25-08-2017, 09:32 PM
TOOL MAKER`S MICROSCOPE
TOOL MAKER`S.pptx (Size: 217.36 KB / Downloads: 20)
INTRODUCTION
The Tool Maker’s Microscope (TMM) essentially consists of the cast base, the main lighting unit, the upright with carrying arm and the sighting microscope.
The rigid cast base is resting on three foot screws by means of which the equipment can be leveled with reference to the built-inspirit level.
The base carries the co-ordinate measuring table, consists of two measuring slides : one each for directions X and Y, and a rotary circular table provided with the glass plate.
The slides run on precision balls in hardened guide ways warranting reliable travel. Two micrometer screws each of them having measuring range of 0 to 25 mm permit the measuring table to be displaced in the directions X and Y.
Principle::
It works on the principle of a screw gauge, but a few changes were added to it to make its operation more easier.
Tool Maker’s Microscope is a precision Optical Microscope that consists of single or multiple objective lenses, which magnifies the object under observation and by the help of eyepiece lens the object is focused and viewed.
A high precision micrometric X-Y stage and the Z axis travel are used to measure the three dimensions [Length (X), Width (Y), Depth (Z)].
The angle is measured with the help of a rotating stage and eyepiece graduation.
Applications:
The tool maker’s microscope is an essential part of engineering inspection, measurement and calibration in metrology labs. Hence is used to the following—
Examination of form tools, plate and template gauges, punches and dies, annular grooved and threaded hobs etc.
Measurement of glass graticules and other surface marked parts.
Elements of external thread forms of screw plug gauges, taps, worms and similar components.
Shallow bores and recesses.
Procedure:
Switch on the projection lamp. Get familiar with the least count, linear and angular readings of the tool maker’s microscope and nomenclature of the thread shown
Place the given specimen (thread gauge shown)
on the glass table plate. Viewing through the
eyepiece, rotate the knob for moving carrier arm
on column to get the sharp image of the specimen
kept on the glass plate. Position the specimen such
that the table movement in the X direction is
Parallel to the direction of the pitch measurement.
This is checked by ensuring the crosswire touching the
tips (crests) of all the teeth during table movement in
the X direction.