Above: Feature Photo credit: M. Klein, Isofinishing
FREE SAMPLE PROCESSING * CONTRACT FINISHING SERVICES * TURN-KEY FINISHING SYSTEMS
For additional information or sample processing information contact:
by Dave Davidson – Deburring/Finishing Specialist
SME Manufacturing C248 – Spokane, Washington

Advisor: Machining/Material Removal Technical Community 
dryfinish@gmail.com  |  509.230.6821
https://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.

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 micro machined into the final part. Engineers have pushed material development of super alloys, 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 a specially engineered combinations 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 dryfinish@gmail.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.

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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.

barfunc
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: SME Webinar Presentation on Centrifugal Isotropic Finishing by Dave Davidson (SME Tech Advisor) and Jack Clark (Surface Analytics.com)

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Further reading:  Internet resources

(1)  “Isotropic Mass Finishing for Surface Integrity and Part Performance”,  Article From: Products Finishing, Jack Clark, from Surface Analytics, LLC and David Davidson, from SME Deburr/Finish Technical Group, Posted on: 1/1/2015, [Barrel, vibratory, centrifugal and spindle finish can improve part performance and service life.]  http://www.pfonline.com/articles/isotropic-mass-finishing-for-surface-integrity-and-part-performance

(2)  “Turbo-Charged Abrasive Machining Offers Uniformity, Consistency”  Article From: Products Finishing, by: Dr. Michael Massarsky, President from Turbo-Finish Corporation, and David A. Davidson, from SME Deburr/Finish Technical Group.  Posted on: 6/1/2012.  [Method can deburr, produce edge contour effects rapidly]  http://www.pfonline.com/articles/turbo-charged-abrasive-machining-offers-uniformity-consistency

(3)  “Turbo-Abrasive Machining and Finishing”. MANUFACTURING ENGINEERING – Aerospace Supplement, by: Dr. Michael Massarsky, President from Turbo-Finish Corporation, and David A. Davidson, from SME Deburr/Finish Technical Group. [Method first developed for the aerospace industry can improve surface integrity and part performance]  http://www.slideshare.net/dryfinish/turboabrasive-machining-me-aerospace-supplement-reprint

(4)  “The Role of Surface Finish in Improving Part Performnce”, MANUFACTURING ENGINEERING, by Jack Clark, Surface Analytics.com and David A. Davidson, from SME Deburr/Finish Technical Group.
http://www.slideshare.net/dryfinish/november-2012-f4-deburring-1-final

(5)  “Free Abrasives Flow for Automated Finishing”, MANUFACTURING ENGINEERING, , by: Dr. Michael Massarsky, President from Turbo-Finish Corporation, and David A. Davidson, from SME Deburr/Finish Technical Group. [Exciting new methods of surface finishing that go beyond deburring to specific isotropic surface finishes that can increase service life]  http://www.slideshare.net/dryfinish/october-2013-f2-deburring-1

(6) Turbo-Abrasive Machining Demonstration Video:  https://www.youtube.com/watch?v=jYxqCxMIHNo

(7) SME Spokane, WA Factory Floor video, Centrifugal Finishing in the Precision Machine Shop: Demonstration)  https://www.youtube.com/watch?v=dUdKjaysTYM

 AUTHOR BIOGRAPHY –  David A. Davidson, [dryfinish@gmail.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.

Dave Davidson – Deburring/Finishing Specialist
SME Manufacturing C248 – Spokane, Washington
Advisor: Machining/Material Removal Technical Community
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One thought on “Centrifugal Isotropic Finishing for Firearm Manufacturers

  1. Reblogged this on Mass Finishing Part Applications and commented:

    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.

    Like

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