Used Planer Grinders for sale (2,865)

Condition: used, Capacity: 80 m/min Bdodpeg S Dm Njfx Ab Uea Planer feed table, tested. At speeds up to 80 m/min.

Condition: excellent (used), Year of construction: 2016, Steton 5-head four-sided planer. Steton 5-head four-sided planer. The machine after the review does not require a financial contribution. Technical data: - max width of the workpiece 23 cm Bdodpfxei Apuhe Ab Uea - max height 13 cm spindle diameter 40mm - 1 - Horizontal bottom 23 cm - 2 - vertical right 13 cm - 3 - vertical left 13 cm - 4 - horizontal upper 23 cm - 5 - universal 360 degree soundproofing cabin - electric setting of planing thickness - two types of feed speed

Condition: new, Year of construction: 2023, functionality: fully functional, CHILLER UNIT 290 kW – 2 separate refrigeration circuits, shell-and-tube heat exchanger, R32 Cooling capacity: 290 kW at 7/12°C and 35°C ambient temperature Shell-and-tube evaporator for efficient heat transfer and compact design Low-GWP refrigerant R32 Bodpfxou Au I Te Ab Usda Four compressors in two separate refrigeration circuits for high operational reliability and flexible load distribution Low-noise design thanks to optimized sound insulation Completely framed compressor enclosure for efficient protection, easy maintenance, and reduced noise emission Winter package allowing operation at ambient temperatures down to -20°C Ideally suited for industrial processes.

Year of construction: 1987, condition: ready for operation (used), Knife grinders for 800 kofama lignum strips Sharpening bar 800 used 1987 Rating: Table Model: Bdjdpfxjh S Upio Ab Uoa 800 Description: 800 grinders with a slat knife

Year of construction: 1994, condition: excellent (used), 4 side planer 8 8 HARBS heads long table going 3 meters. Machine weight 5500 kg Bdodpfx Ael Dw Nxsb Uoa cardan drive. Head arrangement, bottom horizontal, right vertical, second right vertical, left vertical, top horizontal, bottom horizontal, top horizontal. Upper horizontal. 5.5 kW and 7.5 kW motors. Planing width 230 mm. Planing height 160 mm.

Condition: not inspected (used), Year of construction: 2000, functionality: unexamined, machine/vehicle number: 2259, travel distance X-axis: 6,000 mm, travel distance Y-axis: 3,500 mm, travel distance Z-axis: 1,900 mm, rotational speed (max.): 24,000 rpm, controller model: Siemens 840D, No minimum price – guaranteed sale to the highest bidder! TECHNICAL DETAILS Travel X-axis: 6,000 mm Travel Y-axis: 3,500 mm Travel Z-axis: 1,900 mm B-axis: +/- 110° C-axis: 360° Bdjdeyv A Dkjpfx Ab Usa Spindle speed: 24,000 rpm Spindle taper: HSK 63 Spindle motor: 25 kW Table size: 6,000 mm x 2,500 mm (hole pattern 22H7 / M16) Feedrate X + Y: 30,000 mm/min Feedrate Z: 28,000 mm/min Rapid traverse: 30,000 mm/min MACHINE DETAILS Control: Siemens 840D Tool changer: 40 tools EQUIPMENT Spindle: Fischer (type MFWS 1709/30, 2 units) Milling head: Forest Line (type: fork head, B-axis swivels +/- 110°, C-axis rotates 360°) Richter chip conveyor (scraper conveyor) Blum tool measurement Parking station for milling head (2 units)

