Specifications and Optimal Problem-Solving Approaches for Medical Devices

Example 1: C-Arm X-Ray Machines

Radiography involves using X-rays to create images that reveal the internal state of a person’s body by showing us the extent of X-ray penetration in each area by how light or dark it is in the image. Standard radiography installations capture images while moving the patient and the X-ray emitting device vertically and horizontally. This makes it necessary to consider the X-ray machine’s range of motion when deciding where to place it and poses the challenge of finding a large space for the machine in clinical settings where such space is at a premium. Additionally, there are certain parts of the body that can’t be imaged without moving the machine and the patient both, which can require the patient to hold a painful posture during the procedure.
C-Arm X-ray machines, however, solve both of these problems. Equipped with a C-shaped arm, these machines can rotate their X-ray emitters a full 360° to efficiently capture images of the patient from various angles. These machines save space, make the procedure easier on patients, and prevent X-ray leakage, but they require guide mechanisms capable of highly accurate circular motion.

Highly Accurate Circular Motion Provided by the Curved LM Guide Model HCR

This is where THK’s unique guide mechanism, the Curved LM Guide Model HCR, comes in. The Model HCR consists of blocks with four internal raceways along which balls recirculate infinitely. These are paired with precision-ground curved rails to achieve highly accurate circular motion. It uses the same basic structure as the Four-Way Equal Load Type LM Guide Model HSR, which boasts a considerable track record within and beyond the machine tool industry.
When it comes to the stringent safety and reliability requirements of medical facilities, adopting the Curved LM Guide Model HCR for devices incompatible with previous linear guides is helping to expand the functionality of these devices.

Example 2: Surgical Robots

Endoscopic surgery involves inserting an endoscope into a small incision made in the patient’s body in order to view the inside of a person’s body on a monitor without having to perform a laparotomy. A laparotomy will generally involve a much larger incision and will be more taxing on the patient in the end. Ultimately, it will result in pain and a longer recovery time that patients have to deal with before they can get back to their normal lives.

Surgical robots provide a solution to this problem. Controlled remotely by a doctor, a surgical robot provides a greater range of motion than the human wrist can, and thus allows surgeries to be performed with greater precision. In order to precisely execute the control inputs from the doctor and keep the robot hand from shaking, these robots require guide mechanisms that are compact, lightweight, highly rigid, and highly accurate.

The Miniature LM Guide Series: Compact and Lightweight!

Miniature LM Guide units are ideal for making surgical robots more compact. For one, they allow robot arms to be made smaller and more lightweight. The high rigidity and high accuracy characteristic of the LM Guide also contribute to the reliability of surgical robots by improving operability and nullifying any shaking of the doctor's hands.
THK offers an extensive lineup of miniature LM Guide products, including the models SRS, RSX, RSR, and AHR. The smallest of these is our Model RSR with a rail just 2 mm wide. Compact and capable of bearing load from all directions, these guides can be installed in tight spaces thanks to the low cross-sectional height of their LM rail components. Made of highly corrosion-resistant stainless steel, miniature LM Guide products can be used in various environments. Additionally, for models that contain ball cages, the absence of friction between balls, together with increased grease retention, provides long service life and long-term maintenance-free (lubrication-free) operation and contributes to noise reduction in machines.

Example 3: MRI (Magnetic Resonance Imaging) Machines

Using magnets and electromagnetic waves instead of X-rays, MRIs generate cross-sectional images that give us a glimpse at the internal state of the body. MRI machines constantly generate an exceptionally strong magnetic field, however. If they contain components that can be magnetized, this will invariably affect the accuracy of the machine. The magnetic field also exerts a strong attractive force on iron objects, which can be dangerous. All of this makes designing these machines more challenging. This makes non-magnetic products, which don’t affect the machine’s magnetic field, a much sought-after solution.

The Low-Magnetic Permeability LM Guide Model HSR-M3: Compatible with Strong Magnetic Fields!

For a guide mechanism capable of providing long-term, highly accurate, and stable linear motion even in a strong magnetic field, we recommend the Low-Magnetic Permeability LM Guide Model HSR-M3. Its relative magnetic permeability of 1.02 is achieved using components made of materials with low magnetic permeability so that maximum performance can be achieved even in a strong magnetic field. Additionally, the material used for the Model HSR-M3 is harder than SUS316, itself well-known for its low magnetic permeability, and can thus tolerate higher loads.

Special Alloy THK-NM1: Compatible with a Wide Array of Environments!

THK has also created a special alloy, THK-NM1, that provides even lower magnetism and even greater hardness than what we use for the Model HSR-M3. With a hardness around 60 HRC, well within the 58 HRC to 64 HRC range that’s optimal for bearings, this alloy allows rolling guides to tolerate large loads. It can be used in various products, from the LM Guide to ball screws, ball splines, cross-roller rings, and more. We highly recommend it if you’re struggling with special environments that are too demanding for standard products.
The special alloy THK-NM1 provides high-performance non-magnetic properties and super-high corrosion resistance. Its excellence in terms of non-magnetic properties makes it suited to special environments in cutting-edge scientific fields that aren’t sufficiently covered by conventional products, such as devices that handle charged particles, generate strong magnetic fields, or use highly corrosive chemicals.

THK’s Support for the Medical Industry

In this article, we took a look at some of the medical devices and equipment that support medical facilities as well as THK products suited to the specifications they require. As a maker of precision machine components, THK may at first seem far removed from anything to do with clinical settings. Nevertheless, we will continue to develop products that help solve the various challenges that arise in these settings. Please contact THK for all your medical device and equipment support needs.