Contrary to what appears to be popular belief, 5-axis CNC gear manufacturing is not limited to milling with end mill, ball mill or CoSIMT (Conical Side Milling Tool — it is the generic form of the Sandvik InvoMill and Gleason UpGear tools.) tools, where throughput is too low to prevent production at any significant level. Straight and spiral bevel gear manufacturing on 5-axis CNC machines using face mill cutters provides essentially the same throughput as conventional gear cutting machines — with added benefits.
Free form milling of gears becomes more and more important as a flexible machining process for gears. Reasons for that are high degrees of freedom as the usage of universal tool geometry and machine tools is possible. This allows flexible machining of various gear types and sizes with one manufacturing system. This paper deals with manufacturing, quality and performance of gears made by free form milling. The focus is set on specific process properties of the parts. The potential of free form milling is investigated in cutting tests of a common standard gear. The component properties are analyzed and flank load-carrying capacity of the gears is derived by running trials on back-to-back test benches. Hereby the characteristics of gears made by free form milling and capability in comparison with conventionally manufactured gears will be shown.
Exciting new machine, cutting tool and software technologies are compelling
many manufacturers to take a fresh look at producing their larger gears on machining centers. They're faster than ever, more flexible, easy to operate, highly affordable - and for any type of gear.
What is the best tooling to use when hard milling a gear tooth on a 5-axis machining center? And what makes it the best? We have just bought a DMG Mori mono-block and are not getting the finishes at the cycle times we require.
Developed here is a new method to automatically find the optimal topological modification from the predetermined measurement grid points for bevel gears. Employing this method
enables the duplication of any flank form of a bevel gear given by the measurement points and the creation of a 3-D model for CAM machining in a very short time. This method not only
allows the user to model existing flank forms into 3-D models, but also can be applied for various other purposes, such as compensating for hardening distortions and manufacturing deviations which are very important issues but not yet solved in the practical milling process.
In this article, the authors calculated the numerical coordinates on the tooth surfaces of spiral bevel gears and then modeled the tooth profiles using a 3-D CAD system. They then manufactured the
large-sized spiral bevel gears based on a CAM process using multi-axis control and multi-tasking machine tooling. The
real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected
using the measured coordinates. Moreover, the gears were meshed with each other and the tooth contact patterns were investigated. As a result, the validity of this manufacturing method was confirmed.
