Used Sun-Tec Reinraumtechnik 200°C Y9At417 for sale (72,337)

Condition: used, SUN-TEC Type: Y9AT417 SUN-TEC cleanroom technology heating plate Cleanroom workstation with heating plate 1600 mm x 1200 mm x 2200 mm Rated voltage: AC 200V, 3 phases, 50Hz, 30A Max. temperature: 200°C Condition: used Itsdpfx Agjzdqbqs Ajn Scope of delivery: (See picture) (Subject to changes and errors in the technical data and specifications!) We will be happy to answer any further questions you may have over the phone.

Condition: excellent (used), For sale, in very good condition: TIG welding machine, L-TEC 200 DC. The price is per unit. Ijdpjz Sb Dxefx Ag Aetn

Condition: used, Year of construction: 2001, operating hours: 58,764 h, functionality: fully functional, machine/vehicle number: 502748, clamping force: 1,000 kN, screw diameter: 30 mm, clearance between the columns: 420 mm, displacement volume: 144 cm³, injection pressure: 1.905 bar, ejector force: 41 N, ejector stroke: 150 mm, opening stroke: 500 mm, plate length: 590 mm, plate width: 590 mm, installation height: 250 mm, total length: 4,550 mm, total width: 1,450 mm, total height: 2,000 mm, overall weight: 4,800 kg, heating capacity: 9 kW (12.24 HP), pump power: 30,000 W, height adjustment type: hydraulic, stroke length: 150 mm, tool height: 250 mm, tool weight: 700,000 g, Equipment: documentation/manual, Demag ERGOtech Injection Moulding Machine ERGOtech 100-420-200 NC4 Year of manufacture: 2001 Asking price: €8,000.00 – WITHOUT Wittmann peripheral equipment The injection moulding machine is in good condition and ready for operation. For sale is the ERGOtech 100-420-200 NC4 injection moulding machine. Optionally, all corresponding Wittmann peripheral devices can be included at an additional charge. We purchased the Demag ERGOtech in 2020 during our company expansion to fulfill a customer order and equipped it with matching Wittmann peripheral devices. The machine has been serviced on-site by a DEMAG service technician and is free from defects. OPTIONAL: We also offer for sale all associated Wittmann peripheral equipment: Peripheral Equipment from WITTMANN BATTENFELD Deutschland GmbH: Wittmann Tempro Plus D160 – Dual-circuit temperature control unit TEMPRO-PLUS-D-Standard-2-160 DEMONSTRATION UNIT – used, no defects Equipped with: 2 pcs. Reinforced pump TemproPlus D160-1.0kW (2.4A) 60l 1 pc. Ultrasonic flow measurement 140-180° 1 pc. Digital interface 20mA 1 pc. Packaging for temperature control unit Original price: €6,980.00 Sale price: €3,490.00 Wittmann Compact Chiller Coolmax C30 WITTMANN WATER CHILLER SERIES: COOLMAX C30 DEMONSTRATION UNIT – used, no defects Original price: €4,750.00 Sale price: €2,375.00 WITTMANN BATTENFELD Deutschland GmbH Ijdpfx Agjtltvzo Astn Drying and dosing accessories - 1 pc. DRYMAX-PRIMUS: E30-70-M for drying plastic granules - 2 pcs. FEEDMAX-S:3NET for conveying free-flowing plastic granules, hinged lid with integrated collector motor - 1 pc. HOPPER: MT203 machine hopper 203 for mounting a series 200 separator - 1 pc. DOSIMAX: MC 18 dosing unit for free-flowing granulate Condition – NEW – Unused Original price: €8,467.00 Sale price: €4,233.50 All prices are exclusive of the statutory 19% VAT. PLEASE NOTE: The offer does not include relocation or transportation costs for the machine. These services can be offered and organised separately upon request. For further questions, please feel free to contact me at any time.

