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Comparison of Performance of Austrian made Si3N4 - Nitride Ceramic Tools Used to Machine Grey Cast Iron Work-piece Materials

Abstract:
This article presents comparisons of cutting performance of Austrian made – Si3N4 nitride ceramic – inserts used in machining a Type 422425 grey cast iron work-piece materials. Three commercial ceramic inserts Type FMG121C, FMG122C, and FMG134C were tested. Experiments were focused on tool life tests. A comparison approach involved exponents of Taylor’s type equations over an optimized cutting tool interval i.e. one constant depth of cut of 1mm, one constant feed rate of 0.2mm/rev and the three cutting speeds 250, 320 and 380m/min. Results were obtained from linear regression. Also conducted was an evaluation of intervals of reliability as well as corresponding standard deviations for each regression coefficient in experimental Taylor’s equations. The experiments allowed to compare, from statistical perspectives, at a 95 and greater confidence level, the trends and quantities of experimental cutting inserts. The results showed that a Type FMG122C ceramic insert had the most superior performance compared to other two types of experimental ceramic inserts investigated in this study. It is believed that this information can be useful for both tool manufactures and end users involved in machining cast iron work-piece materials and interested in improved cutting performance.

Introduction:
Generally, ceramic cutting tool inserts (CTI) are acknowledged especially for good machining performance where the exceptionally high speeds and high temperatures are of major concerns (Audy 1996). Good wear resistance due to durability of such tools improves tool life and allows for using cutting speeds up to 1000 m/min. Other advantages of the ceramic materials are their improved resistance to high temperatures up to 1750°C. According to literature source (Humar 2008) the cutting ceramics can be divided to an oxide group or a nitride group based on Al2O3 or Si3N4 components, respectively. The nitride cutting ceramics (NCC) have been found, when compared to the oxide cutting ceramics, better in terms of improved heath shock resistance. However they exhibited lower chemical stability when machining steel work piece materials.
At a department of Technical University of Liberec (Czech Republic) in machining / metrology laboratories, several graduation theses’ topics were set up to investigate and compare the cutting performance of three nitride ceramic cutting inserts of a square shape. The commercial names of the inserts were FMG121C, FMG122C and FMG134C, and they were from an Austrian Research Institute.
Consequently, the prime concern of this study was to carry out the comprehensive tool life tests. It was decided to run long-term tests to examine the life span of the cutting tool inserts. It was noted that that such tests are expensive ad time consuming (Audy 1996, 2002), however, on other hand they provide much accurate results (Audy et al 2002, and Audy 2003, Humar 2008, Beno 1999) than the short-term tests.

Imagine you are going to spend a year in a country. Where would you go and why? What work would you like to do? What would you visit? What is it about this country that attracts you?

If I chose the country I could visit and spend a year , I would probably choose an English speaking country due to improvement of my English skills which I need for my future job. If I thought about it, I've already been to England, so I might pick the United States. I have never been there, but I've been watching American movies and series since my childhood, because American movies are really well-known around the world. I would like to see the life-style of the local public in reality as well, not just in movies. I would likely visit New York, to see the Statue of Liberty. First of all, I would go to some language course for a couple of months and get used to speaking to native American English speakers, and also get an English certificate which could me help to find a good job. Then I would look for a job. I am not sure, if my English skills would be so great that they would help me find a job which I'd like to do - programs developer. However, I could try it. I'm sure that I could work as a shop assistant for some time, until my English skills improved and I could then be able to do some better job which I'd enjoy . In my free time, I would like to acquire some knowledge of New York city's sights. I would like to travel around the United States and see California or Hollywood, for example.

You are planning to visit your friend Robin in Canada. Robin has written to you. Read Robin's letter and then write a letter to Robin.

My friends and I are going to a sports camp in the mountains in July. We'd love you to join us there. We can play tennis, hockey, football, basketball and other sports. We can stay in rooms or sleep in tents. Which would you prefer? We'll look together in the evenings. Is there something special from your country that you could look?
You could fly over to Canada a few days efore the sports camp and stay with me here in the city. What would you like to do before we go to the camp?
Write soon.
Robin

Dear Robin,
It would be great to join you and to spend some time with you guys at the sports camp. I really love sports camps because the activities are fun, not only while doing sports, but also the barbecues, competitions and chatting together. In general, I like all the activities that you mentioned. However, I'm not sporty, I play sports just for fun.
If I could choose, I would prefer to stay in a tent. I always sleep in a room and would enjoy something else for a change.
Sure, I could cook some typical Czech food like a roast sirloin with cream sauce and dumplings. It is very delicious and I think you would all love it.
I'd love to come before that sports camp and see your city - clubs, discos, etc. I really enjoy clubbing in my country with my friends, and I'd like to experience how young people have fun in your country as well.
Kind regards,
Johny

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Maturity is a psychological term used to indicate that a person responds to the circumstances or environment in an appropriate and adaptive manner.

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When you think of learning a foreign language, what comes to mind?

I’m reminded of studying vocabulary and grammar from a book, practicing to speak the language with fellow non-native speakers, and proving my skills in written tests. Now that doesn’t sound very stimulating or promising, does it?

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A typhoon hit my area last night. I could not sleep because of the noisy wind. My friend told me that his car's rear window was broken because something hit it. He called the police to tell them about it.

A while ago, he got a call from his wife, and she told him that there were similiar incidents in his parking lot. That means a robber broke the window glass to stole something last night. The robber might be smart. There was nobody outside in that strong wind last night. And if he made a noise to break the window, it might be dismissed because of the wind. Fortunately, my friend did not leave anything expensive in his car. So nothing was stolen. But the car got wet because of the rain, and he has to pay for the repair. I am sorry for him.