Used Deckel Lkd for sale (698)

Year of construction: 1981, condition: good (used), machine/vehicle number: 2608-0129, Travel for the x-axis - 400 mm Podpfx Ahod Dz Rhj Ajrc Travel for the y-axis 250 mm Travel for the z -axis 340 mm Table Surface area - 600 x 300 mm Turning speed range 40 - 3150 rpm Planetary grinding heads included. With full technical documentation There is no possible drilling and milling - no tooling Transport dimensions: 1.5 x 1.7 x 1.8 m, Weight ; 1300 kg.

Condition: not inspected (used), Year of construction: 2005, functionality: unexamined, machine/vehicle number: 57/2005, travel distance X-axis: 400 mm, travel distance Y-axis: 310 mm, travel distance Z-axis: 305 mm, workpiece diameter (max.): 260 mm, tool length: 900 mm, No reserve price – guaranteed sale to the highest bidder! TECHNICAL DETAILS Travel X-axis: 400 mm Travel Y-axis: 310 mm Travel Z-axis: 305 mm Psdpsxqpitofx Ah Asrc Max. workpiece diameter: approx. 260 mm Max. tool length: approx. 900 mm Spindle power: up to 24 kW Tool holder: SK 50 Speed range: up to 12,000 rpm Grinding wheel changer: 8-position Tool changer: 155-position A-axis swivel range: 360° C-axis swivel range: 224° Feed rate: 2,000 mm/min MACHINE DETAILS Control: PMAC Dimensions & Weight Dimensions (L x W x H): 2,900 x 1,800 x 2,015 mm Total weight: 4,000 kg EQUIPMENT 8-position grinding wheel changer for up to 24 grinding wheels 155-position chain loader for automatic operation Workpiece gripper Measuring probe Automatic central lubrication system Direct position measuring system Infinitely variable spindle speed / feed rate control Hydraulic chuck 1 set of hydraulic collets Additional collets of various diameters for chain loader Grinding wheel holders with spacer rings Documentation Note: The LUST board (inverter drive) is defective and must be replaced.

Condition: ready for operation (used), Year of construction: 1984, functionality: fully functional, turning length: 600 mm, turning diameter: 400 mm, spindle bore: 73 mm, controller model: ELTRO MPULS, No reserve price – guaranteed sale to the highest bidder! Predpfx Ahsxn I Sbs Asc TECHNICAL DETAILS Turning diameter: 400 mm Turning length: 600 mm Swing diameter: 600 mm Spindle bore: 73 mm MACHINE DETAILS Control model: ELTRO MPULS

Condition: ready for operation (used), Year of construction: 2002, functionality: fully functional, machine/vehicle number: 11035534144, travel distance X-axis: 500 mm, travel distance Y-axis: 400 mm, travel distance Z-axis: 400 mm, rapid traverse X-axis: 12 m/min, spindle speed (max.): 9,000 rpm, No reserve price – guaranteed sale to the highest bidder! The payment term is one week after purchase of the machine! Bidding obligates the buyer to collect the machine on time between 17.11.2025 and 21.11.2025! TECHNICAL DETAILS Travel X-axis: 500 mm Travel Y-axis: 400 mm Travel Z-axis: 400 mm Rapid traverse X-axis: 12 m/min Rapid traverse Y-axis: 12 m/min Rapid traverse Z-axis: 12 m/min Feed rate in X, Y, and Z axes: 10,000 mm/min Maximum spindle speed: 9,000 rpm Prodpexm T I Ejfx Ah Aec Tool holder: SK 40 Max. tool length from spindle nose: 290 mm Max. tool weight with automatic tool changer: 6 kg Max. total tool weight in magazine: 50 kg Clamping area: 700 x 500 mm Rotary range: 360° Swivel range: +95/-10° Permissible worktable load: 200 kg MACHINE DETAILS Control model: SIEMENS SINUMERIK 810 D Dimensions & weight Dimensions (L x W x H): 2,300 x 2,000 x 2,300 mm Total weight: 5,000 kg EQUIPMENT 16-position tool changer Rotary table with swivel axis Mechanical table plate clamping Note: The machine vices shown on the table are not included in the scope of delivery.

