Sprue Removal Station

Whirlpool Corporation is the world’s leading major home appliance company, with billions in annual sales and tens of thousands of employees; they also market Indesit amongst many other popular brand names.

Automation means reducing the use of personnel and increasing manufacturing quality, however more economic production processes require reliable machine methods.

Whirlpool Corporation had a special request for DBI Control and wanted us to create an innovative system to help solve a problem in their Bristol factory.

Whirlpool required us to manufacture a rig to apply heat to 4 x separate locations on a base to heat the sprue produced during the moulding process.

A sprue is the passage through which a liquid material is introduced into a mould. During casting, the material in the sprue will solidify and need to be removed from the finished part.

The sprue must be removed without damaging the material and surface structure in order to complete and prepare the component for further manufacturing steps.

The preferred forming process for mass production is injection moulding, and the remaining sprue must be removed in a separate process. It is not clean enough to simply break off the sprue.

If remains are removed by machine, this results in rework if particles stick to the workpiece. DBI Control came up with the ideal solution and made it possible for the whole process to be fully automated.

Whirlpool indicated the locations that the sprue needed to be removed from on each item that would be going through the rig, and the existing production line so we could easily incorporate our system.

DBI Control were asked to provide suitable actuators to compress the sprue, and design and manufacture a control system to electrically and pneumatically integrate it into the existing panel and line.

In our Deeside workshop we manufactured a table-top and support frame made from aluminium with pneumatically operated cylinders mounted on the underside. These were complete with a process heat gun and x4 adjustable nozzles and positional sensors.

We also created one main wall mounted panel made of mild steel (800mm x 600mm x 250mm) with a full kit of LV equipment. We also included a PLC with a Siemens S7-1200 CPU and control devices.

Once we had designed the system electrically and mechanically, we generated a set of electrical schematics to facilitate the manufacture of the enclosures and field wiring.

We configured all the hardware and software to operate the Sprue Removal Station, and once all this was completed, we spent around 4 days at Whirlpools site in Bristol installing the machine.

The advantages to the station we created for Whirlpool is there will be no tool wear or tool changes required, in contrast to sawing, milling or drilling, and a high repeat accuracy and consistent quality, with polished edges and chipless removal of remaining sprue.