Machine alignment

Precise machine alignment reduces wear and tear, minimizes downtime, and reduces flashing such as for alignment of injection molding machines. 

Figure 2 Shaft Alignment. Machine alignment is a must for holding shape tolerances and optimum roll life. Alignment of shoulders from stand to stand is also important, however, larger tolerances can be accommodated.

Special Molds. Some molds may require a complicated design, inserts, and special machining. Alignment pins may be used to ensure a perfect fit. If a rotomolded article contains a large section where no resin buildup is desired, the mold can be shielded with an insulating material such as Teflon. 

Within the plane of a nonwoven material, the fibers may be either completely isotropic or there may be a preferred fiber orientation or alignment usually with respect to a machine or processing direction. In the case of thicker dry-laid nonwovens, fiber orientation may be randomized in the third dimension, ie, that dimension which is perpendicular to the plane of the fabric, by a process known as needle-punching (7). This process serves to bind the fibers in the nonwoven by mechanical interlocking. 

Anchoring. Bismuth alloys that expand on solidification are particularly useful for aligning and setting punches in a die plate. It is much easier to melt and pour an ahoy around a punch than to machine the entire die plate and punch at the same time. This method also makes it easier to relocate parts or change dies. The low temperatures involved do not cause distortion. 

Figures 10-133 and 10-134 illustrate the wide variety of types and facings available. Though flanged joints consume a large volume of metal, precise machining is required only on the facing. Flanged joints do not impose severe diametral tolerances on the pipe. Careful alignment prior to assembly of flat-face and raised-face flanges is not required, and the necessary wrenches are far smaller than those for screwed assembly for the same size of pipe.

Prior to anv machineiy alignment procedure, it is imperative to check for machine pipe strain. This is accomplished by the placement of dial indicators on the shaft and then loosening the hold-down bolts. Movements of greater than 1 mil are considered indication of a pipe strain condition. 

Tests on load are conducted to determine the performance of the machine, such as its efficiency, power factor, speed and temperature rise etc. For all tests, a machine with load should be properly aligned and securely fastened. Load characteristics are obtained by taking readings at high loads, followed by reading at lower loads. This is usually carried out at 125%, 100%, 75%, 50% and 25% of the full load values. 

If the foot inclines from either the outer or inner border, it will always rise upon loosening the base bolt, and correct alignment will be almost impossible. It will be necessary to re-machine all four feet to achieve parallelism between them. 

Hot alignment check. This technique attempts to determine actual alignment status when the machines are hot. When the machines are running, it is impossible to use dial indicator techniques on the shafts. 

Basically, the optical method uses equipment such as alignment telescopes, jig transits, and sight levels. Instruments with built-in optical micrometers for measuring displacements from a referenced line of sight enable an accurate determination of target movements, which are mounted on the machine. 

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