Exploring the Different Types of Grinding Machines

Not to be confused with a milling machine, a grinding machine is a heavy-duty machine that's used to remove material from the surface of a workpiece. While milling machines feature a rotating cutting tool that's placed against a stationary workpiece, a grinding machine features a rotating grinding wheel, which is also placed against a stationary workpiece. There are several different types of grinding machines, however, each of which works in a different way.

 

Bench Grinding Machine

Bench grinding machines are characterized by their bench-like shape. They usually feature two different grinding wheels: one for the removal of material and another for finishing processes. They are called "bench grinding machines" because their grinding wheels are secured to the top of a workbench. As a result, bench grinding machines are easy and convenient for manufacturing workers to use.

 

 

Belt Grinding Machine

Belt grinding machines are characterized by the use of a belt sander. Like other grinding machines, they are designed to remove material from workpieces, thereby making workpieces smaller and with a smoother and more desirable surface. With belt grinding, the belt is coated in an abrasive material, after which it's run against the surface of a workpiece until the desired results are achieved. Belt grinding is most commonly performed on metal workpieces, though it supports workpieces made of other materials as well.

 

Surface Grinding Machine

A third type of grinding machine is a surface grinding machine. Surface grinding machines are unique because they feature an adjustable head. The head on a surface grinding machine can be lowered down to the workpiece. Once lowered, the head can then rotate back and forth under the machine's grinding wheel.

While belt grinding machines are typically used for finishing processes, surface grinding machines are most commonly used for material removal. When compared to other grinding machines, surface grinding machines are able to remove significant amounts of material, making them desirable for such applications.

 

Gear Grinding Machine

 

 

Gear grinding machines are designed specifically for the removal of material from shafts. Using grinding wheels, they can grind the center of a shaft with extreme precision.

 

Die Grinding Machine

A smaller and more basic type of grinding machine is a die grinding machine. Unlike the other machines listed here, die grinding machines are handheld. They are connected to an air compressor, which works to power the machine's grinding wheel. If an air compressor isn't used, the die grinding machine will likely receive power from an electric motor.

 

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Why Spiral Bevel Gears Are So Widely Used in High Load Applications?

Bevel gears play a key part in power transmission roles, being used in helicopters, power generation machines and more; essentially, instances when power musty be transferred across two non-parallel axes. A spiral bevel gear is one which has helical teeth. Like the helical gear, using a spiral bevel gear brings the benefit of less vibration and noise. Spiral bevel gears are used often in vehicle transmissions as drive from the driveshaft must be turned 90 degrees to drive the wheels.

 

Despite the more complicated manufacturing processes that are required to make spiral bevel gears and that two interfacing spiral gears are usually replaced as a set, spiral bevel gears are the gear of choice in high load situations.

 

Another type of spiral bevel gear is the hypoid gear. It is distinct from the spiral bevel gear in that the axis of the gear does not intersect with the axis of the meshing gear. Hypoid gears amplify the benefits of the spiral bevel gear. Since multiple teeth mesh together at the same time, they are able to handle larger loads, while retaining the other useful characteristics of spiral bevel gears.

 

 

Some benefits of using spiral bevel gears:

 

ㆍReduced heat - Spiral bevel gears produce less heat than bevel gears in similar conditions. It makes their use desirable in situations where heat build-up can adversely affect operation of nearby components or safety.

 

ㆍHigh torque - Spiral bevel gears have a relatively larger tooth area, and one which is in mesh. As such they are perfect for high torque and high speed application. It is also one of the reasons why they are used in large trucks.

 

ㆍOffset - With no offset, the teeth of spiral bevel gears slide little between each other. This increases the effectiveness and efficiency of the gear and reduces heat generation.

 

ㆍSmoothness - Abrupt power delivery has the potential to both damage machinery as well as compromise safety; which is why spiral bevel gears with their smooth engagement are preferred when gear engagement should not upset drive.

 

 

Focusing on improving efficiency in the gear processing industry

 

Do you want to purchase a CNC Gear Cutting Machine for your gear manufacturing plant to solve the problem that the processing speed and efficiency of the old Gear Cutting Machine cannot meet the current production requirements? Our CNC Gear Cutting Machine can help customers replace 3-5 old Gear Cutting Machines to greatly improve productivity and save labor costs. Geepro Machinery's CNC Gear Cutting Machine is currently one of the most cost effective and professional hobbing machines you can find in China.

What You Should Know about Spline Milling?

 

Horizontal Spline Milling Machine

 

What Is a Spline?

Typically made of stainless steel, carbon steel, alloy steel, or aluminum alloy, a spline is a shaft that features a series of equally spaced teeth that can be slotted into a mating piece for the purposes of transmitting torque or serving as a means of anti-rotation. They can be internal or external and comprise a variety of tooth shapes depending on function. Rotary devices such as gears can also be fitted onto the spline to serve a variety of functions. Splines are primarily found in rotating mechanisms such as drive shafts.

