Introduction
Jigs and fixtures are important manufacturing tools in custom parts manufacturing. They usually appear paired together when you hear or see them. So it’s easy to confuse these two terms or some people just treat them as the same thing. In fact, they have some similar functions but jigs and fixtures are not interchangeable and even different in many ways.
What are the differences between jigs and fixtures? What jigs and fixtures are used for? Why jigs and fixtures are important in manufacturing? In this post, you will get all the answers to these questions.
What are jigs and fixtures in manufacturing?
Jigs and fixtures are manufacturing tools. They are applied to accurately make duplicated and interchangeable parts. That means jigs and fixtures are specially designed for large numbers of parts. In this way, people can machine or assemble large numbers of parts identically, and ensure the interchangeability of custom parts. Before going deeper, let us first know what are jigs and fixtures in manufacturing.
What is a jig?
The jig is a kind of auxiliary production device that helps to hold, support and locate the workpiece and guide one or more cutting tools. It works together with the workpiece and cutting tools to perform a specific manufacturing task. In addition, the holding of the workpiece and guiding of the tools are located in true positions. And these positions are relative to each other.
Jigs are often custom parts. They are designed to ensure the accuracy and repeatability of the manufacturing. Jigs are usually fitted with hardened steel bushings. One jig can be repeatedly used and manufacturers get the same outcome with each use.
What are the general types of jigs?
There are 7 different types of jigs for your information. They are Template Jig, Plate Jig, Channel Jig, Diameter Jig, Leaf Jig, Ring Jig and Box Jig. In this section, we will explain it one by one for you.
Template Jig: This jig is the simplest of all the mentioned types. It can be fitted onto the workpiece and it has holes for guiding a cutting tool like a drill.
Plate Jig: Plate jig is Similar to template jig since it is an improvement of the template jig. It has drill bushes based on the mentioned holes.
Channel Jig: The channel jig is also a simple type of jig. It has a channel-like cross-section. The component is fitted within the channel and is located and clamped by rotating the knurled knob. The tool is guided through the drill bush.
Diameter Jig: For cylindrical or spherical workpieces, it’s not easy for us to secure them in normal types of the jig. So diameter jig is designed and used to drill radial holes on such workpieces. The workpieces are placed on the fixed V-block and then clamped by the clamping plate which is also positioning the work. Then the tool is guided through the drill bush.
Angle-plate Jig: Used to prop up the workpiece at an angle to facilitate the drilling of e.g. diagonal holes.
Leaf Jig: A jig with a hinged leaf that can be swung open and closed for faster loading or unloading.
What is a fixture?
According to Wikipedia, a fixture is a work-holding or support device used in manufacturing industry. Fixtures are used to securely locate and support the work, ensuring that all parts produced using the fixture will maintain conformity and interchangeability. Using a fixture improves the economy of production by allowing smooth operation and quick transition from part to part, reducing the requirement for skilled labor by simplifying how workpieces are mounted, and increasing conformity across a production run.
What are the general types of fixtures?
Generally, there are many different types of fixtures If we classify them on a different basis. For example, on the basis of machining operation, there are mainly 5 types of fixtures. They are drilling fixture, boring fixture, turning fixture, milling fixture and grinding fixture. Here let us know more specific information about these fixtures.
Drilling fixture: Drilling fixtures include specially designed holes and bushes. They are sometimes used to take the place of or supplement the jigs.
Boring fixture: CNC boring is a type of CNC machining process. Boring fixtures are used to enlarge holes that are already drilled by CNC drilling.
Turning fixture: Turning fixtures are typically mounted on the machine spindle or a faceplate. They are usually used for more complex lathe-made parts.
Milling fixture: Milling fixtures are typically fixed to the work table with fasteners. These fixtures can help to carry out a variety of milling operations.
Grinding fixture: Grinding fixtures are used to support the workpiece in grinding operations.
In addition, we can also classify the fixtures on the basis of the fixture application and their power sources. Based on the application, there are Universal Fixtures, Special Fixtures, Assembled Fixtures, Modular Fixturesand Combination Fixtures. From the power sources point of view, there are Manual fixtures, Pneumatic fixtures, Hydraulic fixtures, Electric fixtures, Magnetic fixtures and Vacuum fixtures.
Applications of Jigs and Fixtures
Jigs and Fixtures are widely applied due to their advantages. Some of the applications are listed below:
- Mass production of automobile parts.
- Inspection of parts in manufacturing industries in continuous production.
- Cutting the ingots in the steel plant.
- In the refrigeration industry.
- Pump assembling process
- For drilling the flanges and drilling holes to any required angles.
- For multi-spindle machining.
- Jigs applied for mass drilling, reaming and tapping.
- Guiding the tools for machining contours.
- Fixtures applied for milling, mass turning, and grinding operations.
What are the differences between jigs and fixtures?
