Used Amada Hfa 330 for sale (221)

Year of construction: 2016, condition: ready for operation (used), travel distance X-axis: 3,050 mm, travel distance Y-axis: 1,525 mm, travel distance Z-axis: 37 mm, overall weight: 21,500 kg, total height: 2,342 mm, number of axes: 4, This 4-axis AMADA EMZ3612M2 was manufactured in 2016, featuring a high-speed servo-electric turret punch press with twin AC servo direct drive. It boasts a 33-ton press capacity and an AMNC-F / AMNC-4ie CNC system for enhanced control. The machine handles sheet formats up to 3050x1525 mm and includes a "King" turret with up to 58 stations. Energy efficiency is optimized with AC servo drives. If you are looking to get high-quality punching capabilities consider the AMADA EMZ3612M2 machine we have for sale. Contact us for more information. Additional equipment • Air-blow oil-mist lubrication • Slug-vacuum system • Digital tool ID / barcode system • Integrated tapping: inch/metric taps (M2.5–M8) • Marking & deburring tools: on-board marking and deburring options Machine Benefits Technical Machine Benefits • Type: high-speed servo-electric turret punch press with twin ac servo direct drive • Press capacity: 33 tons (300 kn) Dodpfxex Nrktj Apwock • Maximum sheet format (without repositioning): 3050 × 1525 mm • Turret type: “king” turret – triple-track, available in 55-station multi-purpose or 58-station version, with 4 auto-index stations including tapping units • Turret rotation speed: up to 30 rpm • Feed clearance: 25 mm between turret plates • Max sheet thickness: 4. 5 mm • Positioning speed (x/y): 100 m/min / 80 m/min Extra Information Machine still under power Dimensions Machine Depth 5436 mm

Condition: excellent (used), Year of construction: 2007, functionality: fully functional, punching force: 20 t, 1 Used Amada EM 2510 NT Servo Electric Cnc Punch Press For Sale Make: Amada Model: EM 2510 NT Punching Force: 20 Tons (200 kN). Axis Travel (X/Y): 2500 x 1270 mm (expandable for larger sheets) with reposition Turret Configuration: Typically 45-stations with 4 Auto-Index stations. Control System: touchscreen control. Positioning Accuracy: Servo-Electric Drive: Replaces hydraulic systems with a, single AC servo motor (AE) or twin-drive (EM) system. This reduces energy consumption, eliminates oil changes, and minimizes maintenance. High Speed and Productivity: Capable of up to 900 hits per minute for marking, and 370 hits per minute on 1-inch centers. AMNC-F/3i Control: User-friendly, touchscreen interface for fast, error-free operations. Environmental Efficiency: The machine requires a low 19 kVA power hookup, drawing less than 5 kW at maximum power. Quiet Operation: Uses brush-type tables to reduce noise and prevent scratching on the underside of sheets. Dcjdpfx Apeyyck Sowsk Tooling Efficiency: Features a "Triplet Track" turret and power vacuum die system to reduce tool changes and prevent slug pulling.

Condition: used, Used cheap Amada Its 2 2.5metre x 80ton 7axis cnc pressbrake Used cheap Amada Its 2 2.5metre x 80ton 7axis cnc pressbrake PRESS BRAKE HYDRAULIC Dcedpfjfuaqmjx Apwek CAPACITY: 80 TONS BENDING LENGTH: 2500mm CONTROL: OPERATEUR NO OF AXIS: 7 FRONT GUARDS ERWIN SICK MACHINE MOUNTED SIDE AND REAR INTERLOCKEDFENCING

