http://dap.cooper.edu/ 2026-04-26T16:20:45-04:00 http://dap.cooper.edu/ http://dap.cooper.edu/lib/images/favicon.ico text/html 2011-05-04T16:45:45-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:abstract&rev=1304541945&do=diff The cost of mechanical testers has prompted the rise of 'Do it yourself' (DIY) testers, consisting of reliable and accurate load cells. However, position accuracy, as well as motor reliability have proven to be problematic in many instances. In response to this, our group has designed a reproducible DIY mechanical tester, which uses the accuracy of a CNC milling machine to significantly enhance the reliability of collected data. In addition to this, we have included a graphical user interface, w… text/html 2011-05-04T16:18:08-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:data_graphs&rev=1304540288&do=diff First Data Acquisition The load cell was held relatively constant for 8 seconds and then released. We simulated one wave at 13 seconds. The load is in volts because that is the raw data acquired from the DAQ board. The conversion of volts to joules is in progress. text/html 2011-05-04T15:59:09-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:minutes&rev=1304539149&do=diff January/February March 3, 2011 * Calvin wrote a simple data storing program in python for us to build off of. * A specific job was given for each member to complete by the end of the week. These included: * Contacting Roland for additional information * Creating testing patterns (sine waves, steps) in mastercam * Converting these patterns into g-code * Setting up the continuous data saving file in python * Looking into using pydaq c as a middle step between the real time dat… text/html 2011-02-15T01:28:06-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:more&rev=1297751286&do=diff [Stuff to add to the QFD chart ~Neil] ---------- [QFD chart ~Alex] The only thing I would add is a relationship between reliability and accurate loads. Other than that it's pretty good -David text/html 2011-03-21T17:17:19-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:old_minutes&rev=1300742239&do=diff January 29, 2011 * Met with Calvin to introduce the project * Familiarized ourselves with the current mechanical testers and the CNC machine on the 7th floor * Discussed General phases of the project * Next Steps: * Create a Problem Statement * Contact Dale for programming information * Use the CNC machine manual to find physical parameters we have for designing the load cell attachment text/html 2011-03-21T21:54:42-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:physical&rev=1300758882&do=diff Watch this SRL and Dynamic test in progress to see the functionality of each component pictured below: This is the spindle for the Roland MDX - 540 CNC Machine we are using. Attached below it is the load cell attachment, which will be connected to the Data Acquisition Board. text/html 2011-02-17T10:47:05-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:previous_work&rev=1297957625&do=diff There have been many modifications to the open source mechanical tester over the past few years at The Cooper Union. The most recent one (seen below) was created by Dale Short and Calvin Ball. Their research pinpoints a few areas where improvement is needed: text/html 2011-05-04T09:18:06-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:programming&rev=1304515086&do=diff [Download the newest version here] * To learn how to use this program, click [here] for the tutorial. * This version was last edited on May 3rd 2011 by David Tan * The bugs from the previous version have been removed Click here for the older versions of our programs text/html 2011-02-22T13:50:16-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:research&rev=1298400616&do=diff * Improved automation * Fewer mistakes from human error * Accuracy * 0.0001 in. * 0.001 mm. * 0.001 degrees (in polar coordinate) * There is an opportunity for quick change-overs between load cells * Many tests may be conducted in one programmable session text/html 2011-05-04T15:52:27-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:schedule&rev=1304538747&do=diff ---------- The date indicates when the tasks should be completed by. The symbols mean the following: ⊗ Not complete — Significant work has been done on this task ✔ Complete ---------- ✔ The physical load cell connection must be made text/html 2011-03-21T21:46:14-04:00 http://dap.cooper.edu/doku.php?id=classes:principlesofdesign:cncmechanicaltester:test_and_terms&rev=1300758374&do=diff Here is a list of a few terms associated with compression testing of materials: * σ=Eδ * Stress - σ, The amount of force applied to the load divided by the cross sectional area, in units of Pa * Modulus of Elasticity- E, A material property that is used to relate stress to strain, in units of Pa * Strain- δ, The change in position over the initial height of the sample (commonly calculated in %) * Toughness - The ability of a material to absorb energy and plastically deform without f…