Compression Test Samples

Smoothening of the compression test samples of MH was done. These are cubes of 10x10x10 mm³ and the dimensions and weights are taken for the calculation of the density. To ensure the effect of the direction of extrusion the samples are divided to giving 8 pieces for each and marking the direction of extrusion and the perpendicular direction of extrusion.

Studied about the EBS9M software which is used to log data from the Loomis extruder.

Vacuum Problem of AMK (Kneader)

We had a problem with the kneader with vacuum. It seemed to have lot of spaces in between its lids. The beading or the sealer which was there to prevent this had so many distortions so that air go inside very easily. And also in between the connecting parts of the machine (like walls in a square house) had a little space on the top where the vertical sealer ends.

So, thought of reducing the space and got the flash that I can use grease to fill out. But it took a lot of amount of grease but ultimately I could go down to -0.2 bars of the pressure, still with some minor leakages. Started the machine to see whether there are other leakages with the screw when its working. But it didn't give any effect and still had a decreasing pressure like -0.24 bars.

Prepared some samples for the compression test of MH project but the elevator was not working so that the Hoover/vacuum pump which sucks powders of cutting (otherwise it will spread all over the lab and it is not safe for everyones health) was not able to get upstairs from down. So I had to stop with only 16 specimens. Have to prepare more 14 specimens for the test and it's a little bit tough work with the small dimensions 10x10x10 mm³ since the accuracy has to be with a tolerance of 0.5 mm.

Presentation

Today as usual had a short meeting with the co-supervisor to discuss about the week's work. So many things has to do but today all the machines were occupied. In the evening a presentation from a Professor came from Poland held about the Chemistry of ceramic processing.
It was a nice one even little bit boring. :)

Sample Preparation for the Compression Test 2

For the MH project the compression test for EKS 92g and 127g pieces were cut yesterday and now it has to be smoothed for a proper grip. Using the sand papers the surfaces were flattened and smoothed at 20mm. 15 samples were prepared for the test and then dimensions were taken, the length and the diameter and also the weight was taken.

Al₂O₃ projects modified firing curve was tested and now the system goes upto 500⁰C and it seems to be broken now. But no carbon is there anymore.

Sample Preparation for Compression Test

For the MH project EKS-92g and 127g batches were sintered earlier and they had to be prepared for the compression test. Since the clay content is somewhat higher the almost all the samples seem to be cracked. So I selected the samples carefully for preparation and cut them into 22.5 mm pieces which have to be reduced and smoothed to 20 mm according to the German standard.

Another kneading of Arg. body was done without fibers for five hours. The cleaning took about 3 hours as before and it is really a long and unhappy process since the two screws of the kneader can not be taken out of the machine. Reaching corners which have to be really cleaned was a painful process.

Interesting Result of Al2O3 project

Kneading of a clear body of Arg. was started in the morning without fibers.

Al₂O₃ fiber is not broken this time. So discussed with the supervisor and checked the fiber under the microscope. It could be seen that still the core has not removed completely but the burnt carbon is remaining. It is quite difficult to make sure whether carbon is there only as a layer or a solid part. Hence, the fiber will be examined under the light microscope and photographed.

Kneading was done for five hours and then the cleaning of the machine. It was very hard to clean the machine as usually happened last times. There was an idea to use MH material to do an over extrusion so that the whole part of Arg. body will come out. But this time only an abrasive liquid was used and it took about 3.30 hours to finish the cleaning.

Another sample was put to the furnace and this time the final temperature will be little bit higher maintaining the previous ramps.

Sieving Fibers

For Bgts samples the system was prepared and another sample was put in the water after equilibrium.

Sieving of the fibers of kneaded test samples were done and two batches were sieved. The separated fibers were dried and then put into small holders named.

Kneading with the Big Kneader

A meeting was held to discuss about the further tasks that has to carried out regarding the projects.

The first thing is that the kneader has to be checked for the vacuum problem and identify the possibilities. Then also for the Arg. project, the test samples have to be sieved and separate the fibers to be checked under the microscope for the lengths.
Furthermore, the geometrical parameters of the 3rd bath of MH project has to be checked like density and shrinkage. And also the extrusion of modified 92g EKA-S 4mm fibers.

The kneader was checked and I could observe that the beading between the two lids of the main feeding has some openings which takes air inside in the vacuum condition. Kneading of the test sample of earlier kneadings were sieved to separate fibers.

