Caterpillar cakes are one of the UK’s best-loved treats, and for one producer they had become a production headache. Cornwall-based Western Mechanical Handling UK Ltd (WMH) worked with Mitsubishi Electric’s Automation Systems Division to automate the delicate final handling step. The new robot cell increases throughput, improves product quality and cuts ingredient waste.
A manual process with costly side effects
WMH’s end customer had been transferring the decorated cakes onto their supporting trays by hand before packaging. Operators didn’t always place the cakes in the same position on the tray, which led to rejected products and lower overall output. The manual process also used too much chocolate ganache, which added cost and wasted ingredients.
The customer asked WMH to automate the transfer. The cell had to handle decorated cakes gently without marking them, while also placing them accurately and dispensing ingredients correctly. To build it, WMH turned to Mitsubishi Electric, its automation partner of many years.
Soft grippers that work like a human hand
The key element of the cell is a soft gripper designed by WMH specifically for food-grade use. It is modeled on the sensitivity of a human hand, so it can pick up decorated cakes without damaging the chocolate or the decorations.
The grippers are fitted to two Mitsubishi Electric RV-7FRLM-D six-axis robots, each with a 7 kg payload. Operators program and control them with an R86TB touchscreen teaching pendant. Both robots are mounted overhead, which keeps the cell compact. They are rated IP65, so they can withstand the strict cleaning and hygiene routines at the customer’s site, which runs 24/7.
Picking cakes from a moving conveyor
Ian Ewing, System Sales Engineer at WMH, points out that food production leaves no margin for error. Even small amounts of downtime or wasted product quickly add up. The brief was to build a cell that combined the dexterity of human hands with the precision of industrial automation. From years of working with Mitsubishi Electric, WMH was confident the robots would deliver the positioning accuracy and repeatability needed to get the best out of its gripper head.
Speed was just as important. If the conveyor had to stop every time the robots synchronized with a cake, throughput would drop and cause delays further down the line. The robots therefore track the conveyor and pick cakes while they are still moving. According to Ewing, the Mitsubishi Electric robots are easy to program, so this was relatively straightforward to achieve.
Results well above the manual process
Jewel George, Robotics Product Manager at Mitsubishi Electric Automation Systems Division UK, says the demanding targets for speed, accuracy and productivity meant the two companies had to work closely to choose the right robots. He describes the RV-FR series as one of Mitsubishi Electric’s most versatile ranges. Mitsubishi Electric supported WMH with the supply, installation and programming of the robots.
The cell is now running at the customer’s plant, and both throughput and quality are well above the levels of the old manual process. As George puts it, it seems you really can have your cake and eat it.