Specialty Work Piece Holding
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Date
2020-12-09
Authors
Guo, Wenjin
Mackay, Matthew
Mark, Jason
Nazar, Liam
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Abstract
Decor Cabinets has asked for a design proposal comprehensively outlining a solution to the hazards posed to their specialty department table saw operators. Small components with awkward aspect ratios are dangerous to operate with the exposed circular saw located on a table saw. This safety concern has been realized by Decor Cabinets in the specialty department where table saws are used due to their functionality and accurate results. The objective of this design project is to increase operator safety while reducing the impact of lost time in the specialty department by transitioning problematic parts away from the table saw to the CNC mill before December 9th of 2020. For this transition to be successful, the design must increase operator safety, meet the current processing times, be compatible with multiple materials, safely affix the part during operation, protect the tooling, and minimize costs with a total budget of $3,000. The team worked with Decor to generate a comprehensive list of metrics capable of governing the success of the design project. Brainstorming and research methods were used to develop conceptual ideas. This stage of the project was completed using Microsoft teams to allow for safe communication of ideas through sketches, CAD models, and supporting images. Our team developed concepts that contained many ideas capable of solving the problem faced by Decor Cabinets. This list was then reduced to the top 5 concepts by evaluating their respective strengths and weaknesses. The final step in choosing a design concept to enter the detailed design phase is the selection process. Like a chain, the selection process is only as strong as the weakest link. The process used selected decision criteria by methodically evaluating key customer needs, using a non-biased approach to identify relationships between the criteria that dictate the weight assigned to each metric, ranking each design concept against each metric, and summarizing the results in a weighted decision matrix. This process resulted in the selection of the Combination concept for the detailed design phase. The fixture concept selected was developed by first calculating the cutting forces generated by the tooling used to manufacture the parts. The worst-case cutting loads were determined to be 8.38 [lbf]. This value was then evaluated in comparison to the vertical and horizontal workholding forces of 535 [lbf] and 324 [lbf] respectively, resulting in confidence of the ability for the fixture to hold the parts in place during operation. The fixture support system was then analyzed to ensure that the calculated value of 0.003 [in] did not exceed the maximum allowable vertical deflection of 1/32 [in]. Various manufacturing considerations were implemented to allow for Decor Cabinets to manufacture this product in-house. At this point in the design, it was important to validate that the detailed design of the fixture did not detract from the original objective of this project. Some final feasibility studies were conducted regarding the objectives surrounding processing time, cost, and failure modes. The final design concept has a substantial gain in processing efficiency (74%) yielding a reduction of 2.76 hours for cutting 120 pieces in a peak production day, and is well under budget at a total material cost of $343.00. All of the risks associated with the potential failure modes were deemed acceptable, not requiring further action at this point. The positive results of the feasibility studies in this section objectively determine that the design project was successful.
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Mechanical Engineering