Condition: ready for operation (used), Year of construction: 2008, General Data Measurements width 2930 mm Measurements depth 3210 mm Measurements height 2900 mm Machine weight 9200 kg Control Unit Brand HEIDENHAIN Model iTNC 530 Main Drive Spindle speed range 28000 rpm Spindle motor power 38/28 kW Tool taper HSK-A63 Podexn U A Hjpfx Ah Aerc Number of axis 5 Movement X-Axis Movement 450 Y-Axis Movement 600 Z-Axis Movement 400 Table Outer length 400 mm Outer width 400 mm Number of tslots 5 Distance between 63 mm Media Chip conveyor Yes Internal cooling Yes Additional Equipment Tool Storage Capacity: 30 tools /Max Tool Weight: 6 kg / Max Tool Diameter: 80 mm / Max Tool Length: 250 mm Graphite Dust Collector Heidenhain Touch Probe TS 649 3D Quick Set for 5-Axis Calibration This 5-axis DMG DECKEL MAHO HSC 55 linear vertical machining centre was manufactured in 2008. Consider the opportunity to buy this DMG DECKEL MAHO HSC 55 linear vertical machining centre if you are looking to get high quality milling capabilities. Contact us for more information about this machine. Application Types Milling

Year of construction: 2001, condition: used, Price: On request Milling machine, VMC Model: CNC Manufacturer: DMG / Deckel MAHO Type: DMU60T Year of manufacturing: 2001 Control: Heidenhain Working-hours: 26266 Travel: 630x560x560mm Spindle-speed: 10.000 rpm Table-dimensions: 1000x600mm Spindle-take: ISO40 Max. Workpiece-weight: 400kg Incl. Filter Interlit SK200-760 Incl. Automatic toolholder Incl. Documents Incl. Video available Machine-weight: 6700kg Machine-dimensions: 3500x2400x2200mm Prsdpfxjwng H He Ah Asc - Year: 2001 - Documentation available: No - Drive system: CNC Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: used, Year of construction: 2008, x-travel 450 mm y-travel 400 mm z-travel 480 mm control MillPlus IT V600 Heidenhain turning speed range - main spindle max. 12.000 min/-1 power capacity - main spindel 10 / 15 kW max. Torque 130 Nm tool taper SK 40 swivellable B: -95 / +30 ° table surface area Ø 450 mm T-slots 7x 14 x 63 mm max. table load 250 kg rotatable C: 360 ° max. workpiecediameter 380 mm max. workpiece height 670 mm number of toolpositions 16 pos. tool taper SK 40 max. tool diameter 80 mm max. tool-dia with free toolbox 130 mm max. tool length 250 mm max. tool weight 8,0 kg feed speeds max. 30.000 mm/min rapid traverse 30 m/min Feed force ( X / Y / Z ) 7 / 13 / 10 kN total power requirement 27,6 kVA weight of the machine ca. 5,2 t dimensions of the machine ca. 3,1 x 3,0 x 3,0 m 5 Axis CNC - MachiningCenter Universal DECKEL MAHO - DMU 40 monoBLOCK - 5-axis simultaneous - only ca. 589h Spindle-hrs.! Operating-Hours: ca. 1.700h Prodpsu Dbpmsfx Ah Aoc - from training center

Condition: like new (used), Year of construction: 2012, operating hours: 23,252 h, travel distance X-axis: 735 mm, travel distance Y-axis: 650 mm, travel distance Z-axis: 560 mm, controller manufacturer: 3D-Control Siemens 840D, workpiece diameter (max.): 840 mm, workpiece weight (max.): 600 kg, total height: 2,897 mm, total length: 3,567 mm, total width: 2,615 mm, table width: 650 mm, table length: 650 mm, overall weight: 12,100 kg, spindle speed (min.): 18,000 rpm, tool length: 315 mm, tool weight: 8,000 g, Year of construction: 2012 CNC controller: 3D-Control Siemens 840D Axes X-axis travel mm: 735 Y-axis travel mm: 650 Z-axis travel mm: 560 C-axis degrees: 360º (0,001) A-axis degrees: ±120(0.001) Feed rates m/min: 40 Rapid traverse m/min: 40 Acceleration in the axes m/s2: 6 Milling/turning table nc: Number of pallets: 1 Table dimensions mm: Ø650 Maximum workpiece size (D x H) mm: Ø840x500 Max. workpiece weight kg: 600 Spindle Spindle speed rpm: 18000 Spindle drive power kW: 13/9 (40%ED/cont) Cooling Cooling through the Spindle Center bar: 40 Prodpfsxrr I Iox Ah Aec Tank capacity: 600 Tool system Tool holder: SK 40 Tool magazine slots: 30 Tool changer: Double Gripper With free neighboring places mm: 160 Max. Tool Length mm: 315 Max tool weight kg: 8 Chip-to-chip time s: 4.9 Equipment Electronic Handwheel Chip conveyor Rigid table with integrated rotary table Infrared probe Internal cooling lubricant supply Rinsing gun Paper band filter Machine running times Under power: 23252 Spindle Working: 6497 Basic machine dimensions / weight Length mm: 3567 Width mm: 2615 Height mm: 2897 Weight kg: 12100