Condition: used, Year of construction: 2023, SUNHUB – Compact Dispenser Year of manufacture: 10/2023 Condition: good condition, as is, operational Equipment: HEAD SunHub -20-NH-UV-20-N.00 DOSING VALVES Ijdpfx Agjzf H Rdj Aotn BP2 5-N-50 – INK PUMP 2.5 kg SCALE ICS06s-6M/f METTLER TOLEDO LABEL PRINTER + CODEBAR SCANNER External Pump 25 kg CONNECTION X-RITE

Year of construction: 2000, condition: good (used), Vitronics Soltec reflow oven, type: 6638 Quantis Pro Ijdpfxjq I Shae Ag Aotn

Condition: used, Year of construction: 2014, functionality: fully functional, power: 4 kW (5.44 HP), input voltage: 400 V, input frequency: 50 Hz, type of input current: three-phase, volume flow: 3,400 m³/h, noise level: 71 dB, overall weight: 425 kg, extraction connection diameter: 200 mm, nominal flow rate: 3,400 m³/h, negative pressure: 2,900 Pa, rotational speed (max.): 3,000 rpm, We offer this used Höcker Polytechnik VACUMOBIL 200 mobile exhaust system, year of construction 2014. Manufacturer: Höcker Polytechnik Model: VACUMOBIL JT200-L JT = jet cleaning (compressed air filter cleaning) The JT version is an upgraded version of the VT (vibration cleaning) version. The JT200-L is ideal for continuous use (CNC, planing line, nesting) Better continuous operation Less maintenance during intensive use Iedpjygw Iqofx Ag Astn Type of input current: three-phase Negative pressure: 2.900 Pa Volume flow: 3.400 m³/h Overall weight: 425 kg Input voltage: 400 V Suction socket: 200 mm Power: 4 kW Rotational speed (max.): 3,000 rpm Input frequency: 50 Hz We also sell our JT300-L model on Machineseeker. If you have any questions or need more information, feel free to send us a message or give us a call.

Condition: used, Year of construction: 2012, operating hours: 32,200 h, The machine offered is an ENGEL VC 200/40 Tech, manufactured in 2012. The machine is currently connected to the power grid. Technical specifications: Manufacturer: ENGEL Model: victory 200/40 tech Year of manufacture: 2012 Control system: ENGEL CC 200 Operating hours: approx. 32,200 h Clamping force: 400 kN / 40 t Screw diameter: 30 mm Injection pressure: 1,451 bar Displacement: 99 cm³ Platen size: 500 × 450 mm Tool height: 200 mm Opening stroke: 400 mm Max. platen distance: 600 mm Centering: 125 mm Ejector stroke: 100 mm Nozzle thread: M28 × 1.5 Smallest tool size: 280 mm Power: 15 kW Machine weight: approx. 2,900 kg Core pull: 1 Air ejector: 2 RSP: 3-part Design: tie-bar-less ____ Itjdpfxjz Ap Ims Ag Ajn Wittmann W702 picker / handling device Manufacturer: Wittmann Type: W702 Year of manufacture: 2012 Serial No.: 0000171976 Article No.: 7F00000506 X-axis: 100 mm Y-axis: 550 mm Z-axis: 90° Weight: approx. 52 kg Voltage: 105–250 V Current consumption: 1.6 A According to the available Wittmann documentation, the handling device has been refurbished. After completion of the work, a functional test and test run were carried out with the result "OK". _____ Cooling unit Manufacturer: aic regloplas GmbH Model: TAE EVO 081 Year of manufacture: 2006 Serial No.: 2200 086 152 Connection: 400 V / 3 Ph / 50 Hz Rated power: 11 kW Max. current consumption: 19 A Protection class: IP54 Max. operating pressure, water circuit: 6 bar Max. water temperature: 65 °C Refrigerant: R407C Refrigerant quantity: 5.5 kg Weight: approx. 331 kg _____ Scope of supply ENGEL victory 200/40 tech injection molding machine Wittmann W702 picker / handling device aic regloplas TAE EVO 081 cooling unit Inspection is possible by appointment. Dismantling and loading are the responsibility of the buyer! The machine is located in Bremen. _____ Subject to prior sale and errors in technical specifications. The technical specifications have been compiled to the best of our knowledge, but do not constitute guaranteed characteristics. Our general terms and conditions apply; the seller is not liable for typing or data transmission errors. The appearance of the offered items corresponds to their age and the images shown. The technology and wear of the offered items are consistent with their age. Used machines are sold exclusively to commercial customers and without warranty.

