Summary

Finger for attachment to SG90 servo for useless box design.
Developed for STEM Academy Tech workshop 2017, The University of Sydney

Print Settings

Printer Brand:

Prusa

                                            <p class="detail-setting printer"><strong>Printer: </strong>                     <div><p>i3 MK2S</p></div></p>                                                                                <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>.1</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>100% (30% works with quality filament)</p></div></p>                                                        <br>                        <p class="detail-setting notes"><strong>Notes: </strong>                    </p><div><p>Solid fill necessary to accommodate forces on horn slot while operating and avoid splitting when inserting horn.</p></div>

Post-Printing

Fitting finger to horn

            <div><p>Horn holds finger firmly with single piece paper inserted with horn.<br>Using inferior PLA (old, poor adhesion between layers) resulted in splitting/delamination.  This was eliminated using quality PLA filament.<br>Mk 8 versions increase area on one side of slot.</p></div>                <p class="detail-title"><strong>Positioning of finger, servo, toggle switch</strong></p>            <div><p>Position toggle switch 30 mm from edge of lid, position servo under lid with side flush to edge and horn in line with toggle switch.<br>In rest position finger tip protrudes and with tip just below lid.  Adjust sweep in code for Arduino.</p></div>

How I Designed This

Design and Dimensions

            <div><p>The task of designing the finger from scratch is ideal to set students.  No CAD knowledge required as SketchUp is well suited to developing the design.<br>Basic cross section created with pencil and arc tools. Push/pull used to form height. Rectangular shape of suitable dimensions push/pull into centre of shorter section 6.8 X 4.9 mm</p><p>Requirements for built prototype using Jiffy box.<br>Overall: 40mm X 40 mm<br>Outer edge finger 19 mm from centre of servo horn hole when inserted fully.<br>Return short section of finger 15 mm<br>Angle of top of finger 110 degrees.</p></div>

finger for SG90 servo useless box