THE MANY BENEFITS OF MICRO-ABRASIVE BLASTING

CLEANING MEDICAL PARTS WITH MICRO-ABRASIVE BLASTING

As medical devices become smaller and more intricate, the type of cleaning method used has a significant impact on the manufacture of these devices. Minute imperfections must be removed to meet the tight tolerance requirements and to ensure the performance of the device. Micro-abrasive blasting provides an effective method for cleaning small parts, and has been increasingly important in the manufacture of medical parts.

A deceptively simple process, micro-abrasive blasting is a refined form of sandblasting where air and abrasive are mixed in a focused stream. The tight focus of the abrasive stream is what makes micro-abrasive blasting so unique. It can blast a restricted area as small as 0.050 in. x 0.080 in. (1.3mm x 2.0mm) without a mask or shield. Manual microblasting applications have long been used in the manufacture of precision parts. Advances in automated microblasting solutions however, have seen significant growth in the medical industry as manufacturers strive for lean solutions to tight requirements. Whether automated, fixtured or manual operation, micro-abrasive blasting is used in a wide range of medical and other industry applications.

MEDICAL MOLDING

Injection molding is used to produce a vast range of medical devices and disposable components. The tooling needed to mold these products is very expensive and requires periodic maintenance to the mold cavities.

Microblasting is used to clean residue and graphite master remains in the mold cavity after EDM processing. The buildup of residue can create an undesired finish on the molded product or may become imbedded in it. Blasting with a soft abrasive like sodium bicarbonate is an effective method because it is sharp enough to quickly eliminate the graphite compounds, yet not hard enough to damage the mold cavity.

Laser machined molds also benefit from micro-abrasive blasting. Precision etching into tool steel leaves laser slag and pulse marks on the mold. If left in the mold, these deposits may break off and contaminate parts during the mold process. In this application, a fine aluminum oxide is commonly used to remove the oxide layers without eroding the tool steel base material

Cardiac pacemakers are also often cleaned with micro-abrasive blasting.

MEDICAL ELECTRONICS

Electronic components are prominent in medical diagnostic and surgical instruments, as well as implantable devices such as cardiac pacemakers and defibrillators. Selected sections of coated wires or leads that are attached to an implantable defibrillator need to be removed. Micro-abrasive blasting with a sodium bicarbonate material is an effective method to selectively remove silicone insulation to expose an electrical conductor on such devices.

Cardiac pacemakers are also often cleaned with micro-abrasive blasting. Where the components are sealed to the can, the excess affixing agent needs to be removed. Microabrasive blasting provides the precision necessary to clean off this residue quickly. Since an attractive overall appearance of the device is also desired, the entire surface of the pacemaker can is also usually cleaned. A peening abrasive such as glass bead is used to remove any blemishes. Due to the round particle form, the glass bead does not cut, it pummels the surface, creating a satin-like finish.

SURGICAL INSTRUMENTS

Surgical tools such as scissors, knives, saws and scalpels are becoming too expensive to throw away after one use. These instruments are increasingly being sent to shops for refurbishment so that they can be reused several times.

Microblasting is used to clean out residue from tight crevices in the tools. Similar to the cleaning of molds, a soft or peening abrasive such as sodium bicarbonate is commonly used. Then, as used on pacemaker cans, glass bead abrasive is used to restore the original finish to the instrument for a likenew finish.

IMPLANTS

Microblasting is used to clean residue on surgical tools.

Medical implant devices fabricated by laser machining and stamping of nickel titanium alloys often contain minute defects and blemishes as a result of the manufacturing process. If left untreated, these imperfections will adversely affect the performance, as well as the life span of the device. Many manufacturers of stents, shunts, cages and other implant devices have turned to micro-abrasive blasting as a means of eliminating these possible sources of problems.

Micro-abrasive blasting has improved efficiency for quantity production.

As with laser machined molds, laser machined stents are left with striations on the walls of the devices. Corrosion occurs more readily to the uneven surface left by the pulse marks than to a smooth surface so it is essential that this residue be removed. Remelt from strut junctions where residual laser slag rebonds itself to the device must also be cleaned from the device to ensure reliability. Microblasting with aluminum oxide has proven an effective method for quickly removing these residues, restoring the uniformity to the material surface.

SYSTEMS APPROACH

In all of these applications, microabrasive blasting is accomplished with a high degree of accuracy, precision and reliability. To create an effective blasting system, a few basic components are required. The micro-abrasive blaster is the heart of the system. It generates the abrasive stream by mixing compressed dry air with the abrasive media. A workstation provides a containment for the spent abrasive and proper lighting. A dust collector removes the spent abrasive from the workstation and an air dryer removes moisture from the compressed air line, which is necessary when working with micron-size abrasive.

Whether an application is best suited for manual, fixtured or automated blasting, engineers in Comco's Applications Lab have the expertise and complete test facilities to determine the right solution. Although microblasting has proven results for a wide range of applications, Comco works with manufacturers to test new applications, refine processes, and develop new automated solutions.

Advancements in micro-abrasive blasting have created a versatile technology that has improved efficiency for quantity production and broadened the field of applications that can benefit from the process. A wide range of models, accessories and abrasives make micro-abrasive blasting not only an efficient process for cleaning medical parts, but also for texturing, cutting and deburring small parts across multiple industries.