Additive Manufacturing

What is additive manufacturing? Before explaining additive manufacturing, let’s try to know what subtractive manufacturing is. Consider turning process in lathe machine as an example. There will be a blank of metal say mild steel and probably in cylindrical shape. We want to make something out of mild steel blank so what we do is we remove some material from it. That is we remove unwanted material from the work piece in other words we subtract material from the work piece so it is an example for subtractive manufacturing. Let’s take another example; we want to make a wooden door with creative designs on it. How would it be made? There will be a wooden material. After taking proper measurement, the unwanted materials are removed so that the remaining will result in the required shape and size. Here also we subtract material from the work piece so it is also an example for subtractive manufacturing. Then what will be additive manufacturing? It is nothing but adding something out of something to make something. In simple terms Additive Manufacturing (AM) is an umbrella term used to describe the technologies that builds 3D objects by adding layer upon layer of materials. That is we design the object and model it using CAD techniques. We input the CAD file into the machine and material will be supplied to the machine via filament like forms. The machine will read and understand the CAD file and produce the 3D object by adding layer upon layer fashion by accurately relating to the cross section of the object in the CAD file. 

The term 3D printing is commonly used in place of AM and the term 3D printer is used for a machine which works on AM techniques. Even though there are some differences between those but for understanding, those differences don’t matter for the time being. Then what is the principle of operation? There are many techniques or processes to produce 3D objects by adding layer upon layer; those will be explained in a different article. For the sake of understanding I mention some names. Stereo Lithography (SLA), Digital Light Processing (DLP), Free Form Fabrication (FFF), Electron Beam Machining (EBM), Selective Laser Sintering (SLS), Selective Deposition Lamination (SDL) etc.

Now let’s discuss the various application of additive manufacturing. Someone says that additive manufacturing technique is a revolution like computer and internet. We can agree or disagree with this but AM does create some revolution to the society. From the early stages to till now, medical industry is dominating the use of additive manufacturing techniques. These processes are not substitute for traditional manufacturing processes. For mass production these cost more. But the traditional manufacturing processes have many limitations. Conventional processes may not be suitable for working on new materials such as smart materials, composites and not economical if the needed parts are very less in number. There comes 3D printing. 3D printing or AM can be used to produce unique things in terms of material, shape or other design parameters. These are cost effective for unit things. They don’t look at the shape but they only consider the CAD file. They read what is there in CAD file after converting into the G-code and make the objects accordingly. This is very suitable for medical applications. The shape and size of heart, bone, tooth etc. will be different for different people and by 3D printing these can be made very easily. This is the reason why medical industry largely depends upon the AM techniques. 

Aerospace sector was also an early adopter of AM techniques. The aircraft and rocket components are made of different composite materials. Traditional manufacturing methods may not work well on these new materials. 3D printing overcomes this limitation. Secondly the rocket parts or aircraft parts have complex shapes and designs. Conventional machining methods may become expensive and face difficulty to produce such models. Even if it is possible to make these complex parts there is another big problem. That is these areas are of research interest. For research purpose or any other thing, the possibility of need of design change is higher. So the shape and size of the objects may also vary. Conventional subtractive manufacturing method becomes less use because of these factors. But AM does overcome these. There is no change needed for a 3D printer to produce an different object while there are many things from small scale to big scale is essential to be changed to meet the production of new object in traditional methods.

Automotive sector also started to use 3D printing techniques for manufacturing especially in sports cars and bikes because they can manufacture complex profiled parts without any extra cost. They can do new experiments. R&D works get simpler. Prototype development gets easier. Interestingly jewelry sector also exploits the power of additive manufacturing. They can try new designs and new models very easily. This is a huge advantage for them both in terms attracting customers and reducing cost. For the sake of demonstration, architectures also use 3D printing techniques. Astonishingly they now seek for direct construction method for building their firms. For making robotic components also 3D printing is very much useful. The application area of 3D printing or additive manufacturing is very large and actually it reduces the product life cycle time from ideation to actual product and there by now we can say that anything can be manufactured now whatever we think in our head.

