
JUMAT - Cylindrical grinding machines
Versatile in every regard
Quality, productivity, availability – the JUMAT external and internal cylindrical grinding machine leaves nothing to be desired. Various sizes and a large number of wheelhead versions offer unrivaled versatility. Paired with the concentrated expertise of JUNKER, each machine is specially matched to the customer‘s requirements.

Highlights
- High dimensional accuracy thanks to various measuring systems
- Long tool life through use of CBN or diamond grinding wheels
- Versatility due to a large number of wheelhead versions
- Minimized undulations due to grinding wheel balancing on two levels
- Fast changeover through patented 3-point mounting interface
Grinding process descriptions
Außen- und Innenrundschleifen
Die Rundschleifmaschinen der Baureihe JUMAT können Werkstücke in einer Einspannung sowohl außen als auch innen schleifen. CBN- und Diamant-Schleifscheiben erlauben das Schleifen mit Hochgeschwindigkeit, sorgen für eine hohe Zerspanleistung und ermöglichen das Schleifen schwer zerspanbarer Materialien.
Außenrundschleifen
Beim Außenrundschleifen werden die Werkstücke zwischen Spitzen oder in einem Spannfutter eingespannt. Zur Steigerung der Produktivität werden bei einigen Anwendungen Satzschleifscheiben eingesetzt. Für das Außenrundschleifen nutzt die JUMAT das Gerad- und Schrägeinstechverfahren.
Beim Geradeinstechschleifen erfolgt die Schnitt- und Zustellbewegung radial zum Werkstück. Die Durchmesser werden entweder in einer Zustellung geschliffen oder mit mehreren Zustellungen und axialem Verziehen.
Beim Schrägeinstechschleifen ist die Schleifscheibe schräg und der Schleifspindelstock (B-Achse) geschwenkt. Die X- und Z-Achse interpolieren. Somit ist man in der Lage Durchmesser und Planflächen in einer Zustellung zu schleifen.
Zum Schleifen von Einstichen oder zum Vorschleifen von Gewinden wird meist eine galvanisch gebundene Schleifscheibe verwendet.
Innenrundschleifen
Das Innenrundschleifen ermöglicht die präzise Bearbeitung von inneren Funktionsflächen wie Bohrungen, Konen oder Planflächen. Verwendet werden Schleifspindeln mit einer hohen Drehzahl, um die gewünschte Schnittgeschwindigkeit trotz des kleineren Durchmessers der Schleifscheibe zu erreichen.
Special solutions

Mittenantrieb
Der Mittenantrieb ist ein Sonderantriebssystem, welches das Werkstück in der Mitte einspannt und über einen Servo-Motor antreibt. Dadurch können beide Werkstückenden parallel bearbeitet werden.

Schleifen von Lenkstangen
In der Automobilindustrie kommen vermehrt elektromechanische, achsparallele Servolenkungen zum Einsatz. Das Außengewinde der Lenkstange schleift die JUMAT in einer Einspannung aus dem Vollen. Das Vorschleifen erfolgt mit galvanisch gebundenen Schleifscheiben, das Fertigschleifen mit keramisch gebundenen CBN-Schleifscheiben.

Schleifen von Kugelgewindemuttern
Der Doppelwerkstückspindelstock mit zwei gegenüberliegenden Einspannvorrichtungen minimiert die Nebenzeit beim Gewindeschleifen von Kugelgewindemuttern: Während auf der einen Seite geschliffen wird, wird auf der anderen bereits ent- und beladen, positioniert und eingespannt. Einzige Nebenzeit: Schwenken um 180 Grad in weniger als 3 Sekunden.
Technical data: JUMAT 1S

- Wheelheader Number
- 1
- Grinding Length
- 150 mm
- Clamping Length
- 150 mm
- Center Height
- 100 mm
- Component Weight
- 5 kg
- Grinding Wheel Diameter
- 350 mm
- Swing Diameter
- 80 mm
- WxDxH mm (without peripherals)
- 1800 x 2500 x 2100
- Weight
- 10000 kg
Wheelhead JUMAT 1S
- /10
- /10i
- /15
- /18
- /20
- /50
Technical data: JUMAT 1000

- Wheelheader Number
- 1
- Grinding Length
- 150 mm
- Clamping Length
- 150 mm
- Center Height
- 100 mm
- Component Weight
- 5 kg
- Grinding Wheel Diameter
- 350 mm
- Swing Diameter
- 80 mm
- WxDxH mm (without peripherals)
- 1500 x 2500 x 2100
- Weight
- 9000 kg
Wheelhead JUMAT 1000
- /10
- /10i
- /15
- /17
- /20
- /50
Technical data: JUMAT 3000

- Wheelheader Number
- 1
- Grinding Length
- 400 mm
- Clamping Length
- 400 mm
- Center Height
- 150 mm
- Component Weight
- 15 kg
- Grinding Wheel Diameter
- 350 mm
- Swing Diameter
- 150 mm
- WxDxH mm (without peripherals)
- 3400 x 2800 x 2200
- Weight
- 12000 kg
Wheelhead JUMAT 3000
- /10
- /10i
- /15
- /20
- /30
- /40
- 3000/50
- /50S
- /60
Technical data: JUMAT 5000

- Wheelheader Number
- 1
- Grinding Length
- 700 mm
- Clamping Length
- 700 mm
- Center Height
- 170 mm
- Component Weight
- 130 kg
- Grinding Wheel Diameter
- 500 mm
- Swing Diameter
- 280 mm
- WxDxH mm (without peripherals)
- 4900 x 3400 x 2350
- Weight
- 14000 kg
Wheelhead JUMAT 5000
- /10
- /10i
- /15
- /18
- /20
- /30
- /30KGi
- /40
- 5000/50
- /50S
- /60
Technical data: JUMAT 6XS

