At ASML, as part of a relatively new standard, each and every bolt in an assembly must be assigned a specific torque. One of my first assignments was to change the material of all of the bolts in an old assembly, and assign a torque spec to each bolt. Normally the ASML bolt calculator is used for one or two connections at a time, in my case, over 100 connections needed to be analyzed. Additionally, the official ASML bolt calculator does not include thermal planar loads due to CTE mismatch between the bolted materials. Calculating these loads one at a time can be very time consuming and prone to human-error.

Noticing this array of problems, I took the initiative to innovate and deliver a highly automated add-on to the original calculator. This saves the designer, and the reviewer, time and headache while reducing the chance of mistakes passing by unnoticed. This add-on utilizes two customized VBA scripts that I wrote, as well as an additional calculator to solve for the estimated planar load due to CTE mismatch–which historically has been done using time-consuming and error-prone FEA. My solution allows the designer to view the details for all of the bolted connections on one screen, facilitating quick review of inputs to catch any mistakes. Now, sweeping changes can be made to the bolted connections in an assembly in a matter of minutes, rather than hours or even days.

These changes have been unofficially adopted by the calculator’s maintaining team and are being offered to designers who need to make large scale changes to the bolted joints in an assembly. I also created self-guided training materials that ensure users can be effective with the add-on in only 15 minutes. Thanks to my efforts, the time savings of somebody making extensive bolt-related changes, as I have, can easily be upwards of 100 man-hours.