Computed tomography (CAT or CT) imaging is an incredible tool doctors use to help detect and diagnose patients noninvasively. Using specialized x-ray technology, the device has the ability to image cross-sectional areas of the body, and it provides greater details than conventional x-rays. Today, Positron emission tomography (PET) is employed to detect tissue conditions on a molecular level using radioisotopes ingested by the patient and detected by highly sensitive sensors in a PET machine. A PET scan measures important body functions such as blood flow, oxygen use, and sugar (glucose) metabolism to help doctors evaluate how well organs and tissues are functioning. PET scans are used in several applications such as cardiology, oncology, and neurology. According to the National Institute of Biomedical Imaging and Bioengineering, combination PET/CT scanners are the primary imaging tool for identifying most cancers worldwide.

Fitted with a vibratory bowl feeder, the parts are introduced as a stream of parts into the machine via a smart conveyor.

The production of radioisotopes in nuclear medicine is an important and challenging process where time is of the essence. From isotope production in the lab to physician usage in the hospital’s nuclear radiology department, the journey must be fast. In some cases, due to the short half-life of these isotopes, suppliers can have as little as two days before the product expires, rendering it an ineffective tracer. The production process can span several locations and processing centers — in some cases across several countries requiring adherence to strict nuclear regulatory requirements; so, it would not be an overstatement to say that time is of the essence.

This arduous journey begins with a precise sizing operation where the donor material is geometrically shaped with strict tolerances adhering to equally strict tracking procedures on a center-less grinding system, in this case, developed by Glebar.

Precision Tracking

To develop a precision thrufeed grinding system, Glebar drew from its experience designing medical system solutions for applications such as cardiovascular guidewires, arthroscopic shavers, dental files, surgical tubing, catheter bodies, and orthopedic bone drills.

The machine utilizes a smart gripper, in a “pinch” action, to meter the parts into the machine.

“We’re always eager to accept a new challenge, and in this case, the fact that our product could contribute toward identifying and healing illnesses in the medical field through radiological means makes our work even more rewarding — like the micro grinding systems our engineers design for surgical guidewires used in stent delivery for the heart, or arthroscopic shaver systems we’ve innovated for orthopedic surgeries,” notes Adam Cook, CEO of Glebar.

For this application, the customer required that the pellet count be carefully tracked through the machine. This necessitated a system that could measure a set frequency of parts that would be programmable on demand. In addition to accounting for all of the components processed, the machine had to separate the set number of parts for data collection.

To accurately singulate and grind the radiotracer source material, Glebar’s precision GT-610 grinding system was selected and modified for the application. The modular system is flexible, therefore lending itself well to this type of process. A granite machine base was employed, providing extreme rigidity and superior vibration damping. Fitted with a vibratory bowl feeder, the parts are introduced as a stream into the machine using a smart conveyor.

The modular GT-610 system is flexible, therefore lending itself well to CT pellet grinding.

The system detects a programmed frequency of parts needed and separates the number of parts processed for data collection. The machine then uses a smart gripper in a “pinch” action to meter the parts into the machine. Data is instantly fed back to the machine’s control system for collection and size compensation.

The machine then grinds the 0.100 in. diameter pellets to the required ±0.0001 in. tolerance in a controlled, safe environment with a CpK of 2.0. A similar process was successful for ground automotive engine components and was adopted for this process due to the similar geometric and material characteristics to the pellets processed in this application.

A gantry system guides components out of the grinding zone into a safe area for collection and part measurement. The machine enclosure ensures that the operator is safe at all times using safety interlocks interfaced to the control system.

At the exit side of the machine, a sensor matches the parts count, which then redirects the part to be measured for offline gauging and post processing. The operator places the component on a laser gauge, which instantly feeds back the diameter of the part and automatically compensates for size variation and simultaneously logs the measured diameter data for traceability and to analyze process capability using statistical process control (SPC), a method for measuring and controlling quality during the manufacturing process.

Ease of Operation

The system measures a set frequency of parts and separates the set number of parts processed for data collection.

At the heart of the GT-610’s system is the machine’s touch screen HMI (human machine interface) controls and software, which simplify the machine’s use so that any operator with limited skills in grinding can operate the system with a screen touch while maintaining the tight tolerances required. Developed by Glebar’s engineers, the software was written specifically for this process and tolerance requirements. This was particularly of interest for the pellet manufacturer since many OEMs are facing a shortage of skilled workers with the ability to produce components with the required high level of precision within such a short operating window. Addressing these obstacles is one of the drivers behind Glebar’s decision to advance its machine technology while simplifying it from an operator’s point of view.

To address the present market labor gap, it is important that the medical device manufacturing industry, which is ever-evolving and fast-moving, employs solutions that can address high-volume production demands to get high-quality life-saving devices to the market rapidly.

Employing automated machine technology, machinists can now operate three or four pieces of equipment with ease, coupled with the ability of Glebar to remotely connect to the machine for diagnostics and process monitoring. The machine now requires very little interaction other than a steady supply of raw material to be processed.

This article was written by John Bannayan, President of Glebar, Ramsey, NJ. For more information, Click Here .


Medical Manufacturing and Machining Magazine

This article first appeared in the April, 2018 issue of Medical Manufacturing and Machining Magazine.

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