Applications in medical technology place high demands on drive components: precision, sterilisability, smooth running as well as low heat build-up in DC and BLDC drives. With DC motors as small as 4mm it’s not surprising that 45 per cent of Maxon Motor’s business is in the medical industry. In this article, Patrick Vega, technical engineer at Maxon Motor UK, talks about the Maxon products used.

A range of motors

In Maxon’s brushed motor range starting from the smallest, we have the DCX 6 which has a diameter of just 6mm. Maxon’s specialism is creating small drives below 70V. Our brushless range starts as small as 4mm diameter with a length of below 21mm with a mass of just 1.2g. EC Flat motors offer brushless technology, lightweight, high torque, compactness and low cost. Our brushless frameless motor has a maximum continuous torque of 1.03Nm, add a gearhead and you have the ability to increase your torque and reduce your speed. The ECX SPEED by maxon is very popular in the medical industry for applications that require high speed and high acceleration. Applications include dental drills and centrifuges. These motors top out at 120,000 rpm. To reach such speeds you will need the available voltage as speed is proportional to the voltage. We can control three main parameters; speed, current and position. We have 1-Q controllers know as DEC controllers, that allow you to set a speed and it will run at that set speed. However, there is no active braking, meaning there is no deceleration apart from the moment of inertia of the rotor and the load. We do have 4-Q controllers which have active braking, so regardless of direction it can be decelerated at a controlled rate. These controller products are the Maxon ESCON, EPOS2 and EPOS4. ESCON controls speed and current and the EPOS controls all three.

EPOS4 EtherCAT cards

The company also recently introduced the EPOS4 EtherCAT cards with combination for EPOS4 encased and module controllers which give real-time feedback. EtherCAT cards support CAN Application Layer over EtherCAT standard according to IEC-61800-7 profile type 1 (CiA 402) and fulfils the relevant conformance requirements. Particularly of interest for precise medical equipment, this EtherCAT feature can provide a response as quick as one millisecond given the appropriate Process Data Object (PDO) mapping. We can also design complete systems at Maxon Medical. A recent system used the new EC Flat Frameless and has been designed to be applicable for exoskeletons. No need to worry and waste time thinking about how to enclose a unit or the best way to mount a motor, encoder and controller in a limited space. We can work together to design and produce a simple plug & play unit. We specialise in the development and production of microdrives for applications such as heart pumps, drug delivery systems, surgical robots, hand and leg prosthesis, surgical hand tools and implantable devices, and is certified to the medical standard ISO 13485. Visit Maxon Motor on stand 44 at Medical Technology, Galway, September 26-27. Or contact us on +44 1189 733 337 or email matthew.dean@maxonmotor.com.