Improve Spindle Life With Colonial Tool
1. Operational Instructions:
Machine Operators and Maintenance Personnel are instructed in the proper use and upkeep of the spindles and their peripheral equipment as a part of the purchase agreement at the Colonial Tool facility prior to shipment.
2. Preventive Maintenance Contract:
A. “Spare” Spindle Method
If the number of spindles purchased is very large, and/or, the spindles are in "in-line" operations where down-time cannot be tolerated, a stock of spare spindles must be considered. The number of spares should be determined by "turn—around—time" for the repairs and the usage pattern that develops over a period of time. Ten to ﬁfteen percent of the number of spindles in service is a normal ﬁgure for determining the number of spares required for interruption-free service.
These standard spindles would be purchased by the customer at an inventory carrying price by the customer, and stores by R.A.S. in a pre-assembled state. The pre—assembled state would consist of a spindle and its components (excluding bearings), manufactured, certiﬁed and stored as a unit. Storing the spindle in this fashion will ensure that the spindle bearings will pg exceed their shelf life, be subjected to transcient vibrations, or endure slumping of the lubricant which can cause the protective ﬁlm to be reduced.
During routine preventative maintenance and diagnostic evaluation, a spindle may show signs of deterioration and impending failure. R.A.S. will deliver to Chrysler in a "Just in Time" basis, a spare spindle for the exchange of the failing spindle. The replaced spindle will be immediately tested by R.A.S. and disassembled to identify the failure mode. Each failed spindle wail have documented analysis and corrective action taken to eliminate reoccurrence.
NOTE: Critical operation spindles such as motorized cylinder boring spindles must be stored in the assembled state because of the design complexity, and run—off time requirements. R.A.S. takes special precautions to ensure the integrity of an idle spare spindle.
B. Periodic In-House Inspection
An arrangement must be made with the customer for R.A.S. to perform periodic inspection’ of the spindles during down-time or holiday breaks. These tests would include comparative vibration signature analysis, spindle runout, preload, end-camming, current draw, temperature, air supply, lubrication and housekeeping. The drive train, including belts, idlers, guards, etc., would be examined for indications of damage or failure. The records of these tests will form an invaluable store of information for predictive failure analysis.
Written reports would be prepared for use by the maintenance and safety personnel to allow them to correct the problems uncovered in the inspection.
3. Training Program:
The aim of R.A.S. training program is two-fold. First, it is meant to give the trainee a "feel" for the proper way to handle the disassembly, inspection and re-assembly of the parts of a “precision” spindle. Secondly, it will show the method of testing a finished spindle to determine whether or not the spindle has been properly assembled.
VCR tapes are available for training seminars held for the maintenance and repair personnel. These tapes show actual scenes of spindles being dismantled, tested and re-assembled by a technician in the R.A.S. clean room.
This training can be done in either the customer's plant or at the facilities of R.A.S. In either case, the following equipment is applicable, and is available at R.A.S., but will have to he provided by the customers inspection department if the training is done in his plant.
Generally no special tools are required to dismantle and re-assemble a standard box spindle, however, R.A.S. employs special techniques that can simplify the process of rebuild, and should be passed on to the customer.
The additional tooling requirements are:
Adjustable pin type spanner wrench
Large surface plate (2' x 4') scraped and lapped to a ﬂatness of 50 micro inches/ft.
Height gage (.0005 in. resolution)
Indicator (.0001 in. resolution)
Hardened precision ground V—Blocks (pair 5")
Bore gages (.0001 resolution) with master rings
Vibration Analyzing Equipment (IRD or Equiv.)
Electronic Tachometer (l0-l0000 RPM)
Electronic Indicators (l0-micro inch resolution)
B. Testing Techniques
The purchase of “precision” spindles automatically implies that machining accuracies in the 50-micro inch range is anticipated. In order to assure that this accuracy can be certified, test instrumentation such as indicators, should be able to resolve l0-micro inches. Surface gages, or height gages, should be rigid enough to repeat a “ZERO” reading within the 50% of the resolution of the indicator.
If the test readings are to be meaningful, they must be repeatable, and capable of verification by another inspector, within about 10% on the average of all readings.
When working in the micro inch range, a particle of contamination that is literally invisible to the unaided eye can completely invalidate a test and make confirmation virtually impossible therefore cleanliness is of paramount importance.
This cleaning admonition applies to the work area and inspection tooling such as V—blocks, height gage, parallels, etc., as well as the individual parts that are to be inspected. Continual vigilance during the spindle assembly, for any speck of contamination and its subsequent removal, will be rewarded by an accurate and long lived spindle unit worthy of the title “PRECISION”.
C. Accuracy Indoctrination
Where maintenance personnel are unfamiliar with precision tolerance in the micro inch regions, accuracy indoctrination is necessary. R.A.S., with its special gauging techniques will familiarize and illustrate the effects of accuracy that is conducive to spindle life and running characteristics.