Hello friends, Today I am talking about Jig and Fixture, Which is widely used in mass production for holding the job and also for guiding the tool.
In this topic firstly we will know about what is jig and fixture and then know various types of jig and fixture and their materials, fundamental principle, etc.
The terms "jig" and "fixture" are sometimes referred to as synonyms, with the two terms sometimes being used together as "jig fixtures".
Although both jig and fixture are used in the mass production process, functionally the two are different tools that will differentiate further in detail.
So, stay connected with us to know what is difference between jig and fixture.
What is Jig?
A jig is a device that holds and locates the work, and guides and controls one or more cutting tools.
The task is to hold and guide the tool in such a way that they are positioned in the correct position with respect to each other.
What is a Fixture?
A fixture is a type of device used to hold and locate a workpiece at the time of inspection or for a manufacturing operation.
The fixtures do not guide the tool.
Advantages of Using Jig and Fixture
There are so many advantages which are as follows:
- Markings and settings are not required
- Uniform parts can be made.
- The production volume increases due to rapid clamping and releasing.
- Reduced operator fatigue.
Fundamental Principles of Jig and Fixture
The following pointers should be kept in mind when designing jigs and fixtures.
- Location loading and unloading
- Clamping
- Motion saving
- Removing machined parts
- Strength
- Guidance of the tool.
Types of Jig
The jig is a device used in mass production to hold the job in position and guide the tool.
It is mostly used for drilling or boring.
The jig is often used with bushings made of tool steel to guide the tool.
According to the work they are found in different types which are as follows:
- Template Jig
- Plate Jig
- Angle Plate Jig
- Channel Jig
- Leaf Jig
- Indexing Jig
Template Jig
This is the simplest type of jig that can be produced at a very low cost.
Can be with or without sleeves or bushings.
If no bushings are used, the entire jig plate is hardened.
In using this, a clamp is fixed over work or without a clamp in work.
Plate Jig
This jig is similar to a template jig but is found in the plate jig belt in the clamp to hold the job.
It can also be with or without bushings.
Angle Plate Jig
This jig is often used for jobs that are machined in right angles with its mounting locator.
If the angle of machining is beyond 90° a modified angle plate jig is used.
Channel Jig
This is a box-type jig whose size is very simple.
The job is held between the two sides, and the operation is performed from the third side.
Leaf Jig
This jig is found as a small size box jig with low or latched hinged limbs, which allows easy loading and unloading of jobs.
Indexing Jig
This jig is mostly used to make holes in precision spaces or to perform other machining operations around the job.
Large size indexing jigs are called rotary jigs.
Types of Fixture
A fixture is a device that is used to hold the jobs only.
According to work, they are found in different types:
- Plate Fixture
- Angle Plate Fixture
- Indexing Fixture
- Vice - Jaw Fixture
Plate Fixture
It is a simple type of fixer that is usually made of a flat plate.
Various clamps and locators are used with this fixture to hold and locate the job.
Angle Plate Fixture
This fixture is mostly used to hold a job that is machined in right angles with its locator.
Modified angle plate fixtures are used when machining is required at any angle other than 90 °.
Indexing Fixture
This fixture is similar to the indexing jig used for machining the job in equal spaces.
Vice - Jaw Fixture
These fixtures are mostly used for machining small jobs.
They are shaped according to the job and are replaced by standard jaw plates of vice.
Supporting and Locating in Jig and Fixture
The following signals should be kept in mind while locating and supporting jigs and fixtures.
- Referencing
- Position of Locators
Referencing
If the job is brought to the correct position with respect to the tool to perform machining operations in precision, it is called referencing.
Position of Locators
While positioning locators, the machined surface of the job machine should always be in contact with the locator as far as possible.
If the locator is prone to any blockage due to chips, etc., then the locators should be relieved.
Materials for Jig and Fixture
Materials used for jigs and fixtures are divided into the following three classes:
- Ferrous Materials
- Non-ferrous Materials
- Non-metallic Materials
Ferrous Materials
Ferrous materials are often used to make jigs and fixtures.
