The brief for this custom machine project was deceptively simple: close the lid of a box.
However, the devil was in the details as per usual. All sides of this particular box had to be squashed inwards from the natural resting state in order for the lid to shut and hold reliably.
The project involved full mechanical design, an integrated control box, and software. All done in house at PDM.
Due to the leading and trailing edges of the box needing to be pulled in, a shuttle design was chosen to pinch the front and rear of the box during closing. To move the shuttle up and down, then return it to the start position we used a core-XY belt drive (commonly seen in 3D printing). This allows us drive our shuttle in two directions without throwing around the weight of a motor as they are both mounted in fixed positions on the frame.
Leveraging digital manufacturing methods such as profile cutting and industrial 3D printing, we were able to build and iterate quickly while not accruing large costs for the customer.
There was no need for any custom machined parts in the entire build. Bearing housings can be seen printed from ABS, along with belt tensioning assemblies, and rollers. Drive pulleys were printed from polycarbonate including broached slot to match the key on the motor shaft. These printed components were not only great for flexibility during construction, but they have proven durable in a harsh production environment.
A variety of sheet metal techniques were employed to speed up the construction phase. Perforated edges were profile cut along bend lines, simplifying the bending process for our sheet metal fabricators. This technique also enabled us to bend 3mm aluminium sheet without seeing cracking on the outside of the bend as would normally be seen with a solid edge. The resulting components were light and strong- a necessity for this design as it operates at high speeds (as can be seen in the video below).