A spline is commonly taken to mean a series of grooves cut in a shaft equally spaced around its circumference. A male spline is designed to fit into a female spline.

This has several advantages. There can be negligible play rotationally between the two shafts. This is probably the best method of joining two shafts so as to maximise the power that can be carried from one to the other. The use of splines also allows for one shaft to slide longitudinally against the other.

Examples

ㆍSplines are used in transmission systems of cars where, due to the up/down movement of the wheels the distance between two points in the transmission will vary.

ㆍSplines are used to hold handles on leadscrews

ㆍSplines are used in gear boxes because the gears can be slid along a spline in order to change gear.

 

What Is Spline Milling?

Spline milling is one of the processes of machining grooves into a chunk of raw material to create the teeth of a spline.

The process of spline milling:

ㆍThe chunk of raw material that will become the shaft of the spline is fitted into the indexing fixture of the milling equipment.

ㆍSide milling cutters are mounted onto the arbor of the fitting equipment with a spacer and shims inserted between them, depending on the desired width of the spline.

ㆍThe arbor is mounted onto the spindle of the milling machine, and the cutters are centered over the raw material that will become the shaft of the spline.

ㆍThe splines are cut into the shaft by a process called straddle milling. The indexing fixture holds the shaft of the spline steady while a groove is cut by the rotating milling cutters along its length. Depending on the depth of the spline, multiple passes along the same groove may be needed. Multiple passes also help to guarantee uniformity throughout the spline.

 

How to Cut Splines on a Shaft?

Spline milling is one of several processes of spline cutting, which is the process of machining teeth into internal or external splines. Spline cutting can be used to create shafts, gears, and other mechanical components that mesh into one another and allow power to be transferred throughout a mechanical system.

There are four main spline cutting techniques:

ㆍBroaching

ㆍHobbing

ㆍMilling

ㆍShaping

 

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The Difference Between Gear Shaping and Gear Hobbing

 

CNC Gear Hobbing Machine

 

It is one thing to look at what gears do and how they work, but it is another thing to look deeper at how exactly gears are made and constructed. Today, that is exactly what we are going to do. Gear shaping and gear hobbing are both common ways to create gears.

Just like any sheet metal is fabricated to form the right mold, shape, size, and so on, gear manufacturing has certain machining processes such as shaping, hobbing, and so on. Gears are required to be set in motion, rotate, and raise the speed of any machine, industrial equipment, automobiles, and so on. So, how are these gears made? CNC machining methods are widely applied in the last stages of gear manufacturing, and milling, casting, forging, and so on are some of the methods used. Gear shaping and hobbing are also two important processes of gear manufacturing. The process to be used depends on gear specifications such as the shape and size required, among other parameters. This post discusses and compares the two methods- gear shaping and gear hobbing.

 

What is Gear Shaping?

 

This is a convenient and versatile method of gear cutting. Truthfully, this is one of the most popular production choices in gear manufacturing. This process is done by using a specific machine to create the teeth of the gear. Shaping is almost a subset of the milling process. This process helps form the gear teeth with the help of a rotating cutter tool, wherein its axis is parallel to that of the gear. The rotating speed and velocity of the cutter must match with the gear blank for teeth formation. A train of gears helps achieve the relative motion between the cutter shaft and the gear blank. Here the cutting may happen either at a downward or upward stroke. This is suitable for shaping of gears closely located toward the flanges or other obtrusive surfaces. This is widely used process for making internal and external gears. High dimensional accuracy is one of the major benefits of the shaping process apart from its cost-effective tools. After this process, surface finishing may be required depending upon the application.

 

What is Gear Hobbing?

 

Cutting splines, sprockets, and gear cutting, in general, is done using this process. Gear hobbing uses a special type of milling machine that allows for the teeth or splines to be progressively cut into the material by a series of cuts made by the tool this tool is called the hob.

Hobbing is a method also used for teeth formation in gear manufacturing. This teeth formation is done on the gear blank with the help of a hob on CNC gear hobbing machines. This machine is a type of special milling equipment. It could be an index hob or a master hob. There are various other types of hobs such as spline, spur, helical, chamfer, roller chain sprocket, straight side, and so on. The gear blank and the hob rotate simultaneously and produce continuous cuts on the blank gear which gives the required depth to the teeth. As mentioned above, the machining processes chosen are largely based on the shape and size of the gear. Likewise, hobbing is applicable for gear shapes such as helical, straight bevel, crowned, worm, face, and chamfering. Also, it is suitable for medium to high production volume. This cost-effective yet efficient process is useful to make several parts irrespective of the quantity.

