Used Gildemeister Nef 280 for sale (234)

Condition: used, Year of construction: 2003, max. Spindle speed 5000 U/min. travel -x axis 160 mm travel -z axis 450 mm numbers of turret head positions 12 Codpfxjv Ehawj Ab Usha tool taper VDI 30 Control Heidenhain iT Plus Dimensions (L x W x H) 4,5 x 2,5 x 2,5 m weight of the machine 3700 kg CNC Turning- and Milling Center | DMG GILDEMEISTER - CTX 310 Additional equipment: - C-Axis The machine is in good condition. Please refer to further technical details in the attachement of the offer. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - #Tags: CTX310 | CTX-310

Condition: used, Year of construction: 2006, spindle speed (max.): 5,000 rpm, total width: 45,000 mm, total length: 19,900 mm, total height: 23,000 mm, travel distance X-axis: 165 mm, travel distance Y-axis: 80 mm, bar length: 600 mm, CNC Lathe (with 2nd spindle, 3 turrets and Y-axis) Spindle bore diameter 65 mm Spindle speed 5.000 R/min Spindle motor 25/20 kW Spindle speed counter spindle 5.000 R/min X-axis movement 165 / 165 / 165 Y-axis movement 80 mm Z-axis movement 220 / 150 / 650 mm W-axis movement (subspindle to mainspindle) 690 mm C-axis indexing 0,0001° Number of turret 3 Number of tools on turret 12 (3x 12) Tool taper VDI 30 Bar feeder LNS Quick Load Servo 65 If you have any questions concerning the machine, please do not hesitate to contact us by phone or e-mail. Chedpfx Ajy Nyrxjb Uoa Feel free to view our other advertisements for a complete overview of our stock.

Condition: used, Year of construction: 2006, spindle speed (max.): 5,000 rpm, total width: 45,000 mm, total length: 19,900 mm, total height: 23,000 mm, travel distance X-axis: 165 mm, travel distance Y-axis: 80 mm, bar length: 600 mm, CNC Lathe (with 2nd spindle, 3 turrets and Y-axis) Spindle bore diameter 65 mm Spindle speed 5.000 R/min Spindle motor 25/20 kW Spindle speed counter spindle 5.000 R/min X-axis movement 165 / 165 / 165 Y-axis movement 80 mm Z-axis movement 220 / 150 / 650 mm W-axis movement (subspindle to mainspindle) 690 mm C-axis indexing 0,0001° Number of turret 3 Number of tools on turret 12 (3x 12) Tool taper VDI 30 Chedsy Nyg Aepfx Ab Uja Bar feeder LNS Quick Load Servo 65 If you have any questions concerning the machine, please do not hesitate to contact us by phone or e-mail. Feel free to view our other advertisements for a complete overview of our stock.

Condition: used, GILDEMEISTER GM35 AC MULTISPINDLE LATHE WITH PIETRO CUCCHI LOADER We can offer a lathe and loader overhauled as new with CE certificate Chodpowrpb Iofx Ab Uoa

Condition: new, Lathe completely overhauled, both electrically and mechanically, restored to like-new condition with repainting. Replacement of the electrical cabinet with a Siemens Series 1500 PLC. Overhead control panel. Replacement of cables and microswitches. Overhaul of the main motor. Replacement of the leaking lubrication oil pump. Replacement of the tool cooling pump. Check of the door closing system with an electromechanical system. Pneumatic unit. Loader interface. End-of-bar position 1. Replacement of all bearings. Overhaul of carriages. Replacement of camshafts. Replacement of all lubrication distributors. Replacement of working and threading clutches. Chodpfx Absd Hza Ij Usa Pneumatic tailstock. Fixed and rotating front chucks. Diameter variation 20. CE certification with attached documents.

Condition: new, Year of construction: 2024, Gildemeister 42ACF: is an automatic multi-spindle lathe designed to meet the demands of high-efficiency production. This model stands out for its versatility, capable of machining workpieces up to 42 mm in size with equal ease and precision. The 42ACF lathe offers a number of features that make it particularly easy to use. These include intuitive programming via a SIEMENS operator panel that makes it easy to set and change spindle rpm, cycle time and threading speed. Chjdpfx Absrpniqs Uja Technical data: ● Number of spindles: 6 ● Maximum bar diameter: 42 [mm] ● Hexagonal wrench: 36 [mm] ● Cross bars : 4 (pos.1-2-4-5) ● Maximum feed length : 130 [mm] ● Main spindle speeds : 400- 4000 [rpm] without threading ● Travel time: 1-1.5 [s] ● Cycle time: 2 to 90 [s] ● Power: 22 [KW] The Gildemeister 42ACF, on the other hand, is a multi-spindle lathe that targets highly specialized industries where precision and accuracy are imperative.

