Prosthetic Arm Force Reducer Team 1 – Halliday's ... - Ohio University

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$Introduction to Numerical Math and Matlab ... - Ohio University$

Table 7.3.2 - Alpha Prototype Total Costs Alpha Prototype a. Total Time to Complete in Hours Complete Manufacture and Assembly 40 b. Labor rate for the Operation ($/hr) $15 (level 2 skilled Labor) c. Labor Cost ($) = a x b 600 d. Basic Overhead Factor 1 e. Equipment Factor 0.5 f. Special Operation/Tolerance Factor 0.25 g. Labor/Overhead/Equipment Cost ($) = c x (1+d+e+f) 1650 h. Purchased Materials/Components Cost 178.17 Total Cost for Alpha Prototype Production: $1828.17 With the final production cost of $1828.17 dollars was simply too high of a price for any person to purchase the system. Table 7.3.3 shows the material costs if ten beta units were produced. For ten prototypes only one section of tubing needs to be purchased which drastically reduces the individual material costs. The total amount of material costs is $508.56 to produce ten units. This is only $50.86 dollars in material costs to produce one beta prototype. This results in a decrease of $127.31 in material costs for every beta prototype. Table 7.3.3 - Material Cost for Ten Beta Units Part Use Price Quantity 2-1/2" DIA. Round Piping Rings $72.89 1 1/2"x1/2" Square Piping Tracks $7.82 5 Pulley Pulley $20.46 10 1/4" DIA. Stock Axle, Misc. $5.95 2 3/32" Wire Rope Cable $1.34/ft 30 Oval Sleeve for 3/32" Rope Cable Attachments $8.43/pack 3 packs 1" OD Flat Washer Bolts for Attachment $8.64/pack 3 packs Truss Head Attach Rings $10.64/pack 3 pack Machine Screw Set Screw Shaft Collar to <strong>Arm</strong> Lock Pulley in Place on Axle $2.84 20 The manufacturing for the beta types would also be reduced considerably. Using the same method for the alpha prototype, the overall manufacturing costs for a beta prototype is shown in Table 7.3.4. From previous experience and time trials the total time to complete the different operations are shown. It is also assumed that the labor will be paid $15 dollars an hour for their work. All of the other factors are the same as the alpha prototype. From this the total 46
manufacturing costs are $525.00. This is a decrease from the alpha prototype of $1125, and puts the overall cost of the system to $575.86. This is an alpha to beta savings of $1252.31. The main reasons for this price drop are the inefficient use of alpha materials and the errors in the manufacturing. This price is in the 10- 15% range of the total prosthetic arm cost of $6000. Table 7.3.4 - Manufacturing Costs for Beta Prototype Operation Operation Operation 1 2 3 Operation 4 Cut Cut square grooves in tracks to pulley axle desired to allow Cut pipe length travel in tubing to and drill the tracks. 1" sections bolt Insert into and turn holes. pulley and down on Mill lock into lathe. opening position Bolt Drill bolt for pulley with assembly to holes axle spacers prosthetic a. Total time to complete operation(s) in hours 5 3 2 3 b. Labor rate for the operation ($/hr) 15 15 15 15 c. Labor Cost ($) = a x b 75 45 30 45 d. Basic overhead factor 1 1 1 1 e. Equipment factor 0.5 0.5 0.5 0.5 f. Special operation/Tolerance factor g. Labor/Overhead/Equipment Cost ($) = c x 0.25 0.25 0.25 0.25 (1+d+e+f) 206.25 112.50 82.50 123.75 h. Purchased materials/Components cost 12.15 7.82 22.44 8.45 Total Labor/Overhead/Equipment Cost $ 525.00 Total Purchased Material/Components Cost $ 50.86 Total Cost for Assembly $ 575.86 7.4 Design Validation Throughout our design and manufacturing phases, interaction with our end user has shaped our project, and allowed us to effectively address real-world considerations. Ultimately, three main goals were set forth from analyzing our customer input: reduction of input force (to reduce strain on the user’s body), increase in grip force (to allow the user to complete a wider variety of tasks with the prosthetic), and to make the product both reliable and serviceable (so the customer can fix it easily, if need be). For the reduction of input force, we decided on a pulley-based mechanical advantage system early on. This configuration guaranteed a 2:1 reduction in user input force, as well as twice as much cable travel to get it open. Since this feature was most important to the user, and would 47
Page 1 and 2: Prosthetic Arm Force Reducer Team 1
Page 3 and 4: 1.0 Introduction Limb loss generall
Page 5 and 6: 2.1 Weighting of Customer Needs Wei
Page 7 and 8: which could limit the use of rubber
Page 9 and 10: design of the two load hook allows
Page 11 and 12: Fig. 4.1.6 - Utah Arm 3 MAGNUM Para
Page 13 and 14: Feature Hosmer Model 7 Work Hook Ot
Page 15 and 16: hook is closed. The harness idea is
Page 17 and 18: purchase it. Safety is another exte
Page 19 and 20: Figure 5.1.2 - Solid Edge Model of
Page 21 and 22: 5.1.4 Concept D - Upgraded Springs
Page 23 and 24: 6.0 Concept Selection 6.1 Data and
Page 25 and 26: Figure 6.1.4 - Input Force FBD The
Page 27 and 28: Since the torques of the both the r
Page 29 and 30: Once the design of the system was u
Page 31 and 32: 7.0.3 Professional/Ethical Standard
Page 33 and 34: Table 7.0.2 - Risk Priority Number
Page 35 and 36: The actual FEA testing involved uti
Page 37 and 38: Another sector that has aided in ou
Page 39 and 40: Figure 7.0.10 Cable Path for Mechan
Page 41 and 42: 7.2.1 Rings (Part #’s THH-001 [El
Page 43 and 44: 7.2.4 Collars 1) Using lathe turn o
Page 45: 7.3 Cost Analysis & Bill of Materia
Page 49 and 50: operation necessary. This convertib
Page 51 and 52: Appendix A - Split Hook Sample Calc
Page 53 and 54: George Platounaris - Interview (12:
Page 55 and 56: Appendix C - Tim Lang’s Forearm D
Page 57 and 58: Health Progress, “Disables Enteri
Page 59: Drawing Package 1. THH‐001……

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