Everything You Should Know About Jigs And Fixtures

Jigs and fixtures are two terms that often tend to be easily confused. In general, jigs refer to tools that hold or guide a cutting tool while it performs a repetitive operation. However, fixtures do not responsible for guiding a cutting tool but for keeping a workpiece steady in a fixed position or orientation. Both are essential tools in precision manufacturing. They can provide a stable and safe mounting point to support a workpiece, enhancing the finished parts’ accuracy, precision, dependability, and interchangeability. Using jigs and fixtures also helps manufacturers reduce errors, increase productivity, and reduce costs.

This article will explore jigs and fixtures, including their types, elements, benefits, applications, and differences. In addition, an introduction to how to manufacture jigs and fixtures will be put in the article. Read on and learn more information about jigs and fixtures.

What are Jigs?

Jigs are a tool that mainly helps control or guide the movement of a cutting tool like a drill and occasionally holds the workpiece simultaneously. Since their primary function is guiding and directing cutting tools, jigs are most typically employed for manual tasks, such as machining and drilling. In many circumstances, jigs are important for manufacturing because they help guarantee that parts are created to exact and repeatable standards.

A common jig use is drill bushings. They can aid with a drill’s proper positioning and angle as it passes through a workpiece. Therefore, a drill bushing leads to superior quality work and may also boost efficiency in production.

It should be noted that jigs are not necessary on CNC machines. These machines provide micron-level precision without assistance because the tool path is programmed digitally and stored in the machine’s memory. However, jigs are still utilized in smaller machine shops for help in manually machining specialized or customized parts and one-offs.

Types of Jigs

Jigs are widely available tools in CNC machining and come in various types. The following are some frequent types of jigs used in machining processes.

Template Jig

The template jig is simple and ideal due to its accuracy. The plate has two holes and serves as a template fitted onto the workpiece. The drill can be guided through these template holes, and the needed holes on the workpiece are drilled in the same relative locations as on the template.

Plate Jig

By integrating drill bushes on the template, a plate jig improves on the template jig. The plate jig drills holes in large parts while keeping the precise spacing between each hole.

Angle-plate Jig 

An angle-plate jig is perfect for holding drill-ready parts at an angle to their mounting locators.

Diameter Jig

A diameter jig is needed to drill radial holes in a cylindrical or spherical workpiece.

Channel Jig

A channel jig is a simple jig with a channel-like cross-section. The component is fitted within the channel and can be located and clamped by turning the knurled knob. In addition, the tool can be guided through the drill bush.

Leaf Jig

A jig has a hinged leaf that can be swung open and closed for faster loading or unloading part. The hinged leaf does not encircle the part completely.

Ring Jig

To drill holes in circular flanged parts, a ring jig is used. The work is fastened firmly to the drill body, and the holes are drilled by directing the tool through drill bushes.

Box Jig

Box jig is a box-like construction, and the work is tightly held within it. In this way, the work may be drilled or machined from multiple angles at a single setting, depending on which face of the jig is turned toward the tool.

What are Fixtures?

Fixtures are tools that precisely and firmly hold a workpiece at the desired position on the machine bed. By completely securing a workpiece, fixtures assure precision and repeatability. They can also be adjusted to hold a workpiece at a given angle, enabling cutting operations to be performed in various directions. Fixtures help reduce mistakes and ensure worker safety by preventing workpieces from being accidentally hurled from the work table. 

Fixtures are frequently used in machining processes, such as milling, turning, planning, slotting, and grinding operations. You can find it on automotive vehicle assembly and optical and laser scanning inspection systems. The application of fixtures also includes a material block fastened within a CNC machine and a vise placed on a workbench. Furthermore, fixtures are also required on an automotive assembly line to secure and guide vehicles throughout the welding and assembling process.

Fixtures are commonly found in CNC machining centers and other automated production equipment. CNC machines may direct and control their cutting tools without jigs, but they will not function effectively if the workpiece is not maintained safely.

Types of Fixtures

Fixtures are tools or devices holding, supporting, and positioning components during manufacturing processes. Below are the common types of fixtures:

Turning Fixtures

Turning fixtures are often fixed on the machine spindle’s nose or a faceplate. When necessary, the fixture may need to be equipped with a counterweight or balance the unbalance fixture. In general, turning fixtures are useful for more complex lathe-made parts.

Milling Fixtures

Milling fixtures are generally fixed on the nose of the machine spindle or a faceplate and are held in place by the workpieces. The table is adjusted and positioned correctly around the cutter. Before beginning the process, the workpieces are placed in the fixture’s base and clamped.

Drilling Fixtures

Drilling fixtures, which consist of a hole and a bushing, are occasionally used in place of (or in addition to) jigs.

Broaching Fixtures

Often, broaching fixtures are used on multiple broaching machines to locate, hold, and support workpieces during operations. Keyway broaching operations are an example of these operations. And keyway broaching operations include keyway broaching, hole broaching, and so on.

Indexing Fixtures

Multiple components require machining on various surfaces for their machined surfaces or shapes to be uniformly spaced. And these elements must be indexed in the same number as the number of surfaces to be machined. The holding devices, such as jigs or fittings, are designed to carry an indexing mechanism. An indexing fixture is one with such a device.

