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Mechanization of Parts Handling. Parts Feeding Fabricated parts must be transported, selected, oriented properly, and positioned for assembly.

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Presentation on theme: "Mechanization of Parts Handling. Parts Feeding Fabricated parts must be transported, selected, oriented properly, and positioned for assembly."— Presentation transcript:

1 Mechanization of Parts Handling

2 Parts Feeding Fabricated parts must be transported, selected, oriented properly, and positioned for assembly.

3 Parts Source Compatibility When writing specifications for purchased parts & when qualifying vendors, the packaging & orientation of parts should be a consideration.

4 Motion & Transfer Start Parts Moving Natural methods used: > Gravity > Centrifugal Force > Tumbling > Air Pressure > Vibration

5 Parts Handling System Desired Features: > No damage to parts > Reliable operation > Accurately locate parts > Sufficient transfer speed > Minimum direct labor > Large carrying capacity

6 Vibratory Bowls Small Parts Commercially Available Recycling Principle > Parts that don’t line up; start over. Wide Variety of Part Shapes Random Orientation Recognize Geometry > Irregularities designed to push, release incorrect orientations. Travel Uphill > Ledges & Tracks: Spiral around & up.

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10 Principles of Parts Orientation Active: Orient by Rearrangement Passive: Orient by Rejection

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16 Vibratory Bowl Analysis Feed Efficiency Effect of the Stations Efficiency of the System Recycled Parts Effect of the Step Device Optimization of Step Height

17 Measure Of Feed Efficiency Efficiency = OUTPUT INPUT Output is the number of correctly orientated parts delivered by the system. Input is the number of parts entering the system.

18 Family of Parts ( Same Basic Shape) Plain Cylinders with Blind Hole Drilled Axially from One End

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20 Variable Length to Diameter Ratio l/d = length / diameter

21 Possible Part Alignments Four: a (Desired) b 1 b 2 c

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23 Natural Resting Aspects Describes the way a part can rest on a Horizontal Surface

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25 Input Matrix for Part 7 (l/d = 1.132) [a b 1 b 2 c] = (.27.35.35.03)

26 Effect of Step Device Purpose is to increase the proportion of parts in alignment “a”.

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29 Impact Of Step Device 50 % parts enter as a exit as a 100% parts enter as b 1 exit as a 30% parts enter as b 2 exit as a 80% parts enter as c exit as a

30 Efficiency of the System Input x Impact = Efficiency of Alignment a.27 x.50 =.135 b 1.35 x 1.00 =.350 b 2.35 x.30 =.105 c.03 x.80 =.024 Total.614 Efficiency of the System = 61.4%

31 Recycled Parts Calculate the chances (probability) that a part will be tossed back k times before reaching an acceptable alignment.

32 Probability the part will be kicked back k times P k = [ E/100 ] [ 1 – E/100 ] k Where: E = Efficiency of the system k = Number of kickbacks

33 System Recycled Parts P 0 = (.614)(.386) 0 = 0.614 P 1 = (.614)(.386) 1 = 0.237 P 2 = (.614)(.386) 2 = 0.0915 P 3 = (.614)(.386) 3 = 0.0353 P 10 = (.614)(.386) 10 = 0.00005 Five out of a Hundred Thousand will be kicked back (10) times before achieving an acceptable alignment.

34 Average Number of Kickbacks k AVE = 1 – E/100 E/100 This Example: k AVE = 0.386 / 0.614 = 0.6287

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36 Optimization of Step Height Calculate the System Efficiently for increments of step height within practical range. Maximum Allowable = 7 mm Goal: Optimize design for each of the 8 parts. Find the step height that gives the maximum efficiency.

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39 Summary Graph of Part Shape Effect on Efficiency of Orienting System > No Step Device > One Step Device > Two Step Devices

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