The sample from the Brgts project, the earlier sample shows a weight loss. After the system became equilibrium, another sample was put in to water. The sample was kept five hours in hot water, taken out, dried using a tissue and kept for further drying in air.

Kneading with the Big Kneader

Since the cleaning of the big kneader takes about at least two hours the kneading was started early in the morning. Now it is with the same Arg. body and 8mm fibers and same as earlier the test samples had to be taken out at intervals. After 4 hours and 45 minutes, we tried to vacuum the device to make an extrusion of the kneaded material but the vacuuming seemed to be not working. Hence, the extrusion was stopped and cleaning started, it took about 3 hours to be finished.

For another project I had to give hand by doing a test on three samples. Each and every sample had to be placed in hot water of which the temperature had to be between 50⁰ - 60⁰ degrees. The beaker with water was placed on the electronic heater (electronic hotplate) and when the temperature was in equilibrium in between the mentioned temperature a sample (Tablet like) was carefully put into the middle using a tweezers. After five hours the samples had to be taken out and dried and weigh. The intention was to remove the binder which is dissoluble in water.
The weight of the first sample has reduced but it was kept to be dried more in air.

Kneading with Glass Fibers (small kneader)

Kneading of the Arg. body was started in the morning with glass fibers using the small kneader and it had to be kneaded for five hours and test samples had to be taken out after 30min and each and every hour. These samples will be sieved and fibers will be separated to observe the length of the kneaded glass fibers. Cleaning of this small kneader takes about 45 min to one hour.
The kneading has to be done using the big kneader so that it was cleaned off the oil and fixed for the next day use.
Al₂O₃ fibers still break up in the sintering process even this time another program was used. Now I am going to check whether the heating rate at the beginning has something to do with the fiber explosion.

Failure in the Sintering Process

As a sample of test sample 2 was put to the furnace CeramAix to sinter I looked at the results today in the morning. But there was no sample left on the Zirconia substrate. Probably the fiber is broken into pieces and blown away with the heat flow.

Since it is arguable about the inside flows which can break the structure of the fibers, the use of a crucible would be a good idea and I was provided with a crucible. Using it another sample was put to the furnace and this time it will go upto 1400⁰C and sinter Al₂O₃.

Al2O3 Program Change

Since there was no change of the result of firing Al2O3 fibers with slower heating rates we (with the supervisor) decided to use a higher rate and check the results.
Using the changed program I put a sample to the furnace.

Kneading of another sample of bare body was done for 5 hours with the EMU Memo which logs the current used during kneading within every one minute period. Cleaning of the machine took about 30 mins.

As today is Friday lab cleaning was done at 2 O' clock.

Al2O3 Second Firing Results

Al2O3 sintered fibers were taken out from the kiln. But as the problem occurred in the previous firing, after this firing there was no fibers found. Everything is broken into pieces. Have to find a solution for this problem.

Kneading Material

For the project Arg, another sample of body should be kneaded with fibers inside 6%. Hence, the kneading was started but after some time it was observed that the kneaded was stopped. There was a problem with the power outlet so that the kneading had to be started from the scratch.

Compression test for the third batch of project MH was done. It showed some interesting results. According to that clay with different kinds of silica had different strengths. According to strength,
1. Double layer Silica
2. Single layer Silica
3. Mixed Silica (Double and Single layer)

Sample Preparation

In the morning had a meeting with the co-supervisor and granted some work that has to be done within next few days. For one project (Arg) I have to do 3 kneadings.

1. with fibers - 6% - 5 hrs
2. with glass fibers - 6% - 5hrs
3. without fibers - 5 hrs

and also prepare samples for compression test on project MH and help my colleague for that.

So started work with kneading the sample without fibers.
Then sample preparation of MH for the compression test.

In the evening started to clean the small kneader after getting instructions from the co-supervisor.

Spaghetti Production

From the second batch of the Project MH, spaghetti of 1.5 and 0.5 was produced from ES 26g and 52g.

Production of 1.5 mm did not have any problem while 0.5 production (extrusion) had a problem. Time to time the extrusion was stopped because of some granules stuck inside or above the 0.5 die. So it had to be cleaned each and every time it stops making the process longer.

For Al2O3 project another 4 number of samples (fibers) were prepared and put to the furnace using another program which was changed according to the TGA results.