Condition: ready for operation (used), Year of construction: 2002, operating hours: 4,486 h, functionality: fully functional, travel distance X-axis: 3,000 mm, travel distance Y-axis: 2,360 mm, travel distance Z-axis: 1,500 mm, rotational speed (max.): 18,000 rpm, controller model: Fidia C20 mit Bedienteil HPX, The machine is in fully operational, very good condition. It has been dismantled, is in storage, and available immediately! TECHNICAL DETAILS Travel range X-axis: 3,000 mm Travel range Y-axis: 2,360 mm Travel range Z-axis: 1,500 mm Rotary axis A: 105° Rotary axis C: 300° Clamping area: 5,000 mm x 2,000 mm Table load: 15,000 kg/m² T-slot spacing: 18H12 / 250 mm Feed rate X, Y, Z axes: 20 m/min Axis acceleration X, Y, Z axes: 1.5 m/s² Max. spindle speed: 18,000 rpm Bodpeywgyrsfx Ab Ueda Torque: 90 Nm Tool holder: HSK 63A MACHINE DETAILS Spindle power: 28 kW Connected load: 40 kW Main fuse: 80 A Spindle hours: 4,486 h Machine hours: 146,161 h Dimensions & Weight Space required for machine with peripherals (L x W x H): 7,300 x 5,600 x 5,600 mm Machine weight: 16,500 kg EQUIPMENT 3-sided enclosure, without extraction ducts

Condition: ready for operation (used), Year of construction: 2008, functionality: fully functional, machine/vehicle number: PE-305L-1307, rotational speed (max.): 12,000 rpm, travel distance X-axis: 400 mm, travel distance Y-axis: 250 mm, travel distance Z-axis: 250 mm, controller model: SIEMENS 840D, TECHNICAL DETAILS X-axis travel (longitudinal): 400 mm Bsdpeyvq Sijfx Ab Uoda Y-axis travel (cross): 250 mm Z-axis travel (vertical): 250 mm Resolution X, Y, and Z axes: < 0.1 µm Feed rate X, Y, and Z axes: max. 24 (48) m/min Rotary axis for workpiece (A-axis) Indexing mode resolution: < 0.0001° Speed range as rotary axis: max. 200 rpm Speed range universal rotary axis: max. 2,500 rpm Torque: max. 88 Nm Swivel axis for grinding head (C-axis) Swivel range: 225° Resolution: < 0.0001° Swivel speed: max. 360°/s Grinding spindle (motor spindle) Max. speed: 12,000 rpm Drive power: 15 kW Taper: HSK 50 E MACHINE DETAILS Control: SIEMENS 840D Drive technology: SIMODRIVE 611D Connected load: 30 A Number of axes: 5-axis EQUIPMENT GEA Multitron Junior air extraction system, year of manufacture 2008 Volmat FA-120S filtration system with cooling, year of manufacture 2008 Motoman MX100 industrial robot with control cabinet, 400V (not functional) Note: The machine has already been completely dismantled.

Condition: excellent (used), Year of construction: 2000, functionality: fully functional, machine/vehicle number: 663015, Walter Helitronic Mini Power Production 5 Axis CNC Tool & Cutter Grinder Universal tool and cutter grinder (CNC controlled) Made by Walter, model Helitronic Mini Power Production, s/n663015, year 2000 Description: Suitable to manufacture and regrind metal and woodworking tools of all kinds. Run with 1 micron filtration system, so the machine is very clean. Specifications: • Longitudinal traverse (X-axis) 350 mm, • Vertical traverse (Y-axis) 200 mm, • Cross traverse (Z-axis) 470 mm, • Rotary table swiveling range (C-axis) +/- 200°, • Work head ISO 50, center height (with / without worktable) 145 / 190 mm, • Max. diameter of workpiece 100 mm • Max. length of workpiece 270 mm • Max. dia. of grinding wheel 150 mm • Peak performance 11,5 kW, grinding spindle motor 9kW,speed 0 - 9500 rpm, • Connected load approx. 25 kW (460 volts 3ph / 60 Hz), • Dimensions w x d x h = 2600 x 2550 x 1970 mm, weight approx. 3950 kg, color grey RAL 7035 / grey RAL 7043. Accessories: • Control HMC 500 Windows XP Upgrade • Includes: 2021 Ebbco Filtration & Chiller unit Model PMF-MWF5-623-P-40K capable of filtering & chilling up to 2 grinders. 40,000 BTU Chiller & filtration up to 1 Micron. • Booster Box Upgrade option along with a spare Booster Box as well that could be used as a backup or for up to 3 other Walter machines. Value of each booster box is $10,000 a piece. • Stepless speed control, probe, pneumatic workpiece clamping • Fire extinguishing system • Mist Extractor • Oil collecting pan, 2 grinding wheel flanges • Complete set of Manuals Bsdpsu Ez Huefx Ab Usda Software: • Tool Studio Version 2.1 Standard & Steptools • WWM Software Condition: • New Y axis Motor & Ball screw Installed 2021 • New Spindle Installed 2021 • New Electrical cabinet air conditioner Installed 2021 • All new encoder & motor cables for A, C, X, Y & Z axis Installed 2021 • Currently in production producing very accurate & consistent tools. Can be viewed under power • We have all of the shipping bracket, so the machine will be safely secured for shipping. • We can load onto a flatdeck for shipping for $900. We can also provide shipping & crating quotes if you would like.

