As you can imagine trucks come in all different sizes and serve different purposes for the industry they're being used for.
This means they are specifically set up to perform individual tasks and therefore get fitted with various equipment before they are put on the roads. For this particular case we needed to fit a Power Take Off (PTO) to the engine, also known as a “live drive”. A PTO is a type of mechanical power source, it provides some sort of rotating shaft or flange that’s driven from either the trucks engine or transmission to which hydraulic pumps or gearboxes can be fitted to for the purpose of driving external systems.
For example a concrete truck will have a PTO fitted that is responsible for providing the power to rotate the big agitator (big spinney concrete filled barrel on the back). Or a container truck will have a pump attached to a PTO that provides hydraulic pressure to the arms that load and unload containers on and off the truck.
Now this particular truck we had needed a rather large and powerful PTO installed. The one we wanted to fit had a huge mounting flange on it, as it was designed to suit two different mounting styles of pump to be attached. Only problem was there was going to be some clearance issues between this over engineered flange and a particular cooling pipe for the transmission. We did however know that we only needed to use the smaller of the two flange patterns, so we figured we could potentially machine away the unrequired excess of the flange to clear the pipe. But we knew it was going to be tight and we didn’t want to spend in the tens of thousands purchasing the PTO only to find we couldn’t get enough clearance.
So what did we do?
Using the various technical data available to us, I was able to CAD model the basic shape of the PTO housing, using accurate flange patterns and known dimensions of height. We then 3D printed the dummy PTO housing so we could fit it to the truck, and see what kind clearance we actually dealing with. Of course, as is, the PTO wouldn’t fit, the wider 2 bolt winged pattern of the flange housing was indeed interfering with the transmission cooling inlet pipe, but as we were only needing the smaller 4 bolt flange pattern to mount our pump to, we were able to trim up the 3D printed housing until we had enough clearance, and then evaluate whether we still had enough flange left for mounting our pump to.
"In this instance our kiwi intuitive was correct, we were going to be able to modify the PTO housing with a successful outcome. But thanks to 3D printing we were able to verify an uncertainty and potentially save a financial headache if it were to go the other way."