Condition: used, Automatic High Quality Grinding Automatic High Quality Grinding Machine Type : Other All punch operators know the importance of tool maintenance on part quality and tool life. The AMADA TOGU is the solution; an automatic tool grinder design specifically for high quality grinding of sheet metal tooling. Unmanned operation Simple operator control Quick, reliable grinding of all standard tooling Supplied with jigs for shear angle grinding Restores tooling to optimum condition resulting in high quality parts Enables regular regrinding to maximise tool life USED AMADA AUTOMATIC TOOL GRINDER MODEL TOGU-III MACHINE SPECIFICATIONS Model ……………. TOGU-III Dsdpfxsfuai Uj Apweck Max. Diameter Tool Size ……………. 6.30 Max. Grinding …………… .039” Main Axis Motor …………… 2 H.P. 2 P Main Axis Rotation Speed ………….. 3000R.P.M. (60Hz) Main Axis Travel …………… 9.45” Main Axis Feed Motor …………….. DC Servo Motor (0.05 H.P.) Main Axis Feed Speed-High ………… 23.6 I.P.M. Main Axis Feed Speed-Middle ………. 2.36 I.P.M. Main Axis Feed Speed-Low …………. 0.002 I.P.M. Table Motor ……………. 0.134 H.P. 4P Table Rotation Speed …………… 72 R.P.M. (60Hz) Cooling Water Pump Motor ………….. 0.08 H.P. 2P Cooling Water Pump Flow …………… 0.9 CFM (60 Hz) Machine Weight …………….. 1,058 lbs Power Supply …………….. AC220V 3 Phase 2.5 kVA (Transformer Used Outside 220v Area) Air Supply …………… 60 C.F.M. Grinding Wheel …………….. CBN 5.31 Benefits: Fast and Easy to Use Fully automated machine Unmanned grinding cycle Easy operation – load ᐳ inputᐳ start Programmable re-grind amount High Quality Finish Automatic feed of wheel prevents tool burn Automatic grinding wheel dress indication Excellent surface finish Safe Unique safety locking system ensures operator safety Visual operation/standby indication Coolant and Filtration System Automatic coolant application prevents tool burn High quality finish maintained by filtration of coolant liquid

Condition: excellent (used), Year of construction: 1995, functionality: fully functional, pressing force: 170 t, working width: 3,100 mm, working range: 3,100 mm, AMADA MULTI AXIS CNC 170 TONS X 3100 HYDRAULIC DOWNSTROKING PRESS BRAKE WITH AMADA OPERATEUR II 8 AXIS CNC CONTROL Description TYPE HYDRAULIC DOWNSTROKING Dcsdpfx Apev Iftgjwsk CAPACITY 170 TONS CONTROL AMADA OPERATEUR II NO OF AXIS 8 INCLUDING Z1 AND Z 2 BENDING LENGTH 3100mm OPEN HEIGHT 450 STROKE LENGTH 180 THROAT DEPTH 410 MOTOR SIZE 15 KW FRONT GUARDING ERWIN SICK MACHINE MOUNTED ELECTRONIC GUARDS SIDE FENCING REAR INTERLOCKED WEIGHT 11 TONS

Year of construction: 2000, condition: good (used), Used Amada Tp150ex 150ton press / stamping machine Amada TP150 EX electric Power Press with feed Atkin Bhp feed and Atkin BHP decoiler New/year 2000 TP150 Model Amada TP-150EX Weight 16 tons Accessories Sick Guards Hydraulic Overload Variable Speed Drive Hydraulic Tool Clamping Dsdpfx Ajn Smg Tepweck Capacity 15o tons Supplied New July 2000 Stroke 175mm Bed Area 1250 x 750 x 160mm Ram Area 700 x 550mm Ram Adjustment 100mm (motorised) Die Height 390mm Ideal for automotive or aerospace sheet metal press work New c and h frame presses also available.

Year of construction: 2012, condition: excellent (used), Used compact / small foot print Amada Lasmac LC – 1212 a IV NT flat bed 2d cnc laser cutting machine for sale: Dcodpfx Ajimwcbspwsk Fully serviced single bed very clean Amada LC – 1212 a IV NT cnc laser – Video at the bottom of this listing Specification: Most recent work carried out by Amada UK: New turbo blower recently fitted New lenses and mirrors in August 2022 Fully serviced with Amada Uk Year / New 2012 Power: 2.5kw Machine Model: LC – 1212 a IV NT Travel method: X-Axis Material Travel, Y Axis: laser Beam Travel Axis Travel Distance X x Y x Z M: 1270 x 1270 x 300 Positioning Speed X x Y x Z m/min: 80 x 80 x 60 Cutting feed rare X x Y m/min: 0 – 20 Control Method: X-, Y- and Z-axes (simultaneously controlled) + B – axis Max. sheet size X x Y x Zmm: 2540 x 1270 x 300 Repeatable positioning accuracy mm: +0.005 Oscillator model: AF2000E-LU2.5 AF4000E Oscillation Process: fast axial flow, high frequency discharge excitation Ideal if you are looking to bring laser cutting in house and space is a premium Delivery and installation can be arranged AMADA LASMAC LC1212 MK IV 2.5 KW NT LASER CUTTING MACHINE MACHINE CAPACITY 1270 X 1270 2540 WITH ONE REPOSITION