There are also limitations for additive manufacturing. In most cases the problems are associated with the type of process or technique so those will be discussed in the respective article as I mentioned above. Some general cons of AM are discussed below. The time taken to produce one product is quit higher. Conventional processes make many things at little time and are suitable for mass production while additive manufacturing method is not suitable for mass production as it decreases the productivity. Even though for large firms, it is cost effective, it is expensive for small scale users. Buying a decent 3D printer itself costs high. There is also liability issue. The layered structure is also a problem. It decreases the smoothness and there by affects the quality. Even thought there are many limitations for additive manufacturing, more researches are being done and hope these problems will be vanished away. 

Unconditional love

Today, she called me many times; Morning, noon, evening and night! Because I was sick. She was very eager to know the condition of my health at each moment. In the morning, I told her that I would consult the doctor forenoon but I didn’t. In the evening, when she called and asked about the doctor’s comments, I replied that I hadn’t consulted the doctor. She became very angry and said so many things. I got very nice advises such as if you never consult, the illness would increase etc. ;) At the end of the evening, after sunset, I consulted the doctor and bought medicines and informed details to her. Then she became normal and got some satisfaction to mind. 

I thought how much she cares for me! From the birth to till now! I was a new born baby. She cared, loved and spent uncountable nights for me. Then I became a child. She cared, loved and taught what is good and what is bad. Then I started schooling. She cared, loved and enlightened me how to behave in society. Then I started to go to university away from home. She is caring, loving and praying for me every time. This is what we call it as Unconditional love and we get its purest form from our mothers. I love you my mother :)

TCS interview experience

There were three rounds viz technical, managerial and HR.

They asked following questions to me.

1. Technical round
1. Tell me about yourself
2. Explain your main project
3. Application areas of your main project
4. How cost effective your project is ?
5. Favorite topic in mechanical engineering (I said thermodynamics and fluid mechanics)
6. What is open system and closed system?
7. Draw p-v and T-s diagram of Carnot cycle
8. Differences between petrol engine and diesel engine
9. What is a turbine?
10. What are the different manufacturing techniques?
11. Have you worked on sheet metal?
12. How to make a cylinder with sheet metal?
13. What is polymorphism in c++ ?

     2. Managerial and HR

1. Tell me about yourself
2. What is the unique thing which differentiate you from other students?
3. Do you read any book ?
4. Newspaper main headline
5. Current most discussing topic in the country
6. Tell me about your family?
7. How do you help your father as a mechanical engineer?
8. Are you willing to work out of state?
9. Are you willing to work on shifts?
10. Do you have higher study plan? why?
11. What do you know about TCS?
12. Why TCS?
13. TCS projects
14. What type of job you would like to do?
15. Have you heard IOT ? Explain
16. Hobbies
17. Extra curricular activities
18. Do you have any questions?

Finally I got placed in TCS EIS and IOT department.

Photography while travelling

Most of us love to travel. Travelling around the globe will be the ambition of many. I also love it and more over I love to take photos while travelling. Not of mine, ;) or selfies but the scenes which we have seen. They remind us all the things happened in our journey. Greatest moments with friends, incredible views of nature, sun set, clouds, beauty of flowing rivers etc. While remembering these, we actually will get refreshment and feel to such an extent that we will think the journey was on the previous day. The below image was taken by me while travelling from Quilon to Calicut by train (about 330+ km).

Quilon and calicut are two main towns of kerala, God's own country. My college is situated in quilon and my home is near calicut so this journey was not new one for me as I usually do once in every month but the thing is, in my last journey, I didn't give the rest for my camera option of my smartphone. I have taken most of the scenes through window of the train. I'm not a professional photographer at all but I love to take photos and I believe that there is a photographer's mind in everyone. Later when I look at the photos which I have taken, I have got an awesome feel which can't be described by words. Taking photos will be a hobby of many but giving some seriousness and imparting selective nature will change the scenario.

    

The above image was also taken by me when I have gone to korome village which is in wayanad district of kerala. Believe me you will never ever forget this place. Specialities are calm atmosphere, awesome weather condition, mix of different cultures, natural beauty, good number of places for tourism etc. I have taken this image of bamboo just before the rain that is why the sky looks like dark. The images which I have taken remind me many things and give me some kind of happiness even now. So keep your camera on and get the feel. Best wishes. 

