Orchid nursery Hazeu Orchids in Delfgauw in the Netherlands has robotised part of its internal transport system. The robot sets down pots with young orchid plants on mobile benches, where they are grown on until they are ready for sale. The art is to get as many orchids as possible on each bench so as to optimise productivity at the nursery. But to avoid damaging the plants, it is important not to put the pots too close together.
Javo, a Dutch systems engineering firm from Noordwijkerhout, has built Hazeu Orchids a robot on the Sysmac platform with electronic components from Hoofddorp-based Omron. This robot sets down around 2,000 to 3,000 plants per hour on the mobile benches exactly the right distance apart.
The family business in Delfgauw grows various Phalaenopsis varieties on seven hectares. Most of its 4.5 million plants go directly to large retail chains – supermarkets, hardware stores and garden centres – without going to auction first. According to co-owner Chiel Hazeu, who is responsible for cultivation and technology, growing Phalaenopsis is a delicate process. “The orchid is a fragile plant. But retailers want beautiful plants of consistent, uniform quality and, of course, attractively priced. An orchid won’t sell if the quality isn’t up to scratch. This not only places tough demands on handling in the nursery, during transportation, at the logistics centres and in the stores but also on the packaging and presentation.”
Plants per square metre
Besides temperature, atmospheric humidity and fertilisation, one of the main factors affecting productivity is the number of plants the nursery can grow per square metre of available space. “The more growing plants you have per square metre, the higher your ultimate production will be. But you can’t place orchids too close together or they will get damaged. The leaves grow out over the side of the pot and the roots also tend to grow out of the pot and take root in nearby pots. This makes the plants very susceptible to damage when you move them. So before we set out the plants in the second growing area, we fit a transparent plastic collar around each pot.”
This protects the plant, but even more importantly, it holds the leaves together. “This way we can put more pots next to each other. Without the collar, we would get around 56 plants per square metre on the mobile benches in the second growing area; with the collar, we get up to about 65.” That’s around 15% more,” Hazeu points out.
The Hazeu brothers are always on the lookout for new technologies and ways to improve working practices in the nursery and boost the quality of the end product. This is important in terms of pricing, reducing losses and optimising productivity. Using special stakes and clips to secure the flower spikes and fitting plastic collars round the pots have proved to be effective measures, but Hazeu is also exploring the potential of process automation. “Because orchids are so fragile, most operations are still done by hand,” he explains.
That applies to sorting, but also to the tasks of fitting the collars and securing the flower spikes. “We have investigated the potential for using cameras for sorting and quality control, for instance, but as yet that’s too complex and expensive for orchids. We automated the supply of pots for sorting and fitting collars using conveyor belts back in 2012. The most logical next step was to automate the process of setting down pots on the mobile benches.”
System manufacturer Javo was commissioned to build the machine. “We make a lot of machines for filling, moving and handling pots and trays, or equipment that meets health and safety requirements,” Sales Manager Peter Rijnders explains. Omron, one of Javo’s regular suppliers, was also involved in developing the robot. The robot for Hazeu Orchids was the first one to be built on the Sysmac platform, enabling it to be developed and programmed as an integrated whole, including the interface, PLCs and servo drives.
The work the robot does is not particularly complicated in itself. Once the pots have been fitted with a collar, they are brought in on a conveyor. The belt consists of a line of individual pot cups, as orchids in pots are quite unstable. The plants are lined up a pre-programmed distance apart in the robot. Once sensors have checked that the row is full, a “fork” with adjustable tines picks up the row of pots and places it on the mobile bench.
There is an additional subtle movement programmed in. The fork gently nudges the row of pots against the previous row and then backs up slightly before setting down the pots. This prevents the pots from knocking against the leaves or roots of plants in the previous row and falling over. This extra bit of programming has reduced the number of fallen pots by more than 99%, which means less damage and no need to manually intervene to pick up the pots. Because the Omron controller is so user-friendly, it was relatively easy to incorporate this extra movement.
A linear drive is used to ensure precise movements of the fork. The arm equipped with the fork is suspended from a gantry and is controlled using industrial servo motors.
The safety program is quick and easy to configure and adjust in the safety controller thanks to the use of standard safety modules. This makes it possible to seamlessly integrate the safety controller into the application and control unit.
There are two robots installed at Hazeu: one on a line with first-rate plants ready to move on to the next stage of the growing process, and another on a line for plants that are too small as yet and need more time to develop. A program has been written for the robots that calculates how many pots are to be placed on the mobile benches and how they are to be spaced, based on pot and plant size. These profiles are stored in a database and can be easily selected on the colour touch screen, which also displays information about the robot’s status and any error messages.
Since the robots can be communicated with remotely, the two suppliers can constantly monitor their status and performance and can tweak the control software if necessary.
So far the robots have not needed much maintenance, however, and they have been operating problem-free since they were introduced in June 2014. Each robot has a capacity of about 700 cycles of the robot arm per hour, but initially this was not fully utilised. “Currently, all the pots are handled by the robots and we have been gradually stepping up the capacity,” Hazeu explains. “Besides the fact that they prevent damage, the robots have reduced our labour costs by around 20%.”
For some time now, Hazeu Orchids has been working with a robot that automates some of their internal transportation. The pots with collars are brought in on a conveyor belt and lined up in rows in the robot a pre-programmed distance apart. A fork fitted with sensors sets them down on the mobile bench. An additional programmed movement prevents the plants from damaging each other.
Text: Theo Snijders. Images: Leo Duijvestijn and Wim van IJzendoorn.