Condition: used, Year of construction: 2005, Serial Number 177554 YOM 2005 Mazatrol 640m Control EIA & Mazatrol Programming 30 Tool Magazine CAT Tooling 4th Axis Swarf Conveyor Mazak Tool length measuring unit Iedpszilp Tjfx Ag Aetn Spindle thru coolant UK Buyers - Price £42,000 +VAT Carriage/delivery is additional

Condition: used, Year of construction: 2010, functionality: fully functional, machine/vehicle number: P9293, Machine for inserting gaskets into the frame profile for PVC window frames, manufactured by TECHNOROP. In good working condition. The machine is also equipped upstream with a tilting conveyor that allows the frame to be transferred from the previous machine and lifted vertically to be automatically positioned on the machine table. Iodpfoy U Uicox Ag Astn Manufacturer's documentation is included, including electrical diagrams, pneumatic diagrams, and the user manual.

Condition: excellent (used), Year of construction: 2007, functionality: fully functional, clamping force: 2,000 kN, screw diameter: 55 mm, displacement volume: 618 cm³, injection pressure: 2,183 bar, injection weight: 562 g, mold height (min.): 400 mm, ejector force: 80,000 N, ejector stroke: 180 mm, plate length: 860 mm, plate width: 570 mm, total length: 6,300 mm, total width: 1,900 mm, total height: 2,300 mm, overall weight: 14,200 kg, Clamping force: 200t Year of manufacture: 2007 Injection shot weight: 562g Injection unit .../1350 Screw diameter: 55 mm Specific injection pressure: 2183 bar Injection volume: 618 ccm Injection shot weight: 562 g Tool clamping system 200/... Clamping force: 200 t Tool plate dimensions: 860 x 570 mm Ejector force: 80 kN Ejector stroke: 180 mm Tool height: 400 mm Itedpfx Asz Hmm Ejg Aen Opening stroke: 750 mm Maximum distance between plates: 1150 mm Weight: 14200 kg Dimensions (m) length x width x height: 6.3 x 1.9 x 2.3 m Equipment: - 2 x hydraulic cores on the moving platen - pneumatic valve - robot - 8-zone hot runner system - 8-section rotameter

Condition: used, Year of construction: 2003, CLAMPING UNIT Clamping force: 500 kN Locking force: 500 kN Distance between tie bars: 370 x 370 mm Max. opening stroke: 400 mm Min. mould height: 210 mm (160 / 135 mm with ZE 214) Max. distance between platens: 610 mm (660 / 710 mm with WA 211) Platen size (H x V): 540 x 530 mm Max. mould weight: 580 kg Max. mould weight on moving platen: 380 kg HYDRAULIC EJECTOR Ejector stroke: 125 mm Ejector force: 41.2 kN Ejector retraction force: 14.8 kN INJECTION UNIT (200) Screw diameter: 30 mm L/D ratio: 20 Injection pressure: 1900 bar Stroke volume: 106.0 cm³ Shot weight (PS): 94 g Max. dosing stroke: 150 mm Barrel heating power: 8.3 kW Iedpjz D U Ixefx Ag Ajtn Hopper capacity: 20 l INJECTION UNIT – HORIZONTAL Max. nozzle stroke: 361 mm Nozzle penetration depth: 40 mm Nozzle contact force: 60 kN INJECTION UNIT – VERTICAL (parting line injection) A min / A max: 100 / 300 mm B min / B max: 100 / 468.5 mm Max. nozzle stroke: 368.5 mm Nozzle contact force: 15 kN GENERAL Oil tank capacity: 180 l Pump motor: 18.5 kW Total installed power: 26.8 kW Dry cycle time (EUROMAP 6a): 1.80 s – 224 mm / 1.80 s – 259 mm Net weight (without oil): 3400 kg Dimensions horizontal (L x W x H): 3.9 x 1.2 x 2.0 m Dimensions vertical (L x W x H): 3.9 x 1.2 x 3.4 m Noise level (idle / full load): 56 / 71 dB(A)

