JHI-3012NC/CNCHome > Products > Internal Grinder > JHI-3012NC/CNC



  • End Face Grinding Device (Optional)
  • Swiveling spindle head
  • Motor Fixing Bar
  • Precise Feed Positioning
  • Spindle Head Driven by Servo Motor
  • Automatic Belt Tension Control
  • Hydraulic Power / Lubrication Unit

  • The structural parts are manufactured from high quality Meehanite cast iron, tempered and precision machined for maximum durability and long service life. The machine design meets human-engineering theorem, and features easy operation and extra high precision.
  • Versatile cyclic grinding motions include fully automatic grinding, coarse grinding trimming, fing grinding and spark-free grinding. High accuracy, convenient operation and increased productivity. The machine is ideal for both mass production and small lot flexible grinding operations.
  • The spindlehead employs high accuracy roller bearings, featuring high accuracy, high rigidity and quiet running. It can be swiveled +8° , making the machine ideal for grinding big taper of workpiece.
  • The feed axis employs up and roller type linear guideways combined with servo motor drive. It provides rapid traverse and high positioning accuracy, and is suitable for fully automatic grinding functions, such as blind hole grinding, end face grinding and taper grinding.
  • The control system consists of high quality electronic parts that meet European safety regulations. The electrical cabinet features dust-proof and water-proof construction. The control system also features self-diagnostic function with warning lamp indication.
  • The machine is equipped with the advanced FANUC control with 8.4" colorful display. The CNC control uses macro machining programs that greatly reduce preparation thime while upgrading machining efficiency.
  • Forced lubrication system for bed surfaces reduces friction to a minimum. The bed is designed with heat dissipation and outstanding strength, ensuring maximum stability.

End Face Grinding Device (Optional)

  • When requested, the machine is available to equip with an End Face Grinding Device, allowing the machine to perform internal and end face grinding at one time.
  • This not only greatly increases machining efficiency but also achieves high perpendicularity accuracy.

Swiveling spindle head

The workhead can be swiveled +8° allowing for grinding tapered parts.

End Face Grinding Device

Motor Fixing Bar

Just as the motor starts running, a vibration occurs.
The fixing bar is used for holding the motor in place. Amicrometric adjustment knob is provided for adjusting the belt tension.

Motor Fixing Bar

Precise Feed Positioning

The grinding wheel feed is driven by a high performance servo motor, combined with precision ball screw transmission, providing high positioning accuracy.

Precise Feed Positioning

Spindle Head Driven by Servo Motor

  • The spindle head is driven by a high performance servo motor, providing accurate variable speed change.
  • The servo motor drive features no speed loss and constant torque output no matter if the spindle is running at high or low speed. It guarantees outstanding grinding surface quality.
  • The servo motor drive allows spindle positioning control for convenient workpiece release.
Spindle Head Driven by Servo Motor

Automatic Belt Tension Control

  • The belt tension is automatically controlled by the motor weight to assure proper belt tension at all times.
  • This ensures full power transmission from the motor.
    The specially designed belt tension eliminates too tight or too loose tensiion problems that may affect grinding quality.
Automatic Belt Tension Control

Hydraulic Power / Lubrication Unit

The hydraulic power unit consists of two gear pumps, providing hydraulic power to the chuck and wheel dressing device. It also delivers lubrication oil to base slideways.
The hydraulic power unit consists of high quality parts, featuring low noise running and long service life.
A fan cooling device is mounted on the hydraulic power unit, providing efficient heat dissipation.

Hydraulic Power / Lubrication Unit

Massive Machine Structure

Optimal Structural Design
Guarantees Lifetime Accuracy

To maintain the long term accuracy after years of operation, the machine structure of the JAINNHER Internal Grinding Machine is carefully designed and manufactured.

