May 2020

34 n PHARMACEUTICAL AND MEDICAL May 2020 www.drivesncontrols.com Closed-loop steppers take the heat out of peristaltic pumps B y replacing open-loop stepper motors with integrated closed-loop models, a manufacturer of peristaltic pumps used in bioreactors has been able to reduce the operating temperature which was previously too high. The pumps have internal tubing that separates the media from the components and offers a sanitary way of supplying the bioreactor with fluids to grow cell cultures used in the development of newmedicines. The stepper motors drive the pump head, compressing and releasing the pump tubing to move media into the bioreactor chamber. Previously, excessive heat was being generated by the open-loop stepper motors, raising the temaperature of the fluids being pumped into the bioreactor. This was adversely affecting processing times and reducing yields. By changing to closed-loop steppers incorporating encoder feedback and servo-control firmware, the motor current can be controlled to meet the torque demands precisely. Open-loop stepper motors operate continuously at full current regardless of the load, resulting in high levels of heat being generated. The closed-loop steppers draw only as much current as is needed, and produce much less heat. The closed-loop motors also run quieter and more smoothly. Switching to the closed-loop steppers has also enabled the life sciences manufacturer to standardise on a single-size Nema 23 stepper for all combinations of pump tubing and media, instead of having to stock several different pump and motor sizes. This change to a single motor has allowed the company to develop a standard pump head assembly that requires only tube adapters to be switched to dispense different materials to the bioreactor. Using an integrated motor design has also reduced the number of components needed and decreased the space needed in the control panel. The integrated motor – which combines a stepper motor, encoder, drive, controller and connectors in a single package – has also eliminated the need for cabling to connect separate motion control components together, freeing up panel space. Dual-port Ethernet connections allow daisy-chain connections of Ethernet signals among multiple motors, thus reducing the length of the networking cables that need to be routed around the equipment and back to the control panel. The integrated closed-loop stepper motors being used for the pump were supplied by the US manufacturer Applied Motion Products. They incorporate encoder feedback and servo- control firmware that controls the motor current precisely to meet the torque demands. n Amanufacturer of peristaltic pumps used in a bioreactor systemhas been able to solve heating problems by changing fromopen-loop stepper motors to integrated closed-loop versions that draw less power. By changing from open-loop to integrated closed-loop stepper motors, the peristaltic pump manufacturer has reduced the amount of heat being generated, cut cabling and saved panel space Pharmacy robots are just what the doctor ordered Sweden's biggest online-only pharmacy, Apotea, began seven years ago by sending out a handful of packages a day. Now it delivers more than 170,000 packages every week and stocks more than 18,000 prescription-free products and 8,000 prescription drugs. The company employs more than 650 people and its sales exceed SEK2bn (£163m). Apotea does not have any physical stores. To stay ahead of competition, it has automated some operations at its new logistics centre in Morgongåva. “Our customers want fast deliveries, they want it to be cheap, and they prefer to have it free-of-charge,”explains the company’s business development manager, Maria Alriksson.“This is our challenge and something that we focus on every day.” On a busy day about 35,000 packages leave the centre to be delivered to customers across Sweden. To handle the large order flows, the company is using three industrial robots. A local company, Löfqvist Engineering, developed software that allows the ABB IRB 4600 robots to sort and package products into designated cages for distribution. The general-purpose robots fit in with the short cycle times required at the fulfilment centre. As well as boosting productivity by 30%, the robots have also improved sustainability and freed up time for employees to domore challenging and interesting work.“Our workers have gone from just lifting packages to becoming machine operators,”reports Apotea’s CEO, Pär Svärdson.“The fact that they get more varied and qualified work is very positive for our employees.” The robots are equipped with ABB’s SafeMove2 software that can turn an industrial robot into a collaborative one. Sensors built into the robots stop all movement when a human operator enters the cell. This is useful for Apotea because its employees need to change load cages frequently. Once the operator steps out of the cell, the robot can be restarted with the push of a button. Apotea is on a growth curve. Last year, the company shipped two million more packages than during 2018, and it has the capacity to expand further in the future. Svärdson expects to double the number of robots it uses.

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