Condition: excellent (used), Year of construction: 2008, functionality: fully functional, machine/vehicle number: 693068, overall weight: 7,300 kg, power: 30 kW (40.79 HP), Walter Helitronic Vision CNC Tool & Cutter Grinder with Pallet Loader Universal tool and cutter grinder (CNC controlled) Made by Walter, model Helitronic Vision, s/n 693068, year 2008 Description: Suitable to manufacture and regrind metal and woodworking tools of all kinds. Can be viewed under power. Specifications: • Longitudinal movement (X-axis) 480 mm • Y axis vertical movement 320 mm • Z-axis transverse movement 700 mm • Rotary table swivel range C-axis +/- 200 ° • Workpiece Holder ISO 50 Bedjuqzdpspfx Ab Ueda • Max. Workpiece diameter 320 mm • Workpiece length circumferential grinding 370 mm • Workpiece length for face machining 320 mm • Accuracy linear resolution 0.0001 mm • Radial resolution 0.0001 ° • Diameter of the spindle 100 mm • Grinding wheel mount: HSK50 • Diameter of the grinding wheel 200 mm • Grinding spindle speed 0 – 12,000 rpm., • Top performance 30 kW • Connected load 35 kW (460 V / 60 Hz) • Weight approx. 7,100 kg • Dimensions L x W x H 3649 x 2490 x 2301 mm Accessories: • Does not include wheel opening stick fixture seen in the pictures • Stepless speed control, probe, pneumatic workpiece clamping • Electrostatic mist extractor • Fire extinguishing system • Oil collecting pan, 2 grinding wheel flanges, Complete set of Manuals • Turmoil Drive Chiller • Loader Pallets: 8pcs – 3/16”, 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, 3/4”, 1-1/4” • 10pcs - HSK Wheel Arbors Software: • Windows XP Pro Svc Pack 3 • Tool Studio V3.3 • The computer was upgraded & is very fast rendering tools in Tool Studio Condition: • Excellent condition, very accurate & consistent. October 2023 Y axis Complete rebuilt, Linear motor, rails, Compensation Cylinder, Festo Booster Pump done by United Grinding. • 1 Micron Filtration system was used on the machine (not included), so it’s been kept extremely clean • We can load onto a flatdeck for shipping for $1200. We can also provide shipping quotes if you would like & crating for Sea Freight shipping.

