Jigs and Fixtures

With the rapid advancement in manufacturing technology, consumerism has increased over the years. Therefore, to meet the higher demands, manufacturers have come up with innovative methods of producing high-quality products at a much faster rate.

The production process has observed the introduction of inventive manufacturing concepts such as Lean Production System, Cellular Manufacturing, Single Minute Exchange of Dies, and Tact Time Analysis. These creative approaches require the need for a horde of efficient, cheaper tools, and work-holding devices.

The manufacturing company requires a simple work positioning strategy and devices for correct operations. This is to ensure:

  • Non-complexities in assembly and unit cost reduction,
  • Reduction in the massive manufacturing cost, and
  • Increase their profitability.

The industry has resorted to easing upthe supply chain in a bid to maintaining a low amount of inventory. This resulted in the emergence of better and cost-effective work-holding devices which ensure better quality products, increase throughput, and reduce lead time. The requirement for production standard work-holding devices has paved the way for two specific terms named: Jigs and Fixtures.

The jig is the device which guides the tool, while the fixture is a tool that securely and firmly holds the job in position during machining operations.

Jigs

In simple terms, a jig is a tool that guides the machining tool.

A common type of jig is the drill jig, which guides the drill for making holes at desired locations. Using drill jigs increases production rate drastically.

 

Fixtures

A fixture is a tool which firmly grips a workpiece on the machine bed accurately at the desired location. The fixture also reduces the loading, unloading, and fixing the time of the workpiece, which significantly reduces the non-productive hours.

 

 

Difference between Jig and Fixture

“Jig” and “Fixture” are many times referred to as the synonyms of each other while sometimes both of them are used together as jig fixture. Although both jig and fixture are used in the mass production process, functionally the two are quite different tools.

Let us go through the main points which differs a Jig from a fixture

 

Jig
Fixture

A jig controls and guides the machining tool

A fixture holds and supports the component precisely for machining operations

Jig ensures accuracy, repeatability, and interchangeability

The fixture provides a reduction in error by holding a component firmly on a table

Jigs are usually on the lighter side

The fixture is bulky, rigid and heavy

Jigs can be put in place and held by hand pressure

Fixtures are always placed firmly on a machine table

Drilling, reaming, tapping, boring are some of the standard jig functions

Fixtures are used explicitly in milling machine, slotting machine and shapers

Jigs cost more

Fixtures are not that cost-savvy compared to Jigs

Jigs require intricate design operations

Fixture design operations are relatively less complicated

 

Advantages of Jigs and Fixtures

Jigs and Fixtures have made manufacturing processes less time consuming, more precise, and hassle-free from a human factor perspective. The benefits of jigs and fixtures including but not limited to, the following:

  • Increase in production
  • The consistent quality of manufactured products due to low variability in dimension
  • Cost reduction
  • Inter-changeability and high accuracy of parts
  • Inspection and quality control expenses are significantly reduced
  • The decrease in an accident with improved safety standards
  • Due to relatively simple manoeuvrability, semi-skilled workers can operate these tools which reduce the cost of the workforce.
  • The machine tool can be automated to a reasonable extent
  • Complex, rigid and, heavy components can be easily machined
  • Simple assembly operations reduce non-productive hours
  • Eliminates the need for measuring, punching, positioning, alignments, and setting up for each work-piece thereby reducing the cycle and set up a time
  • Increases technological capacities of machine tools
  • More than one device can be used simultaneously on a work-piece
  • Setting of higher values of some operating conditions like depth of cut, speed, and rate of feed can be attained because of the increased clamping capability of jigs and fixtures.

Both jigs and the fixtures are used to ease up machining operations and reduce the non-productive time of any mass production process. The principle of location or the 3-2-1 principle, CAD tools, and FEA tools are used for the design of both jigs and fixtures. In the next article, we will go through more detailed information about 3-2-1 principle and design standards of jigs and fixtures.