Condition: new, TECHNICAL DATA: - Number of spindles: 6 - Maximum bar diameter: 20 [mm] -Bar passage extension on request 25 [mm] - Cross carriages : 4 (pos.1-2-4-5) - Maximum feed length: 100 [mm] - Main spindle speeds : 400 - 4000 [rpm] with threading,400- 5000 [rpm] without threading - Travel time: 0.7 [s] - Cycle time: 1.4 - 60 [s] - Power: 11 [KW] ELECTRICAL PROVISION FOR LOADER INTERFACE Hardware and Software Interface for Loader ELECTRICAL EQUIPMENT consisting of theAC motors (protection type lP 54), main motor and feed with a PLC programmable Siemens S7-1500 DOCUMENTATION: CE certification with manuals Wiring diagrams I Hard copy + 1 Copy on USB with files in .pdf format EC Directive 2006142lCE - 2014130/EC Cedpfx Aoq Nzl Tob Ujha 2O14I68IUE STANDARD

Condition: like new (used), Lathe completely overhauled from an electrical and mechanical point of view as new with painting Cedpfx Abjwit Elo Ueha

Condition: new, Year of construction: 2024, Gildemeister 20ACN allows, again via SIEMENS operator panel, to set and change spindle rpm, cycle time and thread speed easily. It can machine workpieces up to 25 mm in size with equal ease and precision. It offers the possibility of mounting NC slides. Position 6 consists of: NC parting slide and NC take-up slide, NC take-up spindle with variable rpm, with synchronization and stop. The NC take-up spindle, specifically programmed, has the option of becoming a C-axis. Csdpfx Abouqh Ihs Uoha Technical data: - Max. round bar diameter mm 20 / 25 - Max. square bar diameter mm 17 - Bar pusher mm 100 / 125 - Front spindle stroke mm 86 - Longitudinal guide block stroke mm 50 - Radial slide stroke mm 42 / CNC 50 - Axial slide stroke mm 50 / CNC 56 - CNC cutting stroke mm 42 - CNC pickup slide stroke mm 42 - CNC Pickup Spindle Stroke mm 100 - Continuous spindle speed rpm rpm 420 - 5,000 - Rapid traverse times s 0.5 - 0.7 - Main drive power 11 kW / CNC 15 kW - Installation area without bar guide mm 4,000 x 1,900 - Net weight kg 5,500 The Gildemeister 20AC, on the other hand, is a multispindle lathe that targets highly specialized industries where precision and accuracy are imperative.

Year of construction: 1999, condition: ready for operation (used), Fresh oil lubrication capacity: approx. 3l, voltage: 400V, frequency: 50Hz, fuse protection (slow-blow) according to VDE 0100: 80A, permissible voltage fluctuation at 400V: ±10%, connected load: 44kVA, length: 3210mm, width: 1750mm, height: 1750mm, weight: approx. 4.6t, with chip conveyor. An on-site inspection is possible. Codpfjza E Sqox Ab Ueha