Condition: good (used), Year of construction: 2023, functionality: fully functional, type of input current: three-phase, total height: 1,200 mm, total width: 790 mm, total length: 1,200 mm, input voltage: 380 V, ground cable length: 3,000 mm, overall weight: 205 kg, warranty duration: 12 months, type of cooling: water, hose package length: 5,000 mm, input current: 16 A, laser power: 2,000 W, laser wavelength: 1,080 nm, Equipment: documentation/manual, type plate available, Handheld Laser Welding Machine AIRTECH 2kW – Top Technology for Efficient Sheet Metal Welding Demonstration Unit – Excellent Condition Discover the smart and high-performance solution for precise laser welding: the Airtech handheld laser welding system with 2,000 watts of power! Perfectly suited for demanding sheet metal fabrication – efficient, safe, and highly versatile. Itjdpfxjn Sl Dbs Ag Ajn Highlights and Features: - Power output: 2,000 watts for superior weld quality and speed - Laser wavelength: 1080 nm, continuous operation with modulation frequency up to 20 kHz - Handheld laser welding head – ideally designed for ergonomic operation - Robust housing and intelligent internal structure for maximum durability - Touchscreen display for intuitive operation - Optional automatic multifunctional wire feeder - Safety features: three-color alarm, safety interlocks, and protection against operating errors - Cooling via separate water circuit with 13-liter tank capacity - CE-certified components according to European standards Your Benefits - Work safely thanks to comprehensive protection mechanisms and alarm systems - Flexible applications, including automatic wire feed and robot integration - Low operating costs and easy maintenance due to well-designed engineering and long-life components For more information or consultation, the Airtech team will be happy to assist you!

Condition: excellent (used), Year of construction: 2016, Viessmann Vitocrossal 200 Type:CM2 Year: 2016 Output: 311Kw Мы говорим по русски! Viewing please only by telephone arrangement! Preferred sale to dealers, traders or export. All information without guarantee, errors and prior sale reserved. The seller accepts no liability for typing and data transmission errors. Itedpfxjtu True Ag Aen Of course we also take care of all formalities Loading possible

Condition: good (used), Year of construction: 2008, clamping force: 500 kN, Demag Systec 50/370-120 (2008) Screw size: 18 mm Itodpfx Agey Eyq He Ajn tie bar distance: 370x370mm machine is in good working condition immediately available at our warehouse.

Year of construction: 2020, condition: used, The system is designed for the semi-automatic gluing and pressing of finger-jointed box bodies made of solid wood and plywood, the system is floor-mounted and can be manually adjusted to accommodate different box sizes, up to two pneumatic cylinders can be installed on each of the four sides of the boxes for pressing, for smaller boxes the number is reduced to one cylinder per side, a dispensing system is provided for glue application, which applies the glue to the finger joints of the boxes using assembly aids, equipment: table made of aluminum profiles, two aluminum profile rails each in longitudinal and transverse direction, adjustable to the required box size using clamping levers, up to four pneumatic diaphragm cylinders for clamping the longitudinal sides, four guided pneumatic cylinders with brackets for moving the assembly aids, up to eight pneumatic cylinders for pressing the boxes, dispensing system, weight: 370kg, with documentation. An on-site inspection is possible. Itjdez S Iwdspfx Ag Asn

Condition: excellent (used), Year of construction: 2006, operating hours: 69,000 h, functionality: fully functional, machine/vehicle number: 163769, Here we offer a permanent maintained injection molding machine. from the following machine we have other machines of the same type and same year in stock also with Geiger Robot Manufacturer Engel Type Victory 200/80 Tech year of construction: 2006 Control system: CC 200 Extras -installed Languages: German Englisch -25 mm (wear and corrosion protected) - control CC200 - enlarged clamping plates (B plates) - minimum installation height 250 mm - maximum platen distance 700 mm - quality switch / PD protocol + graphics - 5 x CEE 400 V / 3 x Schuko 230 V - 4 freely programmable inputs and outputs - handling interface Euromap 12 - Host computer interface Engel EMS - Geiger EA Mini 2001 SLI (#156686 0504 4417 / year 2005) - without material hopper or conveyor Itodpfxjm Nclvo Ag Ajn Clamping unit clamping force: 80 to./ 800 kN tie bar dimension: tie bar-less clamping platens: 730 x 600 (hxv) platen distance: 700 mm max installation height: 250 mm min. opening stroke: 450 mm Injection unit screw diameter 25 mm stroke volume: 69 ccm injection pressure: 2090 bar / 2400 increased Weight: 5,200 kg. dimensions: 4,00 mtr. x 1,40 mtr. x 2,00 mtr LxWxH from our warehouse Hannover /Germany free loading on truck of the buyer or free delivery against freight reimbursement Viewing under electric power possible functional guarantee

