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Answer any three of the following: (i) Identify three safety features that should be incorporated into a centre lathe; (ii) List three reasons for using a cutting fluid when machining; (iii) Explain, with reference to metrology, the use of slip gauges; (iv) Distinguish between orthogonal and oblique cutting forces; (v) Describe how surfaces are machined by forming and generating - Leaving Cert Engineering - Question 7 - 2007
Question 7
Answer any three of the following: (i) Identify three safety features that should be incorporated into a centre lathe; (ii) List three reasons for using a cutting ... show full transcript
Worked Solution & Example Answer:Answer any three of the following: (i) Identify three safety features that should be incorporated into a centre lathe; (ii) List three reasons for using a cutting fluid when machining; (iii) Explain, with reference to metrology, the use of slip gauges; (iv) Distinguish between orthogonal and oblique cutting forces; (v) Describe how surfaces are machined by forming and generating - Leaving Cert Engineering - Question 7 - 2007
Step 1
Identify three safety features that should be incorporated into a centre lathe
Answer
A centre lathe must incorporate several essential safety features, including:
- Moving parts must be guarded: This ensures that operators are protected from the moving components of the lathe, reducing the risk of injury.
- Stopping controls must be readily accessible: All emergency stops and operational controls should be positioned for easy access to enhance safety during operation.
- A braking system that will stop the chuck quickly: This is crucial for halting the lathe swiftly in case of an emergency, preventing accidents.
Step 2
List three reasons for using a cutting fluid when machining
Answer
Cutting fluids serve multiple purposes in machining:
- Wash away cutting chips: This helps to clear the work area and prevent the chips from interfering with the machining process.
- Keep the cutting tool cool: By dissipating heat generated during machining, cutting fluids help maintain tool integrity and prolong tool life.
- Reduce friction between cutting tool and workpiece: This improves the efficiency of the machining process and enhances the surface finish of the product.
Step 3
Explain, with reference to metrology, the use of slip gauges
Answer
Slip gauges, also known as gauge blocks, are precision blocks made from hard metal or ceramic that are used for achieving accurate measurements. They can be stacked together to create precise lengths, enabling the calibration of measuring instruments. The surfaces of these gauges are finely finished to ensure accuracy when stacked, which is vital for metrological applications. They can be employed to check other gauges, ensuring that they meet the required standards.
Step 4
Identify a use for any two of the milling cutters shown.
Answer
The milling cutters illustrated can be used as follows:
- Dovetail cutter: This cutter is primarily utilized for machining dovetail slides on machine slides, making it ideal for precision fixtures and tooling.
- End mill: End mills have cutting edges along their length, which allows them to cut flat surfaces and create slots or pockets in the workpiece. They are versatile tools for various milling applications.
Step 5
Describe, with the aid of a diagram, any one of the following: Surface grinding
Answer
Surface grinding is a machining process that utilizes a rotating abrasive wheel to produce a smooth finish on flat surfaces. The workpiece is held in place on a magnetic chuck, while the grinding wheel moves across the surface, removing small amounts of material. The grinding wheel can be lowered incrementally to achieve the desired flatness. Below is a diagram illustrating this technique:
_________
| |
| Work |
----> | is |
| fed to |
| grinder |
|_________|
Table moves across