Condition: good (used), Year of construction: 1998, dia. of draw-in collets 17,5 mm internal taper of cone draw-in collets MK 1 , Mk 2, Ga speeds of grinding spindle 2800 U/min total power requirement 0,25 kW weight of the machine ca. 67 kg dimensions of the machine ca. 510 x 565 x 290 mm Milling cutter grinder with a base cabinet for grinding milling cutters or styli in a central and offset position. The dividing head holder allows for circular movements in all directions, as well as longitudinal and transverse Pjdpfsxr Raiex Ah Asrc movements of the tool axis. The tool holder has a 40 mm longitudinal adjustment, a 10 mm lateral adjustment, and a 15 mm fine adjustment of the dividing head holder relative to the grinding spindle. Machine dealer with own stock of 1600 m².

Condition: not inspected (used), functionality: unexamined, machine/vehicle number: 2881-0191, travel distance X-axis: 700 mm, travel distance Y-axis: 550 mm, travel distance Z-axis: 500 mm, controller model: SIEMENS DIALOG 112, spindle speed (max.): 8,000 rpm, No reserve price – guaranteed sale to the highest bidder! Payment is due one week after purchase of the machine! Placing a bid obligates you to collect the machine on time between 17/11/2025 and 21/11/2025! TECHNICAL SPECIFICATIONS Travel X-axis: 700 mm Prodpjxm Ty Iefx Ah Aec Travel Y-axis: 550 mm Travel Z-axis: 500 mm Feed rate X, Y, Z: 1 - 10,000 mm/min Rapid traverse X, Y: 30 m/min Rapid traverse Z: 20 m/min Setup mode speed X, Y, Z: 1 - 2,000 mm/min Table width: 550 mm Table length: 900 mm Table load: 800 kg Max. setup height: 600 mm Distance spindle nose to table: 150 - 650 mm Max. spindle speed: 8,000 rpm Tool magazine positions: 40 Holder diameter: 40 mm Tool holder: SK 40 Max. tool diameter for standard tools: 80 mm Max. tool diameter for special tools with free adjacent slots: 140 mm Max. tool diameter for boring heads with free adjacent slots: 200 mm Max. tool length from spindle nose: 300 mm Max. tool weight: 12 kg Control model: SIEMENS DIALOG 112 MACHINE DETAILS Dimensions & Weight Dimensions (L x W x H): 3,500 x 3,300 x 2,900 mm Total weight: 8,000 kg EQUIPMENT Documentation/manual Chip conveyor Note: The magnetic clamping plate shown on the table is not included in the scope of delivery.

Condition: used, x-travel 400 mm y-travel 200 mm z-travel 400 mm No. of spindle turning rate 18 Predpfexqrdtox Ah Ajc speeds 40 - 2000 U/min table surface area 730 x 240 mm tool adaptor SK 40 flute distance 4 / 12 mm number of feeds 18 feed range 8 - 400 mm/min rapid traverse 1200 mm/min total power requirement 2,2 kW weight of the machine ca. 1400 kg dimensions of the machine ca. 1700 x 1400 x 1700 mm - Robust/powerful universal milling machine - NEWALL digital display - Coolant device

