Thursday, October 10, 2013

GMT Metrology bed plates and special products

Large Size GMT Cast iron bed Plate
Size: 6000X4000 mm (consists of 4000x1500– 4 Nos)
Cast Iron Bed Plates
Size : 7000 X 500 X 250 mm
Cast Iron Bed Plate
 Size : 4000 X 1250 mm
Cast iron Matched surface plates
Size : 4000 X 3000 mm (3000 X 1000 – 4 Nos)
Cast Iron Bed Plate
Size : 9000 X 350 mm
(3000 X 350 – 3 Nos)
Cast Iron Matched Surface Plate
Size : 6000 X 3000 mm
(3000 X 1000 – 6 Nos)
Cast Iron Matched Surface Plate
Size : 4800 X 2400M
(2400 X 1200 – 4 Nos)


GMT is among the leading belt grinder manufacturer in India. Belt Grinding Machines achieve rates of high production efficiency, quality finish and economy never realized in any other method of grinding or polishing. For example, by changing grit sizes, a machine may be converted from a heavy duty grinder to a fine micro-polisher.
Belt grinding machines can be adopted for semi-automatic or fully automatic working. Further, in most applications, belt grinding imposes less strain on the workpiece when compared to other forms of grinding, cracking, burning etc, do not occur.
belt grinder

Classification of Belt Grinding Machines
Abrasive belt grinding machines are usually classified by the surface that forms the backup of the coated abrasive at the work area. This backup has an important effect on the material removal rate and on the finish. The backup governs choice of contact pressure, the angle of cut and the speed of operation.

Belt Grinding Machines may be broadly classified according to the backups used as :
  1. Platen Grinding Machines:
  2. Contact Wheel Grinding Machines
  3. Free Belt Grinding Machines
  4. Centreless Grinding Machines
In construction, all the machines are similar. A coated abrasive belt runs over two pulleys - one driving pulley one idler pulley. There is (a) provision to prevent the belt from 'walking' or 'running' off the pulleys.
belt grinder

Accuracy, applications and features of GMT Planetary Lapping Machines

planetary lapping machine
Planetary Lapping Machine
lap plate
Lap plate with work carriers
Optical flat
One light band to two light band over 75Ø component. (i.e. 0.3µ to 0.6µ over 75mmØ).
Surface finish : 0.2µ Ra.
Parallelism : 0.002mm over 75mmØ.
Applications :
These machines can be very sucessfully used in:
Electronic industries for lapping silicon wafers, germanium wafers, ferrite and piezo electric ceramics.
Pump industries for lapping mechanical seals made of tungsten carbide and ceramics.
Air compressor industries for lapping compressor valve plates.
Automotive industries for lapping thrust washers and distance pieces used in power steering.
Features :
The machine is constructed on a rigid welded hollow section steel frame, which houses a AC motor offered with variable frequency drive and a worm and worm wheel reduction gear unit.
The central gear, internal ring gear and work carriers are driven a AC motor.
The drive from the AC motor is taken through a worm and worm wheel reduction unit and then goes centrally through the main spindle to the central gear to the internal ring gear, through the work carriers.
The drive from reduction gear unit is through a unidirectional clutch arrangement. This arrangement ensures a smooth motion when the machine is started. This feature also eliminates breakage of fragile components like silicon and germanium wafers while starting and stopping the machine.
Both the lap plates are stationary. The differential motion given to the work carrier results in a random figure of '8' motion. This ensures that the component comes in contact over the entire area of the lap plate in so far as is feasible in line with the geometry of the component.
A special camel back straight edge permits rapid and accurate assessment of the flatness of the lap plates.
A set of special cast iron lapping gears are supplied with the machine for relapping the top and bottom lap plates.
An independent slurry pump feeds the mixture of abrasive and oil to an abrasive feed assembly.It is then distributed through a spider to the working face by means of strategically located holes. A separate stirrer motor is attached with the pump to continuously stir the abrasive with oil.
The main spindle bearings are sealed against ingress of the abrasive slurry. The used slurry is carried away by a suitable arrangement and is collected in a removable tank.


GMT Flat Lapping Machines

GMT Planetary Lapping Machines can lap both sides of a work piece simultaneously. As a consequence work pieces are processed efficiently without manual interruption to get improved parallelism and acts as an surface finishing machine. This double sided lapping machine is an ideal lapping tool for lapping silicon wafers and germanium wafers. 

GMT planetary lapping machines finds application in electronics, quartz, ceramics, semiconductor, surgical instruments and optical industries 

Workpieces to be lapped are placed inside the work carriers. The work carriers are gear cut on the outer diameter and recessed to hold the component inside. Abrasive fluid is fed onto the lap plates continuously. 

The planetary lapping machines are ideally suited to lap thin, fragile materials like silicon and germanium wafers extensively used in electronic industries. Other materials made of tungsten, ceramics, steel, bronze, carbon, aluminum, cast iron, plastics, stainless steel, stellite, ferrite and alumina can also be lapped on these machines.