A pre-owned dual-stacking palletising robot from Pacepacker Services is enabling the fast-growing supplier of aggregates and renders Stonepack to keep its next-day delivery promise to customers.
In March 2013, Stonepack, one of Scotland's largest dedicated suppliers of aggregates and renders to the construction and landscaping trade, opened a new site in Broxburn, near Edinburgh. The rationale behind this move was that it would give the firm a presence in the central belt of Scotland, allowing it to expand southwards.
"When we first opened in 2006 competitor lead times was running to a week. From day one, we pledged to offer next day delivery if customers placed their orders by midday, and to stick to this, we needed good automation capacity. At the same time, we wanted to ensure that the quality and presentation of our products was in no way compromised by the speed at which we were completing orders," explains Hayden Thomas, Managing Director of Stonepack.
With a Pacepacker sack packing and palletising line already performing well at its site further north in Forfar, Angus, Stonepack turned to the Essex-based automation specialist for this project.
Stonepack's requirement was for a heavy duty robot to palletise 25kg plastic sacks at speeds of 12 sacks per minute. The contents of the sacks range from decorative stone to dry dash chips, gravel and sand.
To minimise its capital investment, Stonepack opted for a pre-owned Blu-Robot costing approximately £30,000 less than a brand new robot. The reconditioned FANUC arms are supplied to packaging users pre-programmed and complete with end-of-arm tooling, controls and a 12-month warranty with service and spares back-up.
Whilst the standard Blu-Robot is capable of palletising 8 to 10 bags per minute, the dual stacking robot at Stonepack can palletise 12, enabling the company to achieve its target output of 2,500 sacks per day.
"We wanted a dual stacking configuration so that as soon as the robot has finished palletising a stack, it starts to palletise on the other pallet in the cell," explains Hayden. "This is an extremely time-efficient configuration as the robot is always in use – it can start loading a new pallet while the full pallet is being transported to the delivery area."
According to Chris Francis, sales manager at Pacepacker, the Blu-Robot is ideal for palletising heavy loads in an abrasive, high wear environment.
Because Blu-Robots were originally built for the automotive industry, by nature they are robust and hard-wearing," explains Chris. "They also tend to have higher payloads than robots built specifically for packing tasks – the one at Stonepack has a payload of 80kg. This means it can very comfortably handle 25kg bags, and, if needed, could be upgraded to handle two sacks simultaneously. Many originate from spray paint lines and are approximately 35% of the way through their expected 100,000 operational hour lifespan, so they run as efficiently as a new robotic system."
Certainly, from Stonepack's point of view, the Blu-Robot is more than fit for purpose. "These robots are designed for far more stressful tasks than we give them, and for the difference in price, they have plenty of life left in them. The Blu-Robot has given us the confidence to take on more customers knowing that we will still be able to offer next day delivery," says Hayden.
Pacepacker's relationship with Stonepack stretches back to 2008, when, at the start of the recession, it supplied a weigher and robotic palletiser to automate the existing manual operation at Stonepack's Forfar packing facility.
"During the downturn, the large national bagging companies shut their doors, and regional players like us picked up more work. We were growing at an extremely fast rate and have been ever since," recalls Hayden.
The existing manual set-up was struggling to keep up with demand, but as a young company, Stonepack was not in a position to replace all of its equipment. Respecting this, Pacepacker supplied a new weighing system - essentially a sack clamp mounted on loadcells - which used Stonepack's existing overhead belt feeder, a FANUC M710 dual static robotic palletising system and a 90 degree bag kicker to 'knock down' sacks leaving the heat sealer into a horizontal position for presentation to the palletiser. At that stage, sacks were still prepared and fed into the heat sealer by hand.
Within 18 months, the installation of a Pacepacker Total Bag Control (TBC) system automated this aspect of the packing operation too. The TBC is a fully automated system for stretching and transporting filled sacks into a heat sealer. Because the system never lets go of the bags, it ensures consistent presentation and reliable sealing.
"What was a two-man operation became a one-man operation and capacity has tripled," says Hayden. "At full pelt, this line can pack 10 bags per minute, which equates to a tonne every four minutes."
The Blu-Robot installation at the Broxburn site provides another example of how Pacepacker tailors its approach to specific business challenges. Central to Stonepack's customer charter is the option of next day delivery, and by increasing throughput with a flexible, modular, future-proof automation solution, Stonepack can continue to expand its geographical reach, without compromising on quality.