Centrifugal Isotropic Finishing for Firearm Manufacturers

FREE SAMPLE PROCESSING * CONTRACT FINISHING SERVICES * TURN-KEY FINISHING SYSTEMS

For additional information or sample processing information contact: by Dave Davidson – Deburring/Finishing Specialist, ddavidson@deburring-tech-group.com | 509.563.9859 | http://dryfinish.wordpress.com

Firearm Finishing for Manufacturers

Since the discovery of gunpowder, people have been designing and building all makes and models of firearms. What started out as a simple means of igniting the powder to propel the projectile through the barrel has evolved into a set of high precision set of manufactured firearm components. The improved fit and finish has allowed for the increased reliability and performance of today’s precision firearm components and overall finished product.

The firearms industry is in a continual flux of change and improvement. Some of the ongoing updates include the incorporation of exotic alloys, new means of manufacturing and the refined functionality of the final assemblies. The surface finish of each individual component or part is integral to the final assembly performance and in meeting these increasingly stringent design specifications.

Many parts through-out industry benefit from the refined surface finishes that can be developed with Centrifugal iso-Finishing Technology. This type of finishing can markedly improve the fit and function of cooperating parts and components.

Interchangeable Parts

As seen in complex and innovative modern designs, interchangeable parts have become staples of all precision manufacturing, some most notably in the firearm industry. Many of today’s firearms components are stamped, injection-molded, 3D printed or layered in an additive process and then micromachined into the final part. Engineers have pushed material development of superalloys, reduced corrosion, friction and plating applications, as well as innovative processing techniques to make interchangeable parts a reality. Likewise, consumers have pushed for ever-increasing customization options to go along with the increased repeatability and performance of each firearm.

Cast and Machined Alloy Steel Handgun Slides

Refined and Repeatable Firearm Finishing

In working as partners with both major and niche firearms manufacturing companies, ISO Finishing has been able to develop and perfect specific finishing methods and recipes to precisely fit each unique, targeted application. Some parts may require heavy deburring with any number of ceramic or stainless steel media and solution mixtures while others may require the final finesse of specially engineered combinations of organic media.

Some of the many components we have finished with various firearm finishing methods include:

Aluminum machined receivers
Carbon alloy frames
Open field sites
Firing Pins
Stainless steel slides
Custom casings and munitions
Cast frames
Vented ribs

We are capable of handling projects of any size or complexity along with any number of metals and alloys. Our facility can efficiently process prototype runs to ongoing production runs in the tens of thousands. To learn more or for fee sample processing, contact us at ddavidson@deburring-tech-group.com

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Below is some process video footage demonstrations of high-speed centrifugal isotropic finishing. These automated edge and surface finishing methods are capable of producing very refined low micro-inch surfaces that can improve functional part performance and service life.

Below: Centrifugal Iso-finishing operations in a contract precision machine shop.

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Isotropic Micro-Finishing Part Photography by Mark Riley, BV Products

Centrifugal barrel finishing

Centrifugal barrel finishing (CBF) is a high-energy finishing method, which has come into widespread acceptance in the last 25-30 years. Although not nearly as universal in application as vibratory finishing, a long list of important CBF applications have been developed in recent years.

Similar in some respects to barrel finishing, in that a drum-type container is partially filled with media and set in motion to create a sliding action of the contents, CBF is different from other finishing methods in some significant ways. Among these are the high pressures developed in terms of media contact with parts, the unique sliding action induced by rotational and centrifugal forces, and accelerated abrading or finishing action. As is true with other high energy processes, because time cycles are much abbreviated, surface finishes can be developed in minutes, which might tie up conventional equipment for many hours.

Centrifugal Barrel Finishing principles – high-intensity finishing is performed with barrels mounted on the periphery of a turret. The turret rotates providing the bulk of the centrifugal action, the barrels counter-rotate to provide the sliding abrasive action on parts.

The principle behind CBF is relatively straightforward. Opposing barrels or drums are positioned circumferentially on a turret. (Most systems have either two or four barrels mounted on the turret; some manufacturers favor a vertical and others a horizontal orientation for the turret.) As the turret rotates at high speed, the barrels are counterrotated, creating very high G-forces or pressures, as well as considerable media sliding action within the drums. Pressures as high as 50 Gs have been claimed for some equipment. The more standard equipment types range in size from 1 ft3 (30 L) to 10 ft3, although much larger equipment has been built for some applications.

Media used in these types of processes tend to be a great deal smaller than the common sizes chosen for barrel and vibratory processes. The smaller media, in such a high-pressure environment, are capable of performing much more work than would be the case in lower energy equipment. They also enhance access to all areas of the part and contribute to the ability of the equipment to develop very fine finishes. In addition to the ability to produce meaningful surface finish effects rapidly, and to produce fine finishes, CBF has the ability to impart compressive stress into critical parts that require extended metal fatigue resistance. Small and more delicate parts can also be processed with confidence, as the unique sliding action of the process seems to hold parts in position relative to each other, and there is generally little difficulty experienced with part impingement. Dry process media can be used in certain types of equipment and is useful for light deburring, polishing, and producing very refined isotropic super-finishes.

Below: Photo gallery of parts finished with the Centrifugal Iso-Finishing Technology

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AUTHOR BIOGRAPHY – David A. Davidson, [ddavidson@deburring-tech-group.com]

Mr. Davidson is a deburring/surface finishing specialist and consultant. He has contributed technical articles to Metal Finishing and other technical and trade publications and is the author of the Mass Finishing section in the current Metal Finishing Guidebook and Directory. He has also written and lectured extensively for the Society of Manufacturing Engineers, Society of Plastics Engineers, American Electroplaters and Surface Finishers Association and the Mass Finishing Job Shops Association. Mr. Davidson’s specialty is finishing process and finishing product development.