Usually, the following ferrous materials are used
- Cast Iron
- Carbon steel
- Alloy Steel
- Tool Steel
Cast Iron
It is used to make jigs and fixtures because it is cheaper and takes less time to fabricate.
Carbon steel
The following carbon steel is often used to make jigs and fixtures:
- Low carbon steel
- Medium Carbon Steel
- High Carbon Steel
Low carbon steel
It is mostly used to make base plates or supports of jigs and fixtures.
Medium Carbon Steel
High Carbon Steel
It is often used to make bushings, and locators, wear pads, etc. For jigs and fixtures.
Alloy Steel
It is not used mostly for making jigs and fixtures, but it can be used for certain tasks.
Tool Steel
This steel can be made in the right standard.
It is used in jigs and fixtures to form parts that require high wear resistance.
Often jig bushings are made from this steel.
Non-Ferrous Materials
Non-ferrous materials are often used to make jigs and fixtures these are following:
- Aluminum
- Magnesium
- Bismuth
Aluminum
It is mostly used for jig or fixtures.
Because it is light in weight and has good machinability.
It does not require a heat treatment process to increase its hardness.
Magnesium
It is also used to make jigs or fixers because it is lighter in weight and can be machined easily than aluminum and steel.
Bismuth
It is a low melting alloy used to make special holding devices for jigs and fixtures such as Nest or Vice Joss.
Non-Metallic Materials
Non-metallic materials are also used to make jigs and fixtures.
Jigs or fixtures used for limited production can be made with these materials better, cheaper, and quicker.
Often the following Non-metallic materials are used:
- Urethane
- Wood
- Epoxy and Plastic Resin
Urethane
It is often used for secondary clamping.
A block made of urethane is placed between the job and the clamp.
While clamping, it holds the part well and does not allow the job surface to deteriorate.
Wood
It is used for jigs and fixtures that do not require precision. It is used to make special bushings and inserts.
The bushings made of this material have external grooves so that when the bushings are pressed or pasted into the jig or fixtures, the grip is very good.
Epoxy and Plastic Resin
It is mostly used for making special clamps for jigs or fixtures.
Nest and jaws are often made from this material, which is toughed and cheap. Resins are light in weight, strong toughed, and often deformable.
Difference Between Jig and Fixture
| Jig | Fixture |
|---|---|
| A jig is a work holding device that holds, supports, and locates the workpiece and also guides the cutting tool to perform a specific operation. | A fixture is a work holding device that holds, supports, and locates the workpiece for a specific operation but does not guide the cutting tools. |
| The main objective of jigs is to provide repeatability, accuracy, and interchangeability in manufacturing products. | The main objective of fixtures is to create a secure mounting point for a workpiece, allowing support during operation and increasing accuracy, precision, reliability, and interchangeability in manufacturing products. |
| Jig guides the workpiece in the machining process | Fixtures only hold the workpieces securely. |
| The jigs are light in construction for quick handling and clamping. | Fixtures are heavy in construction and are often bolted rigidly to the machine table. |
| Gauge blocks are not required. | Gauge blocks can be provided in the fixture for effective handling. |
| Jigs are used in unidimensional machining such as drilling, reaming, counter boring, tapping, etc. | Fixtures are used in multidimensional machining such as milling, planing, slotting, turning, grinding and shaping tools, etc. It is also used for assembling and inspection works. |
| Jigs are not usually fixed to the table and often come in portable and compact variants. | The fixtures are mounted on the table to provide proper support to the workpiece. |
| Its cost is more. | Its cost is less as compared to jig. |
| The jig uses mostly standard parts like bushings, screws, etc. | Fixtures are made from gray cast iron or steel parts by welding or bolting. |
| The jig comes into contact with the cutting tool to perform the task. It precisely determines the angle and position for the equipment to function. | The fixture never comes into contact with the cutting tool. |
| Their design is complicated. | Designing fixtures is less complicated than jigs. |
So, friends here I discussed what is Jig and Fixture are and their types as well also know in detail what is difference between jig and fixture is.
I hope you like this topic if any queries then you can ask me through a comment.
Thank You.
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