JHC-24S > Products > Centerless Grinder Machine > JHC-24S
  • The Grinding Wheel Spindle runs on hydrostatic bearings, extended tool life and increase acccuracy under heavy cut loads.
  • Lower Slide is equipped with a heavy bearing, precision linear motion system (slide way system) and C3 Class Ball Screw and a total length of 1,350mm.
  • Upper Slide is equipped with heavy loading linear motion system and C3 Ball Screw with Fine Tuning and positioning ability up to 0.001mm.
  • The machine body is designed for both conventional as well as CNC machines. Double Feed axis and Double slides design are easily accomplished with automatic and computerized Numerical Control (CNC) System. This enables it to eliminate the trouble caused by former single feed axis while CNC and automated.
  1. 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. 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. 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. 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. 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. 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 ±5 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. 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.
  8. 8. Grinding Accuracy
    • Workpiece: Ø2 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 m
    RMAx= 0.28 m
    Rz= 0.24m
    RMS= 0.02m
    Rt= 0.22 m
    Rtm= 0.20 m
  9. 9. Operation Applications

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.

CNC Coordinate
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