Condition: ready for operation (used), Year of construction: 2006, operating hours: 38,407 h, spindle speed (max.): 5,000 rpm, travel distance X-axis: 300 mm, travel distance Z-axis: 650 mm, spindle motor power: 26,000 W, total height: 2,900 mm, total width: 2,500 mm, overall weight: 12,000 kg, controller manufacturer: SIEMENS, controller model: 840 Powerline, product length (max.): 7,855 mm, number of slots in tool magazine: 24, number of axes: 3, This 9-axis Gildemeister TWIN 65 was manufactured in 2006. It features a spindle power of 65 kVA and a maximum spindle speed of 5000 rpm. The machine includes a tool magazine with 24 tools and a turret-type tool changer. With a robust weight of 12,000 kg and dimensions of 7855 mm x 2500 mm x 2900 mm, this horizontal turning machine is equipped with special features like a touch probe and internal coolant supply. If you are looking to get high-quality turning capabilities, consider the Gildemeister TWIN 65 machine we have for sale. Contact us for further details. • Machine design: 60° slant bed • Guideways: Roller guideways • Max turning diameter: 250 mm • Max turning diameter (standard): 120 mm • Max turning length: 900 mm • X1 travel (upper slide): 300 mm • Z1 travel (upper slide): 650 mm • Y1 travel (optional): ±40 mm • X2 travel (lower slide): 180 mm Chjdpfoyvz Ibsx Ab Uoa • Z2 travel (lower slide): 650 mm • X3 travel (counter spindle): 175 mm • Z3 travel (counter spindle): 670 mm • Main spindle chuck size: 175 / 200 mm • Maximum rod diameter (without reducing tubes): 62 / 65 mm • Spindle bore diameter: 79 mm • Spindle nose diameter: 170 mm • Collet diameter: 66 mm • Front bearing diameter: 120 mm • Main spindle power (40/100% ED): 35 / 25 kW • Main spindle speed range: up to 5000 rpm • Main spindle torque (40/100% ED): 370 / 270 Nm • Spindle drive type: AC motor with integrated spindle motor • C-axis: Integrated for oriented stopping and contouring • C-axis speed: 2000 rpm • C-axis holding torque: 270 Nm • Counter spindle power (40/100% ED): 26 / 21 kW • Counter spindle speed range: up to 5000 rpm • Counter spindle torque (40/100% ED): 290 / 230 Nm • C-axis (counter spindle) speed: 2000 rpm • C-axis (counter spindle) holding torque: 230 Nm • Rapid traverse X/Z (slide 1): 30 / 30 m/min • Feed force X/Z (slide 1): 4.0 / 7.0 kN • Positioning resolution X/Z: 0.0005 mm • Motor torque X/Z: 6 / 10.5 Nm • Motor speed X/Z: 3000 rpm • Ball screw pitch X/Z: 20x32 / 20x40 mm • Rapid traverse X/Y/Z (with Y-axis): 30 / 15 / 30 m/min • Feed force X/Y/Z: 4.0 / 4.0 / 7.0 kN • Positioning resolution X/Y/Z: 0.0005 mm • Motor torque X/Y/Z: 6 / 6 / 10.5 Nm • Motor speed X/Y/Z: 3000 rpm • Ball screw pitch X/Y/Z: 20x32 / 10x32 / 20x40 mm • Rapid traverse X/Z (slide 2): 30 / 30 m/min • Feed force X/Z (slide 2): 4.0 / 7.0 kN • Positioning resolution X/Z (slide 2): 0.0005 mm • Motor torque X/Z (slide 2): 6 / 10.5 Nm • Motor speed X/Z (slide 2): 3000 rpm • Ball screw pitch X/Z (slide 2): 20x32 / 20x40 mm • Rapid traverse X/Z (counter spindle slide): 15 / 30 m/min • Feed force X/Z (counter spindle slide): 4.0 / 7.0 kN • Positioning resolution X/Z (counter spindle): 0.0005 mm • Motor torque X/Z (counter spindle): 10.5 / 10.5 Nm • Motor speed X/Z (counter spindle): 3000 rpm • Ball screw pitch X/Z (counter spindle): 10x32 / 20x40 mm • Number of tool stations: 12 • Tool holder: VDI 30 • Tool changer type: Turret • Tool shank size (DIN 69880): 30 / 40 mm • Number of driven tool stations: 12 • Driven tools: all 12 stations capable of driven tools • Driven tool power (40/100% ED): 11.7 / 8.4 kW • Driven tool torque (40/100% ED): 28 / 20 Nm • Driven tool speed: up to 4000 rpm • Tailstock stroke (optional): 300 mm • Tailstock force: 150 / 630 daN • Center size: MK 4 • Hydraulic tank capacity: 20 l • Hydraulic pump power: 2.2 kW • Hydraulic pressure max: 90 bar • Clamping pressure main spindle: 80 bar • Clamping pressure counter spindle: 70 bar • Clamping pressure tailstock: 50 bar

