Three Precautions for Operation of Universal Tool Microscopes
Attention to the focusing sequence of eyepiece and objective lensMany operators start focusing directly with the objective lens during measurement. After focusing on the specimen, they align and measure using the reticle in the eyepiece. If the reticle is blurry, they then adjust the eyepiece for focus. This procedure is incorrect and will cause ghost images of the focused specimen. The correct method is to first focus the reticle inside the eyepiece until it is clear, and then focus on the specimen. This ensures both the reticle and the specimen image remain sharply defined.
Removal of burrs and scratches on the workpiece surface before measurementWorkpieces may develop burrs and scratches during processing, usage and transportation. These subtle defects can cause alignment errors on the universal tool microscope or make the measuring surface lie out of focus, forming partial ghost images and affecting measurement accuracy. All surface burrs and scratches must be thoroughly removed before measurement.
Correct mounting of workpiecesThere are two common mounting methods for workpieces on a universal tool microscope:(1) Mounting of flat workpieces. The measuring surfaces of flat parts must be kept on the same focal plane to avoid partial ghost images. For parts with chamfers on the measuring surface, place the chamfer facing downward; otherwise poor focusing and inaccurate measurements may occur.(2) Mounting of shaft-type workpieces. Shaft parts are positioned by center holes. Clean the center holes thoroughly before mounting to eliminate dust, debris and burrs. Contaminants will cause misalignment between the shaft centerline and the instrument axis, resulting in large measurement errors. After installation, check the runout of the shaft outer diameter using the horizontal line of the eyepiece reticle to verify correct mounting.