Condition: used, Year of construction: 2003, x-travel 800 mm y-travel 700 mm z-travel 600 mm turning speeds 12000 1 U/min control Heidenhain total power requirement 59 kW Pedpfxjrc Ip Is Ah Aerc weight of the machine ca. 10,6 t

Condition: used, Year of construction: 2005, x-travel 880 mm y-travel 630 mm z-travel 630 mm Prodpfxjvn Ur Ee Ah Asc control iTNC 530 Heidenhain turning speed range - main spindle max. 18.000 min/-1 power capacity - main spindel 28 / 19 kW max. Torque 121 / 82 Nm tool taper HSK-A 63 swivellable B: +30° / -120 ° table surface area Ø 700 / 1.250 x 700 mm max. table load 650 kg rotatable C: 360 ° max. workpiecediameter 850 mm max. workpiece height 550 mm number of toolpositions 32 pos. tool taper HSK-A 63 max. tool diameter 80 mm max. tool-dia with free toolbox 160 mm max. tool weight 8,0 kg change-time chip to chip 10 sec feed speeds max. 30.000 mm/min rapid traverse 30 m/min Accelaration 5 m/s² total power requirement 48 kVA weight of the machine ca. 14,0 t dimensions of the machine ca. 6,5 x 5,0 x 2,9 m 5 Axis CNC - MachiningCenter Universal DECKEL MAHO - DMU 80 monoBLOCK - NC-Rotary Table (C-Achse) integrated in rigid-table - Swivel-Milling-Head (B-Axis) - only 6.100h Spindle Hours

Operating hours: 63,151 h, condition: used, Empty weight: 3.000 kg Dimensions (LxBxH): 205 x 260 x 210 cm Price: On request - Documentation available: Yes - Serial number: 65391 - Operating hours: 63151 - Number of axes [pcs]: 3 - X-axis travel [mm]: 600 - Y-axis travel [mm]: 450 - Z-axis travel [mm]: 450 - Table length [mm]: 900 - Table width [mm]: 500 - Max. spindle speed [rpm]: 4000 - Options: Digital readout - Transport dimensions: 2050mm x 2600mm x 2100mm (l x w x h) - Transport weight [kg]: 3000kg - Transport packages [pcs.]: 2 Prsdpfx Ahswnh Dys Asc Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: ready for operation (used), Year of construction: 2003, operating hours: 24,243 h, Control Unit Brand HEIDENHAIN Model TNC 530 Predpfxjxqtffo Ah Aec Main Drive Number of axis 4 Tools Number of index 100 Type of tool holder HSK 63 Additional Equipment 40 bar IKZ This 4-axis DMG DECKEL MAHO DMF 300 was manufactured in 2003. It features a vertical machining center with 100 ATC tools, HSK 63, and a 40 bar IKZ. Consider the opportunity to buy this DMG DECKEL MAHO DMF 300 vertical machining center. Contact us for more information about this machine. Application Types Milling

Condition: not inspected (used), operating hours: 28,461 h, functionality: unexamined, machine/vehicle number: 28850008692, travel distance X-axis: 630 mm, travel distance Y-axis: 500 mm, travel distance Z-axis: 500 mm, controller model: SIEMENS SINUMERIK 810 D, table load: 500 kg, No minimum price – guaranteed sale to the highest bidder! Psdpfx Ahoxm Tu Ee Ajrc The payment deadline is one week after purchase of the machine! Placing a bid obligates you to collect the machine on time between 17/11/2025 and 21/11/2025! TECHNICAL DETAILS Travel X-axis: 630 mm Travel Y-axis: 500 mm Travel Z-axis: 500 mm Rapid traverse X-axis: 30 m/min Rapid traverse Y-axis: 30 m/min Rapid traverse Z-axis: 30 m/min Feed rate X-axis: 0–30,000 mm/min Feed rate Y-axis: 0–30,000 mm/min Feed rate Z-axis: 0–30,000 mm/min Tool holder: SK 40 Number of tool positions: 24 Table width: 500 mm Table length: 800 mm Max. table load: 500 kg Loading height: 850 mm MACHINE DETAILS Control model: SIEMENS SINUMERIK 810 D Dimensions & Weight Dimensions (L x W x H): 3,000 x 2,400 x 2,400 mm Total weight: 8,000 kg Operating hours: 28,461 h

Condition: used, Year of construction: 1999, x-travel 800 mm y-travel 650 mm z-travel 550 mm Control Mill Plus auto power on hours ca. 45.000 h turning speed range - main spindle 30.000 min/-1 tool taper HSK 50 E In our opinion, the machine is in good used condition and can be inspected under power by appointment. Accessories, tools and clamping devices shown are only included in the scope of delivery if this is noted in the additional information. Pedpfx Asxrg Ehoh Asrc Subject to changes and errors in the technical data and information as well as prior sale!

