Smoke Detector Assembly Line

The Challenge

The main objective was due to the age of the device, there were no features on the components that could be changed to aid automation. The system would have to allow the device to be manufactured and assembled in a more controlled manner than the current process, and allow them to introduce stricter process control.

• Fully automating the assembly and testing of the device.
• No design changes of the device to aid the automation.
• Produce a fully assembled device every 4.5 seconds.
• Ensure 100% inspection of the device throughout the process.
• Modular construction to allow for future proofing

Cater for various device configurations therefore including product recipes.

Solution

The assembly system was designed around a race track type conveyor.  The conveyor system ran in a continuous loop feeding pallets from station to station indexing the pallets every 4.5 seconds to give the required throughput.  The pallets had tooled plates mounted to the top face to allow accurate location of the component parts, making up the machine ‘nests’.

On the system there are a number of stations carrying out checks which ensure that the assembled parts are present and that the correct part is installed for the relevant assembly.  The pips and the headless screws are checked to ensure they are present, the PCB is also checked to ensure it is the correct variant.

Assemblies that failed an inspection at any stage the assembly stations up streamed from the failure point onwards inhibited to reduce wastage of components.  Once the failed assembly reaches the reject station all parts in the nest will be unloaded in to a reject collection box.

Completed and verified assemblies are picked and placed on to an offload conveyor which transports the assemblies to the test equipment.