Condition: excellent (used), Year of construction: 2001, functionality: fully functional, working width: 3,100 mm, bending force (max.): 130 t, control type: CNC control, number of axes: 6, Equipment: CE marking, european tool clamping system, lower tooling, safety light barrier, upper tooling, Used Amada HFE 3metre x 130ton cnc pressbrake for sale TYPE Dedew Ugg Ejpfx Apwjck HYDRAULIC DOWNSTROKING CAPACITY 130 TONS CONTROLLED AXIS Y1, Y2, X, R1 R2 Z1 Z2 MAX BEND LENGTH 3000 MM OPEN HEIGHT 470 YEAR 2001 STROKE LENGTH 200 THROAT DEPTH 420 MOTOR POWER 11 KW FRONT GUARDING MACHINE MOUNTED ERWIN SICK ELECTRONIC SIDE INTERLOCKED FENCING REAR INTERLOCKED FENCING TONNAGE 1300 KN APPROACH SPEED 100 MM/SEC BENDING SPEED 1 – 10 MM/SEC RETURN SPEED 1-100 MM/SEC OIL CAPACITY 110 LITRES WEIGHT 7800 KG BACK GUAGE STROKE (X AXIS) 700 MM/S MAX GUAGE 1000MM

Condition: excellent (used), Year of construction: 2012, functionality: fully functional, pressing force: 220 t, working width: 4,100 mm, working range: 4,100 mm, Model: Used Amada HFE M2 220t 4metre x 220ton, 8 axis Press Brake For Sale Hydraulic Down Stroke Year 2012 Tonnage 220 tonnes Max. Bend Length 4280 mm Stroke Length 200 mm Approach Speed 1 - 100 mm/sec Dcjdpfxjv Tdbge Apwsk Bending Speed 1 - 10 mm/sec Return Speed 1 - 100 mm/sec Oil Capacity 195L Motor Power Weight 17450 Kg Dimensions Machine Length 5070 mm Machine Depth 2075 mm Machine Height 3085 mm Distance Between Side Frames 3760mm Beam width 180 mm Table height 960 mm Open Height 470 mm Throat Depth 420 mm

Condition: excellent (used), Year of construction: 2001, Used High Quality, Very Clean and Fully Serviced Large Format Amada Vipros King 368 Cnc Punch Press For Sale Complete With 1600 Throat To Process 3metre x 1.5metre Sheet Metal year 2001 price POA specification 30 TONS CAPACITY 58 STATION 4 AUTO-INDEX HYDRAULIC CNC PUNCH PRESS COMPLETE WITH LKI MP3000 LOAD -UNLOAD MANILPULATOR description Dcsdpor D R Rusfx Apwok CAPACITY 30 TONS TYPE BRIDGE FRAME SERVO CONTROLLED HYDRAULIC RAM BRIDGE FRAME SERVO CONTROLLED HYDRAULIC RAM CONTROL FANUC 18P MAX AXIS TRAVEL 1525 X 2000 MAX SHEET SIZE 1525 X 4000 MAX SHEET THICKNESS 3.2MM 58 STATIONS THICK (H) 24 x 12.7 mm 24 x 31.7 mm 4 x 50.8 mm 1 x 88.9 mm AUTO-INDEX STATIONS 2 X 31.7mm 2 X 114.9mm MAX SHEET WEIGHT 150 KG 120 KG AT MAX SPEED MAX HIT RATE 860 STROKES PER/MIN POWER AND AIR REQUIRED 30 KVA 400V +/- 10%50 Hz AIR 5.0 kgf/cm/2 AIR FLOW 250 L/MIN COOLING WATER FLOW Min 40 1/min WEIGHT 14000kg SERIAL NO. MAX SHEET SIZE 3000mm X 1500mm MIN SHEET SIZE 1000 MM X 300mm SHEET THICKNESS RANGE 0.5mm – 6.0mm MAX LIFT CAPACITY 170 KG WITH DOUBLE SHEET DETECTION MAX PALLET LOAD 3000KG POWERAND AIR REQUIRED 10 KVE AIR 6 BAR FLOW RATE 650L/MIN

