Cutting fluids are an essential part of machine cutting operations - Leaving Cert Engineering - Question 7 - 2019

To prevent rancidity, cutting fluids must be regularly monitored and maintained. This includes filtering out any debris and contaminants that can promote bacterial growth. It is also important to maintain the fluid at a proper pH level and to regularly add biocides that inhibit bacterial growth. Continuous circulation of the fluid helps keep it clean and prevents stagnation, which reduces the risk of rancidity. Additionally, routine replacement of the fluid when it shows signs of degradation ensures the cutting fluid remains effective.

Up-cut milling involves the cutting tool rotating against the direction of the workpiece feed. This method tends to produce a rougher finish but is suitable for certain machining conditions.

On the other hand, down-cut milling rotates the tool in the same direction as the workpiece movement, resulting in a smoother finish due to continuous engagement with the workpiece.

Here are the diagrams:

Up-cut Milling:

<--- [Cutting Tool] 
[Workpiece] --->

Down-cut Milling:

[Workpiece] --->
<--- [Cutting Tool]

Two significant safety features of a bench grinder are:

1. A face guard that shields the operator from flying debris during grinding operations.
2. Emergency stop switches that allow for immediate shutdown of the grinder in case of an emergency, enhancing operator safety.

A drill bit is primarily used to create round holes in a material, while a reamer is used to enlarge and finish the holes created by the drill. Drills are designed for cutting, where they remove material, whereas reamers improve the hole's accuracy and surface finish without removing significant material. Reamers also have several cutting edges to provide a finer finish.

The rake angle refers to the angle of the cutting edge relative to the surface being machined and influences how the chip is formed during cutting. A positive rake angle generally enhances cutting performance.

On the other hand, clearance angle is the angle between the cutting edge and the workpiece, allowing clearance for the cutting tool and preventing it from binding.

Diagram illustration:

[Workpiece]
 /|
[Cutting Tool]
 / | (Rake Angle)
/____________
(Clearance Angle)

One method to securely fasten a machine vice is by using T-slot bolts. The bolts can be placed in the T-slots of the drilling table, allowing the vice to be aligned precisely. Once positioned, the bolts are tightened to ensure stability, thus ensuring the vice remains firmly in place during operation.

The manufacturing process for tungsten carbide insert tips includes mixing tungsten carbide powder with cobalt and other powdered materials. This mixture is then compacted under high pressure. The compacted powder is sintered in a high-temperature furnace to fuse the particles, producing a solid insert. The final inserts are ground to precise dimensions to ensure they fit accurately into cutting tools.

1. Tungsten carbide inserts retain their cutting edge at high temperatures more effectively than high-speed steel (HSS), resulting in better performance under challenging conditions.
2. They allow for easier tool replacement, reducing downtime and maintaining productivity, as inserts can be swapped out without needing to replace the entire tool.

CNC technology enhances productivity by enabling precise machining at greater speeds than manual processes. CNC machines operate continuously and can perform multiple tasks without interruptions, significantly increasing production rates.

CNC machines offer consistent production quality, assuring that each part manufactured is identical. This reliability stems from their automated processes, which minimize human error and variations in part production.

Automatic tool change allows machines to switch between cutting tools without operator intervention. This process increases efficiency by enabling continuous operation, especially in batch production.

A test run simulates the machine's operation to ensure that all functionalities are working correctly before commencing production. It helps identify any issues in the machining setup, allowing adjustments to be made.