 

Accuracy

There are benefits that come with each gear production. For example, the movement accuracy of gear hobbing is high. While that is not the case for gear shaping, gear shaping is more accurate in the surface finish. This is because the mechanic gear shaper is more complex. When comparing the two even further, the manufacturing process is simpler and easier to manufacture more accurately.

 

Productivity

In most scenarios, gear hobbing is more productive than gear shaping. This is because, in gear hobbing, there is not a large number of redundant metals. There is an instance, however, where gear shaping can compete with gear hobbing in terms of productivity. That scenario occurs when the gear is smaller in size and the teeth have a large and small-tooth width.

Looking at the accuracy and productivity allows you to better see the difference between gear shaping and gear hobbing. These two gear producing systems are alike, yet have their differences. Hopefully, this explanation gives you a better foundation to understand that.

 

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A Short History of Gears and Where Gear Manufacturing Is Today

 

CNC Gear Hobbing Machine

 

Gears were a logical continuation of the invention of the wheel. That gears are called the biggest invention after the wheel is not unthinkable. In any case, we can't live a normal day in our lives without gears: without gears no production, no energy, and no transport. The use of gears is so obvious that we never dwell on where they come from. In this article, out of respect for the gear, we will detail the interesting history.

Gears are such a common simple machine that it's hard to think there was ever a time before they were used. But just like the wheel or any other man-made invention, gears had a starting point and a course of evolution over thousands of years that have led to their current state today.

 

Gears Are Actually a Natural Product

baby-lantaarnachtigeBut were the ancient Greeks really the inventors/ Research biologists at the University of Cambridge are certain that the ancient Greeks were not the first. The three-millimeters small bug Issus coleopterans, a lantern bearer like those in Europe and North Africa, uses this mechanism already for millions of years. The gear is not a human invention of the ancient Greeks, but a mechanism that arose through evolution in nature.

Nymphs of the insect have an ingenious system of gears that causes their rear legs “click” together and at the same time run away and then jump forward. Using electron microscopy and high-speed cameras biologists captured the precise operation of the insects' mechanisms. It is known so far as the first working gear system from nature.

>> Shop for our CNC gear hobbing machines here

 

 

CNC 5 Axis High Speed Gear Hobbing Machine

 

First gear was developed

It's hard to say when the first gear was developed, but some of our earliest records point back to around 2700 BCE, with gears featuring in a device called the Chinese South-Pointing Chariot. This chariot featured a gear that would automatically turn a directional arrow so it always pointed south, no matter which way the chariot itself turned. It was one of the earliest ways to gauge cardinal directions without the use of magnets.

Gears were also formally mentioned by Aristotle in some of his writings around 400 BCE. He described gears as capable of reversing the direction of momentum, and we've found artifacts dating back almost this far with gears as central components, such as in wheels and rudimentary clocks. Gears also featured prominently in inventive sketches by Leonardo da Vinci, circa 1500.

By the 1600s, scientists and engineers were figuring out mathematical concepts like velocity ratios and involute curves, allowing them to use gears for more complex and more heavy-duty tasks, but it wasn't until the 1800s when the first form cutters and gear hobbing machines emerged, allowing gears to be mass-produced and refined in terms of form and performance.

The next major step forward was in 1897 when Herman Pfauter invented the machine that could cut both traditional “spur” gears and helical gears, driving production further forward. Over the next hundred years or so, the development of NC hobbing machines and full 6-axis machines would start to perfect how we design, cut, and manufacture gears.

 

Today Gear Manufacturing

Today, gear manufacturers primarily use CNC machines to cut gears from blanks, and our level of precision is driven by sophisticated design software and advanced engineering theories. Modern gears are exceptional pieces of work, capable of lasting centuries (or longer, if cared for properly), and technology continues to advance to bring us better ways of producing gears.

 

If you are interested in CNC Gear Hobbing Machine or need a quote for a large project, be sure to contact us today!

Difference Between Gear Milling and Gear Hobbing

 

CNC Gear Hobbing Machine

 

Gear is a vital component for rotating machines, with teeth mesh with another toothed part to transmit torque. How gears are made? Other than casting, forging, CNC machining can be applied to achieve the final shapes, dimensions, and surface finish of a gear. Here we introduce and compare two gear manufacturing methods – gear milling vs gear hobbing, what are the differences between them?

 

What is Gear Milling?

 

Gear milling is a common CNC milling operation and gear-cutting process of creating a gear. It can be operated either after or instead of forming processes including casting, forging, and extruding. Gears are usually made from metal, plastic, and wood. Many metal and plastic gears made by die-casting, injection molding, or additive manufacturing may not require cutting. For coarse-pitch gears, the generative gear milling technology can improve efficiency, expand the pitch capacity of the machine, reduce cutter cost, and may decrease the machining times.

 

What Cutter Used in Gear Milling?