Condition: used, Nelmor 1436 grinder with a 100 HP, 3 phase motor, and approx. 15' 9" screw auger, winning bidder responsible for proper removal. Bsdpfx Ajxd D Nujb Ujda

Condition: good (used), Year of construction: 2002, LANDIS 3SE 14"x 60"ANGLEHEAD CNC GRINDER REBUILT BY LANDIS & TOOLED 2002 Equipped with: NEW FANUC CONTROL 2007 2-Axis Template Truform Servo Step Profile 30 Degree 30" Wheel Dead Headstock Table Traverse Marposs E39 Marposs Table Gauge Bsdpjrtr Easfx Ab Uoda Lateral Locator 3-Gauge TIR Gauge Steady Rests Wheel Balance Servo Motor-Traverse Stepping Motor Mist Collector Specifications: Swing: 14" Center Distance: 60" Motor: 1200 rpm Motor Pulley Diameter: 7.031" Spindle Pulley Diameter: 6.5" New Wheel Diameter: 30" Worn Wheel Diameter: 22" Max. Wheel: 8500 sfpm Max. Workhead: 333rpm X-Axis Ball Screw Pitch: 5mm per rev. X-Axis Total Stroke: 14.74" X-Axis Motor Pully Wheel Feed Diameter: 3" X-Axis Ball Screw Pulley Diameter: 3" Z-Axis Ball Screw Pitch: 10mm per rev. Z-Axis Total Stroke: 72.88" Z-Axis Motor Pulley Diameter: 3" Z-Axis Ball Screw Pulley Diameter: 6" Total Stroke: +/-2mm Total Marposs Voltage Output: =/-10vdc Dresser One Revolution of the Stepping Motor: .045" Diamond One Revolution of the Stepping Motor: .005" Weight: 25,000 lbs.

Condition: used, Year of construction: 2018, total width: 900 mm, total height: 1,250 mm, Weight: 800 kg Dimensions (LxBxH): 130 x 90 x 125 cm Price: On request - Details: - └ Description: Bearings sound bad - Year: 2018 - Documentation available: No - CE marking present: Yes - CE certificate present: No - Serial number: 63CE00007-8 - Max. planing width [mm]: 630 - Min. planing height [mm]: 2 - Max. planing height [mm]: 288 - Worktable length [mm]: 860 - Worktable width [mm]: 630 - Planer block diameter [mm]: 100 - Number of cutters [pcs.]: 4 - Number of cylinders height adjustment [pcs]: 4 - Extraction nozzle diameter [mm]: 160 - Height adjustment: Manual - Options: Braked motor, Digital readout - Feed speed: Manual - Feed speed control: Continuously adjustable - Voltage [V]: 400 - Current consumption [A]: 17.5 Bdedpfxoyu Sd Ae Ab Uja - Fuse [A]: 32 - Transport dimensions: 1300mm x 900mm x 1250mm (l x w x h) - Transport weight [kg]: 800kg - 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 Yorick Diebels

Condition: used, total width: 1,000 mm, total height: 1,600 mm, Empty weight: 1.300 kg Dimensions (LxBxH): 340 x 100 x 160 cm Four-sided planer SCM Sintex 380V 4 spindles Spindle below / above 7.5kW Spindle left/right 7.5kW Max working height 105mm Max working width 180mm Input table 2300mm Spindle diameter 40mm Bedpoyw Sg Dofx Ab Uoda Total dimensions 3400x980x1600mm (LxWxH), weight 925kg - Documentation available: No - CE certificate present: No - Number of spindles [pcs.]: 4 - Min. planing height [mm]: 100 - Feed table length [mm]: 2300 - Feed roller diameter [mm]: 120 - Feed motor [kW]: 7.5 - Diameter extraction nozzle [mm]: 120 - Voltage [V]: 380 - Transport dimensions: 3400mm x 1000mm x 1600mm (l x w x h) - Transport weight [kg]: 1300kg 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 Yorick Diebels

