Roto clear units - Scraper conveyor for swarf (Subject to errors and technical data changes)

Condition: ready for operation (used), Year of construction: 2011, operating hours: 937 h, General Data Measurements width 1530 mm Measurements depth 775 mm Measurements height 2253 mm Machine weight 1800 kg Control Unit Brand Siemens Casdpfjxuax Hjx Addja Model Sinumeric 840D Main Drive Spindle speed range 40000 rpm Number of axis 5 Movement X-Axis Movement 120 mm X-Axis Rapid Traverse 10 m/min X-Axis Accuracy P10 μm Y-Axis Movement 120 mm Y-Axis Rapid Traverse 10 m/min Y-Axis Accuracy P10 μm Z-Axis Movement 200 mm Z-Axis Rapid Traverse 10 m/min Z-Axis Accuracy P10 μm Table Table load 10 kg Tools Max tool diameter 49 mm Max tool length 130 mm Type of tool holder HSK-32 Media Power consumption 25 kVA Additional Equipment Workpiece Measurement: DMG PP-400 Infrared probe Tool Measurement: RS NC-4 Coolant Conditioning Equipment: KM 10 This 5-axis DMG ULTRASONIC 10 was manufactured in 2011. It features a Siemens Sinumeric 840D control, a spindle with 40,000 rpm max speed, and a tool magazine with 60 slots. The machine offers a compact footprint and includes options like a DMG PP-400 Infrared probe and RS NC-4 tool measurement. If you are looking to get high-quality milling capabilities consider the DMG ULTRASONIC 10 machine we have for sale. Contact us for more information about this machine. Application Types Milling

Condition: used, Year of construction: 2017, x-travel 750 mm y-travel 650 mm z-travel 560 mm Cajdpfx Ajxwzfteddea Control 3D HEIDENHAIN TNC 640 table-size 800 x 650 mm rotary table 650 mm table weight 600 Kg c-axis ° b-axis -120+120 ° Tool diameter 840 mm toolpiece height max. 500 mm rapid taverse 40.000 mm turning speeds 20.000 U/min Tool adapter HSK-A63 Torque 130/86 0 engine output 35 kW Internal cooling system 40 bar Machine on 26.972 h Spindle hours 11.412 h tool change unit 60 pos. Internal cooling system 40 bar total power requirement 49 kW weight of the machine ca. 11.600 kg -Tool charger -No. Positions in the tool charger 60 -Tank with 500l paper filter -Active refrigerator cabinet -Infrared measuring probe Heidenhain piece -Blum laser probe measuring device -chip extractor -Cleaning gun with 2 bar 40 l/min pump -3D quick set -HEIDENHAIN HR-510 Portable Steering Wheel

Condition: like new (used), Year of construction: 2013, operating hours: 7,100 h, functionality: fully functional, turning length: 650 mm, turning diameter over cross slide: 350 mm, turning diameter: 385 mm, spindle speed (min.): 4,500 rpm, spindle bore: 67 mm, travel distance X-axis: 255 mm, travel distance Z-axis: 800 mm, For sale: Used DMG NEF400 V3, 5th Generation ISM 2-axis universal lathe with C-axis. Travel distances: X: 255mm Z: 800mm Swing over bed: 385mm Swing diameter: 350mm Turning length: 650mm Equipment: - Main spindle as integrated spindle motor - Max. spindle speed: 4,500 rpm - Drive power: 8.0/11.5 kW (100/40% duty cycle) - 12-position VDI30 disc-type turret with 6 driven positions - C-axis and spindle brake (hydraulic) - Automatic tailstock, MK4 mounting, travel: 680mm - CNC control Siemens 840D Solutionline with ERGOline Control, Sinumerik Operate, and ShopTurn 3G - Operating system: Linux - Technology cycle for applying alternating spindle speeds for vibration-critical setups - Manual tool measurement device in work area - Hydraulic unit - Coolant spray gun - Mechanical oil mist separator - Reinforced coolant pump: 12 bar, 23 l/min - Chip conveyor with discharge height of 1,250mm, discharging to the right Bar machining package consisting of: - Workpiece pickup unit with left-side conveyor for parts up to max. 65mm diameter, 150mm length, and 3kg max. weight - Bar clamping device inner draw-tube diameter max.: 67mm - Interface for bar loader magazine - Foot switch for tailstock operation - Hydraulic 3-jaw chuck SMW-AUTOBLOK - RMS sensor (Relocation Machine Security) Machine available immediately! Machine ready for operation! Loading by us included! Transport can be arranged upon request! Cjdpsxzqnrjfx Addsaa

Condition: excellent (used), Year of construction: 2022, Table size 600 x 500mm diameter, table load 400 kgs, Traverses XYZ 600 x 500 x 500mm, B axis -5/+110 degrees, C axis 0.001 degrees Rapid feedrates 80m/min, Caodpfx Aow Nq E Usddoa 60 station toolchanger, spindle taper HSK 63, spindle speed 20,000rpm, Siemens 840D Ergoline control, swarf conveyor, Through Spindle Coolant,

Condition: as good as new (ex-display), Year of construction: 2017, operating hours: 2,038 h, functionality: fully functional, travel distance X-axis: 600 mm, travel distance Y-axis: 560 mm, travel distance Z-axis: 510 mm, workpiece length (max.): 900 mm, workpiece width (max.): 560 mm, workpiece height (max.): 630 mm, workpiece weight (max.): 600 kg, FANUC system. The machine was originally purchased for demonstration purposes at a training center and was later occasionally used in a tool shop. The machine is very well-preserved and fully functional – it can be tested under working conditions. Csdpjxy E R Eefx Addoaa