Condition: used, Machines for export from company closure Stock No. 62506 = RAPID Type DGL 5000 / 500 double mitre saw = Weight approx. 1,200 kg = Special price EUR 1,800 Stock No. 54183 = MÜLLER hydraulic press 10 ton, without hydraulic pump = Weight approx. 1,200 kg = Special price EUR 1,000 Stock No. 57780 = MÜLLER hydraulic press Type HEP 40 = Weight approx. 2,200 kg = Special price EUR 1,900 Hydraulic press – separate hydraulic power unit = Weight approx. 3,000 kg Chodpfjy Erzdsx Ab Uea Stock No. 60507 = WEBO drill with 4 spindles = Weight approx. 1,900 kg = EUR 1,600 Stock No. 57592 = ALZMETALL drill with 2 spindles = Weight approx. 1,700 kg = EUR 1,200 Stock No. 60699 = WEBO column-type drill MK5 = Weight 1,600 kg = Special price EUR 1,600 Stock No. 60177 = WEBO radial drilling machine Type R4bR = Weight approx. 2,800 kg = Special price EUR 1,900 Stock No. 57432 = GILDEMEISTER Type GD 160 = Weight approx. 4,000 kg = Special price EUR 1,900 --- Many more machines in stock, available for immediate export. For example: 10 units welding machines, CLOOS, ESS etc. 2x HITACHI SEIKI CNC lathes

Condition: ready for operation (used), Year of construction: 2004, operating hours: 60,425 h, functionality: fully functional, turning length: 1,050 mm, turning diameter: 465 mm, travel distance X-axis: 300 mm, chuck outer diameter: 325 mm, controller model: Fanuk Series 21I-TB, TECHNICAL DETAILS Chedjy Hg S Hopfx Ab Usa Max. turning length: 1,050 mm Turning diameter over cross slide: 350 mm Max. turning diameter: 465 mm Chuck diameter: 325 mm X-axis travel: 300 mm Z-axis travel: 1,050 mm Max. spindle speed: 3,500 rpm Max. torque: 630 Nm Spindle bearing diameter: 120 mm Max. bar diameter: 90 mm Tailstock stroke: 850 mm Quill stroke: 150 mm Rapid traverse X/Z axis: 30 m/min Number of tool turret positions: 12 Tool holder: VDI 40 MACHINE DETAILS Control: Fanuk Series 21I-TB Drive power: 33 kW

Year of construction: 2000, condition: good (used), Gildemeister MF Sprint 42 Straight driven tools: 4 pcs Static oil Work tools not included Chedpfoyiym Uox Ab Uja

Condition: ready for operation (used), Year of construction: 2005, operating hours: 19,229 h, functionality: fully functional, machine/vehicle number: 8043943123C, turning length: 1,050 mm, turning diameter: 465 mm, travel distance X-axis: 300 mm, travel distance Z-axis: 1,050 mm, controller model: Siemens 840 D, TECHNICAL DETAILS Turning diameter: 465 mm Turning length: 1,050 mm Swing diameter: 680 mm Chuck diameter: 325 mm Chsdpfx Absy D I Ttj Uja X-axis travel: 300 mm Z-axis travel: 1,050 mm Spindle speed range: 3,500 rpm Rapid traverse X/Z: 30 m/min MACHINE DETAILS Control: Siemens 840 D Number of tool positions: 12 positions Tool holder: VDI 40 Weight: 7,500 kg Operating hours Spindle hours: 19,229 h Power-on hours: 81,347 h Note: The machine can be inspected under power upon request.

Condition: excellent (used), Hello, I have for sale a DMG GILDEMEISTER CTX 310 V3 CNC LATHE with driven tools. TECHNICAL AND VISUAL CONDITION: Very Good Type: CNC Lathe Manufacturer: GILDEMEISTER Model: CTX 310 V3 Control system: Heidenhain Data Pilot 4290 Country of origin: Germany Year of manufacture: 2003 - Total machine operating hours: 9,144 h Machine specifications: Chsdpfxey Rb H Ho Ab Uea - Turret: 12 tool positions for VDI-30 holders + TurnPlus attachment - Max spindle speed: 5,000 rpm - C-axis - Driven tools - Hydraulic tailstock - Through-spindle - Max turning diameter (X-axis): 190 mm - Max turning length (Z-axis): 455 mm - Cooling system - SMW AutoBlock three-jaw hydraulic chuck - Spindle bore diameter: 50 mm - Chip conveyor - Full programming manual - Mechanical and electrical documentation - Machine weight: 3.8 t - Loading included in the price The machine has undergone a full service inspection. 100% operational. Connected and ready for work. Stal-Com has been engaged in sales, service, and training on DMG group CNC machines for 19 years. We specialize in all models of Gildemeister lathes as well as Deckel Maho machining centers. Every machine undergoes a meticulous technical check. Apart from Polish customers, our machines are also purchased by clients across Europe and parts of Asia. Each machine can be inspected in operation, as we also provide machining services. After purchasing a machine from us, we conduct operator training and can also set up production of parts at the customer's facility. We cooperate on a long-term basis with many companies, supplying them with further machine tools.

