If you’ve spent any time researching parts fabrication, chances are good you’ve come across the term “gear chamfering.” This is a step in the finishing process that any professional pulley and gear company should offer. While it might seem optional, it is actually a very important factor in finishing parts to the highest possible quality.
Before we address that, however, let’s take a closer look at gear chamfering: what it is, why we do it, how it’s done, and what tools we use. Once you understand its uses and process, you’ll never want an unchamfered gear again.
What is Gear Chamfering?
Gear chamfering is a process whereby the edges of gears are finished to create smooth transitions between angles. Rather than leaving an abrupt right angle, for instance, a small 45-degree angle may be created between the horizontal and vertical slopes to ease the transition. There are variations on the placement and angle of the transition between two facets, but that’s the general idea.
The gear chamfering process is similar to beveling, in which an angle is cut into the side of the finished edge. However, rather than creating that angle on the entire edge (so that the top of the edge is longer than the bottom, for instance), chamfering only cuts part way through the top. That means a beveled edge is entirely not perpendicular to the face, while the two facets of a chamfered piece of metal are perpendicular – with a transition zone.
As with beveling, chamfering is sometimes confused with deburring. This latter process does not involve cutting an edge between two facets, however. Instead, it means using tools to remove the small bits of metal and imperfections that naturally occur during the machining process. However, there is a natural line of burring where two perpendicular angles meet, which the chamfering process naturally takes care of.
Why Are Gears Chamfered?
There are several purposes of gear chamfering. These include:
- Safety: Sharp edges between perpendicular facets of metal parts are dangerous. They’re more likely to damage other equipment and people. They’re also more likely to break off, which can lead to high-velocity projectiles – also, it goes without saying, unsafe for humans or equipment.
- Protection of parts: The other main purpose of gear chamfering is to protect the gear itself. Sharp edges tend to wear away, which may affect the performance of the part over time. Chamfering smooths edges and makes this less likely, which means the gear will last longer overall.
- Protection of other equipment: Small pieces naturally wear away from sharp perpendicular surfaces. When these fall into machinery, they can degrade the machine itself or other parts, so you’ll also reduce the chances of that happening by making sure your gears are chamfered.
- Financial savings: By replacing parts less (both gears and the equipment in which they’re used), you can see sometimes-dramatic savings.
Note: In many ways, deburring provides the same services – reduction of wear, protection of gears and equipment, and prevention of projectiles. Whatever company you work with to source your gears, make sure they provide both services.
What is the Chamfering Process?
Gears can be chamfered in many places. Depending on your needs, gear chamfering may be ideal for the length of the gear’s tooth or across the top of each tooth, usually both. Gear chamfering is also useful at the base of each tooth, where it transitions to the next. If there is space between the teeth, then you will likely want to chamfer the lateral edges of the gear where it meets the top (circular area).
One can accomplish gear chamfering in many ways, including rolling, contour milling, hobbing, skiving, grinding, and hobbing. Each of these slightly different processes creates a chamfered edge, either with a clearly defined angle between two facet, or with an undefined edge whose goal is simply to wear away sharp edges and remaining burrs. The basic process goes like this:
- The part is molded or machined
- The edges are chamfered using one of the above processes
- Remaining burrs are smoothed away
- The part is ready for use
Gears may be chamfered in dry-cutting environments or using lubricants. However, dry cutting is significantly faster and easier to automate, and so is increasingly gaining ground over other methods.
What Tools Are Used For Chamfering?
Hobbing uses gear-shaped protrusions called “hobs” to create the chamfers on the gear itself. Each hob is dedicated to a tooth of the gear, and they work in tandem to create identically chamfered surfaces on each tooth. This works best for creating large quantities of gears.
You can also accomplish gear chamfering on bevel machines. These contour milling or fly-cutting processes create a seamless chamfered edge, often using carbide tips. In this process, each tooth is chamfered separately. However, due to increases in automated technologies, machines now perform this process (rather than by hand), so individual edges are identical.
Chamfer rolling uses large, round surfaces that roll past a spinning gear, taking off sharp edges and again creating identically chamfered surfaces along the teeth and edges of the gear.
Depending on the company with which you work, they may use different tools or processes. It’s important to work with someone who can explain exactly how they chamfer gears and why this will meet your needs. Make sure before you place any gear order that a) they offer chamfering and b) you understand their process.
Let IPG Meet Your Gear Chamfering Needs
Looking for high-quality chamfered gears for your industry needs? IPG prides itself on providing custom products, built to your standards, that will stand the test of time. We specialize in timing belt pulleys and timing pulley stock, but create a wide range of other parts for our many partners.
From aerospace to agriculture, robotics to automation, packaging to pharma, we’re here to meet your every need. Feel free to get in touch with us to learn more today.