From harsh environments to automated warehousing, tubular linear motors can offer a range of significant benefits. This article looks at the three most common kinds of actuation compared to tubular linear motors, which are gaining currency in manufacturing, logistics and elsewhere due to their precision, speed, efficiency and other benefits.
There is stored energy and there is kinetic energy – or movement. Motors turn the first into the second. As with everything else, ways to create movement have evolved. One comparatively recent kind of actuation, tubular linear motion, is gaining in favour in applications as diverse as machine tool building, factory automation, packaging, printing and material handling.
ANCA Motion is an Australian developer and manufacturer of motion control systems, hardware, and software, including for its sister company, ANCA CNC Machines. ANCA CNC Machines has used LinX tubular linear motors for its globally-renowned tool and cutter grinders since 2014, introducing them in their FX Linear and MX Linear tool grinding machines.
Customers have also welcomed the better surface finish, increased efficiency and improved reliability gains at reduced operating cost in their machines incorporating LinX tubular linear motors within the precision toolmaking industry, where micron-level resolution, as well as throughput, are important.
In the Australian context, energy, labour and other inputs are high. According to a 2019 estimate, Australian electricity and gas prices have roughly doubled since the year 2000. Finding labour has also been one of the biggest issues in Australian manufacturing. any way to lift the productivity of a workplace and its staff deserves consideration.
Pneumatic
Pneumatic actuators have a history going back roughly to World War Two. Today they’re a factory staple, used to quickly (and noisily) move between two set points. Pneumatics are well-understood and widely-used, though they are also inefficient.
They’re a major user of electricity in factories. According to one estimate, using compressed air to perform a task directly takes 10 times the energy of using electricity directly, due to the creation of waste heat. Depending on the size of a factory, getting compressed air to a source might require multiple compressors and/or a complicated reticulation system. Leaks throughout such a network are expensive. One major bottleneck they can create is their inflexibility. Recalibrating air pressure between different batches can sometimes take hours.
ANCA Motion’s LinX motors, on the other hand, work on servo-based, closed-loop control, and changing set points is quick and painless, meaning minimal time between one batch and another. They have an integrated position sensor with 10um of resolution, eliminating the need for an external encoder and simplifying system integration, and also allowing for higher quality and throughput.
The saving on energy costs quickly offsets the upfront cost, and a payback period versus pneumatics is generally 18 months.
Ballscrew
At more than a century old, ballscrew motion goes back even further than pneumatics. It is still around, and used in a broad set of applications, from power steering to moving robotic arms. It is an indirect drive method, using a nut and thread to turn rotational movement into linear movement.
Ballscrew motion has its usefulness, proven by its longevity, but also its shortcomings. It is unable to accelerate and decelerate quickly. The contact between moving parts creates wear and friction, and requires lubricants, which can become a source of contamination. Wear also leads to increased maintenance costs and a decrease in performance over time. Another source of problems is backlash, or lost motion, which is caused by the necessary gap between the thread and nut.
LinX motors are much more nimble in comparison, with no backlash due to their direct-drive nature, and resulting in zero friction between their forcer (a sleeve with copper coils) and shaft (a sealed stainless steel tube containing magnets.) The lack of friction means less wear and better longevity, and better quality for tools or whatever other product they are involved in making.
LinX motors are also capable of achieving velocities as high as 10m per second, meaning a major boost for productivity.
Flatbed linear
Flatbed linear motors (often simply called linear motors) are regularly described as an unrolled version of a rotary electric motor, with the rotor (containing magnets) the stationary part and the forcer (containing coils) the moving part.
Non-factory examples include maglev trains and railguns. Within industrial settings, such linear motors have found their high precision, velocity and force abilities applied to scenarios such as material handling and in machine tools. A major way they improve on ballscrew motion is by having no backlash or reversal error.
A downside to this kind of direct drive motor is its inability to be used in harsh environments. Mechanical stress and heat are also generated due to the attractive forces between the rotor and forcer. This can require use of a separate chiller to control, which in turn increases the total cost of ownership. The strong downforce causes extreme wear of the motor’s railings and it requires frequent replacement.
The answer to this, tubular linear motors, makes full use of magnetic flux, and has greater thermal stability and an increased lifespan due to no contact between forcer and shaft, with zero attractive forces due to LinX motor’s symmetrical design. These features make it suitable for use in harsh applications. This leads to a lower total cost of ownership and better precision.
Australian engineering heritage, global reputation
ANCA Motion’s linear motors were originally developed to give ANCA CNC Machines an edge in a highly competitive global industry. ANCA is a world-leader in CNC tool grinding technology, with a series of world firsts since beginning in 1974. It exports almost all of what it makes at its Melbourne headquarters.
The LinX series has a heritage in tool manufacture, but it has a growing list of customers the world over, and the motors are used across various industries in diverse applications. These include pick-and-place, labelling, pressing, reject sorting, stacking, transfer, line distribution, and many other material handling applications within automated warehousing.
Besides LinX, ANCA Motion offers a range of servo drives, human-machine interfaces and control systems. As well as custom motors, the company supplies standard LinX linear motors in two ranges: M-Series (continuous force of 80 N to 287 N, peak force of 1200 N) with IP 66 rating and S-Series (continuous force of 335 N to 630 N and peak force of 4270 N.) with IP 67 rating.
ANCA Motion has decades of experience in developing motion control solutions and partners with customers to develop custom solutions. This is supported with a local team of engineering, sales and service experts ready to help expand Australia’s sovereign manufacturing capability.