Grinding Fixtures

Grinding fixtures might be regular work-holding devices like chucks, mandrels, shaped jaw chucks, magnetic chucks, etc. They are used to support a workpiece during grinding operations.

Regarding external surface grinding, cylindrical grinding uses plain or tapered mandrels. The bore is used to locate and hold the workpiece on the mandrel, allowing the exterior surface to be machined properly concentric to the bore. 

And for internal grinding, the chuck is the most often used fixture. The fixture has the same design as turning and boring fixtures for holding irregularly shaped components.

Boring Fixtures

The boring fixtures incorporate nearly all the prevailing principles of jig and fixture design. Their construction does not need to be as robust as milling fixtures because they never must withstand as heavy cutting loads as involved in milling operations.

Tapping Fixtures

Tapping fixtures are specifically designed to place and securely hold identical workpieces to cut internal threads in drilled holes. Such fittings will always be required for odd-shaped and unbalanced parts, especially when these parts are to be performed the tapping process on a mass scale.

Duplex Fixtures

Duplex fixtures hold two comparable components at the same time and machines these two components at two separate stations at the same time.

Welding Fixtures

Welding fixtures can retain and support the different welded components in their right places while preventing them from distorting. The clamping must be light yet robust, and clamping elements must be placed away from the welding region. The fixture must be quite sturdy and stiff to survive the welding forces.

Assembly Fixtures

The purpose of assembly fixtures is to support various components in the correct relative position during assembly.

Main Elements of Jigs and Fixtures

Jigs and fixtures may look like simple tools, but they are comprised of several elements. The main elements of jigs and fixtures are listed below:

Body: The bulk of a jig or fixture is its body. The body is a plate, box, or frame structure that holds the components to be machined. The body needs to be strong and rigid to withstand significant forces.

Locating Elements: These elements are placed on workpieces in the precise location for cutting tools. They are typically made from hardened steel.

Grinding and Setting Elements: These elements guide the cutting tool in the case of a jig and aid in correct tool movement in the case of a fixture.

Clamping Elements: These elements hold the workpiece securely in place and resist cutting forces.

Indexing Elements: Indexing elements are not always available. However, many workpieces are indexed for distinct places to execute machining operations on various surfaces or locations. Sometimes, these elements must be incorporated into a jig or fixture.

Positioning Elements: These have various fastening devices and are used to secure the jig or fixture to the machine at the right location.

Bushings: Typically constructed of tool steel, bushings are used in some jigs to guide the operation of the machine tool.

Benefits of Using Jigs and Fixtures

Using the jig and fixture in any machining operation has many benefits. Here are the main advantages of jigs and fixtures: 

Increased Productivity

Jigs and fixtures significantly reduce the time required to mark, measure and clamp workpieces for each operation. By allowing quick and consistent setups and tool/workpiece positioning, jigs, and fixtures speed up production and increase throughput. Parts can be manufactured and inspected efficiently with minimal handling or adjustment required.

Improved Quality

Jigs and fixtures provide a precise guide or support for cutting tools, measuring equipment, and workpieces. This results in components produced to the same high standards with accurate dimensions and minimum variability. The risk of errors and defects is reduced, minimizing scrap and rework. Quality can be controlled effectively even when using less skilled labor. 

Reduced Cost

Jigs and fixtures assist in accelerating manufacturing processes, lowering total labor costs per part. For example, the raw material may swiftly align and set up in a well-designed custom fixture. It would take considerably longer to set up using standard fixtures. Scrap rates are also lowered since the likelihood of faulty parts is much reduced.

Accurate Tool Guidance

Jigs guide the movement and positioning of cutting tools during operations like drilling. They allow tools to be fed and oriented precisely for quality results. Fixtures securely support workpieces during machining or measurement.

Increased Interchangeability

Jigs and fixtures manufacture multiple identical pieces, enabling a high degree of part interchangeability. Components can be used without selection or fitting, as they are produced to uniform specifications. This reduces final assembly time and the requirement to have replacement parts available. 

Reduced Wastage

By precisely guiding cutting tools and workpieces during operations, jigs, and fixtures help avoid errors and misalignments that can lead to wasted material. Scrap and rejected parts are minimized, resulting in cost savings. Material yield and efficiency are maximized using jigs and fixtures.    

Increased Safety

Jigs and fixtures rigidly clamp workpieces, reducing risks from sharp tools or moving parts. They minimize the need for operator intervention in dangerous areas. Setups also provide a safer working environment, even for inexperienced staff. 

Reduced Manpower Needs

Jigs and fixtures automate production by speeding up operations and reducing the need for measurement, judgment, and manipulation on each cycle. This decreases labor demands and the level of operator skill required. Staffing overheads and training costs are lowered, with less specialized expertise needed to achieve results.

Application of the Jigs and Fixtures

Jigs and Fixtures are commonly used because of their benefits. Some of the applications are as follows:

• Jigs are used to do bulk drilling, reaming, and tapping.
• Fixtures are used in milling, bulk turning, and grinding.
• Guiding the tools for machining contours.
• Mass production of automobile parts.
• Continuous production part inspection in manufacturing industries.
• Cutting the ingots in the steel plant.
• For drilling flanges and holes at all needed angles.
• For multi-spindle machining.
• In the refrigeration business.
• Pump assembly process.