This is a design proposal that I was asked to carry out for a Swedish world leading manufacturer of compressors, generators, construction and mining equipment, industrial tools and assembly systems. They required a magazine system to present end-pieces for the pre-assembly of pneumatic cylinders.
The second stage for the robot assembly of pneumatic cylinders involves
the sub-assembly of end-pieces and half-pistons. End-pieces need
to be handled by a magazine system because they are too large for
conventional vibratory feeders. A magazine system is required at
the pre-production facilities that is a scaled-down version of the
future production system, within budget limitations. The cost of
the system is split between the fixed cost for the transfer of parts to
the robot and the variable cost of end-piece storage. The
variable storage cost is proportional to the capacity of the magazine
system. There is also an indirect labour cost for the filling and
transport of magazines, in addition to the equipment material cost. The
prototype can have the same transfer device as the production model,
but with a smaller capacity.
The only economical method of magazine loading is to fill them at the
point of final manufacture. This is because the time taken to insert a
part into a magazine can approach the time taken to insert it into the
part-built assembly. Nevertheless, end-pieces have to be
transported from manufacture to assembly and magazines are the best way
of doing this, whilst also giving protection to the surface finish.
The capacity of the magazine is as large as possible to achieve the
minimum number of journeys from manufacturing to assembly during the
shift. If demand for each cylinder diameter is equal then the
magazine must contain in excess of sixty parts for a refill only once a
shift. A single vertical stack magazine would be in excess of
three metres high. It is therefore proposed that a number of units
should be combined to form one magazine. Three magazines of twenty
end-pieces seems reasonable.
The system shown is one method of end-piece distribution. The
illustration shows one magazine to store one style of end-piece.
The production version for the Swedish manufacturing plant would have
three magazines per end-piece, each behind the another.