Condition: used, Year of construction: 1970, total height: 1,700 mm, total length: 1,400 mm, total width: 900 mm, Empty weight: 500 kg - Year: 1970 - Documentation available: No - CE certificate present: No - Serial number: CH - Control: Conventional - Motor power: 1.4kW - Transport dimensions: 1400mm x 900mm x 1700mm (l x w x h) - Transport weight [kg]: 500kg - Transport packages [pcs.]: 1 Bedpfx Aoyxqzceb Usda 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: 1998, total width: 2,220 mm, total height: 1,900 mm, Dimensions (LxBxH): 450 x 222 x 190 cm Price: On request - Year: 1998 - Documentation available: No - CE marking present: Yes - CE certificate present: No - Serial number: 83929 - Number of spindles [pcs.]: 5 - └ Spindle 1: - - Spindle type: Horizontal spindle - - Motor power [kW]: 7.5 - └ Spindle 2: - - Spindle type: Vertical spindle - └ Spindle 3: - - Spindle type: Vertical spindle - - Motor power [kW]: 11 - └ Spindle 4: - - Spindle type: Horizontal spindle - - Motor power [kW]: 11 - └ Spindle 5: - - Spindle type: Horizontal spindle - - Motor power [kW]: 7.5 Bdedpfx Abjxr U Nue Uea - Transport dimensions: 4500mm x 2220mm x 1900mm (l x w x h) - 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 Yorick Diebels

Condition: used, Year of construction: 2004, total height: 1,500 mm, total length: 1,100 mm, total width: 1,100 mm, Empty weight: 750 kg Price: On request - Year: 2004 Bdedpfx Abeyplvno Uea - Documentation available: No - CE certificate present: No - Serial number: 9010522 - Transport dimensions: 1100mm x 1100mm x 1500mm (l x w x h) - Transport weight [kg]: 750kg - 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: used, Year of construction: 1999, Price: On request - Year: 1999 - Documentation available: Yes - CE marking present: Yes - CE certificate present: No - X-axis travel [mm]: 900 - Y-axis travel [mm]: 550 - Z-axis travel [mm]: 360 - Table width [mm]: 790 - Table depth [mm]: 380 - Max. grinding wheel diameter [mm]: 400 Bedpfxswnhyhe Ab Uoda - Max. spindle speed [rpm]: 3400 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, Thicknesser Bodpfxjwnh Tbj Ab Uoda Robland D510 Serial no. Year of construction 2008 Table dimensions 510x850mm Max. working width 510mm Min-max working height 250mm Max planing depth 8mm 4 knives Tersa 4 throughput speeds 5/8/10/16 m/min Electrical high/low 380V, 5.5kW, 6000 Rpm Dimensions: 1200*880*1100mm, weight 480kg - Year: 2008 - Documentation available: No - CE marking present: Yes - CE certificate present: No - Serial number: - Max. planing width [mm]: 530 - Max. planing height [mm]: 300 - Max. planing depth [mm]: 530 - Planing shaft speed [rpm]: 5000 - Worktable length [mm]: 880 - Planer block diameter [mm]: 110 - Cutter type: Tersa - Number of cutters [pcs.]: 4 - Extraction nozzle diameter [mm]: 150 - Max. feed speed [m/min]: 19.5 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 Yorick Diebels

Condition: used, total height: 1,550 mm, total length: 1,600 mm, total width: 1,200 mm, Empty weight: 2.100 kg - Documentation available: No - CE marking present: Yes - CE certificate present: No - Drive system: Conventional - Power [kW]: 4.5 - Distance between centres [mm]: 480 - Centre height [mm]: 100 - Transport dimensions: 1600mm x 1200mm x 1550mm (l x w x h) - Transport weight [kg]: 2100kg Bdodpewnh Tzefx Ab Uja - Transport packages [pcs.]: 2 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, Price: On request Four-axis planer Kuper SWT 23 XL-5R Year of construction 2008 min/max Working height 8/150 mm min/max Working width18/230 mm Bdodpfx Ajwnit Asb Uoa Spindle speed 6000 rpm Spindle diameter 40 mm Motors Spindle - horizontal down 7.5kW  Spindle - vertical right 7.5kW Spindle - vertical left 11kW Spindle - horizontal top 11 kW Dimensions 3100 x1850 x 1750 mm (L x W x H), weight 4000 kg Outfeed table  Weidner buffer table Type DBT 4500B Dimensions 4500 x1750 x 97 mm (L x W x H) Available from November 2024 - Year: 2008 - Documentation available: No - CE certificate present: No 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 Yorick Diebels