Condition: excellent (used), Year of construction: 2020, operating hours: 4,950 h, functionality: fully functional, machine/vehicle number: CMX 800 V, travel distance X-axis: 800 mm, travel distance Y-axis: 560 mm, travel distance Z-axis: 510 mm, workpiece weight (max.): 800 kg, table width: 560 mm, table length: 1,100 mm, table load: 800 kg, rotational speed (max.): 15,000 rpm, overall weight: 5,400 kg, operating hours of spindle: 4,950 h, type of input current: three-phase, Equipment: chip conveyor, documentation/manual, rotational speed infinitely variable, DMG CMX 800 V Like new – very well maintained and rarely used Machine depth: 2,426 mm Machine weight: 5,400 kg Table length: 1,100 mm Table load capacity: 800 kg Cedpfx Adjxwu U Iodsaa Table width: 560 mm Distance from table surface to spindle nose: 11.98 cm – 62.99 cm

Condition: good (used), For sale is a CNC milling machine DMG DMU 50 V with Heidenhain 426/430 control, 5 axes. The item is in good condition. Technical specifications: Travel X-axis: 500 mm Travel Y-axis: 380 mm Travel Z-axis: 400 mm Table: NC rotary/swivel table Rotary/swivel axes: B-axis approx. -10° / +95° C-axis (rotation): 360° Max. workpiece weight: approx. 200 kg Table surface: Ø 500 x 380 mm Main spindle: SK 40 (ISO 40) Max. spindle speed: approx. 10,000 rpm Max. tool length: approx. 280 mm Max. tool weight: approx. 6 kg Transport dimensions: 2.45 x 1.76 x 2.38 m Machine weight: approx. 3,500 kg Total power requirement: approx. 17 kW Transport and loading can be arranged Europe-wide for an additional charge, if required. Prices exclude VAT. Inspection possible by appointment. Please contact us, our team will be happy to assist you. Trade-in or exchange possible! Machinery Purchase / Sales PURCHASE & SALE OF PRODUCTION & METALWORKING MACHINES AND MORE. Are you looking for a high-quality yet affordable metalworking machine for your production? Or would you like to sell yours? For more information or contact options, please visit our website. Codpfx Adjxvzy Uedoaa

Condition: used, Year of construction: 2011, x-travel 2.600 mm y-travel 700 mm z-travel 700 mm Control SIEMENS SINUMERIC 840D table-size 2.900x700 mm table weight 2.150 Kg tool adaptor SK 40 DIN 69872 workpiece length - max. 300 mm workpiece weight 6 kg workpiece dia. 80/130 mm 30 fach main drive 18,4/14 kW speed 14.000 mm/min rapid traverse 40 m/min feed 40 m/min Machine on 18.859 h Spindle hours 5.666 h internal coolant system feed 40 Bar/600 l Chip coveyor inkl. Machine on 19.230 Spindle hours 5.998 h total power requirement 55 kW weight of the machine ca. 14.520 kg Cjdpfx Ajv Da T Heddjaa dimensions of the machine ca. 10.280 x 7.230 x 3.042 mm Acceleration in the axis 4 m/s2 -Cleaning gun -Portable handwheel -Direct measurement system

Condition: used, Year of construction: 2018, x-travel 650 mm y-travel 520 mm z-travel 475 mm Control Siemens 840D sl Operate CELOS Codsxwdriopfx Addoaa turning speed range - main spindle 20 - 20.000 min/-1 power capacity - main spindel 35 / 25 kW max. Torque 130 / 86 Nm tool taper SK 40 table surface area Ø 630 x 500 mm max. table load 300 kg swivellable B: -35° / +110 ° rotatable C: 360 ° number of T-slots 7x 14H7 x 63 number of toolpositions 60 pos. tool taper SK 40 max. tool diameter 80 / 130 mm max. tool length 300 mm max. tool weight 6,0 kg rapid traverse ( X / Y / Z ) 42 m/min total power requirement 39 kVA weight of the machine ca. 7,8 t dimensions of the machine ca. 5,0 x 4,0 x 2,8 m 5 Axis - CNC - Machiningcenter Universal DMG MORI - DMU 50 - 5-Axis-Simultaneous-Machining - NC-Swivel-Rotary-table - internal coolant supply - Operating-Hours: Power-On: ca. 7.802h Spindle: ca. 4.834h - Direct measuring system X, Y, Z - Work area flushing - MPC Machine Protection Control - DMG MORI PROFIBUS automation interface (incl. automatic loading door on the right side of the machine) - ATC (Application Tuning Cycle) - PH 150 pallet loading and unloading station - with handling system and pallet magazine - Rotary storage with 10 pallet holders - Handling capacity 150 kg - Job Manager - Comfort Plus control - incl. pallets and clamping devices

Condition: excellent (used), Year of construction: 2018, Table size 600 x 500mm diameter, table load 400 kgs, Traverses XYZ 600 x 500 x 500mm, B axis -5/+110 degrees, C axis 0.001 degrees Rapid feedrates 80m/min, 120 station toolchanger, spindle taper HSK 63 spindle speed 20,000rpm, Siemens 840D eRGOline control Swarf conveyor. Caodpfx Aswnpzaeddea Through Spindle Coolant

Condition: good (used), Year of construction: 2016, Table size 1100 x 560mm, Traverses X Y Z 800 x 560 x 510mm, Spindle speed 12,000rpm, Caodpfxoxddk Eo Addoa spindle taper BT40, 30 station ATC, FANUC control, Table load 800Kg, Through spindle coolant, Swarf conveyor.

Condition: excellent (used), Year of construction: 2018, Maximum workpiece diameter 285mm, maximum workpiece length 280mm, Bar capacity 38mm, X axis stroke 480mm, Z axis stroke 285mm, spindle speed 6,000 rpm, power 5.5Kw, swarf conveyor. Cjdpfowb A Hcex Addsaa