  • The machine base is manufactured from high quality cast iron (FC30), tempered and stress relieved for maximum stability of material.
  • Great span between slideways provides firm support for wheel head assembly.
  • Ruggedly constructed throunghout for outstanding rigidity and stabiliyt.
  • Scientific rib reinforcement on the base structure for increased machine rigidity and deformation-free performance.
Massive Machine Structure

State-of-the-Art CNC Control

The CNC internal grinding machine is equipped with a FANUC (Oi-Mate TC) control. It employs macro (macro programs) operation interface combined with the use of an 8.4" colorful LCD screen, greatly upgrading production and providing outstanding grinding accuracy.


It can conduct fine surface grinding of interior radii and end faces, and the device monitors the wheel during operation, protecting it from overloading.

State-of-the-Art CNC Control

Automatic Grinding Cycle

Automatic Grinding CycleAutomatic Grinding Cycle
Grinding Wheel Specifications WA 80K5V5A
Workpiece Size Ø27 ± 0.003 mm
Workpiece Material SNCM220
Total Grinding Amount 0.34 mm
Rough Grinding Feed Rate 40 mm/s
Ratio 100%
Rough Grinding Amount 0.32
Finish Grinding Feed Rate 25 mm/s
Ratio 100%
Finish Grinding Amount 0.02 mm
Feed for Rough Grinding 0.005 mm
Feed for Finish Grinding 0.002 mm
Polishing Time 30 sec.
Wheel Dressing for Rough Grinding 0.01 mm
Wheel Dressing for Finish Grinding 0.01 mm
Roundness Accuracy 2 um
CapacityRange of I.D. grinding Ø20-300mm Ø6-150mm
Max grinding depth 300 mm 150 mm
Max holding length 1200 mm 200 mm
Swing over bed 480 mm 500 mm
Swing in chuck guard 350 mm 280 mm
Wheel feeding(X axis)Rapid feed speed 5 m/min 5 m/min
Max.stroke 200 mm 100 mm
Min.setting unit 0.001 mm 0.001 mm
Wheel feeding(Z axis)Rapid feed speed 8 m/min 8 m/min
Max.stroke 800 mm 450 mm
Min.setting unit 0.001 mm 0.001 mm
Work headSpindle speed 10-1000 rpm 10-1000 rpm
Spindle Cylindrical type A2-5
Swivel angle -3°+12°(f) ±15°
Workhead tableSwivel angle - -
Rotary tableRpm - 0-20 rpm
Min.unit - 0.001°
Swivel angle - -90°
MotorG/W pindle motor Standard 5HP 2P
optional 7.5HP 2P
Build-in type
7.5 KW/10HP
Spindle head motor Servo 3.5 KW(for NC)
Fanuc Servo 3.5KW(for CNC)
Fanuc Servo 3.5 KW
Z-axis servo motor Servo 2 KW(for NC)
Fanuc Servo 1.8KW(for CNC)
1.2 KW
X-axis servo motor Servo1 KW(for NC)
Fanuc Servo 1.2KW(for CNC)
0.75 KW
Coolant 1/4HP 2P 1/4HP 2P
Hydraulic lubrication 1/4HP 4P 1/4HP 4P
Hydraulic system 1HP 4P 1HP 4P
Rotary table - -
PackingSize of Case 4400x2200x1800 mm 2900x1900x2100 mm
Net weight 6300 Kgs 3100 Kgs
Gross weight 6700 Kgs 3300 Kgs
Grinding wheel spindle

A. Grinding wheel spindle
(alternative of 10,000~30,000 rpm)

3-jaw chuck

B. 3-jaw chuck

Levelling plate

C. Levelling plate

Coolant tank

D. Coolant tank

Tool box and tools

E. Tool box and tools

Paper filter

A. Paper filter

Magnetic separator

B. Magnetic separator

End face grinding attachment

C. End face grinding attachment

Grinding wheel spindle

D. Grinding wheel spindle

Hydraulic 3-jaw chuck

E. Hydraulic 3-jaw chuck

Hydraulic rotary cylinder

F. Hydraulic rotary cylinder

Oil mist lubricator for grinding wheel

G. Oil mist lubricator for grinding wheel (For spindle speed over 30,000 rpm only)

Oil Skimmer

H. Oil Skimmer