Condition: used, Year of construction: 2002, total width: 7,660 mm, total height: 2,090 mm, Dimensions (LxBxH): 160 x 766 x 209 cm Four-side moulder Weinig Profimat 26 S, 6head Year of construction 2002 Machine number 95514 min/max Working height 8/120 mm min/max Working width 20/230 mm Working speed 5/24 m/min Spindle speed 6000 rpm Spindle diameter 40mm Engines 1. Spindle - under ..kW 2nd/3rd Spindle - left/right .kW Bdedpfxjwng I De Ab Uja 4. Spindle - above 11kW 5. Spindle - above 11kW 5. Spindle - under ..kW Dimensions 3900 x 1800 x 1900 mm (L x W x H), weight 2500 kg - Year: 2002 - Documentation available: No - CE certificate present: No - Transport dimensions: 1600mm x 7668mm x 2090mm (l x w x h) 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 Yorick Diebels

Condition: used, total width: 3,900 mm, total height: 1,800 mm, Empty weight: 4.200 kg Dimensions (LxBxH): 190 x 390 x 180 cm - Documentation available: No - CE marking present: Yes - CE certificate present: No - Serial number: 90-58-07 - Number of spindles [pcs.]: 4 - └ Spindle 1: - - Motor power [kW]: 7.5 - - Spindle diameter [mm]: 50 - └ Spindle 2: - - Motor power [kW]: 7.5 - - Spindle diameter [mm]: 50 - └ Spindle 3: - - Motor power [kW]: 15 - - Spindle diameter [mm]: 50 - └ Spindle 4: - - Motor power [kW]: 15 - - Spindle diameter [mm]: 50 - Max. planing width [mm]: 240 - Max. planing height [mm]: 85 - Feed table length [mm]: 1440 - Feed motor [kW]: 5.5 Bdsdpfewnh U Eex Ab Usa - Diameter extraction nozzle [mm]: 150 - Transport dimensions: 1900mm x 3900mm x 1800mm (l x w x h) - Transport weight [kg]: 4200kg - 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 Yorick Diebels

Condition: used, total height: 2,700 mm, total width: 2,000 mm, total length: 4,500 mm, Empty weight: 12.000 kg - Documentation available: No - CE certificate present: No - Drive system: Conventional - Table width [mm]: 1000 - Magnet width [mm]: 1000 - Options: Digital readout - └ Type of digital readout: Newall 2-A - Control: Conventional - Transport dimensions: 4500mm x 2000mm x 2700mm (l x w x h) - Transport weight [kg]: 12000kg - Transport packages [pcs.]: 3 Bsdpfxew A Nglo Ab Ujda 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: 1998, total height: 2,500 mm, total length: 5,900 mm, total width: 3,000 mm, Empty weight: 6.700 kg Price: On request - Year: 1998 - Documentation available: Yes - CE marking present: Yes - CE certificate present: No - Serial number: 199851086/1098 - Drive system: Conventional - Power [kW]: 11.0 - X-axis travel [mm]: 1200 - Y-axis travel [mm]: 680 - Z-axis travel [mm]: 400 - Table width [mm]: 1600 - Table depth [mm]: 670 - Magnet width [mm]: 1200 - Magnet depth [mm]: 600 Bodpfx Abex E Ukne Uoda - Control: Conventional - Motor power: 11.0kW - Transport dimensions: 5900mm x 3000mm x 2500mm (l x w x h) - Transport weight [kg]: 6700kg 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