Year of construction: 2003, condition: excellent (used), Amada GS 630 sheet metal hydraulic cutting machine for sale G Series Hydraulic Shear – Video at the bottom of this listing Specification: Dsdpfx Aoimwcqepweck Model: 630 Max Plate Thickness mild steel (mm): 6.35 Max Plate Thickness stainless steel (mm) 4 Max Cut Length (mm) 3050 Max Stroke / min 35 Motor Size (Kw) 5.5 Machine Weight (Kg) 6150 Back gauge speed (mm/s) 100 Back gauge Range (mm) 10-1000

Condition: good (used), Year of construction: 1994, pressing force: 25 t, working width: 1,200 mm, working range: 1,200 mm, High Quality Used AMADA PROMECAM ITS2 25-12 1.2metre x 25ton cnc pressbrake for sale Djdsrhirzjpfx Apwjck Year 1994 Specification 25 TONS X 1250 HYDRAULIC UP STROKING 3 AXIS CNC PRESS BRAKE COMPLETE WITH HURCO AUTOBEND 7 CNC CONTROL description TYPE HYDRAULIC UPSTROKING CONTROL HURCO AUTOBEND 7 BENDING PRESSURE 25 TONS BENDING LENGTH 1250 STROKE LENGTH 100 TABLE WIDTH 60 NO. OF AXIS 4 AXIS CONFIGURATIONS Y X AND R SIDE FENCING REAR INTERLOCKED

Condition: excellent (used), Used Amada 60ton C frame press for sale SPECIFICATION Djdpfjyk D Dtjx Apwock MODEL TP -60 CAPACITY 60 ton NUMBER OF SLIDE STROKES 50 Hz 45-80 strokes/ minute STROKE LENGTH 120 mm SLIDE ADJUSTMENT 70 mm SLIDE AREA (R-L x F-B) 500 x 400 mm BOLSTER AREA & THICKNESS (R-L x F-B x thickness) 900 x 550 x 80 mm SHUTHEIGHT 370 mm MAIN MOTOR 5.5 x 4 kWXP AIR PRESSURE REQUIRMENT 5.0 kgf/cm2 MAXIMUM NUMBER OF FLYWHEEL ROTATIONS 1170 r.p.m. MINIMUM AIR PRESSURE FOR CLUTCH ON STOPPING TIME 165 msec BRAKE MONITOR SETTING, DEGREES BEYOND T.D.C. 15 degree SERIAL NO. 07312665 MANUFACTURE DATE 1992.4 MANUFACTURED BY AMADA CO., LTD.

Condition: ready for operation (used), functionality: fully functional, Year of construction: 2011, operating hours: 13,000 h, machine/vehicle number: MP2512C1, sheet thickness (max.): 6 mm, working length: 2,500 mm, working width: 1,270 mm, rapid traverse X-axis: 80 m/min, rapid traverse Y-axis: 60 m/min, No reserve price – guaranteed sale to the highest bidder! Bidding obligates you to collect the item on time by 15/12/2025!  The machine has been regularly serviced by Amada. TECHNICAL DETAILS Punching working area X x Y: 2,500 x 1,270 mm Dcjdoxzf T Aopfx Apwsk Laser working area X x Y: 2,000 x 1,270 mm Rapid traverse X-axis: 80 m/min Rapid traverse Y-axis: 60 m/min Accuracy: ±0.07 mm Maximum material thickness: 6 mm Press force: 200 kN Max. strokes X-axis: 370 rpm Max. strokes Y-axis: 280 rpm MACHINE DETAILS Power consumption: 22 kVA Machine weight: 18,000 kg Operating hours Laser hours: 13,000 h Punching hours: 17,000 h Note: Information regarding the tools can be found in the attached images.

Condition: ready for operation (used), Year of construction: 2016, functionality: fully functional, pressing force: 50 t, overall weight: 3,350 kg, Equipment: safety light barrier, We are offering this ready-to-use Amada HFE MK2 5012, 50 ton, 4-axis CNC press brake. Year of manufacture: 2016 Press force: 50 tons Max. bending length: 1250 mm If you have any questions or need further information, please feel free to send us a message or give us a call. Dcedpfey H Hgwex Apwjk The seller assumes no liability for typing or data transmission errors. The machine's condition in terms of appearance, technology, and wear corresponds to its age; used machines are sold without any guarantee or warranty.