Fiber Project

After doing the sintering process with the fiber specimens, it is realized that there is something wrong either in the firing program or in the material. So a TG (thermogravimetric) analysis had to be done.

I have received the results from the TG analysis and drew the graph according that. There I could obviously see that the firing curve I used was wrong. Because the decomposition of the inner core of the fiber overlaps with the debinding process of the outer layer (The layer which should be remained after sintering).

So I changed the firing curve very carefully considering some factors according to the TG analysis results. I will sinter some more samples very sooner to check the effects.

Getting Better

The fingers which were squeezed in last year just before the Christmas days are now getting better. It seems that I am going to loose the two nails and at the same time coming new nails. Have to be so careful when working, not to stick with anything around. Otherwise the nails will be forcefully removed making a great disaster. ;)

I am really wondering how nicely the human body works. It is wonderful and amazing.

-- cheers

Rechecking Calibration

Calibration of the Sensors had been done by the service maintenance and I wanted to recheck the data I gathered earlier with the Micra-M device.

Problem: There were some transducers like 1400 bar transducer for what the Micra-M can't be calibrated because of the limitation of the calibration device we had. It can only go upto 550 bars since it is calibrated only till that pressure. but it can go upto 1000 bars. So tried to calibrate it until 1000 bars. But the values were getting a difference when the values are out of the range 200 - 500 bar. For the 350 bar sensor it was hard to calibrate Micra-M because it showed different input values each and every time it is rechecked.

Compression test of some ceramic rods were done according to a German norm. It is obvious that the sample preparation according to the norm is not that easy and it has an effect on the strength test.
The test was done on four types of batches and it is seen that one is really good in strength and the strength has been almost doubled than the last batch.

For another project, some tubes had to be sintered and one was put to the kiln to be debindered with the given temperature curve. To be certain about the results only one type of tubes was used rather than all the types. So one can be sure on the results when interpret them.

So at last it is another week end.. :)

Happy and Feel great.

I finished writing the Micra-M and DaqPRO programming manual which consists of 13 pages including front and contents page and the Data sheet pages too. Started today with writing the programming of DaqPRO and had to take some pictures of the device since the pictures I had were not enough giving details.
After all finished the manual gave handed it over to the supervisor. His appreciation is motivating. It is really nice to have that kind of appreciation after doing some work.
Thanks Frank. You are really a good and a kind supervisor.

(Asked Frank for the permission to participate to the BrainStore workshop and he granted the permission. Such a nice person.)

Writing Manual

I am continuing my writing of the manual putting all the data available in a correct order. I have to write about two devices. One is the Micra-M Digital Instrument and the DaqPRO Data Logger. DaqPRO Data Logger is used to acquire the output from the Micra-M on a computer and save data for later use. It can be programmed to use with different sensors and save the defined sensors.
Have to insert some guiding pictures to assist the user to make more sense about the process. At the end of the day I totally finished writing about the Micra-M programming and tomorrow have to start with DaqPRO programming.

-- cheers

Micra-M manual

Now I am fully equipped with the details of the Micra-M device. So started writing the manual of which the main requirement is to give the user a proper idea how to create it. Brief introduction and overview to the programming method was written. But have to finish all the parts before tomorrow afternoon. Have to get some more data for another transducer too. for 350 bar transducer.

Calibration

The Ditel Micra-M device calibration with the pressure sensors were little bit hard. I had to check each and every point regarding the signal it outputs. After manually selecting the required points using the calibrating device which has a wheel and a meter using which I could give known pressures to the sensor, the data was noted for later use (That is the main purpose of the task)
So 100 bar, 200 bar, 350 bar, 500 bar, 700 bar, 1400 bar pressure sensors were used to the calibration.
Using another device called DaqPRO, the values or the analog output can be calibrated to recieve data on a computer. So it was also done at the same time.

Thw whole day I had to play with the device so in the evening had a little bit ache in the eyes. Now it feels good. :)

In New Year

In the new year 2009 started to work after the accident I have met with.
But still working only with the computer and preparing a manual for a measuring device used with pressure sensors.

I have to calibrate all the sensors and store those data for later use.
It's fun since I love to work with electronics and computers. Already I have done a rough calibration of two sensors and have to fine tune them.

Finally have to write the manual of the process of calibration.

Happy New Year

A year has gone like a wind with ups and downs.
This year will be a great, happy and joyous new year for everyone.

-Cheers