Condition: excellent (used), For sale: GILDEMEISTER CTX 410 V3 CNC LATHE with driven tools TECHNICAL & VISUAL CONDITION: Very Good Type: CNC Lathe Manufacturer: GILDEMEISTER Model: CTX 410 V3 Control: Heidenhain 4290 Country of origin: Germany Year of manufacture: 2006 The machine is fully equipped with both static and driven tool holders. Machine specifications: - Turret: 12 positions for VDI-30 tool holders (all stations are driven) - Max spindle speed: 5,000 rpm - C-axis - Driven tools - Tailstock - Max turning diameter (X-axis): 320 mm - Max turning length (Z-axis): 600 mm Cedey Rb Ecepfx Ab Uoha - Coolant system - Hydraulic collet chuck on the main spindle (can be replaced with 3-jaw chuck) - Main spindle with through-hole (bore diameter: 66 mm) - Finished parts catcher - Chip conveyor - Complete programming manual - Mechanical and electrical documentation - Machine weight: 5 tons - Loading included in the price The machine has undergone a complete inspection. Fully operational and ready to work—currently connected and available for demonstration. About the company: Stal-Com has been trading, servicing, and providing training on DMG Group CNC machines for over 20 years. We specialize in all Gildemeister lathe models and Deckel Maho machining centers. Every machine undergoes a thorough technical inspection. We supply not only customers in Poland, but also across Europe and parts of Asia. Each machine can be inspected live in production, as we also provide subcontract machining services. After purchase, we provide operator training and can help set up production at the customer’s facility. We work with many clients under long-term partnerships, supplying additional machines as needed.

Condition: excellent (used), Year of construction: 1995, Equipment: documentation/manual, FOR SALE: CNC LATHE GILDEMEISTER CTX400 TECHNICAL AND VISUAL CONDITION: Very good Type: CNC Lathe Manufacturer: GILDEMEISTER Model: CTX400 Control: Heidenhain 1190 Country of origin: Germany Year of manufacture: 1995 Machine specifications: - Turret: 12 tool stations, VDI-30 tool holders - Max. spindle speed: 5000 rpm - Hydraulic tailstock - Parts catcher - Max. turning diameter X-axis: 290 mm - Max. turning length Z-axis: 600 mm - Coolant system - Three-jaw hydraulic chuck 200 mm - Spindle bore: 66 mm - Through-spindle - Chip conveyor - Complete programming manual - Mechanical and electrical documentation - Machine weight: 5.5 tons - Loading onto truck included in the price The machine has undergone a full technical inspection. 100% operational. Connected and ready for work. Chjdpfxsy Rbr Ne Ab Uja Stal-Com has been selling, servicing, and providing training on CNC machines from the DMG group for 17 years. We specialize in all models of Gildemeister lathes as well as Deckel Maho machining centers. All machines undergo a thorough technical inspection. Besides Polish customers, our machines are purchased by clients throughout Europe and parts of Asia. Each machine can be inspected under power during production, as we also provide machining services. After purchasing a machine from us, we offer operator training and can help set up part production at the customer's site. We work with numerous companies on a long-term basis, supplying them with further machine tools.