Condition: ready for operation (used), Year of construction: 1999, functionality: fully functional, operating hours: 70,104 h, pressing force: 81 t, total length: 3,100 mm, total width: 2,180 mm, total height: 2,540 mm, overall weight: 5,750 kg, working width: 2,550 mm, Equipment: emergency stop, We offer this ready-to-use Amada HFBO 80-25 press brake, year of manufacture 1999. If you have any questions or need further information, please feel free to send us a message or give us a call. Dodpey H Eqbsfx Apwjck The seller accepts no liability for typographical or data transmission errors. The machine's appearance, technical condition, and wear are consistent with its age; used machines are sold without any warranty.

Condition: used, Micro welding head unit, spot welding system with welding head, inverter power source, I/O module, welding inverter MIYACHI PECO / AMADA WELD TECH GmbH Type ISQ20 Kompakt ISQ-AC/DC-AWS-EXT-250A 22KVA + PECO F160S Year of manufacture: 2011 The system consists of the following components: - Welding inverter MIYACHI PECO Type ISQ20 Kompakt ISQ-AC/DC-AWS-EXT-250A 22KVA with MFT1 control panel - External welding transformer MIYACHI PECO (mounted on the welding head frame) - External interface module MIYACHI PECO Type ISQ-MG - Spot welding head MIYACHI PECO Type F160S – 25 mm stroke with Heidenhain measurement system - Connection cables Mains voltage: 3x 400 V AC Mains frequency: 50 / 60 Hz Connected load: 22 KVA Welding current types: AC / DC Output current: max. 10 kA Output frequency: 1 - 10 kHz Welding time: max. 640 ms/pulse Current measurement: external toroidal coil Control panel: MFT1 (independent removable control unit) Analog input: pressure sensor for proportional valve Analog output: proportional valve control Interface: RS232 Protection class: IP30 - Error monitoring and process control - Monitoring of current, voltage, power, energy - Test pulse for part recognition - Program memory for 99 programs Inverter dimensions (W x H x D): 216 x 420 x 560 mm Inverter weight: approx. 21 kg Spot welding head MIYACHI PECO F160S Rated current: max. 5 kA Electrode stroke: 25 mm Closing stroke: pneumatic - Adjustable force ignition from 1.2 to 550 N Dedpfx Ajpy Uzyopwjck - Heidenhain distance measuring system Welding unit with 5 pneumatic cylinders and Festo valve terminal Type CPX Welding head mounted on horizontal guide rail and can be moved 20 mm via pneumatic cylinder. 3 pneumatic cylinders available for workpiece clamping (2 units with 46 mm stroke, 1 unit with 20 mm stroke). Throat depth (distance from welding tip to frame): 300 mm Welding tip height above floor: 315 mm Welding unit dimensions (W x H x D): 410 x 760 x 700 mm Welding unit weight: 75 kg Total weight: 100 kg 2 nearly identical units available, price per complete unit.

Condition: used, Cutting length: 3100 mm Steel cutting capacity: 12 mm Dcedpjxuh Ipjfx Apwok Backgauge: 1000 mm

Condition: used, Year of construction: 2015, Working hours machine: 31888 (17.01.2024) h Working hours laser on: 19090 (17.01.2024) h Working hours beam on: 6475 (17.01.2024) h Laser power: 4000 Watt Max. punching force: 300 kN Control: AMNC 3i Working range laser: 2500 x 1170 mm Working range punching: 3050 x 1525 mm Length: 7870 mm Width: 5880 mm Height: 2666 mm Electrical connected load: 85 kVA x-axis: 100 m / min y-axis: 80 m / min Weight of machine approx.: 30000 kg Dcedpfx Ajypt R Hspwok Standard configuration - Patented servo-electric double drive- Punching force 300 kN- 32 tool stations (4 rotatable stations)- max stroke rate: 400- max material thickness 6mm- Automatic focus adjustment- Automatic gas pressure control- HS sensor cutting head- Nozzle cleaning- Splash guard- Good parts flap Extended machine accessories - TSU tool changer 300 Automation

