Lean Process Shellcase Induction Annealing

The goal of this project is to design a faster, cheaper, more reliable annealing process that will simplify shell casing production flow while maintaining similar quality of current neck annealing operations.

=Problem Definition=

Background
Vista Outdoor is a global designer, manufacturer and marketer of consumer products in the outdoor sports and recreation markets. Ammunition comprises about 60% of thier business as the world’s leading producer of centerfire, rimfire, and shotshell cartridges. They are a wholly and vertically integrated manufacturer, taking in raw materials and controlling the fabrication process thru to the retail shelf space as well as direct to consumer sales. This project will work directly with the Lewiston facility where they manufacture some of the most iconic brands in the industry, servicing civilian recreationalists and more than 80% of law enforcement nationwide.

Cartridge shellcases are formed from brass wire through backward extrusion draws and subsequent forming and cutting operations. This intensive work hardening shortens grains and increases latent energy, reducing the ductility needed in the finished part. Targeted ductility is required to allow for case mouth expansion during loading and firing while still retaining adequate head hardness characteristics.

Current anneal processes use natural gas‐powered, belt‐fed, batch ovens. This method forces a tradeoff between thruput and part‐to‐part consistency; As parts are ‘stacked’ on a conveyance belt, the depth of the stack determines the time needed ‘in soak’ at temperature to sufficiently reach the middle‐most parts. Defects introduced by this process can propagate through an entire batch or, if not, at least prove inseparable from good parts. Batching is currently done in 10,000 to 20,000‐piece bins, increasing in‐process inventory and material handling costs.

Case mouth anneal is of critical importance to shellcase function and safe firearm operation. Cases that are too hard can split at the mouth upon firing. This is not detrimental assuming the split stays in the mouth and doesn’t propagate down the case body and vent propellant gas into the unsupported portions of the chamber. In some cases, however, a hard case mouth can split during seating of the projectile which can prevent the round from chambering properly in the firearm. Conversely, cases that are too soft will not have enough hoop strength to retain the projectile during the combustion event. If the projectile is dislodged from the case mouth before sufficient pressure is generated, this can lead to an increased combustion volume and inability to reach the intended peak pressure. This can result in a “bullet‐in‐bore” defect where the projectile becomes lodged before exiting the muzzle end of the bore. This is the most critical of defects as a second round fired into the now‐obstructed bore can cause catastrophic failure of the firearm. Even notwithstanding a second firing, the firearm is now inoperable; a life or death mishap in a lethal force encounter.

Deliverables
This project’s success will hinge on the ability to properly anneal the case mouth. Equipment developed is not expected to run at the two part per second rate typically needed to match upstream operations but must demonstrate the ability to consistently anneal with a high rate of confidence. Quality of anneal will be verified in a number of ways including: microscopy to look for appropriate grain growth, micro‐hardness evaluations, and function testing of sufficient quantity to establish statistical probability of defect rate. A one‐in‐a‐million defect rate is unacceptable as we load 18 million rounds each and every week of centerfire handgun alone!

This projects end goal is to produce the following...

o One‐part flow case mouth annealing device applicable to 9mm, .40, and .45

o A near zero defect rate

o Analysis and flow diagrams documenting current and ideal state process

o Cost saving analysis from reduction in human labor and inventory

o A process that does not pose a hazard to employees

=Design Considerations=

Convert Excel Product Requirements here

=Project Learning=

Design proposition 1:

Annealer could be inserted as the shells come from the hopper, leading into the calibration machine. This is our primary design focus.

Design proposition 2:

Annealer could be inserted as the shells exit the tapering machine. This is an alternative approach consideration.

=Test Bead Prototype=

This prototype was used to demonstrate the functionality of using induction to heat shell casings and to validate the math models for our design.



=Final Design= This Final Prototype Design was selected based on our previous testing. This unit has a digital readout of current (in decivolts) and can be adjusted with built in controls. It can be set to run continuously or manually based on user needs. It also contains safety features such as an on-board cooling system that insures instrument safety during use.



=Testing=

Test 3: Drop Test


=Design Modification=

=Final Design Validation=

=Team Members=

=Additional Documentation=

Project Schedule

Meeting Minutes Archive

Presentations

Client Interview