By William Fang, Engineer | Chieftek Precision USA
Chieftek Precision USA supplies linear stages and motors, linear encoders, servo drives, direct-drive rotary tables, and linear guides to the medical device and laboratory industries.
Of course, the original focus of Chieftek was on the design and manufacture of miniature linear guides.
Today these precision linear offerings — including Chieftek miniature rail (MR) series linear guides — continue to lead in the medical industry.
Beyond these miniature guides, Chieftek guide and slide components for medical designs include standard and wide four-row ball-bearing linear guides; four-row roller-type linear guides; and ST miniature stroke slides with two rows of balls and a gothic ball track with 45° contact for load capacity comparable to that of a mono block (carriage).
The linear guides operate in an array of medical applications that include pharmaceutical dispensers, blood-testing equipment, physical-therapy machines, airway-clearance devices, eye-surgery positioners, and other surgical and dental tools.
Consider just a few of the linear-guide options and design elements that improve medical designs.
Stainless steel for hygiene: Besides carbon steel (which is useful where cost control is an objective) miniatures slides from Chieftek also come in stainless steel. Such construction is indispensable in medical equipment that must remain hygienic and resist corrosion even when subject to caustic cleaning solutions (and maintain precision over the life of the machine). Chieftek offers stainless steel versions of its MR series as standard.
Cleanliness with highly engineered sealing and lubrication solutions: The Chieftek MR series ZU-type carriage block has lubrication pads along with end seals and bottom seals. The latter can prevent lubrication grease from leaking from the runner block, which is key for medical equipment installed in critical patient or laboratory settings.
In addition, the lubrication pad conserves grease and extends the how long the guides can operate before needing relubrication.
Embedded inverse-hook design to let slides run faster: Some linear guides from Chieftek include dovetailing carriage geometry to securely mate with the runner block (carriage) and complement the operation of the load-bearing set of recirculating stainless-steel balls.
Some such slides have other unique features as well.
Recall that the rolling balls subject the carriage’s end caps (which are typically plastic) to impact force during their two directional changes as they recirculate through the carriage. So to resolve the resulting impact forces in some designs, Chieftek includes plastic hooks to secure the block components and distribute the resulting stress over an area that’s larger than that of other designs.
Chieftek introduced this carriage feature as a way to boost the maximum speed of its linear guides — for use in automated equipment such as laboratory machines that must quickly test large sample arrays, for example. These linear guides complement the operation of high-speed axes that are actuated by belt drives and other mechanisms, including those on carriers and axes that rapidly move items between stations.
Durable end reinforcements protect blocks from external strikes and internal roller forces: Some linear slides from Chieftek integrate stainless-steel endplates on their carriage blocks. These outperform plastic endcaps where objects might strike the carriage on its ends. Reinforcing endplates also boost maximum allowable speed on otherwise identical designs — for example, from 3 m/sec to 5 m/sec in some cases. Maximum acceleration is to 250 m/sec2 for some linear-guide offerings with this feature.
Manufacturer expertise to support customized builds: Chieftek engineers have extensive experience in the application of linear guides in medical equipment and related machine builds. That means they can make recommendations on an array of design options — factors such as the omission or inclusion of preload. Consider this parameter as one example: In its miniature linear-guide literature, Chieftek classifies preload as V0 fit with positive clearance for smooth running; standard VS fit to balance precision and life; and V1 fit with a light preload to maximize axis rigidity, vibration mitigation, and load balancing — though with modest increases in friction and wear as well as a modest decrease in maximum acceleration. Extensive experience means that Chieftek offers medical design engineers ways to quantify the effects of this and a whole host of other design choices — and make the optimization of linear motion designs a simpler process.
Chieftek’s 2017 expansion of its manufacturing facilities made it the largest manufacturer of miniature linear guides in the world. For more information, visit chieftek.com.
Also be sure to download the Chieftek MR catalog as a PDF by clicking here.
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