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Robotics helps improve on tradition

28 July 2019

The use of automated production cells by Wade Ceramics provides a good demonstration of how automation technology can be combined with traditional manufacturing processes to deliver increased output, improved quality and consistency.

Wade Ceramics operates across two production sites in Stoke, with its Bessemer Drive facility specialising in the production of flagon containers supplied to several premium-brand alcoholic spirits manufacturers. Production is made up of a combination of refillable and non-refillable flagons and both standard and bespoke designs.

Production of the flagons is an intricate process that takes between 16 and 20 hours. Each flagon passes through multiple stages, beginning with casting in clay through to decoration and inspection of the final glazed product prior to packaging and despatch. Each flagon is fired twice in one of two kilns – initially following the casting and fettling stage and again once the coloured glazing has been applied. 

When preparing the case for automation, and discussing possible solutions the company had a number of objectives. These included introducing technology to maintain the highest levels of consistency and eliminate potential quality issues. One such example was the positioning of individual flagons prior to the first kiln firing. If situated too closely together the flagons can become fused during the firing process, resulting in them being scrapped. 

The introduction of two robot cells situated at the in-feed to the first kiln ensured repeatable product positioning in this area. Each cell includes a machine vision system which locates the flagon as it is presented to the in-feed area of the kiln, and ensures it is placed correctly by the robot. 

Inconsistencies in the glazing around the base of the flagons was another issue which the company hoped to solve through the use of automation. The glaze must be evenly applied over the complete surface of every flagon. 

Imprecise wiping following the application of the glazing powder caused some of the powder to be removed from the bottom of the flagons, resulting in an uneven finish. The solution to this, developed by Wood Automation & Control’s Systems Division, was a robotic cell incorporating an automated ‘foot wiping’ system to ensure precise and consistent wiping of each flagon base without removing the glazing powder. This cell uses a robot to pick up each flagon and presents it to a rotating cleaning mat for wiping, before passing it to the conveyor of the second kiln.

Simon Miles, applications and proposals manager at Wood Automation & Control’s Systems Division, explained the challenges that had to be overcome when developing a solution to this application: “One of the biggest hurdles in developing the foot wiping cell was the need for the robot to be able to keep pace with the powder glazing machine. To keep everything synchronised, we needed to complete foot wiping process within a target Takt time of just 16 seconds.” This included getting the products to the robot from the glazing machine and making sure that the flagons were properly tracked when they arrived at the robot and when they were subsequently arranged on the Kiln batts, located on the out-feed conveyor to the second kiln. 

“Getting the process right involved extensive testing to arrive at the optimum configuration,” said Miles. “To ensure that the robot stays within the target Takt time, the system tracks the position of the flagons as they enter the foot wiping cell, allowing the robot to pick up each flagon squarely. Similarly, once the flagon base has been wiped, the robot places the finished unit in a specific location on the kiln batt on the out-feed conveyor, enabling it to get into position to accept the next flagon as quickly as possible.”

A further complication was that the cell had to include an extra step for non-refillable flagon variants. This required the robot to remove a temporary plastic cap shield from the top of the flagon as it exited the glazing machine and prior to placement onto the kiln batt. Thorough testing by Wood Automation & Control’s Systems Division, along with the accuracy and speed of the robot, means that both the foot wiping process and removal of the plastic caps for non-refillable flagons can be comfortably performed within the target cycle time. Also, as a result of the improvements delivered by the robotic foot-wiping process flagon reject rates have fallen to just 1.5%.

As a production operation running 24 hours per day and seven days a week, Wade Ceramics needed to ensure that the installation of the new automated cells would not inhibit production. To minimise the potential for any disruption, Wood Automation & Control’s Systems Division built and tested all four cells before final installation on site. 

“The complexity of this project, coupled with the need to get the automated system up and running as quickly as possible once installed, meant carrying out thorough testing to ensure any initial problems were ironed out,” said Miles. “As a result, we were able to install everything on site within a two-week shutdown with production being ramped up as the system became fully operational.”

“The methods that we use, together with the design of our production process and the improved performance achieved through our use of automation, enables us to produce around 3.5 million flagons per year – more than any of our competitors, while maintaining the highest standards of product quality,” explained Stuart Shickell, head of engineering at Wade Ceramics. “We now have the best of both worlds, using automation and robots to boost our efficiency whilst maintaining the traditional hand-crafted look and feel of our products that is core to our reputation.”

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