DM308 Jig and Fixture Design Quiz

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Questions and Answers

What is the main difference between jigs and fixtures?

Jigs guide the cutting tool, while fixtures may have a means of setting the cutting tool. (correct)

Jigs are mobile devices, while fixtures are stationary.

Jigs provide workpiece location, while fixtures provide workpiece clamping.

Jigs are used in milling operations, while fixtures are used in drilling operations.

Which machining operation typically uses jigs?

Grinding

Turning

Milling

Drilling (correct)

What is the purpose of a fixture in a machining operation?

To provide workpiece confinement

To guide the cutting tool

To move freely in multiple planes

To locate and clamp a workpiece (correct)

What is a likely characteristic of a drill jig?

Means of guiding the cutting tool Signup and view all the answers

Where are milling fixtures often clamped in a machining setup?

Machine tool table or chuck Signup and view all the answers

Why is simple confinement of a workpiece not enough for proper location?

It doesn't guarantee accurate positioning for machining operations. Signup and view all the answers

What is the main purpose of clamping in the context provided?

To hold the workpiece securely against locating points Signup and view all the answers

In clamping considerations, why is it important to direct clamping pressure to supported and/or rigid positions of the work?

To ensure easy loading and unloading Signup and view all the answers

Why should a clamp maintain a force according to the principles of clamping?

To ensure stability of the workpiece Signup and view all the answers

What should the position of clamps strongly influence according to the context?

The location points of the workpiece Signup and view all the answers

Why is it necessary for a clamping force to be directed through supported or rigid positions?

To avoid directing it through unstable zones Signup and view all the answers

Which area should the force F3 be within for stability according to the text?

Within the shaded area Signup and view all the answers

What is the consequence if one pad wears out or a piece of grit is left on a pad?

The workpiece will rock and may warp if clamped in that position. Signup and view all the answers

Why should a rough surface only be located on a three-point location?

To ensure stability and prevent rocking of the part. Signup and view all the answers

What happens when a rough surface is brought against a continuous surface?

Only the high spots of the rough surface will be in contact with the continuous surface. Signup and view all the answers

Why should a relieved location be used for positioning a part?

To allow only the outer edges to bear, ensuring a stable position. Signup and view all the answers

What were the key achievements related to the world's most accurate space optics as mentioned in the text?

Form error < 20 nm, Surface roughness (Rq): < 5 nm Signup and view all the answers

What should design always consider when dealing with swarf during machining?

Allowances for swarf that is not cleared. Signup and view all the answers

What is the purpose of a 4 Jaw chuck in workpiece location?

To hold irregular shaped workpieces securely Signup and view all the answers

Which type of chuck is suitable for circular or triangular work shapes?

3 Jaw chuck Signup and view all the answers

What issue arises from redundant location in workpiece fixing?

Perfect alignment of location holes and pegs is required Signup and view all the answers

Why should redundant location be avoided in workpiece design?

To prevent constraints on one degree of freedom Signup and view all the answers

In the context of workpiece location, what is the purpose of a 'Diamond Pin Locator'?

To influence the workpiece along a specific direction Signup and view all the answers

What should be the relationship between the width of a locator and the diameter of a location hole?

Locator width slightly smaller than hole diameter Signup and view all the answers

What is the 3-2-1 Principle of Location?

To locate a part fully, place and hold it against three points in a base plane, two points in a vertical plane, and one point in a plane square with the first two. Signup and view all the answers

How many degrees of freedom are eliminated by points 1, 2, and 3 in the 3-2-1 Principle of Location?

Three degrees of freedom Signup and view all the answers

What surface condition should be considered when choosing the best form of location for a workpiece?

Finished surfaces Signup and view all the answers

In what situation may a finished surface be located against a fully contacting surface rather than locating points?

When four points are needed for stability Signup and view all the answers

Why might locating surfaces on four points rather than three introduce new difficulties?

It creates stability issues similar to those with unsteady tables Signup and view all the answers

Study Notes

Jigs and fixtures are used as locating and clamping devices during machining operations, with jigs mainly used in drilling and fixtures in milling, turning, and grinding.
A drill jig includes means of locating and clamping a workpiece and guiding the cutting tool, while a fixture includes means of setting the cutting tool before the cutting process.
Principles of clamping involve directing force to secure the workpiece against disturbing forces, maintaining workpiece location, and minimizing hazards to operator, workpiece, and cutting tool.
The position of clamps is influenced by the location points of the workpiece, with considerations for avoiding unopposed moments and ensuring stability.
Redundant location in fixtures should be avoided to prevent constraints on workpiece movement, with examples such as using diamond pin locators to prevent such issues.
The 3-2-1 Principle of Location involves holding a part against three points in a base plane, two points in a vertical plane, and one point in a plane square with the first two to fully locate the part.
Surface condition considerations for locating surfaces include finished surfaces, semi-finished surfaces subject to deviations, and rough surfaces with wide variations.

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Description

Test your knowledge on jig and fixture design principles of locating and clamping with this quiz based on the content from DM308 Production Techniques 2. The quiz covers basic concepts, principles, and application cases related to jig and fixture design.