Lathe: Evaluation of environmental footprintSummaryThe main environmental impact is quantified by a calculation of power usage whilst the lathe is idle and operating, as the useof coolants and lubricants were deemed insignificant and the lathe is operated manually. Furthermore, there is no energy usagedue to a ‘warm-up’ time. As will be explained, it was decided the most appropriate calculation of power would from the equation:P=VISpecificationSupplier Rice Machinery Inc.Producer SHARPModel number 1340FSerial number 236901Supply voltage / V 440 (3 phase)Supply frequency / Hz 60Full load ampage / A 4.3Motor Lasert Motor 3MeasurementsWarm-up Idle OperatingVoltage / V 0 440 440Current / A 1.57 2.00 (for 0.1” cut depth)2.30 (for 0.2” cut depth)N.B. All operating measurements where taken for typical operating conditions, i.e. 1600 rpm with a feed rate of 0.01 in/rev.AssumptionsIt would also be possible to evaluate the energy usage of the lathe by multiplying the duration of use by an estimation of power from Power = Us x Material Removal RateHowever, because the lathe is manual, the feed rate and depth of cut will vary whilst teams are using it and hence anestimation of MRR would not lead to a more accurate calculation of energy usage. In addition, the current drawn does not varysignificantly for various cut depths and consequently an average value of current is used.Analysis of additional elements On the manual lathe no coolants are used. A lubricant is available if required and it may be brushed onto the work piece byeach team. Consequently, the quantity was deemed to be insignificant, particularly as it is would be so small it would be difficultto measure. The lubricant used in the shop is ‘Tap Magic Cutting Fluid with EP-xtra’. The environmental effects are minimalbecause it does not contain any ozone depleting substances or regulated chemicals and it is non-corrosive and bio-gradable.However, it may release toxic fumes when burned; including but not limited to : hydrogen chloride, hydrogen sulfide, carbonmonoxide, and short chain hydrocarbons. It is stable at ambient temperatures and pressure, however elevated temperaturesand exposure to strong alkalis, oxidizers, and/or acids will promote decomposition. Such decomposition results in the release ofhydrogen chloride, hydrogen sulfide, and sulfur from the product. At normal room temperatures, decomposition is virtually nil.Exposure to strong direct sunlight may cause decomposition and discoloration of some components present in this product. Asthis is not too harmful we felt our conclusions were justified. The lathe is manual so no power is required for the computer/controller. No abrasives are used.Practical procedure for applying the model to determine the environmental impact 1. Weigh the workpeice before commencing the machining operation2. Record the total duration of ‘idle time’, measured in seconds3. Record the total duration of ‘operating time’, measured in seconds4. Calculate the energy use of the machine by multiplying the three columns above i.e.Energy use / J = duration x volts x ampsWarm-up Idle OperatingVoltage / V 0 440 440Current / A 1.57 2.15Duration of use / sEnergy use / J = duration x volts x amps 05. Weigh the workpiece after finishing the machining operation and record the reduction in weightmass before (measured in 1) – mass after (measured at 5) = mass lost_______________ - ______________ =
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