Condition: good (used), Year of construction: 2004, Demag ergotech sys 50-200 (1992) Itedpsyyztfsfx Ag Ajn

Condition: used, Year of construction: 1998, CLAMPING UNIT Clamping force: 2000 kN Locking force: 2200 kN Max. opening stroke: 575 mm Itedpfx Aez D U Rmsg Aen Min. mould height: 310 mm Max. mould height: 660 mm (760 mm with WA) Max. distance between platens: 1235 mm (1335 mm with WA) Platen size (H x V): 830 x 830 mm Distance between tie bars (H x V): 560 x 560 mm Max. mould weight: 2500 kg Max. mould weight on moving platen: 1700 kg HYDRAULIC EJECTOR Ejector stroke: 180 mm Ejector force: 80 kN Ejector retraction force: 35 kN INJECTION UNIT (840) Screw diameter: 50 mm L/D ratio: 20 Injection pressure: 1946 bar Stroke volume: 442 cm³ Shot weight (PS): 400 g Max. dosing stroke: 225 mm Max. nozzle stroke: 400 mm Nozzle penetration depth: 40 mm (30 mm with SPI) Nozzle contact force: 80 kN Barrel heating power: 14.8 kW Electric screw drive (WA): 20.5 kW Hopper capacity: 70 l

Condition: excellent (used), Year of construction: 2006, clamping force: 500 kN, screw diameter: 22 mm, clearance between the columns: 355 mm, overall weight: 2,700 kg, Clamping force: 50 t Year of manufacture: 2006 Injection unit .../200 Screw diameter: 22 mm Ijdpfszt Ih Tjx Ag Aotn Specific injection pressure: 2800 bar Injection volume: 41.8 ccm Mould clamping system 50/... Clamping force: 50 t Mould plate dimensions: 520 x 520 mm Tie bar clearance: 355 x 355 mm Mould height: 210 mm Opening stroke: 400 mm Maximum platen distance: 610 mm Weight: 2700 kg Dimensions (m) L x W x H: 3.8 x 1.1 x 2.1 m Control: NC4

Condition: like new (used), Year of construction: 2023, functionality: fully functional, total width: 5,150 mm, total length: 16,000 mm, total height: 4,850 mm, temperature: 2 °C, We are offering this like-new Heidinger I-1751 refrigerated storage room, manufactured in 2023. Type: I - 1751 Year of manufacture: 2023 Double refrigerated storage room, 2-8°C (unused) Each with a Viessmann double door, 2m x 2.7m Isdpfx Ajykrtpog Ajtn Redundant design Internal dimensions approximately 16m (L) x 5.15m (W) x 4.85m (H) each Walls made of 100mm sandwich panels No separate floor, therefore accessible with a forklift Compressors: 4x Bitzer Ecostar LHV5E/2DES-3.F1Y-40S Evaporators: 4x Güntner GACC RX 040.1/2WN/DJA4A.UNNN The refrigerated storage room was built for storing medication and has never been put into operation after acceptance by the manufacturer. The pallet racking shown in the pictures is not included in the offer. Dismantling and transport are the responsibility of the buyer. If you have any questions or require further information, please do not hesitate to send us a message or call us.

Condition: reconditioned (used), functionality: fully functional, Year of construction: 2007, machine/vehicle number: 647/07, overall weight: 1,000 kg, total length: 2,500 mm, total width: 2,500 mm, total height: 4,700 mm, input frequency: 50 Hz, input voltage: 400 V, type of input current: three-phase, Good morning, I have a CWT 95/1200 cooling tower for sale. It is a forced-draft cooling tower. The technical specifications are shown in one of the photos. Documents for the forced-draft cooling tower: - Declaration of Conformity - Technical and Operational Documentation Isdoz Szfbopfx Ag Aetn - Information Sheet Renovation work carried out: - Motors rewound - Bearings replaced - Sealing systems replaced I am happy to provide any additional information by phone or email.