Year of construction: 2004, condition: used, table length 1250 mm table width 1250 mm burner heads 1 Control Fanuc output 1000 Watt Dodpfohly Hlox Apwock travel -z axis 100 mm travel x / y 1260/1260 mm traversing speed 30/30/42 mm/sec gas consuption 10 Liter/Std. total power requirement 22 kW weight of the machine ca. 3,5 t dimensions of the machine ca. 10 m

Condition: like new (used), Year of construction: 2017, functionality: fully functional, operating hours: 2,600 h, controller model: Fanuc 32 C, control type: CNC control, Equipment: documentation/manual, Standard programs such as parameter settings Dressing settings Speed settings Program management settings Limitation of travel distances x + y Dcodpfew I Tt Sex Apwek Basic parameter settings Grinding wheel management program Warming-up cycle program Surface plunge grinding program Measuring program 15 kVA transformer Full enclosure Meister G3 Spindle upgrade to 3.7 kW, disc 225 mm ETHER interface for network connection Control module with extended memory Fanuc Macro B option Program creation for batch programs Programmable spindle speed WinWop program for contour creation (Windows) WINWop program for error compensation WinWop postprocessor CGS Complete Grinding Solutions software Option Dressing Swiveling profile dressing device Diamond dressing wheel Pre-dressing device VPA 100 L Diamond wheel 100 mm for pre-dressing device Regrinding package diamond wheel G3 / W Option – Clamping and Balancing Magnetic chuck 400 x 200 400 mm stop bar with prism Fully automatic balancing device, size 1 Grinding wheel flange for G3, bore 51 mm Option Filter Systems Belt filter system 175 l Extraction unit for emulsion mist 500 Inquiries only from Europe, preferably the EU.

Condition: used, Year of construction: 2006, pressure 80 t chamfer lenght 2550 mm distance between columns 2050 mm Stroke beam 200 mm max. opening beam/table 470 mm C-recess 350 mm max travel X-axes 700 mm Z1+Z2 axes controlled by cnc nein, manuell 4 finger mm max. distance R-axes 200 mm Quick speed,inspeed 100 mm/sec bendingspeed 0-10 mm/sec opening speed 100 mm/sec Number of working hours 43000 h length 3100 mm width 1600 mm height 2550 mm Dodpfx Apetv Rlbeweck weight 5750 kg total power requirement 9 kW dimensions of the machine ca. 3x2x2,5 m Control Amada OP2002 All machines can be viewed under power at all times. Demonstrations of the machines possible at any time.

Condition: used, Year of construction: 2004, pressure 80 t chamfer lenght 2550 mm Dcsdpfxsxyzzae Apwok distance between columns 2050 mm Stroke beam 350 mm max. opening beam/table 620 mm C-recess 420 mm traveldistance X1+X2 cnc programmable 700 mm Z1+Z2 axes controlled by cnc 0-2000 mm max. distance R-axes 200 mm Quick speed,inspeed 100 mm/sec bendingspeed 0-10 mm/sec opening speed 100 mm/sec Number of working hours 24000 h length 3380 mm width 1800 mm height 2750 mm weight 6100 kg total power requirement 9 kW dimensions of the machine ca. 3x2x2,5 m All machines can be viewed under power at all times. Demonstrations of the machines possible at any time.

Condition: ready for operation (used), Year of construction: 1999, functionality: fully functional, stroke length: 350 mm, controller model: Amada Operator, bending force (max.): 320 t, working length: 4,100 mm, TECHNICAL DETAILS Press force: 320 t Bending length: 4,100 mm Stroke: 350 mm MACHINE DETAILS Control: Amada Operator Dodexwnxtopfx Apwock Total power requirement: 32 kW Dimensions & Weight Space requirements: approx. 4,300 x 2,600 x 3,400 mm Machine weight: approx. 23,500 kg EQUIPMENT Amada quick-change tool holder Amada lower tool holder Controlled axes: y1, y2, x, r, z1, z2 Rear safety doors Two-hand foot operation

Condition: ready for operation (used), Year of construction: 2000, operating hours: 20,000 h, functionality: fully functional, workpiece length (max.): 3,000 mm, workpiece width (max.): 1,500 mm, TECHNICAL DETAILS Sheet size: 1,500 x 3,000 mm MACHINE DETAILS Operating hours: 20,000 h EQUIPMENT Material handling Tools Dcedpfx Apow Swdiewok Grinding machine