“Your the BOM!” That little quip is dedicated to the person who decorated my birthday cake a couple weeks ago. As a writer, I’m obviously a stickler for grammar. Imagine my humour when my wife brings home my delicious ice cream cake with “Happy Birthday Daddy Your Old” written
atop in electric blue icing. She knows me well, so she didn’t dream for an instant to have them correct the grammar. If you’re reading this and don’t know what the error is, then please do not get into cake decorating.
I see a lot of BOM’s in my field of work; nearly as many BOM’s as schematics. BOM is an acronym for Bill of Materials. Next to the hydraulic schematic, the BOM is the most prized tool for troubleshooting a machine failure, and they are the first things I ask for when I arrive on the crime scene of a hydraulic homicide. The problem - in at least half of the troubleshooting situations I’m sleuthing - is non-existent, incomplete or out-of-date schematics and bills of material.
The work to create proper documentation where it does not exist would be difficult and time-consuming. A hydraulic specialist would have to draw out the schematic as best as can be seen on the machine, which could be impossible if there are cartridge valves inside integrated manifolds. Creating a BOM would be possible but time consuming, as it would simply require cataloguing all the components on the machine (as long as they all have readable nameplates).
If your machine does have documentation, I highly recommend that it is confirmed to be accurate and updated if needed. Machine documentation should be treated as family heirlooms, locked up in safe-deposit boxes and retrieved only when the many copies you’ve made have disintegrated. On top of keeping the documents safe, I can’t say how important it is keep the documents up to date. For the sake of cost or convenience, valves are often changed from one brand to the next. A Bosch Rexroth valve may have been unavailable and was swapped for a similar Vickers version of the valve. Without the BOM reflecting the change, there could be confusion during troubleshooting. “No Steve, it says here the clamp valve is Rexroth, try looking on the other side of the machine!”
Also, machines often get upgraded for various reasons; power, speed and safety to name a few. The layout of plumbing or components on the machine may no longer match the schematics. I personally pore over the machine drawings during a failure, even before I look at the machine itself. If the layout or function is not the same as the schematic shows, it can take you hours to figure out what the difference is if the machine isn’t performing as it should.
I recommend you change the documentation with every change on the machine. If you don’t already have your drawings in CAD format, I recommend also that you hire someone to put them in electronic format. It takes minutes to change one symbol or part number and then print out fresh drawings. If you have to make those changes by hand, you either have to draw out the entire circuit from scratch or scribble over the current one, making it look like a dog’s breakfast.
Now go get “you’re” documents and update the dickens out of them!