Condition: excellent (used), Year of construction: 2007, operating hours: 70,000 h, functionality: fully functional, machine/vehicle number: ERGOTECH 200 - 840, clamping force: 2,000 kN, screw diameter: 50 mm, clearance between the columns: 560 mm, displacement volume: 442 cm³, mold height (min.): 340 mm, plate width: 860 mm, plate height: 860 mm, pump power: 30,000 W, The machine is fully operational and was working with injection until the end. Ijdjyxn Tvopfx Ag Astn

Year of construction: 1990, condition: ready for operation (used), functionality: fully functional, Connection voltage: 380V, connected load: 7.5 kVA, specific power consumption 2 kW/m² Global UV weathering tests with global spectrum (similar to xenon arc), but using fluorescent tubes Test chamber volume: 200 liters Test area: 0.75 m² Test chamber dimensions (H x W x D): 1100 x 800 x 250 mm Temperature range without insulation: -20°C to +90°C Temperature range with insulation: +10°C to +90°C Itodpfx Ajytr Swjg Aon Temperature consistency: ±2 K Dew point temperature range: +5°C to +40°C Humidity range: approx. 15–95% relative humidity Sample humidification with 8 spray nozzles The system utilizes fluorescent UV light sources to simulate the damaging spectrum of sunlight in the laboratory, thereby accelerating aging effects such as color change, loss of gloss, cracking, embrittlement, and material degradation. Programmable cycles of UV exposure, temperature control, and optional humidity or condensation phases are used to realistically replicate and reproducibly repeat environmental stresses. Dismantling by buyer.

Condition: used, Year of construction: 2001, CLAMPING UNIT Clamping force: 2000 kN Locking force: 2200 kN Max. opening stroke: 575 mm Min. mould height: 310 mm Isdsz D Uv Njpfx Ag Aotn Max. mould height: 660 mm (760 mm with WA) Max. distance between platens: 1235 mm (1335 mm with WA) Platen size (H x V): 830 x 830 mm Distance between tie bars (H x V): 560 x 560 mm Max. mould weight: 2500 kg Max. mould weight on moving platen: 1700 kg HYDRAULIC EJECTOR Ejector stroke: 180 mm Ejector force: 80 kN Ejector retraction force: 35 kN NJECTION UNIT (120) Screw diameter: 30 mm L/D ratio: 20 Injection pressure: 2420 bar Stroke volume: 124 cm³ Shot weight (PS): 110 g Max. dosing stroke: 175 mm Max. nozzle stroke: 350 mm Nozzle penetration depth: 40 mm (30 mm with SPI) Nozzle contact force: 80 kN Barrel heating power: 7.9 kW Electric screw drive (WA): 12.6 kW Hopper capacity: 70 l GENERAL Oil tank capacity: 500 l Pump motor: 22 / 30 kW Total installed power: 30 kW (38 kW with electric screw drive) Dry cycles (EUROMAP 6a): 1830 / 1900 per hour Dry cycles without nozzle retraction: 2200 / 2300 per hour Net weight (without oil): 6200 kg Dimensions (L x W x H): 5.1 x 1.6 x 2.1 m (length without injection unit overhang) Noise level (idle / full load): 66 / 77 dB(A) Demag Ergotech 150-840 NC4 INJECTION UNIT (840) Screw diameter: 60 mm L/D ratio: 20 Injection pressure: 1351 bar Stroke volume: 636 cm³ Shot weight (PS): 570 g Max. dosing stroke: 225 mm Max. nozzle stroke: 400 mm Nozzle penetration depth: 40 mm (30 mm with SPI) Nozzle contact force: 80 kN Barrel heating power: 23.1 kW Electric screw drive (WA): 20.5 kW Hopper capacity: 70 l GENERAL Oil tank capacity: 500 l Pump motor: 22 / 30 kW Total installed power: 45 kW (53 kW with electric screw drive) Dry cycles (EUROMAP 6a): 1700 / 1870 per hour Dry cycles without nozzle retraction: 2000 / 2200 per hour Net weight (without oil): 7700 kg Dimensions (L x W x H): 5.4 x 1.6 x 2.1 m (length without injection unit overhang) Noise level (idle / full load): 66 / 77 dB(A)

Condition: excellent (used), Year of construction: 2007, 1,0 St. gebr. Spritzgießmaschine Itedpfou Eu Tnox Ag Asn Hersteller: ENGEL Typ: VICTORY 200/28 TECH Baujahr: 2007 Schließkraft: 28 Tonnen Holmabstand: HOLMLOS Schnecken DN: 25 mm Max. Hubvolumen: 49 ccm³ Spritzteilgewicht 44 g/PS Steuerung: CC200 Ausstattung: - 1 x Kernzug