Differences between Jigs and Fixtures
| Jig | Fixture |
| It is a work-holding device that holds, supports and locates the workpiece and guides the cutting tool for a specific operation. | It is a work-holding device that holds, supports and locates the workpiece for a specific operation but does not guide the cutting tool. |
| Jigs are not clamped to the drill press table unless large diameters are to be drilled. It’s necessary to move the jig to bring one each bush directly under the drill. It is mostly attached to the machine table. | Fixtures should be securely attached to the machine table upon which the work is done. |
| The jigs are special tools particularly in drilling, reaming, tapping and boring operations. It is generally lighter in weight than the fixture. | Fixtures are specific tools used particularly in milling machines, shapers and slotting machines. The fixture is generally heavier than the jig. |
| Gauge blocks are not necessary. Jig feet are used in its construction. | Gauge blocks may be provided for effective handling. In its construction, such feet are not used. |
| Bushes are used in a jig for guiding the cutting tool. | Bushes are not used in fixtures. |
| The jig is widely used on drilling machines. It is specially used for drilling, reaming & boring operations. | The fixture is widely used on milling and grinding machines. It is specially used for milling, turning, grinding operations. |
| Jig designing is complex. Jig cost is more. | Fixture designing is less complex. The fixture cost is less as compared with the jig. |
Why jigs and fixtures are important in manufacturing?
Jigs and fixtures are important in manufacturing. There are some advantages of Jigs and fixtures below for your information:
- They eliminate the setting time required before machining.
- They improve the machining accuracy and also increase the production capacity.
- They require less skilled operation and reduce the production cost.
- They help to increases the utilization of machine and labor.
- They simplify the work handling and increase the quality of production in the industry.
- They enable the quick setting of a tool and the proper positioning of the work.
What are the elements of jigs and fixtures?
It seems that jigs and fixtures are simple in construction, but they are actually made up of several elements. Their main elements are body, locating elements, clamping elements, grinding and setting elements. In this section, please let us describe it one by one below:
Body: The body is a plate, box or frame type structure. In this element, the workpiece would be located. So it should be quite sturdy and rigid.
Locating elements: Locating elements locate the workpiece in a proper position in relation to the cutting tool.
Clamping elements: Clamping elements would firmly secure the workpiece in the located position.
Grinding and setting elements: These elements perform differently in the jig and fixture. Let’s put it this way, they would guide the cutting tools in the jig. But these elements would help in proper tool acting in the fixture.
Positioning elements: These elements include different types of fastening devices. The fastening devices are used in securing the jig or fixture to the machine at the proper position.
Indexing elements: Indexing elements are normally provided in some special cases. To perform machining operations on different surfaces or different locations, many workpieces may have to be indexed to different positions. In such cases, the machinist would incorporate the indexing elements in the jig or fixture.
What raw materials are used to make jigs and fixtures?
Jigs and Fixtures are made of a variety of materials, some of which can be hardened to resist wear. Generally, the following raw materials are used to make jigs and fixtures.
- High speed Steel
- Die steels
- Carbon steels
- Collet steels
- Non shrinking tool steels
- Nickel chrome steels
- High tensile steels
- Mild steel
- Cast Iron
- Nylon and Fiber
- Phospher bronze
How to make jigs and fixtures?
When you consider making jigs and fixtures, there are some different options for you. The point firstly coming up to people’s minds is CNC machining which has been the dominant method for a long time. Nowadays, 3D printing is also a viable alternative.
1. Make jigs and fixtures by CNC machining
CNC machining is the main manufacturing method of jigs and fixtures. Because jigs and fixtures are normally custom designed and built for specific parts. The required quantity is small. And CNC machining is a cost-efficient way to produce custom parts in small quantities. It’s best for robust steel jigs and fixtures with simple geometries. Generally, CNC machined jigs and fixtures have much better strength and accuracy. Therefore, most steel jigs and fixtures are CNC machined.
2. Make jigs and fixtures by 3D printing
3D printing is additive manufacturing. It is an alternative to CNC machining for the rapid manufacturing of jigs and fixtures. Please note 3D printers are efficient in manufacturing one-off items. With 3D printing, the custom jigs and fixtures can have more complex geometries than CNC machined ones. And for plastic jigs and fixtures (via SLS, for example), 3D printing may be a more affordable option instead.
7 Factors to be Considered while Designing a Jig or Fixture
- Jigs and fixtures should be foolproof to prevent misplacement
- Production cost should be less than predicted cost savings
- Location points should be clear (and ideally adjustable) to minimize idle time
- Clamping arrangements should not be complicated
- Jigs and fixtures should be robust enough for use but lightweight enough for easy handling
- Tools should have ample clearance
- There must be adequate space for chip clearance
Conclusion
Jigs and fixtures are important manufacturing tools in custom parts manufacturing. There are some differences between jigs and fixtures. We explained what are jigs and fixtures in this article. And we summarized the differences between jigs and fixtures. Of course, there are some factors you should consider while making jigs and fixtures. Here in this article, we covered all the important points regarding Jigs and Fixtures. It’s worth repeated reading and studying.
