Application and Use of Measuring Tools - Lab Report Example

Lab Report Introduction This experimental procedure comprises a set of activities that serve to instill and develop students’ technical skills concerning measurement, hand sketching, and creation of CAD drawings. Using a vernier calipers and a micrometer screw gauge as high precision measuring tools, internal and external measurements of a Duplo block were to be determined. Additionally, measurement features and precision aspects of these instruments were reviewed for familiarity. Sketching and outlining drawings of this Duplo block entails a combined application of techniques in engineering that aid in manufacture of objects, with Duplo block as a sample (Benedettelli, 2014). Like any other laboratory experiments, reference is made to physical background of measurement tools and CAD version. Each tool requires an apt application to realize the most appropriate experimental results. Objectives 1. To establish familiarity with application and use of measuring tools: vernier calipers and micrometer screw gauge. 2. To refresh skills of technical drawing, establish their appropriate application in manufacturing of objects. 3. To consider processes of manufacture entailed in creating a simple toy, for instance, in this case we utilize a Duplo block. Experimental Procedure This experimental session majorly covers two sections, thus it is subdivided into two procedural steps. For uniformity and smooth flow of ideologies, these two methodologies were reviewed separately. Step 1 In this section, vernier calipers and micrometer screw gauge were used to measure various dimensions of the Duplo block provided. In each case, these tools were aptly applied as described in the material attached to the laboratory manual. The Duplo block used in this experiment had a mixture of rectangular and circular shapes with internal and external diameters. Vernier calipers With reference to manuals provided, the use of vernier calipers to determine internal and external dimensions of the various shapes on the Duplo block was studied. This is inclusive of evasion of any zero errors that might have occurred. Outer dimensions of circular, square and rectangular shapes on this block were determined by placing it between the lower jaws of the vernier calipers (Benedettelli, 2014). For inner dimensions, upper jaws clip inner surface of shapes measured and are screwed until they firmly hold. Measurements of depth are carried out using the movable head adjustable by the screw clamp whose shape and specifications differ for various vernier calipers. Once an object is in position, readings are made off systematically by determining initial significant figures by reading off values just to the left of vernier zero mark, along the main scale. The reading at which markings in vernier scale coincides with a division on main scale forms decimal readings. Thus, measurements on a vernier scale are usually expressed to two decimal place (Benedettelli, 2014). Relative to micrometers, measurements by vernier calipers are less precise. Micrometer The use of ratchet knob, vernier scale and main scale of a micrometer was demonstrated as described in laboratory manuals. This instrument applies in cases where smaller dimensions and higher accuracy is required (Bawa, 2009). In its features, it comprises of an auxiliary (vernier) scale calibrated in hundredth of millimeters that is marked on a spinning thimble. This thimble has fifty equal sub-divisions which allows for an accuracy of 0.01mm. This instrument is utilized in precise measurements of depth of holes, outer shaft diameters (internal diameters can only internal micrometers) and breadth of blocks. In determining measurements, objects are placed between the micrometer jaws, rotating the thimble from the ratchet until firm clamping is achieved. Readings left of the interface of sleeve scale and rotating are recorded. The other significant figures of these measurements are read off where centerline of vernier scale coincides with thimble scale (Bawa, 2009). In using both the venier and micrometer, measurements were taken three times and the average value obtained for high accuracy. Results Assuming that the material making up the Duplo block has negligible thickness, the following dimensions were recorded: Length = 15.8mm Width = 15.8mm Breadth = 9.8mm Outer diameter of circular extrusions = 3.8mm Step 2 With dimensions shown above, hand sketches of this block were made which were then transferred onto CAD software. Discussion Question 1 Manufacture of lego blocks entails involves an automated and highly heated systems that turns elemental plastic pellets (acrylonitrile butadiene styrene, ABS) into recognizable blocks. On arrival at manufacturing facilities, these granules vacuumed into silos for storage before channeling into apparatuses for injection molding, with accuracies of 0.002 millimeters (Robertson & Breen, 2013). At high temperatures of nearly 232 ˚C, these pellets are melted are injected into molds, where they are compressed at pressures of up to 150 tons. Afterwards, assembly machines shape these blocks by varying pressures at specific portions. ABS granules are used to make up these blocks since they are readily available. Question 2 Ribs provide stability and frictional strength during interlocking of blocks. Additionally, they provide a cavity for interlocking with protuberances from other blocks, hence its location (Bawa, 2009). Question 3 In this calculations, height of circular protuberances is assumed to be 4.76mm whereas depth of cavities has same height as the breadth (9.8mm). Original volume of block = length × width × breadth = 15.8 × 15.8 × 9.8 = 2446.472mm3 Volume of 4 outer circles = 4 (πr2h) = 4 (π × 1.92 × 4.76) = 215.96 Volume of 1 inner circle = π × 1.92 × 9.8 = 111.16 Thus, estimated size of block = 2446.472 - 111.16 + 215.96 = 2551.53mm3 Question 4 This Duplo block is perfectly symmetrical as portrayed by various measurements made by vernier calipers and micrometer. The base is a square shape of 15.8 mm on each side, which was measured three times and ascertained. However, irregularities are prone in measurement of breadth and diameters of circular projections (Bawa, 2009). By measuring circular projections with both vernier and micrometer, symmetrical nature of block is verified since all measurements compromise. This block is thus a symmetrical cuboid measuring 15.8mm by 15.8 mm by 9.8mm with circular protuberances of 3.8mm. Question 5 From the hand sketches, interior markings were made which were then transferred onto CAD software by mere approximations with assistance from available drawing commands (Bawa, 2009). Since its an approximation, these markings are not accurately located on the real objects. However, better software programs can create precise markings. Question 6 From their perceptions, manufacturers regard complexity of shapes and number of protuberances as stylistic features (Robertson & Breen, 2013). They can thus provide blocks that are easy to manufacture and use by inventing blocks with one protuberance emerging from the block’s upper surface and a cavity on the lower surface. Question 7 Functionally, protuberances emerge as critical features since they provide surfaces for interlocking with other blocks (Robertson & Breen, 2013). Thus, ridges made on protuberances would engage complementary cavities in other blocks in a strong deformation. Consequently, this enables relative spinning and releasable retaining. CAD Pictures Conclusion This laboratory exercise was a success as aspects to be covered in the objectives were met. Technical skills in CAD drawing, measurements with vernier and micrometer; and manufacturing aspects of Lego blocks were expansively covered. References Bawa, H. S. (2009). Workshop practice. New Delhi: Tata McGraw-Hill. Benedettelli, D. (2014). The LEGO Mindstorms EV3 laboratory: Build, program, and experiment with five wicked cool robots!. Robertson, D. C., & Breen, B. (2013). Brick by brick: How LEGO rewrote the rules of innovation and conquered the global toy industry. Read More