Condition: used, Year of construction: 2007, reus 8000 min-1 U/min Weight 5500 kg Year 2007 Control Siemens 840D Dimensions (L/W/H) 3600 x 2800 x 2400 mm Pedjwm Rqaopfx Ah Aorc travel -x axis 1035 mm travel -y axis 560 mm travel -z axis 510 mm

Condition: excellent (used), Year of construction: 2012, operating hours: 18,648 h, CNC controller: Heidenhain ITCN 530 ERGOline Axes X-axis travel mm: 500 Y-axis travel mm: 450 Z-axis travel mm: 400 C-axis degrees: 360° (0,001º) B-axis degrees: –5° a +110° (0,001º) Rapid traverse m/min: 24 Worktable Table dimensions mm: 630 x 500 Maximum workpiece size (D x H) mm: 500 x 400 Max. workpiece weight kg: 200 Spindle Spindle speed rpm: 18.000 Spindle drive power kW: 13 / 9 KW (40 / 100% ED) Tool system Tool holder: SK 40 Tool magazine slots: 30 Max. Tool Length mm: 300 Max tool weight kg: 6 Equipment Chip conveyor Workarea light Paper band filter Rotating viewing window with laminated glass Cooling Cooling through the Spindle Center bar: 40 Tank capacity: 600 L Machine running times Under power: 18.648 Rated power kVA: 34 Operating Time: 6.226 Basic machine dimensions / weight Length mm: 2.800 Width mm: 2.800 Height mm: 2.600 Prodpfx Ahew Rnxzs Aec Weight kg: 4.450

Year of construction: 1997, condition: used, Price: On request - Year: 1997 - Documentation available: Yes - CE marking present: Yes - Drive system: CNC - Number of axes [pcs]: 5 - X-axis travel [mm]: 1200 - Y-axis travel [mm]: 880 - Z-axis travel [mm]: 800 - Table length [mm]: 5000 - Tool holder: SK40 - Max. spindle speed [rpm]: 18000 - Options: Digital readout - └ Type of digital readout: Heidenhain Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Pedpfx Ajwh Shvsh Aerc Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: ready for operation (used), Year of construction: 1999, Control Unit Brand HEIDENHAIN Model 426 This 5-axis DECKEL MAHO DMU 80P was manufactured in 1999. It features a Heidenhain 426 control system, a 30-slot tool magazine, and a SK 40 toolholder type. The spindle cooling is capable of 40 bar, enhancing its performance for complex machining tasks. Consider the opportunity to buy this DECKEL MAHO DMU 80P universal machining centre. Contact us for more information about this machine. Application Types Milling Psdpoxn Uyfsfx Ah Asrc

Condition: not inspected (used), functionality: unexamined, machine/vehicle number: 11035509414, travel distance X-axis: 500 mm, travel distance Y-axis: 400 mm, travel distance Z-axis: 400 mm, controller model: Heidenhain TNC 426, spindle speed (max.): 9,000 rpm, No reserve price – guaranteed sale to the highest bidder! The payment deadline for the machine is 20/11/2025! Placing a bid obligates you to collect the machine within the specified period from 01/12/2025 to 05/12/2025! TECHNICAL SPECIFICATIONS Travel Travel X-axis: 500 mm Travel Y-axis: 400 mm Travel Z-axis: 400 mm Rapid Traverse & Feed Rates Rapid traverse X-axis: 12 m/min Rapid traverse Y-axis: 12 m/min Rapid traverse Z-axis: 12 m/min Feed rate X-axis: 10,000 m/min Feed rate Y-axis: 10,000 m/min Feed rate Z-axis: 10,000 m/min Maximum spindle speed: 9,000 rpm Work Table (Rotary table with tilting axis) Table width: 500 mm Table length: 700 mm Table load capacity: 200 kg Tool Holder Diameter: 40 mm Tool length: 290 mm Tool weight: 6,000 g Number of magazine tool holders: 16 MACHINE DETAILS Control: Heidenhain TNC 426 Prjdpfx Ajxp Nnmsh Ajc Dimensions & Weight Dimensions (L x W x H): 2,500 x 2,000 x 2,400 mm Electrical Data Total weight: 3,000 kg Input voltage: 400 V Type of power: Three-phase current EQUIPMENT Documentation/manual WNT machine vice (jaw width: 125 mm) Lot of SK 40 tool holders Cutting tools Workshop cabinet with accessories

