A spline is formed whenever keyways get aligned around the circumference of a hole. These splines can have different numbers of teeth, and they can have a number of different shapes, for instance helical, involute, or straight-sided.
Splines are primarily used to connect driven components in any kind of machines and vehicles, and they are also used in a number of other industries which require precision components in splines.
Spline Broaching Details
Spline cutting is one of the most common of all broaching operations, and it involves using a broach to create a series of ridges or teeth around the opening of a pre-cut hole. This is a very efficient and effective way of creating involute, straight, or serrated splines. The automotive industry, for instance, relies heavily on spline broaches to create driveshaft parts as well as transmission parts, among other automobile components.
The grooves on a spline permit an efficient transfer of torque because they’re capable of locking separate components together. Given the fact that the production of modern automobiles has become extremely sophisticated, extraordinary accuracy from spline broaches is an essential part of component manufacture.
For this reason, a number of suppliers and OEMs have opted to collaborate with tooling companies whom they have implicit trust in so that high-quality spline broaches can be used in the creation of essential automobile parts.
Spline Broaching Rotary Tool
Spline and involute rotary shapes have become extremely popular forms that are used in the connection of driven components in vehicles and in many different types of machines. Some typical examples of these kinds of machines would be the clamps for engine shafts, the gear shifters on motorcycles, and power transmissions. Standard splines can manage power transmissions because of the way contact is ordinarily designed into the teeth.
Because of the tremendous variety of tolerances, custom features, and tooth width which are commonly associated with spline broaches, it is generally not possible to keep huge numbers of spline broaches in stock. That means a good percentage of most spline broaches must be manufactured according to customer specifications, rather than being provided by off-the-shelf tools.
All spline form rotary applications require the use of oversize pilot holes, and these pilot holes leave a small radius on the corners of the inner part of the workpiece. This small radius is acceptable in the finished product because contact actually takes place on the outside of the form rather than on the inside. There is also a small radius on the broach at the inside corner of the spline teeth, but this does not get transferred to the finished product because the oversize pilot hole diameter will have removed the material from this area.
From this, it can be seen that the oversize pilot hole is very important for the creation of separated chips during the broaching process, and for reducing the pressure which is necessary to cut the form itself.
One of the most popular processes for which spline broaching is used is spline cutting. This procedure involves machining external or internal splines (which are the teeth or the ridges) onto gears, shafts, and other components typically associated with transmissions. These will then mesh with grooves in a piece that gets mated to them, and which allows power to be passed on from one component to the other.
This has tremendous application in the automobile industry, and it relies heavily on the use of spline broaches. When spline broaches are not used in the spline cutting process, other processes such as milling, shaping, or hobbing can be used to facilitate spline cutting.
Spline broach sharpening and repair
As previously mentioned, it is advisable to have spline broaches sharpened or repaired rather than discarding them after one or two high production runs. Given that these broaches are often custom-made and are fairly expensive, most purchasers desire to get as much value from a spline broach as possible, and this means repairing them when possible, and sharpening them to keep them as effective as possible.
Regular sharpening is a great way to maximize any tooling investment, as well as to maintain the greatest degree of accuracy during broaching operations. When you have sharper spline broaches, that means much tighter tolerances and far less scrap, and it also will result in less downtime because of adjustments and changeovers.
Sharpening services can actually extend the life of a spline broach by as much as 50%, and it’s a service that is well worth availing yourself of since sharpening can generally be accomplished in 24 hours or less. When it’s necessary to carry out more extensive repairs to a spline broach, this is generally also worth your while, as opposed to the purchase of a brand-new custom-made spline broach.
A damaged spline broach can sometimes be de-burred, straightened, and refitted for measurement and dimensions. Before any spline broach is repaired, it will generally be inspected thoroughly, so that the full extent of any damage is understood, and a reasonable expectation of restoration can be had. A good tooling shop will also take before and after measurements using the spline broach so the effectiveness of any repair work done can be confirmed.