How to increase the speed of computer?

Here I explain the different ways to increase the speed of computer (windows 8.1).

First thing you want to do is disable screen saver as follows.

1. Right click on desktop.

2. Click on personalize.

3. Click on screen saver (bottom right corner).

4. Select none from the list of screen savers.

5. Click Apply and then OK.

Then disable start up apps as follows.

1. Move mouse pointer to up right corner and select the search icon.

2. Type task manager and click on task manager.

3. Select start up menu.

4. Now you can see start up apps. Just click the unwanted apps and click on Disable button (bottom right).

You can increase your performance by adjusting power option by following the given steps.

1. Take search field as done earlier and type power option in the field. Click on power option.

2. Choose high performance option.

You can clean the junk files in the c drive by Disk clean up utility. For this follow the given procedure.

1. Select local disk c. Right click. Then select properties.

2. Click on disk clean up button.

3. You can check on check boxes of all items listed. Then click OK.

This process will not delete any personal data. This process deletes junk files only.

There are lots of animations while we are in front of our computers. Actually in performance point of view, they are useless. So disable animations as follows.

1. Select this PC (my computer). Right click. Then select properties.

2. Click on advanced system settings.

3. Select advanced menu. Then in performance section, click on settings button.

4. Select visual effects menu. Choose adjust for best performance option.

5. You can also change this settings according to your choice. Then click on apply then OK.

For more, defragment and optimize drives as follows.

1. Take search field and type Defragment and select the option.

2. Select each drive and click on analyse button and optimize button.

You can clean unnecessary temporary files through the following method.

1. Move mouse pointer towards the windows icon (bottom left corner).

2. Right click and select run.

3. Type %temp% on open field as shown. Then click OK.

4. Select all. Right click. Select delete option.

5. Again take run window as done before. Type temp. Click OK.

6. Select all. Right click. Select delete option.

7. Again take run window. Type prefetch in open field. Click OK.

8. Click continue.

9. Select all and delete them.

Now let's try some Registry tweaks.

1. Take run window. Type regedit in open field as shown. Click OK.

2. Select control panel. Select mouse. Then select mouse hover time. Right click. Select modify field.

3. Type small number. 10 is preferred. Then click OK.

4. Select control panel again. Select desktop. Select menu show delay. Right click. Click modify.

5. Type 10 in value data field.

At last restart the computer.

C++ program for matrix multiplication

//c++ program to multiply two matrices (max 6x6 size *here)

#include<iostream.h>

#include<conio.h>

int main()

{

clrscr();

int r1,r2,c1,c2,a[6][6],b[6][6],c[6][6],i,j; //size of array can be changed

cout<<”Enter the number of rows and columns of first matrix\n”;

cin>>r1>>c1;

cout<<”Enter the number of rows and columns of second matrix\n”;

cin>>r2>>c2;

if (c1!=r2)

                cout<<”\n matrix multiplication is not possible”;

else

                {

                cout<<”\n matrix multiplication is possible”;

                cout<<”\nEnter the elements in first matrix row wise\n”;

                for(i=0;i<r1;++i)

                                {

                                for(j=0;j<c1;++j)

                                                cin>>a[i][j];

             }

                cout<<”\nEnter the elements in second matrix row wise\n”;

                for(i=0;i<r2;++i)

                                {

                                for(j=0;j<c2;++j)

                                                cin>>b[i][j];

             }

                cout<<”\nThe result is\n”;

                for(i=0;i<r1;++i)

                                {

                                for (j=0;j<c2;++j)

                                                {

                                                c[i][j]=0;

                                                For(int k=0;k<c1;++k)

                                                                c[i][j]+=(a[i][k]*b[k][j]);

                     }

              }

                for(i=0;i<r1;++i)

                                {

                                for(j=0;j<c2;++j)

                                                cout<<c[i][j];<<”\t”;

                                cout<<”\n”;

              }

}

getch();

return0;

}