What happens to the workpiece if the cutting tool is dull?
There are many effects of performing a cutting operation with a dull tool. Note that a dull tool has an increased tip radius (see Fig. 21.22 on p. 636); as the tip radius increases (the tool dulls), the cutting force increases due to the fact that the effective rake angle is decreased.
What is specific cutting energy?
[7], specific cutting energy is the energy consumed to remove a unit volume of material, which is calculated as the ratio of cutting energy E to material removal volume V . The specific cutting energy model is then developed as a function of cutting parameters through the cutting energy and material removal volume.
What is specific cutting force?
It can be explained as the force, Fc, in the cutting direction (see picture), needed to cut a chip area of 1 mm² that has a thickness of 1 mm. The kc1 value is different for the six material groups, and also varies within each group.
Why is specific energy in grinding much higher than in single point cutting?
Abstract. Grinding is a multi-point cutting operation. Such high specific energy required in grinding can be attributed to the irregular and random geometry of the abrasive grits, which induce a lot of rubbing and ploughing actions along with the chip formation by shearing process.
Is grinding a finishing process?
Surface grinding is the most common of the grinding operations. It is a finishing process that uses a rotating abrasive wheel to smooth the flat surface of metallic or nonmetallic materials to give them a more refined look by removing the oxide layer and impurities on work piece surfaces.
What are the values of current used in ECG?
What are the values of current used in ECG? Explanation: The values of current in Electro chemical grinding range from 50 to 300 A. 10.
What are normal ECG intervals?
The PR interval is the time from the onset of the P wave to the start of the QRS complex. It reflects conduction through the AV node. The normal PR interval is between 120 – 200 ms (0.12-0.20s) in duration (three to five small squares).
What are the values of accuracy obtained in ECG process?
5. What are the values of accuracies obtained in ECG process? Explanation: The accuracy values obtained by using Electro chemical grinding process is about ± 0.125 mm. 6.
What are the values of current used in EBM process?
What are the values of currents used in EBM process? Explanation: The values of the currents used in the Electron beam machining process are between 20 and 100 mA. 7.
What are the values of material removal rate in EDM?
6. What are the values of material removal rates in EDM? Explanation: In EDM, material removal rates range from 0.10 to 400 mm3/min. 7.
Which material has lowest material removal rate?
Which of the following process have the lowest metal removal rate? Explanation: Lapping is a surface finishing operation and hence have low metal removal rate. 6.
What is the material removal rate formula?
Calculating MRR The calculation for Material Removal Rate is RDOC x ADOC x Feed Rate. As an example, if your RDOC is . 500″, your ADOC is .
When the electrode gap is too small or electrodes are in contact how much material is removed?
When the electrode gap is too small or electrodes are in contact, how much material is removed? Explanation: When electrodes come in contact with one another, short circuits occur and material removed is not possible.
What happens when the current density is low in ECM?
What happens when the current density is low in ECM? Explanation: When current density is lower than optimum, then etching and pitting occurs which are undesired. Explanation: Throwing power of electrolyte must be less in order to obtain a fine dimensional control.
What happens to the material removal rate when reflectivity is higher?
What happens to the material removal rate when reflectivity is higher? Explanation: In LBM, as the reflectivity of the metals is increased the material removal rates of the process are decreased. 9.
What is the expected life of the nozzles used in WJM?
200 hrs
What are the disadvantages of ECM?
Disadvantages
- The risk of corrosion for tool, w/p and equipment increases in the case of saline and acidic electrolyte.
- Electrochemical machining is capable of machining electrically conductive materials only.
- High power consumption.
- High initial investment cost.
Which abrasive will remove low depth of cut in AWJM?
The abrasive particle used for AWJM is usually silicon carbide and aluminum oxide. The abrasive particle is embedded to the water jet purposely to increase the MMR of the process. Conventional/mechanical drilling uses friction and shearing to cut the workpiece.
What is the key element of water jet machining?
The key element in water jet machining (WJM) is a water jet, which travels at velocities as high as 900 m/s. When the stream strikes a workpiece surface, the erosive force of water removes the material rapidly. The water, in this case, acts like a saw and cuts a narrow groove in the workpiece material.
What are the values of jet velocities in water jet machining?
What are the values of jet velocities in Water jet machining? Explanation: Velocity of the water jet stream ranges between 540 – 1480 m/s in WJM.
What is the percentage of abrasive and water in the mixture in AWJM process?
What is the percentage of the abrasives and water in the mixture? Explanation: Abrasive mixture consists of 70 percent water and 30 percent abrasives.
Which motion is responsible to determine the geometry of jobs to be machined?
Relative motion
Which type of feed is needed in turning operation?
longitudinal feed
Which stroke is cutting stroke in shaper?
Forward stroke