标准施工手册 STANDARD PRACTICES MANUAL 20-00-02/70-00-01(90)

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Unbalance  The condition that exists in a part when its principle inertia axis and journal centerline are not coincident. Usually measured in ounce/inches. 
Vector  A line with an arrowhead used to represent magnitude and angle of an unbalance or force. 
Whip or Whirl  Bending or bowing of the journal centerline of a non-rigid rotating body initiated by the centrifugal force generated by unbalance. 

Table 405. Specifications of Recommended Machines
Swing 
Weight,  Pounds  Diameter  Length  Sensitivity 
Machine Model  Min.  Max.  Inch Max.  Inch Max.  Speed (rpm)  Inch Min. 
American  1 oz  35  16  18  60 to 3600  0.000010 
Hofmann 
HD-12.1  (28,34 g)  (15 kg)  (406 mm)  (457 mm)  (0,254 Um) 
American  .4 oz  150  25  32  60 to 3600  0.000010 
Hofmann 
HD-13.15  (11,33 g)  (68 kg)  (635 mm)  (812 mm)  (0,254 Um) 
American  1 oz  15  10  18  60 to 3600  0.000010 
Hofmann 
HD-11.1  (28,34 g)  (15 kg)  (254 mm)  (457 mm)  (0,254 Um) 
American  2 oz  150  36  - 400 to 1500  0.000020 
Hofmann 
Vertical  (56,69 g)  (68 kg)  (914 mm)  (0,508 Um) 
HDV-30-2J 
American  8 oz  250  31  45  60 to 3600  0.000010 
Hofmann 
HD-16.1J  (226,8 g)  (113 kg)  (787 mm)  (1143 mm)  (0,254 Um) 

Repair
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20-00-02/70-00-01

(5)  
Determine the Class of balancing to be performed.

(a)  
Class A is balancing of parts supported on their own journals or surfaces during the balancing procedure. Correction is accomplished utilizing dial angle and amount readings after single spin(s) in each plane.

(b)  
Class B is balancing of parts supported on an arbor designed to provide journals or surfaces for the balancing procedure. Preliminary gimmick (balance) of tooling is not required. Correction shall be accomplished using Vector Calculation or equivalent, assuring part compliance over tooling.

 

(6)  
Perform the balancing procedure.

(a)  
Thoroughly clean part to be balanced (Refer to SECTION II).  Lubricate locating surfaces of part using oil (MIL-L-7808) (SECTION VII).

(b)  
If part journal is not used, install required adapter or tool as specified in applicable manual for unit in work.

(c)  
Set up balancing machine in accordance with manufacturer instructions.

(d)  
Record setup data as required using instructions of balancing machine manufacturer. Conversion number (ounce/inches per unit) shall be corrected if required, using the following equation.

 

weight × radius × 16
ounce / inches per unit =
units ×  454
(e)  
Install part to be balanced in balancing machine in accordance with manufacturer instructions.

NOTE:  The following steps shall be accomplished when using Vector Calculation (Polar graph plotting or theory of 180 degrees turn).

(f)  
Spin part and record angle and amount of reading. Stop rotation of part, rotate arbor on part 180 degrees; then spin part and record angle and amount reading for second position.

(g)  
Record limits of balance as specified in applicable manual for unit in work.

(h)  
Select suitable scale amount and identify radical lines on polar graph paper. The scale selected shall be as large as possible and within the amount readings recorded. Figure 406 reflects a typical Vector Calculation for Plane L or Plane M.  Calculate for one plane at a time.
　
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