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Mechanical Punch Press PROJECT
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Mechanical Punch Press
PROJECT
MECHANICAL SYSTEMS DESIGN
MEEN 4365 & ENTC4360
| Grade Sheet: | ||
| I. Formatting: | Maximum Points | Score Obtained |
| 1. Text formatting – titles, subtitles, paragraphs, pages numbered;
2. Figures & Tables – numbered, titled and referred in the text; 3. Equations – terms explained, numbered and referred in the text; 4. References – numbered and referred in the text; |
20 | |
| II. Content: | ||
| 1. Covered required analyses (1) through (11) or through (15) | 65 | |
| 3. Clarity of writing | 10 | |
| III. Conciseness (no trivial statements, no repetition of ideas) | 5 | |
| TOTAL: | 100 | |
Project Specifications (select your values and write them in ink):
| I | A slider crank punch press designed to punch holes in aluminum sheets of one of the following grads (check one) | ¨ 1100-H12 ¨ 1100-H18
¨ 2014-0 ¨ 3003-0  ¨ 3003-H12 ¨ 6061-0 |
| II | The sheet thickness is between 2.5 and 8 mm. | Your value _______ mm |
| III | The maximum hole diameter is between 40 and 100 mm. | Your value _______ mm |
| IV | The maximum punch stroke is between 25 and 50 times the stock thickness (higher values for thinner material) | Your value _______ mm |
| V | Connecting-rod length between 5 and 8 times the punch stroke | Your value _______ mm |
| VI | Slider eccentricity is between 3 and 5 times the sheet thickness | Your value _______ mm |
| VII | The press performs between 80 and 120 punches per minute, which is equal to the crank RPM | Your value _______ RPM |
| VIII | Belt angle a is between 50 and 80 degrees (see figure) | Your value _______ degrees |
Slider-crank punch press kinematic diagram and pictures of actual equipment.
Project Requirements
(1) Research the known designs of slider-crank punch presses, including patents.
(2) Using the shear strength of the aluminum material selected and the size of the hole to be punched, derive the equations of the punch force vs. punch penetration, assuming a linear reduction of the shear force during punching.
(3) For the selected punch stroke, crank length and connection rod length, demonstrate that the mechanism can be assembled and that the crank can perform a full rotation.
(4) Write the vector equations and the corresponding scalar equations for position, velocity and accelerations of the press mechanism.
(5) Derive the equation of the transmission angle vs. crank angle.
(6) Calculate the limit transmission angle values.
(7) Program in Excel equations (4) and (5) with columns for (A) time, (B) crank angle in radians, (C) crank angle in degrees, (D) punch displacement, (E) punch velocity, (F) punch acceleration, (G) transmission angle, (H) punch force, (K) required crank moment calculated using the principle of virtual work.
(8) Use trapezoid integration to calculate the average crank torque.
(9) Assume constant motor torque input and calculate the required flywheel moment of inertia to be placed on crankshaft that will limit the coefficient of speed fluctuation of the press to accepted values.
(10) Model the press in Working Model. Assign small masses and moments of inertia of the moving links to match the results obtained at step (7).
(11) Select a three-phase motor for the press.
(12) Select a V-belt and pulley transmission for the press
(13) Calculate and size the gear pair of the press, assuming the pinion is solid with the shaft.
(14) Calculate for infinite fatigue life and size the intermediate shaft of the press. Assume the pinion to be halfway between the bearings.
(15) Select a pair of bearings to match the intermediate shaft of the press. Assume the distance between bearings to be 2.5 – 3 times the pitch diameter of the pinion.
(16) Draw the pinion-shaft with dimensions and tolerances. The drawing must be landscape, full page.
(17) Draw the mechanism at scale as shown on the previous page.
NOTES:
- Validate Excel results using Working Model 2D.
- Reliability levels in your strength calculations should be 95 to 99%