- Wheelheader Number
- 1
- Grinding Length
- 500 mm
- Clamping Length
- 600 mm
- Center Height
- 170 mm
- Component Weight
- 130 kg
- Grinding Wheel Diameter
- 500/700 mm
- Swing Diameter
- 280/320 mm
- WxDxH mm (without peripherals)
- 3260 x 3750 x 2450
- Weight
- 17000 kg
Wheelhead JUMAT 6XS
- /10
- /10i
- /15
- /18
- /20
- /30
- /40
- /50
- /50S
- /60
Technical data: JUMAT 6S

- Wheelheader Number
- 1
- 2
- Grinding Length
- 1000 mm
- 750 mm
- Clamping Length
- 1200 mm
- Center Height
- 170 mm
- Component Weight
- 150 kg
- Grinding Wheel Diameter
- 500/700 mm
- Swing Diameter
- 280/320 mm
- WxDxH mm (without peripherals)
- 4100 x 3750 x 2450
- Weight
- 21000 kg
- 25000 kg
Wheelhead JUMAT 6S
- /10
- /10i
- /15
- /18
- /20
- /30
- /40
- /50
- /50S
- /60
Technical data: JUMAT 6L

- Wheelheader Number
- 1
- 2
- Grinding Length
- 1800 mm
- 1500 mm
- Clamping Length
- 2000 mm
- Center Height
- 170 mm
- Component Weight
- 200 kg
- Grinding Wheel Diameter
- 500/700 mm
- Swing Diameter
- 280/320 mm
- WxDxH mm (without peripherals)
- 4900 x 3750 x 2450
- Weight
- 24000 kg
- 28000 kg
Wheelhead JUMAT 6L
- /10
- /10i
- /15
- /18
- /20
- /30
- /40
- /50
- /50S
- /60
Technical data: JUMAT 6XL

- Wheelheader Number
- 1
- 2
- Grinding Length
- 2800 mm
- 2500 mm
- Clamping Length
- 3000 mm
- Center Height
- 170 mm
- Component Weight
- 300 kg
- Grinding Wheel Diameter
- 500/700 mm
- Swing Diameter
- 280/320 mm
- WxDxH mm (without peripherals)
- 6400 x 3750 x 2450
- Weight
- 28000 kg
- 32000 kg
Wheelhead JUMAT 6XL
- /10
- /10i
- /15
- /18
- /20
- /30
- /40
- /50
- /50S
- /60
Equipment and Options
- LONGITUDINAL POSITIONING
A touch probe measures the longitudinal position of the workpiece on a flat surface to compensate for unmachined part fluctuations. The measured values are automatically integrated in the grinding process by the control system.
- CONTROL SYSTEM
The Erwin Junker Operator Panel was specifically developed to control grinding machines. All machine components are controlled using the operator panel – irrespective of the series and the used control system. The identical structure, intuitive menu guidance and visualization of the workpiece geometry make for extreme user convenience and flexibility in operation. Programming takes place directly using the operator panel or an external programming tool.
- Axis drive and guidance
The X axes, with linear roller ways with high pre-load, takes care of ultra-precise positioning of the grinding and regulating wheel head. Drive is executed by a precise, intrinsically rigid ball screw with infinitely variable servo drive and glass scale.
The B axis of the wheelheads is driven by a backlash-free gear. Every angular position is programmable; the position sensor system has a sensational resolution of 0.00001 of a degree. Extreme low noise (vibration) levels are guaranteed with the JUNKER grinding spindles with direct drive – an in-house development – complete with a structure-borne sound sensor and dynamic balancing system in one or two planes.
- Clamping fixture
The patented 3-point mounting interface allows grinding and dressing wheels as well as work holdings to be mounted and centered on grinding spindles, workpiece spindles and tailstock sleeves in record time. Adjustment of the tailstock and, where applicable, the workhead take place using optionally using a chain wheel, a hydraulic cylinder or a CNC axis with rack and pinion drive. An airlift function simplifies position adjustment. Depending on the workpiece, in addition a wide range of clamping systems are also available
- MACHINE BED
The machine bed made of mineral cast provides impressive damping behavior and torsional rigidity. The temperature stability allows fluctuations in the ambient temperature to be compensated with a minimum of effort, ensuring a high level of dimensional stability throughout the whole day.
- IN-PROCESS MEASURING SYSTEM
A swivel-in measurement probe carries out an in-process measurement of the diameters of the main and pin bearing. The control system logs the measured values, calculates
the correction data and generates the precise shape. After grinding, the Machine is able to measure the entire geometry of the crankshaft – depending on requirements:
from the bearing width through the lift height to the taper of each element.- STEADIES
As an option, self-centering three-point steadies ensure stable support. Tracking hydraulic jaws guarantee a balanced ratio of forces at all three support points, and with it a grinding process with repeat accuracy.
Workpieces
- Axle
- Starter shaft
- Drive shaft
- Countershaft
- Bolt
- Bushing
- Electric motor shaft
- Excentric shaft
- Stub shaft
- Gear shaft
- Piston pin
- Piston ring
- Motor shaft
- Pump piston
- Pump pinion
- Pipe
- Rotor
- Worm wheel
- Worm shaft
- Spindle
- Rod
- Stator shaft
- Stud
- Turbine shaft
- Cylinder
- Rolling element
- Shaft
- Tool holder
- Tool Blank
- Gearwheel
- Gear rod
- Spigot
- Cylinder rollers