Robotics are playing an increasingly important role in assisting manufacturers to reach ultra-high production speeds with higher quality products and less wastage.
At the forefront of this technology is a company that has been perfecting roof tile manufacturing plants for the past 100 years, ABECE. The Swedish equipment manufacturer is a world leader in producing ultra-high efficiency plants that are approaching nearly 100% efficiency in terms of material usage, reduced waste and high-speed manufacturing.
In South Africa the ABECE range of plants is distributed and supported by the country’s own technology leader, PMSA, a company which holds similar values and standards as its overseas counterpart. Over the past decade the partnership has driven the brand to become a firm favourite in southern Africa with plants operational throughout South Africa and the sub-Saharan Africa region.
PMSA marketing and sales manager, Quintin Booysen, says the move to automation in all, or some, of the operations in a plant is a necessity in order to reach and maintain high volume production. ABECE’s modern plants have all the necessary technology to mix and extrude high quality concrete, but the real need for speed mostly takes place after the extrusion process.
He explains the process, is mainly too quick for the eye to see. “To maintain production at 140 tiles per minute our equipment prepares the pallets with a micro-quantity of oil which is brushed on at just the right quantity for an even spread.
The ABECE plants are a wonder to see in operation. After batching and mixing of concrete the pallet is rapidly moved into place for extrusion of the tile upper surface on a high speed ABECE extruder.
The next step of automation starts at the servo knife which has both vertical and horizontal movements operated by servos with no pneumatics on either knife for absolute precision and accuracy. With closer tolerances the system easily saves one percent of the concrete used per tile through cutting off excess material to make a perfect tile length, the excess material is returned to the extruder to make tiles and reduce any waste. Exact dimension ensures no overhangs or push marks and leads to less rejects and damages.
After the dual servo knife cuts the tile on the pallet at an exact length it moves to the racking station where it is stacked before being moved to the zero zone for acclimatisation and automatically transported into the hottest part of the curing room.
Even the high precision automated racking system is built for speed with specialised wheels for faster, more reliable movement and less jamming. The ABECE racking and de-racking systems are designed to be the most efficient in the world with hundreds of features built into the system to enable high levels of automation. Precise and minimalistic movement results in less jamming and smoother operation.
Curing efficiently for energy savings
The process of curing can be from 7 hours to 24 hours depending on the cement content of the tile. Once again, for speed of production, the racking systems are efficient and carefully designed to gently handle tiles and reduce damage when curing.
The manufacturer’s innovation extends to curing with an approach that ensures less energy and effort is taken in the even curing of the tiles. By enclosing the entire curing chamber the right environment is created for curing with no heat losses due to constantly opening doors during the loading period.
“The ABECE plants make use of a Hotbox approach that encloses the entire plant and uses the heat of hydration to cure the concrete more energy efficiently. After curing the roof tiles are de-racked and separated from the aluminium or steel pallet. To minimise cement and additional energy for heating, this entire process of curing ideally takes 24-hours for an efficient curing cycle in a highly-automated plant and the precision of manufacture, movement and handling means that there are hardly any quality defects and almost zero defects,” says Quintin.
Quintin explains that after curing, depending on requirements for either topcoat or through colour tile, it may need further processing. Here it will either go to a rotary dryer for top-coated tiles or straight to packing wherever colour through tiles are manufactured.
Robotic packing systems work faster and more precisely with no scratch marks or chipping and less damages. The robots are also able to maintain production outputs around the clock for 365 days per year. Depending on requirements the ABECE plants offer a choice of either a single loader with the ability to load tiles into packs of 10 at up to 70 tiles per minute, or a twin loader for up to 140 tiles per minute. In instances where clients require smaller packages for easier onsite handling, the robots can also split tiles into packs of 5.
Apart from higher speed and flexibility, the robots are also able to identify products and package them accordingly when packaging them onto wooden transport pallets.
Human Man Interface
Through HMI’s all the features of the plant are available through the touch of a button. HMI’s provide a quick interface with the machinery and control everything from the extruders and servo knives, to the racking, curing, packing and conveyor systems. Nowadays, operators and production controllers can get all the information that they need at a glance on screen or even via a mobile device in certain instances. The operations can then be modified and controlled as required, including line speed adjustments, power consumption, plant parameters and alarms.
Post extrusion, the HMI’s typically control stations including:
- Extruder, knife and conveyor system.
- Racking and Hotbox curing chamber with capabilities to show quantity of rack and tiles in the chamber and even colour of tiles in certain racks if specified.
- Packing station (or backend) controls including the rotary drier, loaders and up to six robotic packers, as well as the transport conveyors to the forklifts in the yard.
HMI systems also allows pinpoint identification of faults and allows users to find root causes of faults down to individual sensors. In addition, it provides a visual picture of each section of the production line with visual representations of each process.
Fortunately for owners of existing plants, each and every section can be addressed separately and can be added to existing plants as required.