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NC Centerless Grinder JHC-18

 


1. Main Structure of Machines
They are cast of high grade FC-30 iron, melted by advanced induction furnace, then cast in resin cores. In order to ensure stability and rigidity, they are heat-treated with normalizing procedure prior to machining.
2. Hydrostatic Bearings
Precision ground Hydrostatic Bearings: Substantial decrease in heat deformationassociatedwith Hydrodynamic bearings.Minimal friction, lateral displacement, and pressure .Extended tool life under heavy cut loads.
Grinding Wheel Spindle: The Grinding Wheel Spindle runs on hydrostatic bearings with a high pressure oil film for added precision under heavy loads. Substantially reduces wear while prolonging spindle trueness. SNCM-210H carbon steel hardened beyond HRC60, yielding high torsion resistance.
3. Semi-Hydraulic Float Bearings
They are made of SNCM-220H Ni-Cr-Mo alloy steel and case-hardened, carbonized, then computerized sub-zero degree treated, to surface hardness over HRC 62 at 1.0mm depth. Core hardness is kept at about HRC 25-30 to ensure consistency of high precision grinding operation. Spindles withstand high torsion and have a long and lasting life. They are made of KJ-4 alloy bushing metal with a three point hydraulic cycle system. The semi-hydraulic float spindle is protected by an oil membrane which results in minimal contact friction. This device is specially designed for high speed and heavy load operation.
4. Regulating Wheel Drive
A Japanese servo motor provides control of speeds from 10 to 250RPM and is used for the regulating wheel which can be adjusted to ideal linear speeds. When the diameter of the regulating wheel changes the same linear speeds can still be maintained so as grind the best quality products. The motor is driven by a timing-belt to reduce vibration and noise. Since the motor housing and spindle housing are joined together as an integrated body, when the regulating wheel tilts the motor also follows. This completely overcomes problems caused by unparallelism and torsion of belt pulleys and the belts.
5. Spindle Oil Circulation
There is a variable vane type oil pump for the hydraulic dressing and enforced spindle oil circulation. The oil tank is located outside of the machine for easy maintenance. Two layers of filter plus a pressure regulator ensure the cleanliness of spindle oil and the consistency of oil film thickness, thus extending the service life of the wheel spindle and the steadiness of accuracy.
6. Slide Device
The lower slide consists of two internally mounted V-shaped slides and cuneiform protector to ensure smooth movement, stable operation and prevent the entering of debris or liquid from the working environment. The swivel slides on a dovetail flute and swivels กำ5 degrees. There is a fine tuning hand wheel for precise adjustment. The accuracy per calibration is 0.001mm in diameter for high precision and easy operation.
7. Wheel Dressing Device
The device is made of FC-30 cast iron and normalized then precisely ground. It is driven by a hydraulic system with a step-less speed regulator for easy and steady dressing. There is a safety handle for emergency purposes. In order to upgrade the straightness and the surface
finish on through-feed grinding of long work pieces, please adjust the angle of the dressing device (swivels ±5 degrees). The regulating wheel should be adjusted to resemble a concave barrel to increase contact length while grinding.
Quality of Our Machines
The performance of all our machines is strictly inspected for roundness, straightness and surface roughness on standard work pieces before delivery.
8. Grinding Accuracy
  • Workpiece: Φ2 x 20
  • Metal: SUJ-2
  • Hardness: HRC-62
  • Grinding wheel WA 1000#
  • Machine: JHC-18

CUT OFF= 0.25 mm
TRAVERSING LENGTH= 1.0 mm
MAG= 10000

Ra= 0.02 μ m
RMAx= 0.28 μm
Rz= 0.24 μm
RMS= 0.02 μm
Rt= 0.22 μm
Rtm= 0.20 μm


CNC Coordinate
Measuring Machine
9. Operation Applications


Specifications

 
JHC-18
JHC-18S
JHC-18A
JHC-18AS
JHC-18B
JHC-18BS
Standard work rest (dia.)
Φ1 ~ Φ50 mm
Special work rest (dia.)
Φ40 ~ Φ100 mm
Grinding wheel size
(dia. x width x hole)
Φ455 x 205 x Φ228.6
Φ455 x 255 x Φ228.6
Φ455 x 305 x Φ228.6
Regulating wheel size
(dia. x width x hole)
Φ255 x 205 x Φ111.2
Φ255 x 255 x Φ111.2
Φ255 x 305 x Φ111.2
Grinding wheel speed
1500 R.P.M
Regulating wheel speed
13-316 R.P.M
(10 steps)
10-250 R.P.M
variable speed
13-316 R.P.M
(10 steps)
10-250 R.P.M
Variable speed
13-316 R.P.M
(10 steps)
10-250 R.P.M
bariable speed
Grinding wheel motor
15 HP
15 HP
20 HP
Regulating wheel motor
2 HP
2.9kw Servo Motor
2 HP
2.9kw Servo Motor
2 HP
2.9kw Servo Motor
Hydraulic pump motor
1 HP
Coolant pump motor
1/4 HP
1/2 HP
Regulating wheel feed on handwheel
3.5 mm (Rev) 0.05 mm (Gra)
Regulating micro feed on handwheel
0.1 mm (Rev) 0.001 mm (Gra)
Table feed on handwheel
9 mm (Rev) 0.05 mm (Gra)
Table micro feed on handwheel
0.2 mm (Rev) 0.001 mm (Gra)
Dressing handwheel
2 mm (Rev) 0.01 mm (Gra)
Regulating wheel tilt angle
+5° ~ -3°
Regulating wheel swivel angle
±5°
Floor space (L x W x H)
2300 x 2000 x 1530 mm
Net weight / Gross weight
2800 kgs / 3100 kgs
2900 kgs / 3200 kgs
3000 kgs / 3300 kgs
Size of case (L x W x H)
3200 x 1400 x 1900 mm
* Manufacturer reserves the right to change specification without prior notice.


Operation Applications










Standard Accessories

1. Grinding wheel and grinding wheel flange 2. Grinding wheel and grinding wheel flange 3. Thrufeed standard workrest and blade
4. Infeed standard workrest and blade 5. Tool box and tools 6. Work lamp
7. Diamond tool 8. Thrufeed safety device 9. Flange extractor
10. Levelling screw and plate 11. Thrufeed process gauge 12. Coolant tank with pump (coolant tank will not be equipped with paper filter and hydrocyclone coolant filtering unit)
   
13. Hydraulic tank with pump    


Optional Accessories

1. Magnetic separator 2. Paper filter coolant 3. Hydrocyclone coolant filtering unit
4. Work ejector device 5. Forming dressing device 6. Long V-shaped support
7. Manual parts feeder for infeed grinding 8. Automatic receiver for thrufeed grinding 9. Automatic thrufeed device
10. Vibratory parts feeder and straight line feeder 11. Auto thrufeed taper grinding device 12. Auto infeed forming grinding
13. Wheel balancing arbor 14. Wheel balancing base 15. Off-line gauging, non-contace O.D. measuring system
16. Grinding wheel automatic balancing system 17. Oil cooler 18. Rotary type grinding wheel dressing attachment
19. Jib crane & hook for grinding wheel 20A. Grinding blancer for wheels 20B. Grinding blancer for wheels
   
21. Oil mist / vapour receiver