Condition: used, total height: 2,000 mm, total width: 2,300 mm, total length: 3,000 mm, Empty weight: 3.200 kg Price: On request - Documentation available: No - Drive system: Conventional Prodpswnif Sefx Ah Ajc - Number of axes [pcs]: 3 - X-axis travel [mm]: 800 - Y-axis travel [mm]: 450 - Z-axis travel [mm]: 500 - Table length [mm]: 1050 - Table width [mm]: 625 - Tool holder: ISO40 - Min. spindle speed [rpm]: 32 - Max. spindle speed [rpm]: 1600 - Options: Digital readout - └ Type of digital readout: Heidenhain - Transport dimensions: 3000mm x 2300mm x 2000mm (l x w x h) - Transport weight [kg]: 3200kg - Transport packages [pcs.]: 1 Financial information VAT: The price shown is exclusive of VAT VAT/margin: VAT deductible for entrepreneurs Delivery and trade-in always possible for everything in the industrial sectors Lukas van Rossum

Condition: ready for operation (used), functionality: fully functional, machine/vehicle number: R0101, travel distance X-axis: 800 mm, travel distance Y-axis: 300 mm, travel distance Z-axis: 300 mm, spindle speed (max.): 2,000 rpm, table length: 1,000 mm, table width: 520 mm, No reserve price – guaranteed sale to the highest bidder! The payment deadline for the machine is 20/11/2025! Bidding obligates you to collect the machine on time between 01/12/2025 and 05/12/2025! TECHNICAL DETAILS Travel distances X-axis travel: 800 mm Y-axis travel: 300 mm Z-axis travel: 300 mm Spindle Maximum spindle speed: 2,000 rpm Minimum spindle speed: 25 rpm Chuck diameter: 40 mm Work table Table width: 520 mm Table length: 1,000 mm MACHINE DETAILS Dimensions (L x W x H): 2,500 x 2,000 x 1,800 mm EQUIPMENT Collets Prsdpfx Ahexm Scue Ajc Additional milling table (table dimensions: 700 x 240 mm) Large machine vice (jaw width: 200 mm)

Condition: ready for operation (used), Year of construction: 2010, functionality: fully functional, machine/vehicle number: 278, workpiece weight (max.): 50 kg, grinding wheel diameter: 150 mm, grinding length: 340 mm, rotational speed (max.): 8,000 rpm, workpiece diameter (max.): 250 mm, No minimum price – guaranteed sale to the highest bidder! The payment deadline for the machine is 20/11/2025! Bids are binding and require collection within the period 01/12/2025 to 05/12/2025! TECHNICAL DETAILS Max. grinding wheel diameter: 150 mm Speed range: 1,000 – 8,000 rpm Workpiece spindle taper: SK 50 Max. workpiece weight: 50 kg Max. diameter: approx. 250 mm With tailstock: max. 125 mm Max. length: approx. 500 mm With tailstock: max. 250 mm Max. grinding length: 340 mm X-axis grinding stroke: 340 mm Y-axis traverse: 240 mm Z-axis traverse: 240 mm A-axis speed: 120 rpm A-axis swivel range: 360° C-axis speed: 20 rpm C-axis swivel range: 197° Podpfxjxm Rnvo Ah Asrc MACHINE DETAILS Dimensions & Weight Dimensions (L x W x H): 4,000 x 3,000 x 2,400 mm Total weight: 2,500 kg EQUIPMENT Coolant filtration system Oil mist extraction Documentation