electrolytic rifling solutions
the inside edge
The advantages of electrochemical rifling
The ECR process typically results in excellent surface finish in the grooves (16 µin Ra / 0.4µm Ra or better) without machining marks such as those caused by broaches. Since the conductive groove machining elements on the tool (cathodes) do not contact the bore surface, there is no mechanical wear and repeatable accuracy is excellent. Repeatable accuracy of 0.0003 inch (0.075 mm) is typical. The process time is also excellent with tool traverse speed of 5 to 15 inches per minute (200 to 600 mm per minute).
Stress Free Rifling. Metal is 100% removed by electrolytic action with no cutting, swaging or displacing of material.
Land to groove transition of ECR vs broached
Electrolytic Machining and Rifling (ECR)
Excellent Tool Life. Electrochemical process results in material removal from the positively charged barrel (anode) only, hence wear only occurs on the tool guides which can last for over 1,000 barrels.
ECR has a number of unique aspects… • Grooves have radiused sides as contrasted to the more square corners produced by other methods as depicted in the illustration (it has been noted that ECR groove contour is comparable to or better than a broached barrel which has subsequently been electro-polished and plated)
Finish and Accuracy. The ECR process will consistently produce a high quality finish and repeatable accuracy.
• ECR machining rates on materials such as stainless steel are as fast as on conventional barrel material, with no increase in tool wear (and produces a better surface finish than other methods)
Thinner Gauge Blanks. ECR can be applied to barrels with very thin walls. No extra thickness or barrel length is needed.
• The cathode tools are much less expensive than tools for other methods
High Productivity. The ECR process is as fast as (and in some cases faster than) hammer forging, broaching and cut rifling.
Other aspects of ECR include the ability to produce polygonal and other non-standard rifling forms at the same production rates and surface quality as standard ECR rifling. Also, since ECR tools move through the bore during the process it is possible to machine progressive groove depths by controlling the machining current.
The Electrolytic Rifling process is accurate and reliable which results in consistent part quality.
Any Metal and Alloy. The ECR process quality does not vary with the mechanical strength of the barrel material and is used to rifle many alloys such as Titanium, Stellite, etc. Burr Free Rifling. There are no burrs or tool marks left on the surface.
Electrolytic Rifling (ECR) is an electrochemical process used to produce a wide range of rifling groove configurations in barrels and choke tubes of almost any length or diameter. Our Electrolytic Rifling process can produce constant or gain twist grooves in almost any conductive metal (including high end alloys such as Stellite). The ECR process consists of a machining tool (called a cathode) configured to the desired rifling geometry that is driven through a barrel at a predetermined speed and rotation. Non metallic guides on the tool hold brass conductive groove machining elements a short distance from the bore surface and masks the land surface from machining current. An electrolyte—typically a solution of salt and water—is constantly pumped through the gap between the conductive groove machining elements and the bore surface. As the tool traverses through the barrel, a Direct Current (DC) voltage applied to the tool (–) and the barrel (+), results in a current that conducts through the electrolyte and produces electrochemical material removal of the exposed bore surface immediately adjacent to the conductive c groove machining elements. The groove depth is controlled by the amount of current that flows between the barrel and tool.
Full Selection of Groove Geometry. The ECR process can produce polygonal and many other forms of groove geometry.
ECR is a cost-effective alternative to broaching and hammer forged rifling. Examination of barrels produced by ECR reveals high-quality grooves free from tool marks and tool related stresses (ECR barrels do not require stress-relieving) and accuracy is equal to or better than traditionally-manufactured bores.
from .17 cal up to 40 mm
Achievable results: Feed Rate – 3” to 15” per minute (depending on size, material, groove depth, etc.) Cycle time – as short as 10 to 15 seconds. Gain Twist. The ECR process can produce gain twist as easy as constant twist and progressive depth of grooves is also possible. Current ECR Capabilities: .17 cal to 40 mm
electrolytic rifling solutions
Typical ECR machine for pistols and shorter barrels Extrude Hone Corporation provides many solutions to the firearms industry, including; • rifling of barrels and choke tubes using the Electrolytic process (ECR) • smoothing and blending of barrels and cylinder chambers with Abrasive Flow Machining (AFM) • deburring and deflashing metal components with the Thermal Energy Method (TEM) These unique machining, deburring, and finishing technologies provide increased value to the components through increased strength, accuracy, appearance, and usability. To find out more about these processes and production equipment for your facility or contract services from our facility, contact Extrude Hone.
High-production Abrasive Flow Machining system for polishing gun barrels
The Inside Edge, Extrude Hone, SurfTran, and Dynetics are trademarks and/or service marks of Extrude Hone Corporation and/or its subsidiaries. ©2004 Extrude Hone Corporation firearms solutions 002—feb2004
EXTRUDE HONE Corporation 1 Industry Boulevard P. O. Box 1000 Irwin, PA 15642 USA Phone: 724-863-5900 Fax: 724-863-8759
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the inside edge