In this article, you’ll learn what is Honing? and how honing machine works? Types of honing machines with their working principle, operations, and more.
And also download the PDF file of this article at the end.
What is Honing Process?
Honing is a process that is performed on a job to make it proper size by removing marks and roughness left on a job by the cutting tools. The Honing machine is used to make internal combustion engines, air-bearing spindles, finishing of cylinders and gears.
There are several types of hones, but all include one or more abrasive stones that are under pressure against the surface they are working on. Special honing attachments are fixed for honing.
A flexible electrical drilling machine and a honing stone are used. Honing stone is made of aluminum oxide, silicon carbide, or diamond dust, which are selected according to the metal of the job. The honing stones are of different sizes and shapes such as round, square, or triangular.
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Selection of Honing Stones
The selection of honing stones depends upon the following consideration:
- The metal of the job is to be given honing treatment.
- The hardness of the job.
- Type of coolant to be used for the job.
- The quantum of extra material left on the job.
- Whether rough, medium, or fine honing is required.
- The type of surface finishing required for the job.
Honing tool is almost similar to a large-size adjustable reamer called a hone. Three, four, five, or six honing stones are fixed in it. The number of honing stones is determined according to the job.
These stones can be easily fixed or removed. These can be stretched or shrank to a limited extent. It can also be adjusted according to the job. This attachment can be turned up and down in a flexible drill machine.
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Types of Honing Processes
Following are honing processes, which are described below:
- Manual Honing
- Machine Honing
#1 Manual Honing
In such a type of honing, the hone revolves continuously and the workpiece is moved manually back and forth. This process is rarely used in industries.
#2 Machine Honing
In such a type of honing process, the hone combined rotary and reciprocating motion and reduced manual interaction called machine honing. This process can be classified into two types according to the type of machine.
Types of Honing Machine
Following are the two types of honing machines:
- Horizontal Honing
- and Vertical Honing
#1 Horizontal Honing Machine
In the horizontal honing machine, the longer-size jobs are easily machined. These machines carry a horizontal axis with a honing tool. On some machines, the workpiece is placed on the table and it rotates back and forth.
The hone rotates about its axis and also oscillates slightly. This oscillation movement is controlled either mechanically or hydraulically. In some cases, the honing tool is fixed on a travel head that is rotated and moved simultaneously.
In this machine, the workpiece is placed in a horizontal position and revolved around its axis. This type of machine is used for very long workpieces. The correct machining size is tested with the help of a gauge. Some machines have two spindles.
#2 Vertical Honing Machine
In this type of machining, the tool, as well as the workpiece, are placed vertically. These machines are available in more spindle types.
The workpiece is stationary and the tool rotates. Fixtures are in place to put the workpiece in the exact position. Hydraulic drives exist in modern types of machinery to control tools and workpieces.
Vertical honing machines are generally preferred for small jobs. These machines are mostly used compared to horizontal honing machines.
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Hone and Honing Tools
Following are the different honing tools:
- Flexible hones
- Sharpening stones
- Honing sticks
- Hand hones
#1 Flexible Hones
These are hairbrushes used as honing tools. These include abrasive beads joined to the bristle ends. They are used to smooth the surface or to refine both the internal and external surfaces of the metal. This type of honing tool is also known as flex turning tools.
#2 Sharpening Stones
The sharpening stone is a common abrasive stone used to sharpen the edges or surface of a metal.
#3 Honing Sticks
It is used to give a finishing touch to the inner bores. In this type of tool, the diameter of the wheels used for abrading on the metal surface is shorter. It is mostly used in such cases for grinding or finishing an inner surface of a metal’s inner diameter.
#4 Hand Hones
The hand hones are also known as diamond hones. These honing tools are created to hone the edges of ground-cutting tools. This is an off-hand technique used in the honing process.
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Types of Honing Abrasive
The following three kinds of abrasive honing stones are used in honing:
- Rough hone stone
- Medium hone stone
- Fine hone stone
#1 Rough Hone Stone
In order to remove the boring signs left by the boring tool after the normal boring, a rough stone is used.
#2 Medium Hone Stone
In order to do medium finishing, this type of hone stone is done.
#3 Fine Hone Stone
For finishing on the surface of various jobs, particularly on automobile cylinders, fine hone stone is used.
Features of Honing Tool
The abrasive grain type and grit size are necessary considerations when selecting hones and tools. Options for abrasive grains include:
- Aluminum oxide
- Boron carbide
- Silicon carbide
- Emery or Crocus
- Synthetic diamond
- Cubic boron nitride (CBM)
- Tungsten carbide
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To clean metal by removing roughness from its hole or bore made by a honing tool is called honing operation. This operation is conducted in the following two ways:
- Dry honing
- Wet honing
#1 Dry Honing
Jobs that require rough finishing or from which more extra metal is to be removed, are given dry honing treatment. In other words, coolant is not used. Stones used for the dry honing are of 90 to 120 abrasive grain.
#2 Wet Honing
Jobs that require fine finishing or from which less extra metal is to be removed are given wet honing treatment. Honing stone of 120 to 130 abrasive grain is used and polishing suitable coolant is also used. But with this type of honing metal can be cut only to the extent of 0.005″.
Why Use Honing Process?
It is a cost-effective machining process. Following are the reasons for using the honing process,
- The honing process is used to remove stocks as it is a fast process.
- Used for bore tolerance and bore polishing.
- Honing is used for finishing bores on almost any type of material such as sprayed coatings, CGI, Ceramics, etc.
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Advantages of Honing Process
By honing we get the following advantages:
- There is no friction in the job.
- It makes the job rotate easily.
- The surface becomes plain, which is not possible by any other operation.
- It can keep the original bore centerline.
- Any type of metal can be finished regardless of its hardness.
- High accuracy can be achieved.
Difference Between Honing and Lapping
Following are the 6 difference between honing and lapping:
|1. The size of the job is set right after removing the marks of machining through honing.||1. By lapping surface of the job is made smooth like that of glass or polished surface.|
|2. It is certain that there is a difference in the size of the job after the honing operation is carried.||2. There is not much difference in the size of the job after lapping.|
|3. For honing operation, honing attachment and flexible drill machine is essential.||3. Lapping can be done through the medium of hands.|
|4. For the honing operation, both adequate coolant and lubricant are needed.||4. For lapping, oil mixed in the paste is enough.|
|5. In the honing operation, honing attachment is to be revolved on the job speedily in one direction alone.||5. In the lapping operation, the gap is moved at slow speed or rubbed.|
|6. Honing stone is used for honing.||6. The paste made with abrasive and oil is used for lapping.|
As you know now, honing is an abrasive machining process that creates an exact surface on a workpiece by rubbing an abrasive grinding stone along with a controlled path against it.
As we have already discussed all the different “types of Honing Machines” with their working but still if you have any questions you can ask in the comments. If you liked this article then please share it with your friends.
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