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Millwright Alignment – Study Guide & Practice
Questions
Machine units are typically positioned with their shafts __________ at a __________ angle, or in line with each other - correct answer ✔✔Parallel and 90 degree In vast majority of cases on new installation of machine units, the ____________ unit is identified and installed first - correct answer ✔✔Primary The primary unit is aligned to reference points or lines called _________ and ________ - correct answer ✔✔Centrelines and benchmarks In-line shafts (coaxial shafts) are usually fitted with couplings and are aligned using what procedure? - correct answer ✔✔Coupling alignment The condition where centrelines of two coaxial shafts do not form a straight line is called? - correct answer ✔✔Misalignment 2 misalignment conditions - correct answer ✔✔Offset and angular When you have both vertical and horizontal misalignment it's called? Most situations will have this issue initially - correct answer ✔✔Combination misalignment When all supporting feet of a machine do not equally support the weight of the machine, this is a condition of? - correct answer ✔✔Soft foot
Broken feet, dirt under machine foundation, anchor bolts incorrectly torqued, loose hold down bolts can all contribute to this condition - correct answer ✔✔Soft foot The two types of soft foot? - correct answer ✔✔Parallel and angular This type of soft foot is the amount of gap between one foot of a machine and baseplate or sole plate - correct answer ✔✔Parallel This type of soft foot is the irregular uneven gap between a machine unit foot and baseplate or soleplate - correct answer ✔✔Angular What's the maximum gap that should be left between foot and shim pack? - correct answer ✔✔0.002" The two planes are called what when dealing with misalignment? - correct answer ✔✔Vertical and horizontal In what order is misalignment dealt with? - correct answer ✔✔1) vertical angular
- vertical offset
- horizontal angular
- horizontal offset In short VA VO HA HO which is kinda funny ___________ misalignment is corrected by adding or removing shims from under machine unit to be aligned - correct answer ✔✔Vertical
When a plunger on a dial indicator is depressed the gauge reads ________ - correct answer ✔✔Positive When the plunger on a dial indicator extends, the reading is __________ - correct answer ✔✔Negative TIR stands for? - correct answer ✔✔Total indicator reading The face readings are when the plunger of the dial indicator are __________ to the face of coupling or shaft - correct answer ✔✔Perpendicular Plungers should be placed in which position on the plunger part when taking readings? - correct answer ✔✔Mid range Make sure the plunger is placed _______ to the surface of what is being measured - correct answer ✔✔Square When both shafts are rolled together this helps maintain same relative position of dial reading. This does what? - correct answer ✔✔Eliminates runout Why are machines aligned accurately with each other? - correct answer ✔✔Allow machines and components to work in harmony How is the primary unit aligned? - correct answer ✔✔To reference points and benchmarks What common relationship do machine units have with the primary? - correct answer ✔✔They have all been aligned with the primary
How is an alignment procedure chosen? - correct answer ✔✔By the accuracy required to connect components to the unit What can happen when you have coaxial shaft misalignment - correct answer ✔✔Reduced machine and bearing life, coupling damage, high vibration, downtime, high costs Misaligned coaxial shafts have which misalignment conditions? - correct answer ✔✔Offset and angular To align in-line shafts, which 2 planes need to be resolved? - correct answer ✔✔Horizontal and vertical Why is vertical misalignment corrected first? - correct answer ✔✔Horizontal adjustments can be disturbed easily How is vertical misalignment corrected? - correct answer ✔✔Shims placed or removed from feet of unit being aligned How is horizontal misalignment corrected - correct answer ✔✔Adjusting position of unit on its base with alignment screws preferable What is angular misalignment? - correct answer ✔✔Faces of couplings and the centre lines of shafts are not parallel How is angular misalignment corrected horizontally? - correct answer ✔✔With alignment screws How is vertical angular misalignment corrected? - correct answer ✔✔Shims placed under drive feet
Which factors are considered when choosing a Coupling alignment method? - correct answer ✔✔Speed of equipment Available tools Available time Which tools are used in a rough alignment? - correct answer ✔✔Straight edge Feeler gauges Rim and face dialing Which shims are best used; on the job or pre cut - correct answer ✔✔Pre cut of course Correct method for shimming a foot? - correct answer ✔✔Use 3 or less when possible and place thinnest one in the centre to avoid crinkles Why are alignment screws preferable for alignment? - correct answer ✔✔No damage to machined feet or legs Safe operation Machine can be kept in position while shimming What is total indicator reading? - correct answer ✔✔When you measure from the 12:00 to 6: What safety precautions must be taken when using a hydraulic jack or pry bar on alignments? - correct answer ✔✔Fingers. Things can slip. Block the equipment How are the four readings on a dial indicator compared to ensure accurate alignment? - correct answer ✔✔Coupling deviations, faulty indicator, bad set up, or sag
What 2 readings are required on most alignment methods? - correct answer ✔✔Rim (periphery) and face readings Which checks are performed before coupling alignments? - correct answer ✔✔Check machine base and feet for debris and high spots Check base bolts Check driven unit Coupling runout What are the steps to correct soft foot? - correct answer ✔✔1) remove old shims
- leave hold down bolts loose
- try rocking the drive
- run feeler gauges under feet
- if more than 0.002" Must place shims Name 3 methods to correct soft foot conditions - correct answer ✔✔1) remove driver and machine base and/or feet
- hand cut graduated or hand cut shims
- build up worn feet with polymeric material When do sag corrections in a dial setting applied? - correct answer ✔✔Rim readings only When there is a predetermined amount of sag at the 12:00 position: turning the bezel to a plus value equal to the amount is called: - correct answer ✔✔Compensation for sag
Why is it good practice to mate mark coupling halves? - correct answer ✔✔To keep relative position when rotated. Can eliminate Coupling runout errors ___________ Is the axial movement of a shaft and can affect face readings - correct answer ✔✔End float What should the accuracy be of a rough alignment before laser or indicator readings? - correct answer ✔✔0.020" Rough alignment is the simplest but ___________ method - correct answer ✔✔Least accurate Taper gauge, telescopic gauge or calipers are used to measure ___________ gaps - correct answer ✔✔Large __________ alignment is used when alignment specifications are more crucial than in a rough alignment - correct answer ✔✔Rim and face In rim and face alignment, _________ in the shafts cannot be present - correct answer ✔✔Axial float Jigs can be used on large diameter shafts where only one shaft will rotate with this alignment type - correct answer ✔✔Rim and face geometrically accurate when used on large diameter couplings with short spans - correct answer ✔✔Rim and face advantage Easier to use on small diameter couplings with short spans than other methods of alignment - correct answer ✔✔Rim and face advantage
When one shaft rotates with the rim and face method mistakes can be made because of ___________ of the coupling or shaft - correct answer ✔✔Eccentricity Name 3 disadvantages of rim and face method - correct answer ✔✔Potential Errors from Eccentricity of shaft End float tough to stabilize Dial indicators tough to set up What do wigglers do? - correct answer ✔✔Make readings in narrow spots
