Customized Motion Control
One of Plant’s colleagues had worked with Kerk Motion Products (now part of Haydon Kerk Motion Solutions) when he was involved in the automation industry, and he felt that Kerk might be able to offer the optimal combination of reliability and miniaturization for this mechanism. After consulting with Waters’ engineers, Kerk presented Waters with components that would allow the engineers to produce a sample manager — the heart of the UPLC system — that would meet the company’s reduced size requirements and produce the increased speed and performance that was so vital to the UPLC concept.
Within the sample manager, the Kerk components are being utilized to drive the robotic XYZ mechanism holding the needle that draws liquid samples from each sample plate. To achieve the “X” and “Y” movements, the ACQUITY arm incorporates one Kerk 1⁄4" lead screw and two specially adapted Kerk nuts, and the “Z” motion is accomplished through two Kerk spline shafts and splined bushings.
In the optional sample organizer, a 1⁄2" lead screw and antibacklash nut are employed to produce the Z-axis motion, allowing the robotic machine to shuttle as many as 21 sample plates back and forth to the sample manager. The spline shafts, which run parallel to each other and feature custom splined bushings, provide a drive mechanism for two axes of motion. They are excellent alternatives for applications where hex shafts or square shafts are used (Waters’ original mechanism utilized square shafts). The assembly utilizes lightweight alloy steel spline shafts treated with Kerk's proprietary low-friction Kerkote® TFE coating mated with Kerkite® composite polymer bushings.
“It wasn’t simply performance or size that made the Kerk components so desirable. Kerk’s products offer extremely long wear-life,” Plant said. “This was a critical consideration, as our chromatography systems need to operate at a very high level of reliability. Continuous uptime is very important to most of our customers.”
The launch of the UPLC has been a tremendous success, with praise from countless customers, including some of the world’s most prestigious pharmaceutical companies. “The ACQUITY UPLC (System) will soon become the choice for the development of fast LC methods in the pharmaceutical industry,” said Dr. Anton D. Jerkovich of Novartis Pharmaceuticals Corp., a Waters customer.
This article was contributed by Haydon Kerk Motion Solutions, Waterbury, CT. For more information, visit http://info.hotims.com/28060-321.