Condition: used, Year of construction: 2011, Technical details: weight of the machine ca.: 11 t Chjdpoyz Sdqefx Ab Uja Gildemeister MF Twin 65-II lathe with loading automation. This machine is suitable as a counter spindle machine for 4-axis machining on the main and counter spindles, complete machining (turning, drilling, milling, Y-axis, B-axis) of bar and shaft parts. *

Condition: used, Year of construction: 2003, Technical details: weight of the machine ca.: 11 t Gildemeister MF Twin 65-II lathe with loading automation. This machine is suitable as a counter spindle machine for 4-axis machining on the main and counter spindles, complete machining (turning, drilling, milling, Y-axis, B-axis) of bar and shaft parts. Chedpeyzyudsfx Ab Uja *

Condition: excellent (used), Year of construction: 2009, operating hours: 87,000 h, functionality: fully functional, turning length: 600 mm, turning diameter over cross slide: 410 mm, spindle speed (min.): 22,000 rpm, For sale is a CNC turning center from the manufacturer DMG, type CTX beta 800, built in 2009. Available immediately. The machine is in good condition and fully functional. Technically sound and ready for immediate use. Technical data: Machine type: CNC turning center Manufacturer: DMG Type: CTX beta 800 Year of manufacture: 2009 Control: Heidenhain 4290 Max. turning length: 600 mm Tool turret: 12-position Tool holder: VDI 40 Operating hours: approx. 87,000 h Spindle hours: approx. 22,000 h Linear guide Z1 recently renewed Turret drive S2 recently replaced Machine regularly serviced by customer support technically sound and fully functional Inspection under power possible by arrangement Service and maintenance reports available large accessory package powered tools from WTO further documentation and images available upon request Codpeyq Hq Nefx Ab Ueha If interested, please write or call. Maschinenhandel Nord Gerstenstraße 2 17034 Neubrandenburg

Condition: excellent (used), Year of construction: 2003, functionality: fully functional, I have for sale a renowned brand CNC LATHE GILDEMEISTER CTX 310 V3 with driven tools, C axis. _ Type: CNC Lathe Manufacturer: GILDEMEISTER Model: CTX 310 V3 Control: HEIDENHAIN 4290 + TURN PLUS Overlay Country of manufacture: Germany Year of manufacture 1999 _ Chsdpfevmy Icox Ab Uoa Machine parameters: - head: 12 - tools for VDI 30 holders (Every second socket driven) - max. rpm 6300/min. - max. turning length in the Z axis: 455 mm - max. turning diameter in the X axis: 200 mm - C axis - driven tools - holder on the main spindle: Fi-200mm - max. shaft diameter Fi-51 mm - finished part collector - cooling system - chip conveyor - spindle drive power: 11 KW - DTR - machine weight: 3.2 tons _ WHY IS IT WORTH BUYING MACHINES in PPM? - we have our own service _ stationary and mobile - we have already sold over 700 DMG machines - possibility of starting the machine at the customer's - operator training and delivery of the machine to the customer included in the price - all our machines have undergone a professional technical inspection - 100% ready to work - purchase of the machine is possible through the installment system and leasing.

Condition: good (used), Year of construction: 2003, Main spindle: Speed range - main spindle max. 6,000 min/-1 Drive power - main spindle 16 kW Max. torque 155 Nm C-axis 360 ° Tool turret: Number of tool positions 12 pos. Number of driven tool stations 12 pos. Speed range - driven tools max. 5,000 min -1 Drive power - driven Tools 10 kW Tool holder (VDI 30) Tool shaft 20 x 20 mm Travel paths: x-axis 160 mm z-axis 450 mm Feed rates: Rapid traverse X: 60 m/min Rapid traverse Z: 45 m/min Feed force X: 2.5 kN Feed force Z: 4 kN Rapid traverse C: 200 1/min Max. torque C: 155 Nm Total power requirement Machine weight approx. 3.7 t Space requirement approx. 4.5 x 2.5 x 2.5 m Heidenhain control Hollow clamping cylinder C-axis and tool drive a Cedpfx Ajv Drigsb Usha Chip conveyor Oil and emulsion mist separator with electrostatic filter

Condition: good (used), Year of construction: 2007, Machine is in good working condition. Machine come without automatic line. Chsdpfsxf Iamox Ab Uja Marked equipement with red not come.. Some accesories and machine equipement are also available. More specs of the machine, check last two pictures.

Condition: used, functionality: fully functional, Equipment: documentation/manual, rotational speed infinitely variable, Gildemeister lathe Color: Pink Rose 3 axes X, Z, C Codpfey A Imqex Ab Ueha Type: CTX 400 Series 2 CNC Heidenhain With conveyor With driven tooling With documentation