Browsing by Subject "Cost estimating"

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Cost model for commercially-available additive manufacturing machines
(2021-05-11) Martin Cardenas, Oscar A.; Seepersad, Carolyn
Cost models for individual commercial processes have been developed for additive manufacturing machines in the past; however, software and detailed information about the machines for cost modeling tend to be privatized within the industry. The addition of the Center for Additive Manufacturing and Design Innovation to The Walker Department of Mechanical Engineering at The University of Texas at Austin expanded the additive manufacturing facility to include the EOS M280 DMLS, 3D Systems HiS/HiQ Vanguard SLS, 3D Systems SLA 5000, and the Stratasys J750 Digital Anatomy Printer additive machines. To provide quotes for parts and obtain build-specific information for the aforementioned processes, an open-source software program is developed along with the cost models for each individual process to speed up the required calculations and provide an interface for the operator of the center to experiment with different build parameters. The design of each cost model for all four additive manufacturing processes explores assumptions that define the variables used by the open-source software program to perform calculations. The software program includes an interface for the operator to input part and build parameters to obtain desired outputs. Additionally, the software program includes underlying spreadsheets for the operator to make future edits and keep track of quotes. As part of the cost model for the DMLS, SLS, and SLA machines, a part build time estimation experiment is developed to aid the accuracy of machine related cost calculations. Experimental parts are designed and created to record data and develop an equation for the total build time of a desired part for a given process. The results of this experiment are verified with known machine-generated data to validate the accuracy of the results. Additionally, a case study is performed with an experimental build to verify the results of the cost models when compared to Stratasys’ web quoting tool to validate the behavior of the total cost per part estimation for a given process. Due to implications related to the COVID-19 pandemic and the 2021 Texas snowstorm, delays limited the data gathering from the center. Therefore, future adjustments to experimental data are discussed to further improve the cost model’s accuracy. Furthermore, as more knowledge of these processes is gathered by the center over time, adjustment to values in the cost model will be necessary
Pupil Transportation in Texas
(Council for Advanced Transportation Studies, 1975-07) Briggs, Ronald; Hamby, Kelly; Venhuizen, David
System characteristics and operating costs of 331 school district transportation systems in the state of Texas are described and analyzed. This data is used to derive a model to predict the maintenance and operation: costs of pupil transportation. The model takes the form of a simple loglinear equation which predicts costs per pupil transported from the linear density (pupils per route mile) of the transportation network. This model, along with procedures for estimating an annual bus replacement allowance, is incorporated into a formula for allocating state monies to local school districts for pupil transportation. This method of allocating funds is evaluated relative to existing approaches in Texas and other states, and recommendations are made for state legislation.