 

The gear can be cut on a milling machine or jig grinder utilizing a gear cutter and indexing head or rotary table, the quantity of gear cutter is determined by tooth count of the gear required. Various types of cutters can be used for producing gears, for example, the rack shaper, with six to twelve teeth, straight and move in a direction tangent to the gear. The cutter has to move back to the beginning position for the new round cut.

 

What is Gear Hobbing?

 

Gear hobbing is also a gear manufacturing method to cut teeth into the blank with a hob like an index hob and master hob on CNC gear hobbing machines. The hob and gear blank rotate at the same time in a mesh and cut the teeth by continuous cut, the rotating hob is fed inward until achieving proper depth, then work for the entire gear. Gear hobbing is a great choice for medium to high volume production runs. The hobbing features for gears including straight, helical, straight bevel, face, crowned, worm, and chamfering.

 

How to differentiate gear hobbing and gear milling?

 

1. The way gear teeth are produced

 

In gear milling, a single tooth spacing or gap between gear teeth will be created by a rotating multi-edge cutter at a time, the cross-section of generated teeth is similar to that of the cutter. In gear hobbing, the gear teeth are progressively produced by a series of cuts with a hob. So the hob cuts several gaps simultaneously.

 

Hobbing Machine

 

2. Cutter

 

Gear milling uses a rotating form cutter, when each tooth space is cut, the cutter will return to the starting point and gear blanks are indexed for next cutting process; gear hobbing uses a helical hob cutter, the hob and the workpiece are both rotating constantly when the hob is fed across the face width of the blank.

 

3. The number of teeth cut in one time

 

Each cutter in gear milling is designed to cut a range of tooth numbers, while in gear hobbing, both the hob and gear blank rotate continuously as in two gears meshing until all teeth are cut.

 

4. Price of tool

 

Generally, the gear milling cutting tool is cheaper than that of hobbing, but the productivity of gear hobbing may be higher.

 

5. Application

 

Gear hobbing is more often used for high production runs, and gear milling is a low production process.

 

6. Others

 

– Gear milling requires deburring

– Gear milling is often used when other generating processes are unavailable.

 

If you’re eager to learn more about the gear hobbing machine, or if you have an order you’re ready to place, contact GEEPRO today! We’ll have a quote back to you in less than 24 hours.

The 5 Advantages of Gear Hobbing

Gear manufacturing gives us lots of options. There are a handful of different processes we can use to make dozens of different gear types from dozens of different materials. Accordingly, when we choose a gear manufacturing method, it’s because it’s the best one for the job.

Gear hobbing is just one way we can manufacture gears. It relies on a special form milling machine with a tool known as a hob, which generates the teeth in both gears and splines.

 

CNC 5 Axis High Speed Gear Hobbing Machine

 

So What Are The Advantages of This Process?

1. Speed. Some gear manufacturing processes take a long time, but gear hobbing is relatively fast. The machine is simple, so it doesn’t require as much operational attention, and for some gears, we can stack multiple units to hob them all at the same time.

2. Flexibility. There’s more than one type of hob—and more than one type of hobbing machine. There are countless variations that cater to specialized applications, so you always have options available.

3. Applications. While hobbing is often used for spur gears, the process can be used for a variety of other gears, such as cycloid gears, helical gears, worm gears, ratchets, splines, and sprockets (as long as you have the right tools for the job).

4. Related processes. One of hobbing’s only weaknesses is that it does not work for internal gears (with inward-facing teeth). However, there’s a related process called shaping that can be used instead—with all the same advantages of hobbing.

5. Precision. That said, not just anyone can operate a hobbing machine. With the right expertise, hobbing can be highly precise, resulting in high quality gears.

 

The Perks of Precision in Gear Hobbing

In the world of gear manufacturing, precision makes all the difference. Every stage of the process needs attention, from the initial design of the gears in a given system, to the manufacturing and finishing equipment used to create new gears, to the engineers and operators in charge of overseeing the final production of each gear.

 

Why Precision is So Important?

Better structural integrity. Gears that have been designed professionally, with keen attention to detail, tend to have better structural integrity. Those that have no manufacturing or design flaws, will hold up longer over time.

A better fit. Most gears end up in machines that require a perfect or near-perfect fit. If the gear teeth are out of position by any amount, it will compromise the efficiency of the machine and might lead to gear failure.

Less noise. A gear poorly manufactured gear may also result in more noise in the final application.

Less wear and tear. Finally, gears with even the tiniest imperfections can lead to increased wear and tear; if they don’t fit properly or they have existing defects, those defects will only grow over time. This leads to a lower life expectancy for your gear, and in some cases, an entire failure of your machine. This is especially noteworthy because of how subtle the imperfections can be—practically invisible to the naked eye.

 

If you’re eager to learn more about the gear hobbing machine, or if you have an order you’re ready to place, contact GEEPRO today! We’ll have a quote back to you in less than 24 hours.